Spiro-tetracyclic ring compounds as beta-secretase modulators and methods of use

Synthesis of (rac)-2′-(3,3-dimethylbutyl)-7′-(5-pyrimidinyl)spiro[1,3-oxazole-4,9′-xanthen]-2-amine

A microwave vial was charged with (rac)-2′-Chloro-7′-(5-pyrimidinyl)spiro[1,3-oxazole-4,9′-xanthen]-2-amine (90 mg, 247 μmol), Pd 2 dba 3 (11 mg, 12 μmol), X-Phos (12 mg, 25 μmol), (E)-3,3-dimethylbut-1-enylboronic acid (63 mg, 493 μmol) and potassium phosphate (157 mg, 740 μmol). THF (2 mL) was added and the mixture was heated at 120° C. in microwave reactor for 2 hrs. The mixture was diluted with ethyl acetate and filtered through plug of Celite. After removal of the solvents the residue was purified by flash chromatography on silica gel (12 g Redi-Sep column, 20-100% DCM/MeOH/NH 4 OH 90:10:1 in DCM) to give 2′-(3,3-dimethylbut-1-enyl)-7′-(pyrimidin-5-yl)-5H-spiro[oxazole-4,9′-xanthen]-2-amine (65 mg, 64% yield). This product was hydrogenated at 1 atm of H 2 in MeOH/EtOAc mixture using 10% palladium on carbon (53 mg, 49 μmol) for 60 hrs. The reaction mixture was filtered and concentrated in vacuo and was further purified by reverse-phase HPLC (10-90% CH 3 CN/H 2 O with 0.1% TFA). The fractions containing product were combined and dried overnight under high vacuum to give 2′-(3,3-dimethylbutyl)-7′-(pyrimidin-5-yl)-5H-spiro[oxazole-4,9′-xanthen]-2-amine as its TFA salt.

Step 2: Chiral separation of racemic 2′-(3,3-dimethylbutyl)-7′-(pyrimidin-5-yl)-5H-spiro[oxazole-4,9′-xanthen]-2-amine

Racemic 2′-(3,3-dimethylbutyl)-7′-(pyrimidin-5-yl)-5H-spiro[oxazole-4,9′-xanthen]-2-amine (490 mg) from step 1 was subjected to chromatography using 20:80:0.1 MeOH:CO 2 :DEA at 70 ml/min on a 20×150 mm ChiralPak AD-H column and 100-bar system pressure. The first peak (RT=1.97 min) provided (4S)-2′-(3,3-dimethylbutyl)-7′-(pyrimidin-5-yl)-5H-spiro[oxazole-4,9′-xanthen]-2-amine (210 mg, 99% ee), and the second peak (RT=4.43 min) provided (4R)-2′-(3,3-dimethylbutyl)-7′-(pyrimidin-5-yl)-5H-spiro[oxazole-4,9′-xanthen]-2-amine (>99% ee).

Synthesis of 2′-(3,3-dimethylbut-1-ynyl)-7′-(pyrimidin-5-yl)-5H-spiro[oxazole-4,9′-xanthen]-2-amine

A microwave vial was charged with (racemic)-2′-Chloro-7′-(5-pyrimidinyl)spiro[1,3-oxazole-4,9′-xanthen]-2-amine (100 mg, 274 μmol), cesium carbonate (134 mg, 411 μmol), bis(triphenylphosphine)palladium(II) chloride (19 mg, 27 μmol) and tri-tert-butylphosphonium tetrafluoroborate (16 mg, 55 DMF (1 ml), DBU (21 μl, 137 μmol) and 3,3-dimethylbut-1-yne (167 μl, 1371 μmol) were added. The vial was sealed and heated at 150° C. in Biotage microwave oven for 60 min. The mixture was diluted with 5 ml of EtOAc, filtered through Celite and concentrated in vacuo to give brown oil, which was re-dissolved in 7 ml of EtOAc and shaken with 10 ml of 2N HCl. Acidic aqueous layer was basified with 30% ammonium hydroxide and precipitated brown oil was extracted twice with EtOAc. The organic layers were washed with brine, concentrated, dissolved in 1.5 ml of DMF, filtered through Nalgene PTFE 0.2 mkm filter and subjected to preparative reverse phase HPLC (15-90% ACN in 0.1% aq TFA). The fractions containing product were concentrated in vacuo in order to remove ACN, saturated NaHCO 3 was added and the mixture was extracted with EtOAc (15 ml). The organic layer was washed with brine, dried over MgSO 4 and concentrated to give (rac)-2′-(3,3-dimethylbut-1-ynyl)-7′-(pyrimidin-5-yl)-5H-spiro[oxazole-4,9′-xanthen]-2-amine (49% yield).

Step 2: Chiral separation of racemic 2′-(3,3-dimethylbut-1-ynyl)-7′-(pyrimidin-5-yl)-5H-spiro[oxazole-4,9′-xanthen]-2-amine

Racemic 2′-(3,3-dimethylbut-1-ynyl)-7′-(pyrimidin-5-yl)-5H-spiro[oxazole-4,9′-xanthen]-2-amine (490 mg) was subjected to chromatography using 20:80:0.1 MeOH:CO 2 :DEA at 65 ml/min on a 20×150 mm ChiralPak AD-H column and 100-bar system pressure. The first peak (RT=3.51 min) provided (4S)-2′-(3,3-dimethylbut-1-ynyl)-7′-(pyrimidin-5-yl)-5H-spiro[oxazole-4,9′-xanthen]-2-amine (204 mg, 99% ee), and the second peak (RT=5.44 min) provided (4R)-2′-(3,3-dimethylbut-1-ynyl)-7′-(pyrimidin-5-yl)-5H-spiro[oxazole-4,9′-xanthen]-2-amine (>99% ee).

Synthesis of 7-Bromo-3-fluoro-2-methoxy-9H-xanthen-9-one

The titled compound was prepared in a manner similar to the procedure described in Example 1, but using 2-bromo-4-fluoro-5-methoxybenzoic acid as the starting material, which starting material was prepared as follows:

Synthesis of (S)-2′-(3-methyl-1H-pyrazol-4-yl)-7′-(neopentyloxy)-5H-spiro[oxazole-4,9′-xanthen]-2-amine 2,2,2-trifluoroacetate

A 2-mL microwave vial was charged with (R)-2′-bromo-7′-(neopentyloxy)-5H-spiro[oxazole-4,9′-xanthen]-2-amine (50 mg, 120 μmol) in n-butanol (959 μL), 3-methyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole (49.9 mg, 240 μmol), and potassium acetate (35.3 mg, 359 μmol) in water (240 μL). The vessel was purged with Ar. Bis(di-tert-butyl(4-dimethylaminophenyl)phosphine(dichloropalladium (II) (1.7 mg, 2.4 μmol) was added and the reaction was heated to 120° C. for 30 min in a Biotage microwave initiator. The reaction was then cooled to room temperature and loaded an AccuBOND II SCX cartridge, washed with methanol (3 ml) and eluted with 2N ammonia in methanol (6 ml) to give the crude product. The crude mixture was then purified by reverse-phase preparative HPLC using a Gemini NX C18 column (150×30 mm, 5 um), 0.1% TFA in acetonitrile/water, gradient 10% to 90% over 10 min to give the desired product as the TFA salt. MS m/z=419.0 [M+H] + . Calc'd for C 24 H 26 N 4 O 3 : 418.20.

A vial was charged with (R)-2′-bromo-7′-(neopentyloxy)-5H-spiro[oxazole-4,9′-xanthen]-2-amine (0.050 g, 0.120 mmol), tetrakis(triphenylphosphine)palladium (0) (0.014 g, 0.012 mmol), 2-(tributylstannyl)pyridine (0.132 g, 0.359 mmol), and dioxane (0.6 mL). The reaction was stirred overnight at 100° C. The mixture was diluted with DMSO and filtered through a syringe filter, which was flushed with additional DMSO. The material was purified via Gilson HPLC (10-90% MeCN:H2O). The clean product fractions were partitioned between DCM and saturated sodium bicarbonate solution. The aqueous layer was extracted with DCM, and the combined organic layers were dried with sodium sulfate, filtered, and concentrated to afford (S)-2′-(neopentyloxy)-7′-(pyridin-2-yl)-5H-spiro[oxazole-4,9′-xanthen]-2-amine as a white solid. MS MH+ 416.4

Synthesis of (S)-2′-(neopentyloxy)-7′-(pyrazin-2-yl)-5H-spiro[oxazole-4,9′-xanthen]-2-amine

A vial was charged with (R)-2′-bromo-7′-(neopentyloxy)-5H-spiro[oxazole-4,9′-xanthen]-2-amine (55.6 mg, 0.133 mmol), tetrakis(triphenylphosphine)palladium (0) (15.40 mg, 0.013 mmol), 2-(tributylstannyl)pyrazine (148 mg, 0.400 mmol), and dioxane (0.7 mL). The vial was sealed under a blanket of Ar gas and placed in a 100° C. oil for 16 h. The mixture was then cooled and filtered through celite. The filtrate was evaporated, and the residue was purified by chromatography on a 12-g Redi-Sep column, eluting with 0-10% MeOH/DCM to give a brown oil. This oil was dissolved in MeOH and filtered through a 2 micron filter, then purified further by reverse-phase HPLC (10-90% CH 3 CN/H 2 O with 0.1% TFA). The product containing fractions were combined in saturated aqueous sodium bicarbonate solution with the aid of MeOH. The mixture was extracted with DCM (2×), and the combined organic extracts were dried over sodium sulfate, filtered, and evaporated to give (S′)-2′-(neopentyloxy)-7′-(pyrazin-2-yl)-5H-spiro[oxazole-4,9′-xanthen]-2-amine as a white solid. MS m/z=417.2 [M+H] + . Calc'd for C 24 H 25 N 4 O 3 : 417.19.

Examples 17a & 17b

Synthesis of 2,8-di(pyridin-3-yl)-5′H-spiro[chromeno[3,2-b]pyridine-10,4′-oxazol]-2′-amine (17b) and 2-chloro-8-(pyridin-3-yl)-5′H-spiro[chromeno[3,2-b]pyridine-10,4′-oxazol]-2′-amine (17a)

Step 1: A RBF was charged with 3-chloro-2-cyanopyridine (40 g, 289 mmol), 4-bromophenol (49.9 g, 289 mmol) and cesium carbonate (113 g, 346 mmol). The reactants were suspended in 50 mL of DMSO and allowed to stir at 85 C overnight. The reaction was cooled to RT and to it was added 600 mL of water. The reaction was filtered and the solid washed with water, air dried to provide 3-(4-bromophenoxy)picolinonitrile as a tan solid.

Step 2: A mixture of 3-(4-bromophenoxy)picolinonitrile (57 g, 207 mmol) and 300 g of PPA was stirred at 190° C. for 2 h, followed by 180° C. overnight. After cooling to RT, the reaction mixture was poured into 500 g of ice water. After the PH was adjusted to 7 with KOH, the suspension was filtered. The solid was washed with large excess of water, followed by washing with methanol and acetone. The resulting solid was air dried to give 8-bromo-10H-chromeno[3,2-b]pyridin-10-one as a tan solid with >90% purity. The material was carried on to the next step.

Step 3: To a solution of 8-bromo-10H-chromeno[3,2-b]pyridin-10-one (60 g, 217 mmol) and urea peroxide (42.9 g, 456 mmol) in 120 mL of DCM at 0° C. was added dropwise trifluoroacetic anhydride (63.9 mL, 456 mmol). The resulting reaction was stirred for 2 h. The reaction was quenched with 10% Na 2 S 2 O 3 , extracted with DCM, dried over Na 2 SO 4 and evaporated to dryness to give crude 8-bromo-10-oxo-10H-chromeno[3,2-b]pyridine 1-oxide as a pale yellow solid.

Step 4: To a suspension of 8-bromo-10-oxo-10H-chromeno[3,2-b]pyridine 1-oxide in 100 mL of toluene at 0° C. was added dropwise phosphorus oxychloride (35.8 mL, 391 mmol) followed by 2 mL of DMF and the mixture was stirred at RT overnight. The solvent was evaporated under vacuum and the residue which crashed out of water, was filtered and washed with water, methanol and acetone in sequence. The solid was air dried to give 8-bromo-2-chloro-10H-chromeno[3,2-b]pyridin-10-one as a tan solid.

Step 5: To a suspension of 8-bromo-2-chloro-10H-chromeno[3,2-b]pyridin-10-one (20 g, 64.4 mmol) in 500 mL of THF at −78° C. was added dropwise methylmagnesium bromide 3.0 M in diethyl ether (13.82 mL, 116 mmol). The reaction was allowed to slowly warmed up to 0° C. in about 2 h. The reaction was quenched with NH 4 Cl solution, extracted with EtOAc, dried over Na 2 SO 4 , filtered and evaporated to give the corresponding crude tertiary alcohol. This solid residue was re-dissolved in 100 mL of THF and treated with 30 mL of chloroform and the resulting solution was evaporated on a 75° C. water bath for 10 min to give crude 8-bromo-2-chloro-10-methylene-10H-chromeno[3,2-b]pyridine as a brownish solid.

Step 6: A solution of iodine (12.96 g, 51.0 mmol) in THF at −25° C. was treated with silver cyanate (21.86 g, 146 mmol). After 30 min, a solution of 8-bromo-2-chloro-10-methylene-10H-chromeno[3,2-b]pyridine (15 g, 48.6 mmol) in THF was added dropwise. The slurry was maintained at −25° C. for 2 h until LCMS showed complete consumption of starting material. The slurry was filtered through celite with ether. The brown solution was concentrated to dryness, taken up in THF, cooled to 0° C. and treated with ammonia, 2 m solution in 2-propanol (4.22 mL, 194 mmol) (100 mL). The reaction was allowed to slowly warm to RT and stirred overnight. The solvents were evaporated and the residue was diluted with water, extracted with EtOAc and purified by column chromatography (SiO2, DCM to DCM/EA=3:1 to DCM/MeOH=100:2 to 100:5) to provide 8-bromo-2-chloro-5′H-spiro[chromeno[3,2-b]pyridine-10,4′-oxazol]-2′-amine (impure) as a brownish solid. MS (M+1): 365.9.

Step 7: A mixture of the 8-bromo-2-chloro-5′H-spiro[chromeno[3,2-b]pyridine-10,4′-oxazol]-2′-amine (from step 6, 40.0 mg, 0.109 mmol), potassium acetate (27.3 μL, 0.436 mmol), dichlorobis(triphenyl-phosphine)palladium (ii) (3.83 mg, 5.46 μmol) and 3-pyridylboronic acid (40.2 mg, 0.327 mmol) in 1.5 ml of dioxane/water=2:1 was heated at 110° C. under microwave irradiation for 15 min. LCMS and TLC showed incomplete conversion after 15 min. The reaction was re-heated in the microwave at 130° C. for 20 additional min. After cooling, the reaction mixture was purified by column chromatography (SiO2, DCM to DCM/MeOH=100:1 to 100:5 to 100:10 to 100:20) to afford 2,8-di(pyridin-3-yl)-5′H-spiro[chromeno[3,2-b]pyridine-10,4′-oxazol]-2′-amine as a gum. MS (M+1): 408.0; and 2-chloro-8-(pyridin-3-yl)-5′H-spiro[chromeno[3,2-b]pyridine-10,4′-oxazol]-2′-amine also as a gum. MS (M+1): 365.0.

The following are procedures for preparing intermediates, which were used to prepare Examplary compounds, representative of the present invention. The procedures and Methods hereforth were used to prepare the compounds in Tables I herein.

Synthesis of (S)-3-(3,6-dihydro-2H-pyran-4-yl)-7-(pyrimidin-5-yl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine

Step 1: A 10-20 mL microwave vial was charged with (S)-3-bromo-7-iodo-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine (503 mg, 1.098 mmol), pyrimidin-5-ylboronic acid (143 mg, 1.153 mmol), pd(ph3p)4 (127 mg, 0.110 mmol). The vial was flushed with Ar(g), then THF (5489 μL, 1.098 mmol) and potassium carbonate (1.5 M) (1464 μL, 2.195 mmol) (aq. solution) were added in sequence. The vial was sealed and heated at 110° C. for 2 hours. The mixture was diluted with water and extracted with 10% i-PrOH/EtOAc (3×). The combined organic extracts were dried over sodium sulfate, filtered, and evaporated. The residue was purified by chromatography on a 100-g SNAP column, eluting with 0-100% of a 90:10:1 mixture of DCM/MeOH/NH 4 OH in DCM to provide (S)-3-bromo-7-(pyrimidin-5-yl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine as an off-white solid.

Step 2: A vial was charged with (S)-3-bromo-7-(pyrimidin-5-yl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine (68.1 mg, 0.166 mmol), 2-(3,6-dihydro-2H-pyran-4-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (105 mg, 0.498 mmol), tetrakis(triphenylphosphine)palladium (19.18 mg, 0.017 mmol), THF (830 μL), and potassium carbonate (415 μL, 0.830 mmol) (as a 2.0 M aq. solution). The vial was sealed and placed in a 110° C. for 5 hours. The layers were separated, and the aqueous layer was extracted with EtOAc (2×). The combined organic extracts were dried over sodium sulfate, filtered, and evaporated. The residue was purified by chromatography on a 25-g SNAP column, eluting with 0-60% of a 90:10:1 mixture of DCM/MeOH/NH 4 OH in DCM to give (S)-3-(3,6-dihydro-2H-pyran-4-yl)-7-(pyrimidin-5-yl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine as a white solid

Synthesis of (S)-3,7-di(pyridin-3-yl)-5′H-spiro[chromeno[2,3-c]pyridine-5,4′-oxazol]-2′-amine

A glass microwave reaction vessel was charged with (S)-7-bromo-3-chloro-5′H-spiro[chromeno[2,3-c]pyridine-5,4′-oxazol]-2′-amine (32 mg, 0.087 mmol), potassium phosphate (55.6 mg, 0.262 mmol), Amphos (1.525 mg, 2.153 μmol) and 3-pyridylboronic acid (32.2 mg, 0.262 mmol) in dioxane (0.6 mL) and water (0.200 mL). The reaction mixture was stirred and heated in a microwave at 100° C. for 30 min. The reaction mixture was diluted with water (mL) and extracted with EtOAc (2×5 mL). The organic extract was washed with saturated NH 4 Cl (2×5 mL) and dried over MgSO4. The solution was filtered and concentrated in vacuo to give the crude material as a yellow solid. The crude material was absorbed onto a plug of silica gel and purified by silica gel chromatography (0-10% MeOH in DCM) to provide (S)-3,7-di(pyridin-3-yl)-5′H-spiro[chromeno[2,3-c]pyridine-5,4′-oxazol]-2′-amine as white solid.

Step 1: To a solution of 7-bromo-2,3-difluoro-9H-xanthen-9-one (3.1 g, 9.97 mmol) and 2,2,2-trifluoroethanol (1.445 mL, 19.93 mmol) in DMF (33 mL) at 0° C. was added sodium hydride (0.598 g, 14.95 mmol) slowly in portions. After addition, the mixture was stirred at RT for overnight. Then, H 2 O (100 mL) was added slowly and the mixture was extracted with EtOAc (1×100 mL). The organic layer was collected, dried over MgSO 4 , and concentrated. The residue was then washed with hexane (1×100 mL) to give 2.76 g of 7-bromo-2-fluoro-3-(2,2,2-trifluoroethoxy)-9H-xanthen-9-one as a light yellow solid. MS (ESI, positive ion) m/z: 390.9, 392.9 (M+1).

Step 2: To a solution of 7-bromo-2-fluoro-3-(2,2,2-trifluoroethoxy)-9H-xanthen-9-one (2.00 g, 5.11 mmol) in THF (25 mL) at 0° C. was added methylmagnesium bromide 3.0 M in diethyl ether (3.41 mL, 10.23 mmol) slowly. After addition, the mixture was stirred at RT for overnight. Then, the mixture was cooled to 0° C. and saturated ammonium chloride (50 mL) was added slowly. The mixture was then stirred at RT for 15 min. Then, the organic layer was collected and the aqueous layer was extracted with EtOAc (1×50 mL). The combined organic extracts were dried over MgSO 4 , concentrated, and dried in vacuo to give 7-bromo-2-fluoro-9-methylene-3-(2,2,2-trifluoroethoxy)-9H-xanthene as a brown solid. MS (ESI, positive ion) m/z: 388.9, 390.9 (M+1).

Step 3: To a solution of iodine (0.254 mL, 4.93 mmol) in THF (25 mL) at −20° C. was added silver cyanate (0.616 mL, 16.45 mmol). After addition, the mixture was stirred at −20° C. for 1 h. Then, a solution of 7-bromo-2-fluoro-9-methylene-3-(2,2,2-trifluoroethoxy)-9H-xanthene (1.600 g, 4.11 mmol) in THF (1.5 mL) was added and the mixture was stirred at 0° C. for 2 h. Then, the mixture was filtered through celite with the aid of THF (15 mL). Then, ammonia (6.17 mL, 12.33 mmol) (2 M in i-PrOH) was added dropwise to the filtrate. The resulting mixture was stirred at RT for overnight. Then, saturated Na 2 O 3 S 2 (5 mL) was added followed by saturated NaHCO 3 (5 mL). The mixture was stirred at room temperature for 5 min. The organic layer was collected, dried over MgSO 4 , and concentrated. The residue was then mixed with silica gel and the solid mixture was purified by silica gel column chromatography using ISCO instrument (solid loading, 0%-20% MeOH/DCM) to give 7′-bromo-2′-fluoro-3′-(2,2,2-trifluoroethoxy)-5H-spiro[oxazole-4,9′-xanthen]-2-amine as a light yellow solid.

MS (ESI, positive ion) m/z: 446.9, 448.9 (M+1).

Step 4: To a solution of 7′-bromo-2′-fluoro-3′-(2,2,2-trifluoroethoxy)-5H-spiro[oxazole-4,9′-xanthen]-2-amine (0.250 g, 0.559 mmol) in 1,2-Dimethoxyethane (2.5 mL) at RT was added sodium carbonate monohydrate crystals (0.070 mL, 1.677 mmol), 5-pyrimidinylboronic acid (0.104 g, 0.839 mmol), tetrakis(triphenylphosphine)palladium (0.052 g, 0.045 mmol), and H 2 O (0.5 mL). The resulting mixture was then heated to 90° C. for 5 h. Then, the mixture was cooled to RT and EtOAc (5 mL) was added. The mixture was stirred at RT for 1 min. The organic layer was collected, dried over MgSO 4 , and concentrated. The residue was then dissolved in DMSO (2 mL) and the solution mixture was then purified by preparative HPLC (0%-100% MeCN 0.1% TFA/H 2 O 0.1% TFA) to give a desired product in a solution of MeCN 0.1% TFA/H 2 O 0.1% TFA. Then, solution mixture was neutralized by saturated NaHCO 3 and MeCN was removed in vacuo. Then saturated NaHCO 3 (2 mL) was added and the mixture was extracted with EtOAc (2×15 mL). The combined organic extracts were dried over MgSO 4 , concentrated, and dried in vacuo to give the product depicted above as a colorless solid. MS (ESI, positive ion) m/z: 447 (M+1).

Synthesis of (S)-2-(2-amino-2′-(pyridin-3-yl)-5H-spiro[oxazole-4,9′-xanthene]-7′-yloxy)benzonitrile

Step 1: A vial was charged with (R)-2-amino-2′-bromo-5H-spiro[oxazole-4,9′-xanthen]-7′-ol (210 mg, 0.605 mmol), cesium carbonate (237 mg, 0.726 mmol), and DMF (4033 μL). The mixture was stirred for 15 min, then 2-fluorobenzonitrile (81 μL, 0.665 mmol) was added. The mixture was heated at 85° C. overnight. The reaction was diluted with water and EtOAc. The aqueous layer was extracted with EtOAc (2×). The combined organic extracts were dried over sodium sulfate, filtered, and evaporated. The residue was chromatographed on a 40-g Redi-Sep column, eluting with 0-100% of a 90:10:1 mix of DCM/MeOH/NH 4 OH in DCM. The product isolated this way was impure, so the material was resubjected to chromatography on a 40-g Redi-Sep column, this time eluting with 0-100% EtOAc/Hexane. This gave (R)-2-(2-amino-2′-bromo-5H-spiro[oxazole-4,9′-xanthene]-7′-yloxy)benzonitrile as 94% pure by HPLC. It was a yellow solid after evaporation from DCM/hexane.

Step 2: A vial was charged with (R)-2-(2-amino-2′-bromo-5H-spiro[oxazole-4,9′-xanthene]-7′-yloxy)benzonitrile (75 mg, 0.167 mmol), pyridin-3-ylboronic acid (51.4 mg, 0.418 mmol), tetrakis(triphenylphosphine)palladium(0) (9.67 mg, 8.37 μmol), THF (837 μL), and potassium carbonate (418 μL, 0.837 mmol) (as a 2.0 M aq. solution). The vial was sealed and heated to 100° C. in a shaker overnight. The mixture was diluted with EtOAc and the layers were separated. The aqueous layer was extracted with EtOAc (2×). The combined organic extracts were evaporated, and the residue was chromatographed on a 25-g SNAP column, eluting with 0-80% of a 90:10:1 mix of DCM/MeOH/NH 4 OH in DCM to give (S)-2-(2-amino-2′-(pyridin-3-yl)-5H-spiro[oxazole-4,9′-xanthene]-7′-yloxy)benzonitrile as a pale-yellow solid.

Synthesis of (S)-3-(3,3-dimethylbut-1-ynyl)-7-(pyrimidin-5-yl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine

Step 1: A sealable tube was charged with (S)-3-bromo-7-iodo-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine (2.000 g, 4.37 mmol), pd(ph3p)4 (0.504 g, 0.437 mmol), pyrimidin-5-ylboronic acid (0.568 g, 4.58 mmol) and THF (21.83 mL, 4.37 mmol). The mixture was flushed with Ar then a solution of potassium carbonate (1.5 M) (5.82 mL, 8.73 mmol) was added. The reaction was heated at 110° C. for 2 hours before being diluted with water 50 mL and poured into a separatory funnel containing EtOAc 50 mL. The layers were separated and the aqueous layer was extracted with EtOAc 3×100 mL. The aqeuous layer was then extracted with DCM (3×100 mL). The combined organic layers were washed with brine, dried over sodium sulfate, filtered and concentrated in vacuo to provide a brown oil that was purified by silica gel chromatography (Redi-Sep pre-packed silica gel column (80 g), 0-10% methanol in methylenechloride with 0.1% ammonium hydroxide) to provide (S)-3-bromo-7-(pyrimidin-5-yl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine as a light yellow foam.

Step 2: Combined (S)-3-bromo-7-(pyrimidin-5-yl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine (75 mg, 0.183 mmol), tetrakis(triphenylphosphine)palladium (21.13 mg, 0.018 mmol), copper iodide (3.48 mg, 0.018 mmol), THF (366 μL, 0.183 mmol) and DMF (366 μL, 0.183 mmol) in a reaction vial. To the mixture was added diisopropyl amine (512 μL, 3.66 mmol) then ethynylcyclopropane (60.4 mg, 0.914 mmol). The reaction vial was sealed and heated at 110° C. for 1.5 hours. The reaction was allowed to cool to RT before being diluted with water (15 mL) and poured into a separatory funnel containing ethyl acetate (50 mL). The layers were separated and the aqueous layer was extracted with ethyl acetate (1×25 mL). The combined organic layers were washed with water and then brine, dried over sodium sulfate, filtered and concentrated in vacuo to provide a brown foam that was purified by silica gel chromatography (Redi-Sep pre-packed silica gel column (12 g), 0-10% methanol in methylenechloride with 0.1% ammonium hydroxide) to provide (S)-3-(3,3-dimethylbut-1-ynyl)-7-(pyrimidin-5-yl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine as an orange solid.

Synthesis of (S)-3-(3,3-dimethylbutyl)-7-(pyridin-3-yl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine

Step 1: A sealable tube was charged with (S)-3-bromo-7-iodo-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine (600 mg, 1.310 mmol), Pd(PPh 3 ) 4 (151 mg, 0.131 mmol), pyridin-3-ylboronic acid (161 mg, 1.310 mmol) and THF (6550 μL, 1.310 mmol). The mixture was purged with Ar for 2 minutes then a solution of potassium carbonate (1747 μL, 2.62 mmol) was added. The tube was sealed and heated at 110° C. for 2 hours. The reaction was diluted with water 50 mL and poured into a separatory funnel containing EtOAc 50 mL. The layers were separated and the aqueous layer was extracted with EtOAc 4×50 mL. The combined organic layers were washed with brine, dried over sodium sulfate, filtered and concentrated in vacuo to provide a brown oil that was purified by silica gel chromatography (Redi-Sep pre-packed silica gel column (40 g), 0-10% methanol in DCM with 0.1% ammonium hydroxide) to provide (S)-3-bromo-7-(pyridin-3-yl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine as a light yellow foam.

Step 2: Combined (S)-3-bromo-7-(pyridin-3-yl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine (250 mg, 0.611 mmol), Pd(PPh 3 ) 4 (70.6 mg, 0.061 mmol), copper(i) iodide (23.27 mg, 0.122 mmol) and DMF (4073 μL, 0.611 mmol) in a sealable tube. Added (201 mg, 2.444 mmol) and DIPA (4353 μL, 30.5 mmol), flushed with argon, sealed and heated at 90° C. overnight. The reaction was diluted with water (25 mL) and poured into a separatory funnel containing ethyl acetate (50 mL). The layers were separated and the aqueous layer was extracted with ethyl acetate (1×100 mL). The combined organic layers were washed with water, dried over sodium sulfate, filtered and concentrated in vacuo to provide a brown foam that was purified by silica gel chromatography (Redi-Sep pre-packed silica gel column (12 g), 0-10% methanol in methylenechloride with 0.1% ammonium hydroxide) to provide (S)-3-(3,3-dimethylbut-1-ynyl)-7-(pyridin-3-yl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine as a brown solid

Step 3: To a solution of (S)-3-(3,3-dimethylbut-1-ynyl)-7-(pyridin-3-yl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine (60 mg, 0.146 mmol) in 5 mL of methanol was added Pd/C (5%) (156 mg, 1.462 mmol). The mixture was maintained under an atmosphere of hydrogen gas for 20 hours before being filtered through a celite plug, washing well with methanol. The filtrate was concentrated and the derived residue was purified by silical gel chromatography (12 g, 0-10% methanol in methylenechloride with 0.1% ammonium hydroxide) to provide (S)-3-(3,3-dimethylbutyl)-7-(pyridin-3-yl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine as a white solid.

A vial was charged with (S)-2-amino-7′-(pyridin-3-yl)-5H-spiro[oxazole-4,9′-xanthen]-2′-ol (106 mg, 0.308 mmol) and TFA (1540 μL) to give an orange solution. The vial was submerged in an ice-bath for 15 min, and n-bromosuccinimide (54.8 mg, 0.308 mmol) was added in a single portion. Stirred the mixture for 1 hour, then it was diluted with methanol and evaporated under reduced pressure. The residue was dissolved in methanol and loaded onto a 2-g SCX-2 acidic column. The column was first eluted with methanol to remove impurities, then with 2 M ammonia in methanol to elute the product. The filtrate was evaporated in vacuo to give a brown oil. This oil was chromatographed on a 40-g HP (high performance) Redi-Sep column, eluting with 0-100% of a 90:10:1 mix of DCM/MeOH/DCM in DCM to provide the depicted compound as a yellow solid.

Synthesis of (S)-7-(2-fluoropyridin-3-yl)-3-p-tolyl-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine

Step 1: A vial was charged (S)-2′-amino-3-bromo-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-7-ol (282 mg, 0.809 mmol), p-tolylboronic acid (220 mg, 1.618 mmol), potassium carbonate (559 mg, 4.04 mmol), Pd(PPh 3 ) 4 (46.7 mg, 0.040 mmol). The vial was flushed with Ar (g), then Dioxane (4044 μL) and water (2 mL) were added in sequence. The vial was sealed and placed in an 80° C. oil bath. After stirring for 50 minutes, the mixture was partitioned between brine and 10% iPrOH/EtOAc. The layers were separated, and the aq. layer was extracted with EtOAc. The combined organic extracts were dried over sodium sulfate, filtered, and evaporated. The residue was chomatographed on an 80-g Redi-Sep column, eluting with 0-80% of a 90:10:1 mix of DCM/MeOH/NH 4 OH in DCM to give (S)-2′-amino-3-p-tolyl-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-7-ol (259.36 mg, 0.722 mmol, 89% yield) as an orange solid.

Step 2: A 25-mL flask was charged with (S)-2′-amino-3-p-tolyl-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-7-ol (259.36 mg, 0.722 mmol) in DCM (7217 μL) to give an clear, orange solution. triethylamine (201 μL, 1.443 mmol) and 1,1,1-trifluoro-N-phenyl-N-(trifluoromethylsulfonyl)methanesulfonamide (271 mg, 0.758 mmol) were added in sequence. The mixture was stirred for 4 hours before being loaded directly onto a 25-g silica gel loading column with the aid of DCM. The column was eluted onto a prequilibrated 40-g Redi-Sep column with 0-5% MeOH/DCM to give (S)-2′-amino-3-p-tolyl-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazole]-7-yl trifluoromethanesulfonate (317.34 mg, 0.646 mmol, 89% yield) as a cream-colored solid

Step 3: A vial was charged with (S)-2′-amino-3-p-tolyl-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazole]-7-yl trifluoromethanesulfonate (45.0 mg, 0.092 mmol), 2-fluoropyridin-3-ylboronic acid (38.7 mg, 0.275 mmol), potassium carbonate (229 μL, 0.458 mmol), and Pd(PPh 3 ) 4 (5.29 mg, 4.58 μmol). The vial was flushed with Ar (g), then dioxane (458 μL) (actual amount as 1 mL) and water (0.5 mL) were added in sequence. The vial was selaed and placed in an 80° C. oil bath for 2 hours. The mixture was diluted with EtOAc, washed with brine, dried over sodium sulfate, filtered, and evaporated. The residue was chromatographed on a 12-g Redi-Sep column with 0-5% MeOH/DCM to give (S)-7-(2-fluoropyridin-3-yl)-3-p-tolyl-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine (29.53 mg, 0.067 mmol, 73.6% yield) as a tan solid.

Synthesis of (S)-3-(2,2-dimethylmorpholino)-7-(2-fluoropyridin-3-yl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine

Step 1: A vial was charged with (S)-3-bromo-7-iodo-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine (302.9 mg, 0.661 mmol), 2-fluoro-3-pyridineboronic acid (102 mg, 0.727 mmol), potassium carbonate (457 mg, 3.31 mmol), and tetrakis(triphenylphosphine)palladium(0) (38.2 mg, 0.033 mmol). The vial was flushed with Ar (g), then dioxane (3306 μL) and water (1.7 mL) were added in sequence. The vial was sealed and placed in a 75° C. oil bath for 2 hours. The mixture was diluted with EtOAc (15 mL) and brine (15 mL). The layers were separated, and the aq. layer was extracted with EtOAc (2×15 mL). The combined organic extracts were dried over sodium sulfate, filtered, and evaporated. The residue was purified by chromatography on a 40-g Redi-Sep column, eluting with 0-60% of a 90:10:1 mix of DCM/MeOH/NH 4 OH in DCM to give (S)-3-bromo-7-(2-fluoropyridin-3-yl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine as an off-white solid.

Step 2: A vial was charged with (S)-3-bromo-7-(2-fluoropyridin-3-yl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine (110 mg, 0.257 mmol), DavePhos (12.16 mg, 0.031 mmol), and tris(dibenzylideneacetone)dipalladium(0) (11.79 mg, 0.013 mmol). The vessel was flushed with Ar(g), then lithium bis(trimethylsilyl)amide (772 μL, 0.772 mmol) (1.0 M solution in THF) and 2,2-dimethylmorpholine (61.8 μL, 0.515 mmol) were added in sequence. The vial was sealed and placed in a 75° C. oil bath for two hours. The mixture was diluted with saturated aq. ammonium chloride solution (20 mL) and water (10 mL). The mixture was extracted with DCM (3×20 mL), leaving behing a dark oily solid. The combined organic extracts were dried over sodium sulfate, filtered, and evaporated. The residue was chromatographed on an 24-g Redi-Sep Gold column with 0-70% of a 90:10:1 mix of DCM/MeOH/NH 4 OH in DCM to give (S)-3-(2,2-dimethylmorpholino)-7-(2-fluoropyridin-3-yl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine as a yellow solid.

Synthesis of N-((4S)-2-amino-7′-methoxyspiro[1,3-oxazole-4,9′-xanthen]-2′-yl)-5-chloro-2-pyridinecarboxamide

Step 1: A 5 mL smith synthesizer vial was charged with (R)-2′-bromo-7′-methoxy-5H-spiro[oxazole-4,9′-xanthen]-2-amine (1.248 g, 3.46 mmol), sodium azide (0.684 g, 10.52 mmol), L-ascorbic acid sodium salt (0.057 g, 0.288 mmol), copper(I) iodide (0.131 g, 0.688 mmol), and (1R,2R)—N1,N2-dimethylcyclohexane-1,2-diamine (0.116 mL, 0.736 mmol) in EtOH (6.0 mL), water (2.6 mL) and the reaction was heated to 100° C. in the microwave for 35 minutes. The reaction vial was cooled to RT and concentrated on the rotary evaporator and the resulting residue was taken up in ethyl acetate (125 mL), water (50 mL) the organic layer was separated. The organic layer was dried over sodium sulfate and concentrated to yield the crude product which was purified by silica gel flash column chromatography (using a 40 G ISCO silica gel cartridge), and eluted using hexanes/ethyl acetate gradient. The fractions were combined and concentrated to yield (S)-2′-azido-7′-methoxy-5H-spiro[oxazole-4,9′-xanthen]-2-amine as a yellowish solid. MS (ESI pos. ion) m/z: 324 (M+1).

Step 2: A solution of (S)-2′-azido-7′-methoxy-5H-spiro[oxazole-4,9′-xanthen]-2-amine (1.162 g, 3.59 mmol) in dichloromethane (25 mL) was treated with pyridine (0.775 mL, 9.50 mmol) followed by trifluoroaceticacid anhydride (0.9 mL, 6.43 mmol) at RT. The reaction was allowed to stir for 2 hours during which formation of desired product was detected (M+H˜420) along with traces of unreacted starting material. The reaction was allowed to stir for another 6 hours and diluted with DCM (75 mL), water (20 mL), and separated the organic layer. The organic layer was dried over anhydrous sodium sulfate, and concentrated to yield (S)—N-(2′-azido-7′-methoxy-5H-spiro[oxazole-4,9′-xanthene]-2-yl)-2,2,2-trifluoroacetamide as a yellowish solid. MS (ESI pos. ion) m/z: 420 (M+1).

Step 3: A solution of (S)—N-(2′-azido-7′-methoxy-5H-spiro[oxazole-4,9′-xanthene]-2-yl)-2,2,2-trifluoroacetamide (0.410 g, 0.978 mmol) in ethanol (12 mL) and THF (8 mL) was stirred with palladium hydroxide, 20 wt % pd (dry basis) on carbon, wet, degussa type e101 ne/w (0.136 g, 0.978 mmol) under hydrogen at atmospheric pressure and RT for 2 hours. The catalyst was removed by filtration over a celite-pad, washed with EtOH (15 mL). The combined filtrates were concentrated to yield the crude product (104584-37-2). The product (S)—N-(2′-amino-7′-methoxy-5H-spiro[oxazole-4,9′-xanthene]-2-yl)-2,2,2-trifluoroacetamide was obtained as an off-white solid. MS (ESI pos. ion) m/z: 394 (M+1).

Step 4: A 25 mL RBF containing a solution of (S)—N-(2′-amino-7′-methoxy-5H-spiro[oxazole-4,9′-xanthene]-2-yl)-2,2,2-trifluoroacetamide (0.058 g, 0.147 mmol), 5-chloropyridine-2-carboxylic acid (0.030 g, 0.190 mmol), 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (0.045 g, 0.235 mmol) in DCM (4 mL) and DMF (0.25 mL) was treated with 1-hydroxy-1H-benzotriazole (0.014 g, 0.104 mmol) and stirred for 1.5 hrs at RT. The reaction was diluted with DCM (50 mL) and water (15 mL). The DCM layer was separated, dried over anhydrous sodium sulfate, and concentrated to dryness to yield (S)-5-chloro-N-(2′-methoxy-2-(2,2,2-trifluoroacetamido)-5H-spiro[oxazole-4,9′-xanthene]-7′-yl)picolinamide as a brownish solid. MS (ESI pos. ion) m/z: 533 (M+1).

Step 5: A solution of (S)-5-chloro-N-(2′-methoxy-2-(2,2,2-trifluoroacetamido)-5H-spiro[oxazole-4,9′-xanthene]-7′-yl)picolinamide (0.054 g, 0.101 mmol) in methanol (3.5 mL) was treated with potassium carbonate anhydrous (0.045 g, 0.326 mmol) and stirred at RT for 30 minutes. The catalyst was removed by filtration and the filtrate was concentrated to yield the crude product as a yellowish gummy solid. The crude product was purified by preparative HPLC [gradient 10-90% MeCN (0.1% TFA)/H 2 O (0.1% TFA)] to give pure product which was dissolved in methanol (5 mL) and neutralized by passing the solution through a Polymer Lab-HCO 3 macroporous resin cartridge, and the filtrate was concentrated to give N-((4S)-2-amino-7′-methoxyspiro[1,3-oxazole-4,9′-xanthen]-2′-yl)-5-chloro-2-pyridinecarboxamide as an off-white solid. MS (ESI pos. ion) m/z: 437 (M+1).

Synthesis of R)-2′-(2,2-dimethyltetrahydro-2H-pyran-4-yl)-7′-(pyrimidin-5-yl)-5H-spiro[oxazole-4,9′-xanthen]-2-amine

Step 1: A 100 ml RBF was charged with (R)-2′-bromo-7′-iodo-5H-spiro[oxazole-4,9′-xanthen]-2-amine (3.3 g, 7.22 mmol), pyrimidin-5-ylboronic acid (1.163 g, 9.39 mmol), and tetrakis(triphenylphosphine)palladium(0) (0.834 g, 0.722 mmol). To this were added DME (51.6 mL) followed by sodium carbonate (10.83 mL, 21.66 mmol) (2M solution) and the mixture was heated at 70° C. for 24 hrs. The mixture was diluted with water and ethyl acetate, filtered and organic layer was separated and concentrated. The crude material was purified by FC on 80 g RediSep column using 5-70% gradient of DCM/MeOH/NH4OH in DCM to give (S)-2′-bromo-7′-(pyrimidin-5-yl)-5H-spiro[oxazole-4,9′-xanthen]-2-amine).

Step 2: A 15 ml resealable vial was charged with (S)-2′-bromo-7′-(pyrimidin-5-yl)-5H-spiro[oxazole-4,9′-xanthen]-2-amine (700 mg, 1.711 mmol), 2-(2,2-dimethyl-3,6-dihydro-2H-pyran-4-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (652 mg, 2.74 mmol), 1.5:1 mixture of regioisomers of the double bond, major shown, which contains significant amount of bis-pinaclborane. Potassium carbonate (709 mg, 5.13 mmol) and AmPhos (60.6 mg, 0.086 mmol), 1,4-Dioxane (9978 μL) and Water (1425 μL) were added, the vial was sealed and heated in microwave reactor for 1 hr at 100° C. The mixture was diluted with ethyl acetate, filtered through celite and concentrated, the residue was 1 purified by flash chromatography (20-60% gradient of DCM/MeOH/NH4OH (90:10:1) in DCM) to afford a 450 mg (60% yield) of 1:1 mixture of (R)-2′-(6,6-dimethyl-3,6-dihydro-2H-pyran-4-yl)-7′-(pyrimidin-5-yl)-5H-spiro[oxazole-4,9′-xanthen]-2-amine and (R)-2′-(2,2-dimethyl-3,6-dihydro-2H-pyran-4-yl)-7′-(pyrimidin-5-yl)-5H-spiro[oxazole-4,9′-xanthen]-2-amine.

Step 3: To a solution of (R)-2′-(2,2-dimethyl-3,6-dihydro-2H-pyran-4-yl)-7′-(pyrimidin-5-yl)-5H-spiro[oxazole-4,9′-xanthen]-2-amine (55 mg, 0.125 mmol) in MeOH (2 mL) palladium on carbon (66.4 mg, 0.062 mmol) was added and the mixture was hydrogenated at 50° C. (1 atm of hydrogen gas) for 30 min. Another 20 mg of Pd/C was added and hydrogenation was continued for 1.5 hr at 50° C. The mixture was filtered through a plug of celite and purified by silica gel chromatography (10-80% DCM/MeOH/NH4OH in DCM) to afford (R)-2′-(2,2-dimethyltetrahydro-2H-pyran-4-yl)-7′-(pyrimidin-5-yl)-5H-spiro[oxazole-4,9′-xanthen]-2-amine.

Synthesis of (S)-7-((3-methyloxetan-3-yl)ethynyl)-3-(neopentyloxy)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine

Step 1: To a solution of (S)-2′-amino-7-bromo-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-3-ol (390 mg, 1.120 mmol) in DMF (4481 μL, 1.120 mmol) in a sealed tube was added cesium carbonate (912 mg, 2.80 mmol). After stirring for 1 minute neopentyl iodide (223 μL, 1.680 mmol) was added, the reaction vessel was sealed and heated at 100° C. for 2.5 hours. Reaction was cooled to RT to prevent over alkylation. The reaction was diluted with water (25 mL) and 10 mL of ethyl acetate and stirred for 30 minutes before being poured into a separatory funnel containing ethyl acetate (100 mL) and water (250 mL). The layers were separated and the aqueous layer was extracted with ethyl acetate (3×50 mL). The aqueous layer was then extracted with DCM (3×50 mL). The organic layers were each washed with water and then brine, at which point all the organics were combined, dried over sodium sulfate, filtered and concentrated in vacuo to provide a brown foam that was purified by silica gel chromatography (Redi-Sep pre-packed silica gel column (40 g), 0-10% methanol in methylenechloride with 0.1% ammonium hydroxide) to provide (S)-7-bromo-3-(neopentyloxy)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine as a yellow solid.

Step 2: A sealable tube was charged with (S)-7-bromo-3-(neopentyloxy)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine (75 mg, 0.179 mmol), copper iodide (3.38 mg, 0.018 mmol), tetrakis(triphenylphosphine)palladium (20.53 mg, 0.018 mmol). To this mixture was added DMF (355 μL, 0.178 mmol), diisopropylamine (498 μL, 3.55 mmol) and trimethyl((3-methyloxetan-3-yl)ethynyl)silane (90 mg, 0.533 mmol). The tube was flushed with argon, sealed and heated to 90° C. for 12 hours. The reaction was diluted with water (100 mL) and poured into a separatory funnel containing ethyl acetate (50 mL). The layers were separated and the aqueous layer was extracted with ethyl acetate (2×50 mL). The combined organic layers were washed with water and then brine, dried over sodium sulfate, filtered and concentrated in vacuo to provide a brown oil that was purified by silica gel chromatography (Redi-Sep pre-packed silica gel column (12 g), 0-10% methanol in methylenechloride with 0.1% ammonium hydroxide) to provide (S)-7-((3-methyloxetan-3-yl)ethynyl)-3-(neopentyloxy)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine as a yellow solid.

Synthesis of (R)-7-(neopentyloxy)-3-(pyridin-3-yl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine

Step 1: A 350 mL sealable flask was charged with (R)-2′-amino-3-bromo-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-7-ol (12.10 g, 34.8 mmol) and DMF (99 mL, 34.8 mmol). To this solution was added cesium carbonate (28.3 g, 87 mmol). The resulting brown slurry was stirred at rt for 3 minutes before neopentyl iodide (9.21 mL, 69.5 mmol) was added in one portion. The reaction vessel was sealed and heated at 100° C. After heating for 4 hours another 1 mL of neopentyl iodide was added and heating at 100° C. was continued for another 1 hour at which point the reaction was allowed to cool to room temperature. The reaction was diluted with ethyl acetate (500 mL) and poured into water (2000 mL) before being transferred into a separatory funnel containing ethyl acetate (500 mL). The layers were separated and the aqueous layer was extracted with ethyl acetate (3×500 mL). The combined organic layers were washed with water and then brine. The aqeuous layer was combined with the above brined wash and was then extracted with DCM (2×500 mL). The organic layers were washed with water and then brine. All of the organigs were combined, dried over sodium sulfate, filtered and concentrated in vacuo to provide a brown foam that was purified by silica gel chromatography (Redi-Sep pre-packed silica gel column (330 g), 0-10% methanol in DCM with 0.1% ammonium hydroxide) to provide (R)-3-bromo-7-(neopentyloxy)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine as a light yellow solid.

Step 2: Combined (R)-3-bromo-7-(neopentyloxy)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine (9.15 g, 21.88 mmol), tetrakis(triphenylphosphine)palladium (2.53 g, 2.188 mmol) and 3-pyridylboronic acid (6.72 g, 54.7 mmol). Added THF (146 mL, 21.88 mmol) followed by potassium carbonate (1.5 M) (58.3 mL, 88 mmol). Flushed reaction tube with argon, sealed and heated at 110° C. for 2.5 hours. The reaction was allowed to cool to RT before being poured into a separatory funnel containing ethyl acetate (500 mL). Water (1000 mL) was added and, the layers were separated and the aqueous layer was extracted with ethyl acetate (3×500 mL). The combined organic layers were washed with brine, dried over sodium sulfate, filtered and concentrated in vacuo to provide a brown foam. This foam was purified by silica gel chromatography (Redi-Sep pre-packed silica gel column (330 g), 0-10% methanol in methylenechloride with 0.1% ammonium hydroxide) to provide (R)-7-(neopentyloxy)-3-(pyridin-3-yl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine as a light yellow solid.

Synthesis of (S)-4′-fluoro-2′-(2-fluoro-2-methylpropoxy)-7′-(pyrimidin-5-yl)-5H-spiro[oxazole-4,9′-xanthen]-2-amine

Step 1: A 25 ml RBF was charged with (S)-2-amino-7′-bromo-4′-fluoro-5H-spiro[oxazole-4,9′-xanthen]-2′-ol (629 mg, 1.723 mmol), tetrakis(triphenylphosphine)palladium (199 mg, 0.172 mmol), and pyrimidin-5-ylboronic acid (320 mg, 2.58 mmol). DMF (8613 μL) and sodium carbonate (2M solution) (2584 μL, 5.17 mmol) were added and the mixture was stirred at 85° C. for 2.5 hrs. The mixture was cooled to RT, water (˜5 ml) was added and stirring was continued for 10 min. The precipitate was filtered out, washed with water (3×5 mL), 1:1 i-PrOH/water to remove color and dried in vacuo to afford (S)-2-amino-4′-fluoro-7′-(pyrimidin-5-yl)-5H-spiro[oxazole-4,9′-xanthen]-2′-ol as yellow solid.

Step 2: A vial was charged with (S)-2-amino-4′-fluoro-7′-(pyrimidin-5-yl)-5H-spiro[oxazole-4,9′-xanthen]-2′-ol (61.0 mg, 0.167 mmol), cesium carbonate (82 mg, 0.251 mmol), and DMF (670 μL). The resulting mixture was stirred vigorously for 10 min, then the vial was placed in large ice-bath for 10 min and 2-fluoro-2-methylpropyl trifluoromethanesulfonate (33.3 μL, 0.201 mmol) was added dropwise. The ice bath was removed after 5 minutes and the mixture was stirred at RT for 6 hours before being diluted with water (10 mL) and extracted with EtOAc (3×5 mL). The combined organic extracts were dried over sodium sulfate, filtered, and evaporated. The residue was chromatographed on a 12 g Redi-Sep column, eluting with 5-60% gradient of DCM/MeOH/NH4OH (90:10:1) in DCM to give (S)-4′-fluoro-2′-(2-fluoro-2-methylpropoxy)-7′-(pyrimidin-5-yl)-5H-spiro[oxazole-4,9′-xanthen]-2-amine as an off-white solid.

Synthesis of (S)-2′-(2,2-dimethylmorpholino)-7′-(2-fluoropyridin-3-yl)-5H-spiro[oxazole-4,9′-xanthen]-2-amine

Step 1: A 2-5 ml microwave vial was charged with (S)-2-amino-2′-bromo-5H-spiro[oxazole-4,9′-xanthen]-7′-ol (300 mg, 0.864 mmol) (104780-26-0), Pd 2 dba 3 (39.6 mg, 0.043 mmol), 2′-(dicyclohexylphosphino)-N,N-dimethylbiphenyl-2-amine (40.8 mg, 0.104 mmol) and 2,2-dimethylmorpholine (299 mg, 2.59 mmol). The mixture was capped with argon and LiHMDS (1M in THF) (4321 μL, 4.32 mmol) was added and the vial was sealed and heated at 110° C. in microwave reactor for 1 hr. The reaction mixture was quenched by addition of 2 ml water and EtOAc, then saturated NH 4 Cl was added. The organic layer was filterd through Celite, concentrated in vacuo and purified on a 40 g RediSep column using 15-80% DCM/MeOH/NH4OH in DCM to afford (R)-2-amino-2′-(2,2-dimethylmorpholino)-5H-spiro[oxazole-4,9′-xanthen]-7′-ol.

Step 2: To a solution of (R)-2-amino-2′-(2,2-dimethylmorpholino)-5H-spiro[oxazole-4,9′-xanthen]-7′-ol (370 mg, 0.970 mmol) in DCM (4850 μL), were added triethylamine (270 μL, 1.940 mmol) and 1,1,1-trifluoro-N-phenyl-N-(trifluoromethylsulfonyl)methanesulfonamide (520 mg, 1.455 mmol). After stirring at room temperature for 60 hours the mixture was directly loaded onto 12 g RediSep column and purified using 15-60% DCM/MeOH/NH4OH to afford (R)-2-amino-2′-(2,2-dimethylmorpholino)-5H-spiro[oxazole-4,9′-xanthene]-7′-yl trifluoromethanesulfonate.

Step 3: A 25 mL RB flask was charged with (R)-2-amino-2′-(2,2-dimethylmorpholino)-5H-spiro[oxazole-4,9′-xanthene]-7′-yl trifluoromethanesulfonate (270 mg, 0.526 mmol), tetrakis(triphenylphosphine)palladium(0) (60.8 mg, 0.053 mmol), 2-fluoropyridin-3-ylboronic acid (119 mg, 0.841 mmol), DMF (2629 μL) and sodium carbonate (2M solution) (789 μL, 1.577 mmol). The mixture was stirred under argon for 2 hrs at 85° C. The mixture was diluted with water (2 ml) and extracted with 10 ml of EtOAc. Organic layer was washed with water, brine, passed through plug of Celite and concentrated. The dark residue was purified by silica gel chromatography (5-70% DCM/MeOH/NH4OH in DCM) to afford (S)-2′-(2,2-dimethylmorpholino)-7′-(2-fluoropyridin-3-yl)-5H-spiro[oxazole-4,9′-xanthen]-2-amine.

Method AA17

Synthesis of (S)-7-(cyclopropylethynyl)-3-(2-fluoro-2-methylpropoxy)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine

Step 1: A vial was charged with (S)-2′-amino-7-bromo-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-3-ol (750 mg, 2.154 mmol), DMF (8617 μL, 2.154 mmol) and cesium carbonate (2106 mg, 6.46 mmol). The mixture was cooled to 0° C. and 2-fluoro-2-methylpropyl trifluoromethanesulfonate (966 mg, 4.31 mmol) was added. The reaction was removed from the ice bath and stirred at RT for 45 minutes. The reaction was diluted with water (250 mL) and poured into a separatory funnel containing ethyl acetate (250 mL). The layers were separated and the aqueous layer was extracted with ethyl acetate (3×100 mL). The combined organic layers were washed with water and then brine, dried over sodium sulfate, filtered and concentrated in vacuo to provide a light yellow solid that was purified by silica gel chromatography (Redi-Sep pre-packed silica gel column (40 g), 0-10% methanol in methylenechloride with 0.1% ammonium hydroxide) to provide (S)-7-bromo-3-(2-fluoro-2-methylpropoxy)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine as a light yellow solid.

Step 2: A sealable tube was charged with (S)-7-bromo-3-(2-fluoro-2-methylpropoxy)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine (75 mg, 0.178 mmol), copper(i) iodide (3.38 mg, 0.018 mmol), tetrakis(triphenylphosphine)palladium (20.53 mg, 0.018 mmol). Added DMF (355 μL, 0.178 mmol), diisopropylamine (498 μL, 3.55 mmol) and cyclopropylacetylene (75 μL, 0.888 mmol) and the tube was flushed with argon, sealed and heated to 110° C. for 2 hours. More copper iodide (3.38 mg, 0.018 mmol), tetrakis(triphenylphosphine)palladium (20.53 mg, 0.018 mmol), diisopropylamine (498 μL, 3.55 mmol) and cyclopropylacetylene (75 μL, 0.888 mmol) were added and the black mixture was heated at 110° C. for 3 hours. The reaction was diluted with water (100 mL) and poured into a separatory funnel containing ethyl acetate (50 mL). The layers were separated and the aqueous layer was extracted with ethyl acetate (2×50 mL). The combined organic layers were washed with water and then brine, dried over sodium sulfate, filtered and concentrated in vacuo to provide a brown oil that was purified by silica gel chromatography (Redi-Sep pre-packed silica gel column (12 g), 0-10% methanol in methylenechloride with 0.1% ammonium hydroxide) to provide (S)-7-(cyclopropylethynyl)-3-(2-fluoro-2-methylpropoxy)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine as a tan solid.

Method AA18

Synthesis of (S)-4′-fluoro-7′-(2-fluoropyridin-3-yl)-2′-(tetrahydro-2H-pyran-4-yl)-5H-spiro[oxazole-4,9′-xanthen]-2-amine

Step 1: A RBF was charged with sodium carbonate (2 M, 2 mL), tetrakis(triphenylphosphine)palladium (0.237 g, 0.205 mmol), (S)-2-amino-7′-bromo-4′-fluoro-5H-spiro[oxazole-4,9′-xanthen]-2′-ol (0.75 g, 2.054 mmol), and 2-fluoro-3-pyridineboronic acid (0.579 g, 4.11 mmol) and DMF (5 ml). The solution was heated at 85° C. overnight. The solution was diluted with water (25 ml) and filtered. The solids were triturated with methanol and dried under vacuum to afford (S)-2-amino-4′-fluoro-7′-(2-fluoropyridin-3-yl)-5H-spiro[oxazole-4,9′-xanthen]-2′-ol as a tan solid.

Step 2: A flask was charged with (S)-2-amino-4′-fluoro-7′-(2-fluoropyridin-3-yl)-5H-spiro[oxazole-4,9′-xanthen]-2′-ol (300 mg, 0.787 mmol), TEA (0.219 ml, 1.573 mmol), DCM (5 mL) and 1,1,1-trifluoro-N-phenyl-N-(trifluoromethylsulfonyl)methanesulfonamide (337 mg, 0.944 mmol). The solution was stirred at RT overnight. The solution was loaded directly on a silica column. The product was purified via silica gel column chromatography (RediSep 12 g column) using 5-25% 90/10/1 (DCM/MeOH/ammonia) in DCM to afford (S)-2-amino-5′-fluoro-2′-(2-fluoropyridin-3-yl)-5H-spiro[oxazole-4,9′-xanthene]-7′-yl trifluoromethanesulfonate as a yellow solid.

Step 3: A flask was charged with tetrakis(triphenylphosphine)palladium (29.3 mg, 0.025 mmol), 2-(3,6-dihydro-2H-pyran-4-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (106 mg, 0.506 mmol), (S)-2-amino-5′-fluoro-2′-(2-fluoropyridin-3-yl)-5H-spiro[oxazole-4,9′-xanthene]-7′-yl trifluoromethanesulfonate (130 mg, 0.253 mmol), sodium carbonate (saturated) (0.253 mL, 1.266 mmol) and DMF (2 ml). The solution was heated at 85° C. for 18 hours. The product was purified via Gilson HPLC (gradient elution 20-90% MeCN/H 2 O, 0.1% TFA) to afford (S)-2′-(3,6-dihydro-2H-pyran-4-yl)-4′-fluoro-7′-(2-fluoropyridin-3-yl)-5H-spiro[oxazole-4,9′-xanthen]-2-amine.

Step 4: (S)-2′-(3,6-dihydro-2H-pyran-4-yl)-4′-fluoro-7′-(2-fluoropyridin-3-yl)-5H-spiro[oxazole-4,9′-xanthen]-2-amine (30 mg, 0.067 mmol) and palladium on carbon (7.14 mg, 0.067 mmol) were combined in 10 ml of MeOH and stirred under an atmosphere of hydrogen overnight. The solution was filtered and concentrated to afford (S)-4′-fluoro-7′-(2-fluoropyridin-3-yl)-2′-(tetrahydro-2H-pyran-4-yl)-5H-spiro[oxazole-4,9′-xanthen]-2-amine as a white solid.

Method AA19

Synthesis of (S)-7-(5-chloro-2-fluorophenyl)-3-(tetrahydro-2H-pyran-4-yl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine

Step 1: A vial was charged with (S)-2′-amino-3-bromo-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-7-ol (380 mg, 1.091 mmol), potassium carbonate (754 mg, 5.46 mmol), 2-(3,6-dihydro-2H-pyran-4-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (688 mg, 3.27 mmol), pd(ph3p)4 (126 mg, 0.109 mmol), DMF (5457 μL), and water (2.5 mL). The vial was sealed, placed in 80° C. and heated overnight. The mixture was diluted with water (35 mL) and extracted with EtOAc (3×15 mL). The combined organic extract was dried over sodium sulfate, filtered, and evaporated. The residue was purified by chromatography on a 80-g Redi-Sep column, eluting with 0-100% of a 90:10:1 mix of DCM/MeOH/NH 4 OH in DCM to give (S)-2′-amino-3-(3,6-dihydro-2H-pyran-4-yl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-7-ol as an orange solid.

Step 2: A 25-mL flask was charged with (S)-2′-amino-3-(3,6-dihydro-2H-pyran-4-yl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-7-ol (211 mg, 0.601 mmol) and MeOH (75070 μL). The mixture was sonicated for 1 min to give an opaque mixture. Palladium on carbon (63.9 mg, 0.060 mmol) was added, and H 2 (g) was bubbled through the mixture for 1 min. The mixture was stirred further under a balloon of H 2 (g) for 60 hours. The mixture was filtered through celite with the aid of methanol. The filtrate was evaporated, and the residue was chromatographed on a 40-g Redi-Sep column with 0-100% of a 90:10:1 mix of DCM/MeOH/NH 4 OH to give (S)-2′-amino-3-(tetrahydro-2H-pyran-4-yl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-7-ol as an off-white solid.

Step 3: A 25-mL RBF was charged with [Reactants] and triethylamine (194 μL, 1.392 mmol) in DCM (2.5 mL) to give an opaque mixture. n-phenyltrifluoromethanesulfonimide (261 mg, 0.731 mmol) was added, and the mixture was stirred for 2 hours before an additional portion of triflimide (50 mg) was added. After an additional 2 hours the mixture was diluted with DCM (20 mL) and saturated aq. sodium bicarbonate solution (20 mL). The layers were separated, and the aq. layer was extracted with DCM (2×10 mL). The combined organic extracts were dried over sodium sulfate, filtered, and evaporated. The residue was chromatographed on a 40-g Redi-Sep column with 0-70% MeOH/DCM to give (S)-2′-amino-3-(tetrahydro-2H-pyran-4-yl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazole]-7-yl trifluoromethanesulfonate as a white solid.

Step 4: A vial was charged with (S)-2′-amino-3-(tetrahydro-2H-pyran-4-yl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazole]-7-yl trifluoromethanesulfonate (70.0 mg, 0.144 mmol), 5-chloro-2-fluorophenylboronic acid (75 mg, 0.433 mmol), potassium carbonate (100 mg, 0.721 mmol), and Pd(PPh 3 ) 4 (8.33 mg, 7.21 μmol). The vial was flushed with Ar (g), then Dioxane (721 μL) and water (0.3 mL) were added in sequence. The vial was sealed and placed in an 80° C. for 1.5 hours. The mixture was diluted with brine (20 mL) and extracted with EtOAc (2×15 mL). The combined organic extracts were dried over sodium sulfate, filtered, and evaporated. The residue was chromatographed on a 24-g Redi-Sep Gold column with 0-60% of a 90:10:1 mix of DCM/MeOH/NH 4 OH in DCM to give (S)-7-(5-chloro-2-fluorophenyl)-3-(tetrahydro-2H-pyran-4-yl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine

Method AA20

Synthesis of (S)-2′-(2,2-dimethylmorpholino)-4′-fluoro-7′-(pyridin-3-yl)-5H-spiro[oxazole-4,9′-xanthen]-2-amine 2,2,2-trifluoroacetate

Step 1: A 25 ml RB flask was charged with (S)-2-amino-7′-bromo-4′-fluoro-5H-spiro[oxazole-4,9′-xanthen]-2′-ol (629 mg, 1.723 mmol), tetrakis(triphenylphosphine)palladium(0) (199 mg, 0.172 mmol), and pyrimidin-5-ylboronic acid (320 mg, 2.58 mmol). DMF (8613 μL) and sodium carbonate (2 M solution) (2584 μL, 5.17 mmol) were added and the mixture was stirred at 85° C. for 2.5 hrs The mixture was cooled to room temperature, water (˜5 ml) was added and stirring was continued for 10 min. The precipitate was filtered out, washed with water (3×5 mL), 1:1 i-PrOH/water to remove color and dried in vacuo to afford (S)-2-amino-4′-fluoro-7′-(pyrimidin-5-yl)-5H-spiro[oxazole-4,9′-xanthen]-2′-ol as yellow solid.

Step 2: To a solution of (S)-2-amino-4′-fluoro-7′-(pyrimidin-5-yl)-5H-spiro[oxazole-4,9′-xanthen]-2′-ol (374 mg, 1.027 mmol) in DCM (51330 μL), triethylamine (286 μL, 2.053 mmol) and 1,1,1-trifluoro-N-phenyl-N-(trifluoromethylsulfonyl)methanesulfonamide (550 mg, 1.540 mmol) were added and the mixture was stirred overnight at room temperature. Additional N-phenyltriflimide (100 mg) and TEA (0.1 ml) were and the stirring continued for 4 hrs. The mixture was directly loaded onto 12 g RediSep column and purified using 15-60% DCM/MeOH/NH4OH to afford (S)-2-amino-5′-fluoro-2′-(pyrimidin-5-yl)-5H-spiro[oxazole-4,9′-xanthene]-7′-yl trifluoromethanesulfonate.

Step: A 0.5-2 ml microwave vial was charged with Pd 2 dba 3 (7.39 mg, 8.07 μmol), biphenyl-2-yldi-tert-butylphosphine (5.78 mg, 0.019 mmol) and. The solids were capped with argon and 2,2-dimethylmorpholine (55.8 mg, 0.484 mmol) and LiHMDS (1 M in THF) (0.646 mL, 0.646 mmol) were added and the vial sealed and heated at 110° C. in microwave reactor for 1 hr. The mixture was quenched with 1 ml of water, diluted with EtOAc and saturated NH 4 Cl. The organic layer was filtered through Celite and concentrated. The residue was purified by Prep HPLC (Gilson, 15-90% MeCN in 0.1% aq. TFA) to afford (S)-2′-(2,2-dimethylmorpholino)-4′-fluoro-7′-(pyridin-3-yl)-5H-spiro[oxazole-4,9′-xanthen]-2-amine 2,2,2-trifluoroacetate.

Method AA21

Synthesis of (S)-5-(2′-amino-3-(3,3-dimethylbut-1-ynyl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazole]-7-yl)nicotinonitrile

Step 1: A vial charged with (S)-2′-amino-3-bromo-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-7-ol (0.250 g, 0.718 mmol), Pd(PPh 3 ) 4 (0.083 g, 0.072 mmol), and copper(i) iodide (0.014 g, 0.072 mmol), was treated with 1 mL THF followed by diisopropylamine (1.535 mL, 10.77 mmol). The solution was degassed with argon and 3,3-dimethylbut-1-yne (0.295 g, 3.59 mmol) was added and the vial heated to 80° C. overnight. The reaction mixture was purified directly by column chromatography yielding (S)-2′-amino-3-(3,3-dimethylbut-1-ynyl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-7-ol.

Step 2: A vial charged with (S)-2′-amino-3-(3,3-dimethylbut-1-ynyl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-7-ol (0.200 g, 0.572 mmol) and potassium carbonate (0.087 g, 0.630 mmol) was treated with 2 mL DMF and was allowed to stir for 15 minutes. The reaction mixture was cooled to 0° C. and n-phenyltriflamide (0.245 g, 0.630 mmol) was added. After stirring for one hour the reaction mixture was poured into water and extracted with EtOAc. The organics were dried over MgSO4 and concentrated. Purification of the crude residue by column chromatography gave (S)-2′-amino-3-(3,3-dimethylbut-1-ynyl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazole]-7-yl trifluoromethanesulfonate (0.183 g, 0.380 mmol, 66.4% yield)

Step 3: A vial charged with 5-cyanopyridin-3-ylboronic acid (0.030 g, 0.206 mmol), palladiumtetrakis (10.80 mg, 9.35 μmol), potassium carbonate (0.129 g, 0.935 mmol), and (S)-2′-amino-3-(3,3-dimethylbut-1-ynyl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazole]-7-yl trifluoromethanesulfonate (0.090 g, 0.187 mmol) was treated with 1 mL of dioxane followed by 0.4 mL water. The vial was flushed with argon and was heated to 80° C. for 4 hours. The reaction mixture was diluted with EtOAc and dried over MgSO 4 . The organics were then concentrated, and the crude residue was purified by column chromatography yielding (S)-5-(2′-amino-3-(3,3-dimethylbut-1-ynyl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazole]-7-yl)nicotinonitrile.

Method AA22

Synthesis of (R)-7′-(3,6-dihydro-2H-pyran-4-yl)-3′-fluoro-2′-(pyrimidin-5-yl)-5H-spiro[oxazole-4,9′-xanthen]-2-amine

Step 1: A mixture of 2-(3,6-dihydro-2H-pyran-4-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (276 mg, 1.315 mmol), (S)-2-amino-7′-bromo-3′-fluoro-5H-spiro[oxazole-4,9′-xanthen]-2′-ol (300 mg, 0.822 mmol), potassium phosphate (523 mg, 2.465 mmol) and Cl 2 Pdbis(di-tert-butyl(phenyl)phosphine) (15.28 mg, 0.025 mmol) in 3 ml of dioxane/water=2:1 was heated at 110° C. microwave for 30 min. The reaction mixture was purified by silica gel chromatography (DCM to DCM/MeOH=100:1 to 100:6) to give (R)-2-amino-7′-(3,6-dihydro-2H-pyran-4-yl)-3′-fluoro-5H-spiro[oxazole-4,9′-xanthen]-2′-ol as a white solid.

Step 2: To a suspension of (R)-2-amino-7′-(3,6-dihydro-2H-pyran-4-yl)-3′-fluoro-5H-spiro[oxazole-4,9′-xanthen]-2′-ol (150 mg, 0.407 mmol) and n-phenyltrifluoromethanesulfonimide (218 mg, 0.611 mmol) in 15 mL of dry DCM was added TEA (142 μL, 1.018 mmol). After stirring at RT overnight the solution was evaporated to dryness and the residue was purified by silica gel chromatography (DCM to DCM/EA=4:1 to 3:1 to 2:1 to 1:1) to give (R)-2-amino-2′-(3,6-dihydro-2H-pyran-4-yl)-6′-fluoro-5H-spiro[oxazole-4,9′-xanthene]-7′-yl trifluoromethanesulfonate as a white solid.

Step 3: A mixture of 5-(tributylstannyl)pyrimidine (73.8 mg, 0.200 mmol), AmPhos (4.24 mg, 5.99 μmol) and (R)-2-amino-2′-(3,6-dihydro-2H-pyran-4-yl)-6′-fluoro-5H-spiro[oxazole-4,9′-xanthene]-7′-yl trifluoromethanesulfonate (50 mg, 0.100 mmol) in 0.3 mL of DMF was heated at 130° C. for 1 hour. After cooling and evaporation of the solvent under high vacuum, the mixture was purified by silica gel chromatography (DCM to DCM/EA=1:1 to 1:2 to pure EA to EA/MeOH=100:5 to 100:10) to provide (R)-7′-(3,6-dihydro-2H-pyran-4-yl)-3′-fluoro-2′-(pyrimidin-5-yl)-5H-spiro[oxazole-4,9′-xanthen]-2-amine as an off-white solid.

Method AA23

Synthesis of (S)-4-(2′-amino-7-phenyl-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazole]-3-yl)-2-methylbut-3-yn-2-ol

Step 1: A 25-mL flask was charged with (S)-2′-amino-3-bromo-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-7-ol (1.012 g, 2.91 mmol), copper(i) iodide (0.055 g, 0.291 mmol), and tetrakis(triphenylphosphine)palladium (0.034 g, 0.029 mmol). The vial was flushed with Ar(g), then a septum was attached. DMF (5.81 mL), diisopropylamine (6.11 mL, 43.6 mmol), and 2-methylbut-3-yn-2-ol (1.137 mL, 11.63 mmol) were added in sequence to give a clear, brown solution. A reflux condenser was attached, and the flask was placed in a 75° C. oil bath for 4 hours. The mixture was diluted with water (35 mL) and extracted with DCM (4×20 mL). The combined organic extracts were dried over sodium sulfate, filtered, and evaporated. The residue, which contained a considerable amount of DMF, was loaded onto a 10-g SCX-2 column with the aid of methanol. The column was eluted with methanol to remove impurities, then with 2M ammonia in methanol to elute the product. The filtrate was evaporated, and the residue was chromatographed on an 80-g Redi-Sep column, eluting with 0-10% MeOH/DCM to give (S)-2′-amino-3-(3-hydroxy-3-methylbut-1-ynyl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-7-ol.

Step 2: A 10-mL pear flask was charged with (S)-2′-amino-3-(3-hydroxy-3-methylbut-1-ynyl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-7-ol (111 mg, 0.316 mmol), cesium carbonate (113 mg, 0.348 mmol), and DMF (1580 μL). The resulting mixture was stirred for 5 min, then placed in an ice-bath for 5 min. 1,1,1-trifluoro-N-phenyl-N-(trifluoromethylsulfonyl)methanesulfonamide (124 mg, 0.348 mmol) was added, the ice-bath was removed and stirring was continued for 1 hour. The mixture was partitioned between water (15 mL) and EtOAc (15 mL), with a small amount of brine to break up an emulsion. The layers were separated, and the aqueous layer was extracted with EtOAc (15 mL). The combined organic extracts were dried over sodium sulfate, filtered, and evaporated. The residue was chromatographed on a 12-g Redi-Sep column eluting with 0-6% MeOH/DCM to give (S)-2′-amino-3-(3-hydroxy-3-methylbut-1-ynyl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazole]-7-yl trifluoromethanesulfonate as a feathery-white solid.

Step: A 0.5-2 mL vial was charged with (S)-2′-amino-3-(3-hydroxy-3-methylbut-1-ynyl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazole]-7-yl trifluoromethanesulfonate (72.4 mg, 0.150 mmol), phenylboronic acid (54.8 mg, 0.449 mmol), potassium carbonate (103 mg, 0.748 mmol), and tetrakis(triphenylphosphine)palladium (8.64 mg, 7.48 μmol). The vial was purged with Ar(g), then Dioxane (748 μL) and water (0.37 mL) were added in sequence. The vial was sealed and placed in a 90° C. oil bath for 1 hour. The mixture was diluted with water (15 mL), and extracted with EtOAc (3×10 mL). The combined organic extracts were dried over sodium sulfate, filtered, and evaporated. The residue was chromatographed on a 40-g Redi-Sep column eluting with 0-6% MeOH/DCM to give (S)-4-(2′-amino-7-phenyl-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazole]-3-yl)-2-methylbut-3-yn-2-ol as a slightly tan solid

Method AA24

A 150-mL pressure vessel was charged with 2′-bromo-7′-hydroxyspiro[1,3-oxazole-4,9′-xanthen]-2-amine (845 mg, 2434 μmol) in THF (24 mL), pyrimidin-5-ylboronic acid (754 mg, 6085 μmol), tetrakis(triphenylphosphine)palladium(0) (281 mg, 243 μmol), and potassium carbonate (10.1 mL of a 1.2 M aqueous solution, 12.1 mmol). The vessel was sealed and placed in a 100° C. oil bath at for 4 h. The reaction mixture was cooled to RT and partitioned between EtOAc (50 mL) and water (50 mL). The aqueous layer was extracted with EtOAc (50 mL), and the combined organic extracts were dried over sodium sulfate, filtered, and evaporated. The crude material was purified by chromatography on silica gel (eluting with 30-100% of a 90:10:1 DCM/MeOH/NH 4 OH solution in DCM) to give 2′-hydroxy-7′-(5-pyrimidinyl)spiro[1,3-oxazole-4,9′-xanthen]-2-amine as an off-white solid.

Method AA25

Synthesis of (S)-7-(3-methoxy-3-methylbut-1-ynyl)-3-p-tolyl-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine

Step 1: A vial was charged (S)-2′-amino-3-bromo-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-7-ol (282 mg, 0.809 mmol), p-tolylboronic acid (220 mg, 1.618 mmol), potassium carbonate (559 mg, 4.04 mmol), tetrakis(triphenylphosphine)palladium (46.7 mg, 0.040 mmol). The vial was flushed with Ar (g), then Dioxane (4044 μL) and water (2 mL) were added in sequence. The vial was sealed and placed in an 80° C. oil bath for 1 hour. The mixture was partitioned between brine and 10% iPrOH/EtOAc. The layers were separated, and the aq. layer was extracted with EtOAc. The combined organic extracts were dried over sodium sulfate, filtered, and evaporated. The residue was chomatographed on an 80-g Redi-Sep column, eluting with 0-80% of a 90:10:1 mix of DCM/MeOH/NH 4 OH in DCM to give (S)-2′-amino-3-p-tolyl-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-7-ol as an orange solid.

Step 2: A 25-mL flask was charged with (S)-2′-amino-3-p-tolyl-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-7-ol (259.36 mg, 0.722 mmol) in DCM (7217 μL) to give an clear, orange solution. triethylamine (201 μL, 1.443 mmol) and 1,1,1-trifluoro-N-phenyl-N-(trifluoromethylsulfonyl)methanesulfonamide (271 mg, 0.758 mmol) were added in sequence and stirred for 4 hours. The reaction mixture was loaded directly onto a 25-g silica gel loading column with the aid of DCM. The column was eluted onto a prequilibrated 40-g Redi-Sep column with 0-5% MeOH/DCM to give (S)-2′-amino-3-p-tolyl-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazole]-7-yl trifluoromethanesulfonate as a cream-colored solid.

Step 3: A vial was charged with (S)-2′-amino-3-p-tolyl-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazole]-7-yl trifluoromethanesulfonate (209 mg, 0.426 mmol), copper(i) iodide (8.11 mg, 0.043 mmol), and tetrakis(triphenylphosphine)palladium (49.2 mg, 0.043 mmol). The vial was flushed with Ar (g), then DMF (1704 μL, 0.426 mmol), diisopropylamine (1194 μL, 8.52 mmol), and 2-methylbut-3-yn-2-ol (208 μL, 2.130 mmol) were added in sequence. The vial was sealed and placed in a 70° C. oil bath for 2 hours. The mixture was diluted with EtOAc (15 mL), washed with water (10 mL), washed with brine (15 mL), dried over sodium sulfate, filtered, and evaporated. The residue was taken up in DCM/MeOH (not completely soluble) and chromatographed on a 40-g Redi-Sep column, eluting with 0-8% MeOH/DCM (product came out in a streak) to give (S)-4-(2′-amino-3-p-tolyl-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazole]-7-yl)-2-methylbut-3-yn-2-ol as a light yellow solid

Step 4: A vial was charged with (S)-4-(2′-amino-3-p-tolyl-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazole]-7-yl)-2-methylbut-3-yn-2-ol (134.5 mg, 0.316 mmol), MeOH (3161 μL), and methanesulfonic acid (103 μL, 1.581 mmol). The vial was sealed and placed in a 70° C. oil bath for 4 hours. The mixture was poured into saturated aq. sodium bicarbonate solution (30 mL) and extracted with EtOAc (2×25 mL). The combined organic extracts were dried over sodium sulfate, filtered, and evaporated. The residue was chromatographed on a 40-g Redi-Sep column to give a impure material that was dissolved in methanol and purified by reverse-phase HPLC (10-90% CH 3 CN/H 2 O with 0.1% TFA). The fractions containing product were combined in saturated aq. sodium bicarbonate solution with the aid of methanol, and the mixture was extracted with DCM (3×). The combined organic extracts were dried over sodium sulfate, filtered, and evaporated to give (S)-7-(3-methoxy-3-methylbut-1-ynyl)-3-p-tolyl-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine.

Method AA26

Synthesis of (S)-3-(3-methoxy-3-methylbut-1-ynyl)-7-(pyridin-3-yl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine

Step 1: Combined (S)-2′-amino-3-bromo-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-7-ol (1.260 g, 3.62 mmol), tetrakis(triphenylphosphine)palladium (0.418 g, 0.362 mmol), copper(i) iodide (0.069 g, 0.362 mmol) and THF (14.48 mL, 3.62 mmol) and DMF (14.48 mL, 3.62 mmol) in a sealable reaction tube. Added diisopropylamine (10.14 mL, 72.4 mmol) then 2-methylbut-3-yn-2-ol (1.768 mL, 18.10 mmol) and flushed the reaction tube with argon. Sealed and heated at 110° C. for 3 hours. The mixture was diluted with water (150 mL) and 10% iPrOH/EtOAc (50 mL). The layers were separated, and the aqueous layer was extracted with 10% iPrOH/EtOAc (2×50 mL). The organic layers were combined, washed with water (60 mL), washed with brine (60 mL), dried over sodium sulfate, filtered, and evaporated. The residue was purified by chromatography on a 100-g SNAP column, eluting with 0-100% of a 90:10:1 mixture of DCM/MeOH/NH 4 OH in DCM to (S)-2′-amino-3-(3-hydroxy-3-methylbut-1-ynyl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-7-ol as a brown solid.

Step 2: A vessel was charged with (S)-2′-amino-3-(3-hydroxy-3-methylbut-1-ynyl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-7-ol (0.512 g, 1.457 mmol) in methanol (17.73 mL, 437 mmol). Methane sulfonic acid (0.945 mL, 14.57 mmol) was added, and the vial was sealed and placed in a 55° C. oil bath overnight. Potassium carbonate was added to quench the acid, and the mixture was filtered with the aid of DCM. The filtrate was evaporated, and the residue was soluble in MeOH/DCM, but some potassium carbonate still came through. The residue was purified by chromatography on a 50-g SNAP column, eluting with 0-100% of a 90:10:1 mixture of DCM/MeOH/NH 4 OH in DCM. The material thus obtained was rechromatographed to under the same conditions to give (S)-2′-amino-3-(3-methoxy-3-methylbut-1-ynyl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-7-ol as a pale-yellow solid.

Step 3: A 15-mL RBF was charged with cesium carbonate (358 mg, 1.099 mmol) and (S)-2′-amino-3-(3-methoxy-3-methylbut-1-ynyl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-7-ol (365.01 mg, 0.999 mmol) in DMF (4995 μL). The resulting mixture was stirred for 10 min, then the flask was submerged in an ice-bath for 5 min. n-phenyltrifluoromethanesulfonimide (393 mg, 1.099 mmol) was added as a single portion. The mixture was stirred for 2 min, then the ice-bath was removed and stirring was continued for 1 hour. The mixture was diluted with water (and a small amount of brine to clear an emulsion) and extracted with EtOAc (3×). The combined organic extracts were dried over sodium sulfate, filtered, and evaporated. The residue was purified by chromatography on a 50-g SNAP column, eluting with 0-60% of a 90:10 mixture of DCM/MeOH in DCM. The obtained residue was taken up in water (total 20 mL) and extracted with EtOAc (2×15 mL). The combined organic extracts were dried over sodium sulfate, filtered, and evaporated to give (S)-2′-amino-3-(3-methoxy-3-methylbut-1-ynyl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazole]-7-yl trifluoromethanesulfonate.

Step 4: A vial was charged with (S)-2′-amino-3-(3-methoxy-3-methylbut-1-ynyl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazole]-7-yl trifluoromethanesulfonate (104 mg, 0.210 mmol), pyridin-3-ylboronic acid (77 mg, 0.629 mmol), and tetrakis(triphenylphosphine)palladium (24.22 mg, 0.021 mmol). The vial was purged with Ar (g), then DMF (1048 μL) and potassium carbonate (524 μL, 1.048 mmol) (as a 2.0 M aq. solution) were added in sequence. The vial was capped and heated in a Biotage Initiator microwave reactor for 1.5 h at 70° C. The mixture was diluted with water (10 mL) and extracted with EtOAc (2×10 mL). The combined organic extracts were dried over sodium sulfate, filtered, and evaporated. The residue was purified by chromatography on a 25-g SNAP column, eluting with 0-60% of a 90:10:1 mixture of DCM/MeOH/NH 4 OH in DCM to give (S)-3-(3-methoxy-3-methylbut-1-ynyl)-7-(pyridin-3-yl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine.

Method AA27

Synthesis of (S)-3-(3,3-dimethylbut-1-ynyl)-7-(pyrazin-2-yl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine

Step 1: A vial was charged with (S)-2′-amino-3-bromo-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-7-ol (0.647 g, 1.858 mmol), DavePhos (0.088 g, 0.223 mmol), and tris(dibenzylideneacetone)dipalladium(0) (0.085 g, 0.093 mmol). The vessel was flushed with Ar(g), then lithium bis(trimethylsilyl)amide (1.0 M in THF) (9.29 mL, 9.29 mmol) and morpholine (0.486 mL, 5.58 mmol) were added in sequence. The vial was sealed and heated at 70° C. for one hour at which point the mixture was diluted with water and saturated NH 4 Cl. The mixture was extracted with DCM (3×30 mL). The aq. layer was extracted with ethyl acetate and 10% iPrOH/EtOAc, and the solid was taken with the organic layer. The different organic layers were combined, dried over sodium sulfate, filtered, and evaporated. The material was purified via column chromatography (RediSep 40 g, gradient elution 0-10% MeOH:DCM w/1% NH4OH) to afford (S)-2′-amino-3-morpholino-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-7-ol as an orange solid.

Step 2: A 25-mL RBF was charged with cesium carbonate (0.371 g, 1.138 mmol) and (S)-2′-amino-3-morpholino-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-7-ol (0.336 g, 0.948 mmol) in DMF (4.74 mL). The resulting mixture was stirred for 10 min, then the flask was submerged in an ice-bath for 5 min. n-phenyltrifluoromethanesulfonimide (0.373 g, 1.043 mmol) was added as a single portion and the reaction was allowed to warm to RT overnight. The reaction was cooled in an ice bath and 150 mg of cesium carbonate was added. The reaction was stirred for 10 minutes, then 40 mg of n-phenyltrifluoromethanesulfonimide was added and the reaction was stirred for one hour. The mixture was diluted with water and extracted twice with EtOAc (a little brine was added to help with emulsion). The combined organic extracts were dried over sodium sulfate, filtered, and evaporated. The material was purified via column chromatography (RediSep 40 g, gradient elution 0-7% MeOH:DCM w/1% NH4OH) to afford (S)-2′-amino-3-morpholino-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazole]-7-yl trifluoromethanesulfonate as an off-white solid.

Step 3: A vial was charged with (S)-2′-amino-3-morpholino-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazole]-7-yl trifluoromethanesulfonate (0.120 g, 0.247 mmol), tetrakis(triphenylphosphine)palladium (2.85 mg, 2.467 μmol), and copper(i) iodide (4.70 mg, 0.025 mmol). The vial was flushed with Ar (g), then DMF (0.987 mL), diisopropylamine (0.692 mL, 4.93 mmol), and ethynylcyclopropane (0.104 mL, 1.233 mmol) were added in sequence to give a yellow solution. The vial was sealed and heated to 70° C. for two hours at which point 8 mg of tetrakis(triphenylphosphine)palladium and 0.1 mL of cyclopropylacetylene were added and the reaction was heated to 100° C. and stirred for two hours. The vial was purged with Ar (g), then DMF (1.039 mL) and 2-(tributylstannyl)pyrazine (0.197 mL, 0.623 mmol) were added in sequence. The vial was sealed and heated to 110° C. for one hour. The mixture was loaded onto a 2-g SCX-2 column and eluted 4× with methanol to remove impurities. The product was then eluted with 2M ammonia in methanol. The filtrate was evaporated, and the residue was purified via column chromatography (RediSep 40 g, gradient elution 0-5% MeOH:DCM) to afford (S)-3-(3,3-dimethylbut-1-ynyl)-7-(pyrazin-2-yl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine as a white solid.

Method AA30

A 0.5-2 mL microwave vial charged with (R)-2′-bromo-7′-(neopentyloxy)-5H-spiro[oxazole-4,9′-xanthen]-2-amine (0.1000 g, 0.240 mmol), Mo(CO) 6 (0.063 g, 0.240 mmol), acetoxy(2-(dio-tolylphosphino)benzyl)palladium (0.011 g, 0.012 mmol), sodium carbonate (0.025 g, 0.240 mmol), cyclopropylamine (0.025 mL, 0.359 mmol), and 1,4-dioxane (0.443 mL, 5.03 mmol) was sealed and heated to 170° C. for 30 minutes. The mixture was diluted with EtOAc and water and filtered through celite. The celite was washed with EtOAc and MeOH. The aqueous phase was extracted with EtOAc three times. The organic layer was dried over Na 2 SO 4 and concentrated in vacuo. The crude was purified by silica gel chromatography (2-10% MeOH—CH 2 Cl 2 , then 10% MeOH—CH 2 Cl 2 ). The product was purified again by reverse phase prep HPLC: 10-55% CH3CN (0.1% TFA)-water (0.1% TFA) in 26 min. The fractions were combined and neutralized with solid Na 2 CO 3 , extracted three times with DCM. The organic layer was concentrated to provide (S)-2-amino-N-cyclopropyl-7′-(neopentyloxy)-5H-spiro[oxazole-4,9′-xanthene]-2′-carboxamide.

Method AA31

To the solution of (S)-3-chloro-7-(pyridin-3-yl)-5′H-spiro[chromeno[2,3-c]pyridine-5,4′-oxazol]-2′-amine (23 mg, 0.063 mmol) in MeOH (2 mL) was added 10% Pd on Carbon (10 mg, 0.073 mmol). The mixture was hydrogenated under 1 atm of H 2 for 24 h. After filtration and concentration, the crude material was absorbed onto a plug of silica gel and purified by chromatography through a Redi-Sep pre-packed silica gel column (12 g), eluting with isocratic % to 20% MeOH in CH2CL2, to provide (S)-7-(pyridin-3-yl)-5′H-spiro[chromeno[2,3-c]pyridine-5,4′-oxazol]-2′-amine as white solid.

Method AA32

Synthesis of (R)-3-(3-methoxy-3-methylbut-1-ynyl)-7-(pyridazin-4-yl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine

Step 1: Combined (R)-2′-amino-3-bromo-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-7-ol (2.259 g, 6.49 mmol), tetrakis(triphenylphosphine)palladium (0.750 g, 0.649 mmol), copper(i) iodide (0.124 g, 0.649 mmol) and THF (26.0 mL, 6.49 mmol) and DMF (26.0 mL, 6.49 mmol) in a reaction tube. Added diisopropylamine (18.19 mL, 130 mmol) then 2-methylbut-3-yn-2-ol (3.17 mL, 32.4 mmol) and flushed the reaction tube with argon. Sealed and heated at 85° C. for 3 hours. The mixture was diluted with water (100 mL) and extracted with DCM (1×100 mL, 2×50 mL). The combined organic extracts were dried over sodium sulfate, filtered, and evaporated. The resuling liquid was poured onto a 25-g SCX-2 column and eluted with methanol. The product was then eluted with 2M ammonia in methanol. The filtrate was evaporated and purified by chromatography on a 120-g Redi-Sep column, eluting with 0-100% of a 90:10:1 mixture of DCM/MeOH/NH 4 OH in DCM to give (R)-2′-amino-3-(3-hydroxy-3-methylbut-1-ynyl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-7-ol as a tan solid.

Step 2: A vessel was charged with (S)-2′-amino-3-(3-hydroxy-3-methylbut-1-ynyl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-7-ol (0.679 g, 1.933 mmol) in methanol (23.51 mL, 580 mmol). methane sulfonic acid (0.627 mL, 9.66 mmol) was added, and the vial was sealed and placed in a 70° C. oil bath for 5 hours. The volatiles were evaporated, and the residue was loaded onto a silica gel cartridge in MeOH/DCM. The column was eluted onto an 80-g Redi-Sep column with 30-100% of a 90:10:1 mixture of DCM/MeOH/NH 4 OH in DCM. The fractions containing product were evaporated to give (S)-2′-amino-3-(3-methoxy-3-methylbut-1-ynyl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-7-ol as an off-white solid.

Step 3: A 25-mL flask was charged with (R)-2′-amino-3-(3-methoxy-3-methylbut-1-ynyl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-7-ol (577.53 mg, 1.581 mmol), cesium carbonate (566 mg, 1.739 mmol), and DMF (7903 μL). The resulting mixture was stirred for 10 min, then the vial was submerged in an ice-bath for 10 min. nonafluorobutanesulfonyl fluoride (306 μL, 1.739 mmol) was added dropwise over 2 minutes. The mixture was stirred for 2 hours, then quenched with saturated aqueous ammonium chloride (10 mL), and partitioned between water (15 mL) and EtOAc (15 mL). The layers were separated, and the aqueous layer was extracted with EtOAc (15 mL). The combined organic layers were washed with brine, dried over sodium sulfate, filtered, and evaporated. The residue was purified by chromatography on an 80-g Redi-Sep column, eluting with 0-50% of a 90:10 mixture of DCM/MeOH in DCM to give (R)-2′-amino-3-(3-methoxy-3-methylbut-1-ynyl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazole]-7-yl 1,1,2,2,3,3,4,4,4-nonafluorobutane-1-sulfonate as a white solid.

Step 4: A vial was charged with (R)-2′-amino-3-(3-methoxy-3-methylbut-1-ynyl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazole]-7-yl-1,1,2,2,3,3,4,4,4-nonafluorobutane-1-sulfonate (102 mg, 0.158 mmol), copper(i) iodide (3.01 mg, 0.016 mmol), tetrakis(triphenylphosphine)palladium (18.24 mg, 0.016 mmol), and lithium chloride (10.96 mg, 1.579 mmol). The vial was purged with Ar (g), then DMF (790 μL) and 4-(tributylstannyl)pyridazine (146 μL, 0.474 mmol) were added in sequence. The vial was sealed and placed in a 110° C. oil bath for 4 hours. The mixture loaded onto a 2-g SCX-2 column and eluted 4× with methanol to remove impurities. The product was then eluted with 2M ammonia in methanol. The filtrate was evaporated, and the residue was chromatographed on a 40-g Redi-Sep column, eluting with 0-100% EtOAc/Hexane, then with 0-10% MeOH/DCM. Ther resulting material was still impure, so the material was dissolved in methanol and purified by reverse-phase HPLC (15-80% CH 3 CN/H 2 O with 0.1% TFA). The fractions containing product were combined in saturated aq. sodium bicarbonate solution with the aid of methanol and extracted with DCM (3×). The combined organic extracts were dried over sodium sulfate, filtered, and evaporated to give (R)-3-(3-methoxy-3-methylbut-1-ynyl)-7-(pyridazin-4-yl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine as a white solid.

Method AA33

Step 1: To a solution of (S)-2′-bromo-7′-iodo-5H-spiro[oxazole-4,9′-xanthen]-2-amine (0.250 g, 0.547 mmol) in THF (4.5 mL) was added dichlorobis(triphenylphosphine)palladium (ii) (0.077 g, 0.109 mmol), 1-ethynylcyclobutanol (0.079 g, 0.820 mmol), copper(i) iodide (3.71 μL, 0.109 mmol), and diisopropyl amine (0.613 mL, 4.38 mmol). The resulting mixture was then stirred at RT for 2 h. EtOAc (7 mL) was added and the mixture was filtered. The solid was washed with EtOAc (1×5 mL). The combined filtrates were concentrated. The residue was mixed with silica gel and the solid mixture was purifed by silica gel column chromatography (solid loading, 0%-20% MeOH/DCM) to give the alkynylated product as a brown solid.

Step 2: To a solution of (R)-1-((2-amino-2′-bromo-5H-spiro[oxazole-4,9′-xanthene]-7′-yl)ethynyl)cyclobutanol (0.290 g, 0.682 mmol) in DME (5.5 mL) was added 3-pyridylboronic acid (0.084 g, 0.682 mmol), tetrakis(triphenylphosphine)palladium(0) (0.063 g, 0.055 mmol), sodium carbonate monohydrate crystals (0.217 g, 2.046 mmol), and H 2 O (1.0 mL). The resulting mixture was then heated to 90° C. for 5 h. Then, the mixture was cooled to room temperature and EtOAc (10 mL) was added. The mixture was stirred at room temperature for 2 min. The organic layer was collected, dried over MgSO4, and concentrate. The residue was mixed with silica gel and the solid mixture was purified by silica gel column chromatography (solid loading, 0%-20% MeOH/DCM) to give the depicted product as a brown solid.

Method AA34

Synthesis of (S)-4-(2′-amino-7-(cyclopropylethynyl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazole]-3-yl)-2-methylbut-3-yn-2-ol

Step 1: Combined (R)-2′-amino-3-bromo-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-7-ol (2.259 g, 6.49 mmol), tetrakis(triphenylphosphine)palladium (0.750 g, 0.649 mmol), copper(i) iodide (0.124 g, 0.649 mmol) and THF (26.0 mL, 6.49 mmol) and DMF (26.0 mL, 6.49 mmol). Added diisopropylamine (18.19 mL, 130 mmol) then 2-methylbut-3-yn-2-ol (3.17 mL, 32.4 mmol) and flushed the reaction tube with argon. Sealed and heated at 85° C. for 3 hours. The mixture was diluted with water (100 mL) and extracted with DCM (1×100 mL, 2×50 mL). (DCM was used because this product is partially soluble in water and EtOAc is not as good a solvent for it). The combined organic extracts were dried over sodium sulfate, filtered, and evaporated. The resuling liquid was poured onto a 25-g SCX-2 column and eluted with methanol. The product was then eluted with 2M ammonia in methanol. The filtrate was evaporated and purified by chromatography on a 120-g Redi-Sep column, eluting with 0-100% of a 90:10:1 mixture of DCM/MeOH/NH 4 OH in DCM to give (R)-2′-amino-3-(3-hydroxy-3-methylbut-1-ynyl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-7-ol as a tan solid.

Step 2: A 25-mL flask was charged with (S)-2′-amino-3-(3-hydroxy-3-methylbut-1-ynyl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-7-ol (437.24 mg, 1.244 mmol), cesium carbonate (446 mg, 1.369 mmol), and DMF (6222 μL). The resulting mixture was stirred for 10 min, then the vial was submerged in an ice-bath for 10 min. nonafluorobutanesulfonyl fluoride (241 μL, 1.369 mmol) was added dropwise over 1 min. The mixture was stirred for 3 hours before being diluted with water (20 mL) and a small amount of brine. This mixture was extracted with EtOAc (2×20 mL). The combined organic extracts were washed with brine, dried over sodium sulfate, filtered, and evaporated. The residue was purified by chromatography on an 80-g Redi-Sep column, eluting with 0-60% of a 90:10 mixture of DCM/MeOH in DCM to give (S)-2′-amino-3-(3-hydroxy-3-methylbut-1-ynyl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazole]-7-yl 1,1,2,2,3,3,4,4,4-nonafluorobutane-1-sulfonate as a white solid.

Step 3: A 0.5-2 mL vial was charged with (S)-2′-amino-3-(3-hydroxy-3-methylbut-1-ynyl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazole]-7-yl-1,1,2,2,3,3,4,4,4-nonafluorobutane-1-sulfonate (106 mg, 0.167 mmol), and copper(i) iodide (3.19 mg, 0.017 mmol). The vial was flushed with Ar (g), then DMF (669 μL, 0.167 mmol), diisopropylamine (469 μL, 3.35 mmol), and ethynylcyclopropane (70.8 μL, 0.836 mmol) were added in sequence to give a yellow solution. The vial was sealed and heated overnight in at 80° C. The mixture was diluted with water (15 mL) and extracted with EtOAc (3×10 mL). The combined organic extracts were washed with brine, dried over sodium sulfate, filtered, and evaporated. The residue was purified by chromatography on a 40-g Redi-Sep column, eluting with 0-50% of a 90:10:1 mixture of DCM/MeOH/NH 4 OH in DCM to give (S)-4-(2′-amino-7-(cyclopropylethynyl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazole]-3-yl)-2-methylbut-3-yn-2-ol as a tan solid after evaporation from DCM/hexanes.

Method AA36

Synthesis of (S)-2′-(1H-imidazol-2-yl)-7′-(neopentyloxy)-5H-spiro[oxazole-4,9′-xanthen]-2-amine

Step 1: (R)-2′-Bromo-7′-(neopentyloxy)-5H-spiro[oxazole-4,9′-xanthen]-2-amine (1170 mg, 2.80 mmol), Bis(pinacolate)diboron (1780 mg, 7.01 mmol), Potassium acetate (550 mg, 5.61 mmol) and PdCl 2 dppf with DCM (229 mg, 0.280 mmol) were combined in a 20 ml microwave vial. Dioxane (14 ml) was added, Ar gas was bubbled through, and the vial was sealed and heated to 90° C. After 3 days, the reaction mixture was concentrated and brought up in DMF (˜10 ml). To the dark brown solution was added H 2 O and a precipitate formed. The solution was filtered to give a brown solid. The filtrate was diluted with DCM and washed with sat'd aqueous NaHCO 3 . The precipitate was brought up in DCM (1 ml) and sonicated for 30 s. Addition of hexanes crashed out minimal amounts of the desired product and the precipitate and solution were combined with the organic layer from before and concentrated. The crude mixture was diluted with H 2 O and filtered to give the crude product as a brown solid that was brought up in minimal DCM, sonicated for 20 s, diluted with hexanes, filtered and washed with hexanes to provide (S)-2′-(neopentyloxy)-7′-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-5H-spiro[oxazole-4,9′-xanthen]-2-amine as a brown solid.

Step 2: A solution of (S)-2′-(neopentyloxy)-7′-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-5H-spiro[oxazole-4,9′-xanthen]-2-amine (50 mg, 0.108 mmol) in BuOH (861 μL), 2-bromo-1H-imidazole (0.129 mmol), and KOAc (31.7 mg, 0.323 mmol) in Water (215 μL) was purged with Ar in a sealed tube. AmPhos (1.525 mg, 2.153 μmol) was added and the reaction was heated to 120° C. for 30 min in the microwave. The reaction was cooled to rt, diluted with MeOH (3 ml), loaded onto an AccuBOND II SCX cartridge, washed with MeOH (3 ml) and eluted with 2N NH3 in MeOH (6 ml) to give the crude product which was purified by reverse-phase preparative HPLC using a Gemini NX c!8 column (150*30 mm, 5 um), 0.1% TFA in CH3CN/H2O, gradient 0% to 70% over 10 min to provide (S)-2′-(1H-imidazol-2-yl)-7′-(neopentyloxy)-5H-spiro[oxazole-4,9′-xanthen]-2-amine.

Method AA37

Step 1: To a solution of 5-bromo-2-chloroisonicotinic acid (14.0 g, 59.2 mmol) in toluene (200 mL) was added 4-methoxyphenol (6.16 mL, 77 mmol), and cesium carbonate (38.6 g, 118 mmol). The resulting mixture was stirred at RT and was flushed with N 2 . Then, copper (trifluoromethane) (0.919 g, 1.776 mmol) and EtOAc (0.6 mL) were added. The mixture was then heated to 115° C. for 17 h. Then, the mixture was cooled to RT and was concentrated to 1/10th of the original volume. The residue was then dissolved in EtOAc (400 mL) and water (400 mL). The organic layer was separated and the aqueous layer was collected. The aqueous layer was carefully adjusted to pH=4.0 using concentrated HCl at 0° C. Then, EtOAc (400 mL) was added and the mixture was stirred at RT for 15 min. A brown precipitation (not product) was observed. The mixture was filtered and the filtrate was collected and concentrated. Then, MeOH (200 mL) was added to the residue and a light brown precipitation was observed. The mixture was filtered and the solid was collected. Then, the solid was dissolved in DCM (1000 mL).

The mixture was filtered and the filtrate was concentrated to give the product as light yellow solid. MS (ESI, positive ion) m/z: 280, 282 (M+1).

Step 2: To a RBF was added 2-chloro-5-(4-methoxyphenoxy)isonicotinic acid (1.1 g, 3.93 mmol) and polyphosphoric acid (56 g). The resulting mixture was then heated to 150° C. for 1 h. Then, the mixture was carefully poured to a beaker containing ice and water. Then, the mixture was adjusted to pH=7 using NaHCO 3 (s). Then, the mixture was extracted with EtOAc (2×200 mL). The combined organic extracts were dried over MgSO 4 , concentrated, and dried in vacuo to give the product as a yellow solid. MS (ESI, positive ion) m/z: 262, 264 (M+1).

Step 3: To a solution of 3-chloro-7-methoxy-5H-chromeno[2,3-c]pyridin-5-one (0.410 g, 1.567 mmol) in 1,4-Dioxane (7.0 mL) and Water (2.333 mL) was added 3-pyridylboronic acid (0.289 g, 2.350 mmol), potassium phosphate (0.998 g, 4.70 mmol), and bis(ditert-butyl(4-dimethylaminophenyl)phosphinedichloropalladium II (0.111 g, 0.157 mmol). The resulting mixture was then subjected to a microwave irradiation at 100° C. for 15 min. Then, DCM (10 mL) and H 2 O (5 mL) were added to the mixture. The mixture was then stirred at RT for 5 min. The organic layer was collected and the aqueous layer was extracted with DCM (1×10 mL). The combined organic extracts were dried over MgSO 4 and concentrated. Then, MeOH (5 mL) was added to the residue. A yellow precipitation was observed. The mixture was filtered, and the yellow solid was collected and dried in vacuo to give the product as a light yellow solid. MS (ESI, positive ion) m/z: 305 (M+1).

Step 4: To a solution of 7-methoxy-3-(pyridin-3-yl)-5H-chromeno[2,3-c]pyridin-5-one (363 mg, 1.193 mmol) in DCM (6 mL) was added boron tribromide, 1.0M in DCM (2.98 mL, 2.98 mmol) drop wise. After addition, the mixture was stirred at RT for overnight. Then, the mixture was carefully quenched with MeOH (50 mL). The mixture was then concentrated and DCM (10 mL) was added. A yellow precipitation was observed. The mixture was filtered and the yellow solid was collected. Then, MeOH (200 mL) was added to the yellow solid and the mixture was stirred at RT for 2 h. The mixture was filtered and the yellow solid was collected and dried in vacuo to the product as a yellow solid. MS (ESI, positive ion) m/z: 291 (M+1).

Step 5: To a microwave vial was added 7-hydroxy-3-(pyridin-3-yl)-5H-chromeno[2,3-c]pyridin-5-one (0.312 g, 1.075 mmol), DMF (7.5 mL), cesium carbonate (0.525 g, 1.612 mmol), and neopentyl iodide (0.513 mL, 3.87 mmol). The resulting mixture was then subjected to a microwave irradiation at 130° C. for 15 min. Then, EtOAc (30 mL) and H 2 O (30 mL) were added. The mixture was then stirred at RT for 5 min. A yellow precipitation was observed. The mixture was filtered, and the yellow solid was collected and dried in vacuo to give the product as a yellow solid. MS (ESI, positive ion) m/z: 361 (M+1).

Step 6: To a solution of 7-(neopentyloxy)-3-(pyridin-3-yl)-5H-chromeno[2,3-c]pyridin-5-one (0.230 g, 0.638 mmol) in THF (4 mL) at 0° C. was added methylmagnesium chloride, 3.0M solution in THF (0.425 mL, 1.276 mmol). After addition, the mixture was stirred at RT for 4 h. Then, saturated ammonium chloride (10 mL) and EtOAc (20 mL) were added. The mixture was stirred at RT for 5 min. Then, the organic layer was collected, dried over MgSO 4 , and concentrated to give 240 mg of the product as a light brown solid. MS (ESI, positive ion) m/z: 377 (M+1).

Step 7: A solution of 5-methyl-7-(neopentyloxy)-3-(pyridin-3-yl)-5H-chromeno[2,3-c]pyridin-5-ol (0.240 g, 0.638 mmol) in 1,2-dichloroethane (2.0 mL) was added pyridinium 4-toluenesulfonate (6.41 mg, 0.026 mmol). The resulting mixture was then heated to 65° C. for 6 h. Then, saturated NaHCO 3 (5 mL) was added to the mixture and the mixture was extracted with DCM (2×10 mL). The combined organic extracts were dried over MgSO 4 and concentrated. The residue was then dissolved in a solution of EtOAc/hexane. A light brown precipitation was observed. The mixture was filtered and the light brown solid was washed with hexane (2×5 mL) to give the desired product, which was used in the next step. MS (ESI, positive ion) m/z: 359 (M+1).

Step 8: To a solution of iodine (0.178 g, 0.703 mmol) in THF (4 mL) at −20° C. was added silver cyanate (0.287 g, 1.917 mmol). After addition, the mixture was stirred at −20° C. for 1 h. Then, 5-methylene-7-(neopentyloxy)-3-(pyridin-3-yl)-5H-chromeno[2,3-c]pyridine (0.229 g, 0.639 mmol) was added and the mixture was stirred at 0° C. for 2 h. Then, the mixture was filtered through celite with the aid of THF (7 mL). Then, ammonia (0.958 mL, 1.917 mmol) (2 M in i-PrOH) was added drop wise to the filtrate at 0° C. The resulting mixture was stirred at RT for overnight. Then, saturated Na 2 S 2 O 3 (1.0 mL) was added followed by saturated NaHCO 3 (1.0 mL). The mixture was stirred at RT for 15 min. The organic layer was collected, dried over MgSO 4 , and concentrated. The residue was mixed with silica gel and the solid mixture was purified by silica gel column chromatography using ISCO instrument (solid loading, 0%-20% MeOH/DCM) to give the depicted product as a brown solid, which was then purified by preparative HPLC (0%-100% MeCN 0.1% TFA/H 2 O 0.1% TFA) to give a desired product in a solution of MeCN 0.1% TFA/H 2 O. The solvent, MeCN was removed and saturated NaHCO 3 (4 mL) was added. The mixture was then extracted with EtOAc (2×10 mL). The combined organic extracts were then dried over MgSO 4 , concentrated, and dried in vacuo to give the depicted product as a white solid. MS (ESI, positive ion) m/z: 417 (M+1).

Method AA39

Step 1: To a solution of (S)-2′-bromo-7′-iodo-5H-spiro[oxazole-4,9′-xanthen]-2-amine (1.070 g, 2.341 mmol) in THF (20 mL) was added 1-ethynylcyclobutanol (0.338 g, 3.51 mmol), copper(i) iodide (0.016 mL, 0.468 mmol), dichlorobis(triphenyl-phosphine)palladium (ii) (0.329 g, 0.468 mmol), and DIPA (2.62 mL, 18.73 mmol). The resulting mixture was then stirred at RT overnight. EtOAc (30 mL) was added and the mixture was filtered. The solid was washed with EtOAc (1×5 mL). The combined filtrates were concentrated. The residue was mixed with silica gel and the solid mixture was purifed by silica gel column chromatography (solid loading, 0%-20% MeOH/DCM) to give the product as a light brown solid

Step 2: To a solution of (R)-1-((2-amino-2′-bromo-5H-spiro[oxazole-4,9′-xanthene]-7′-yl)ethynyl)cyclobutanol (883 mg, 2.076 mmol) in DME (7 mL) and H 2 O (2.333 mL) was added tetrakis(triphenylphosphine)palladium(0) (192 mg, 0.166 mmol), 5-pyrimidinylboronic acid (283 mg, 2.284 mmol), and sodium carbonate (0.087 mL, 2.076 mmol). The resulting mixture was then heated to 90° C. for 5 h. The mixture was cooled to RT and EtOAc (20 mL) was added. The mixture was stirred at RT for 5 min. The organic layer was collected, dried over MgSO 4 , and concentrated. The residue was then dissolved in a solution of DMSO (2 mL) and MeOH (2 mL). The solution was then purified by preparative HPLC (0%-100% MeCN 0.1% NH 4 OH/H 2 O 0.1% NH 4 OH) to give the product as a light yellow solid

Step 3: To a solution of (R)-1-((2-amino-2′-(pyrimidin-5-yl)-5H-spiro[oxazole-4,9′-xanthene]-7′-yl)ethynyl)cyclobutanol (0.134 g, 0.316 mmol) in MeOH (2 mL) was added palladium hydroxide (20 mg). The resulting mixture was then stirred at RT under H 2 overnight. The mixture was filtered through celite and washed with MeOH (2×5 mL). The combined filtrates were concentrated and the residue was dissolved in MeOH (2 mL).

The solution was then purified by preparative HPLC (0%-90% MeCN 0.1% NH 4 OH/H 2 O 0.1% NH 4 OH) to give the title compound as a white solid.

Method AA40

Synthesis of (S)-2′-(neopentyloxy)-7′-(pyrrolidin-1-yl)-5H-spiro[oxazole-4,9′-xanthen]-2-amine

A vial was charged with (R)-2′-bromo-7′-(neopentyloxy)-5H-spiro[oxazole-4,9′-xanthen]-2-amine (0.100 g, 0.240 mmol), 2′-(dicyclohexylphosphino)-N,N-dimethylbiphenyl-2-amine (1.132 mg, 2.88 μmol), Pd 2 (dba) 3 (1.097 mg, 1.198 μmol), LiHMDS (1.0 M in THF) (0.959 mL, 0.959 mmol), and pyrrolidine (0.059 mL, 0.719 mmol). The vial was sealed and heated to 100° C. overnight. Additional Pd 2 (dba) 3 (1.097 mg, 1.198 μmol), 2′-(dicyclohexylphosphino)-N,N-dimethylbiphenyl-2-amine (1.132 mg, 2.88 μmol), LiHMDS (1.0 M in THF) (0.480 mL, 0.480 mmol) and pyrrolidine (0.059 mL, 0.719 mmol) were added and the reaction was at 100° C. for 2 hours. The reaction mixture was diluted with a saturated aqueous ammonium chloride solution (10 mL) and extracted three times with DCM. The combined organic extracts were dried over sodium sulfate, filtered, and evaporated. The material was purified via Gilson HPLC (20-90% MeCN:H 2 O). The product fractions were partitioned between DCM and saturated sodium bicarbonate solution. The aqueous layer was extracted with DCM, and the combined organic layers were dried with sodium sulfate, filtered, and concentrated to afford (S)-2′-(neopentyloxy)-7′-(pyrolidin-1-yl)-5H-spiro[oxazole-4,9′-xanthen]-2-amine as a white solid.

Method AA41

Synthesis of (S)-3-(3-methoxy-3-methylbut-1-ynyl)-7-(pyrimidin-5-yl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine

Step 1: A 10-20 mL microwave vial was charged with (S)-3-bromo-7-iodo-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine (503 mg, 1.098 mmol), pyrimidin-5-ylboronic acid (143 mg, 1.153 mmol), tetrakis(triphenylphosphine)palladium (127 mg, 0.110 mmol). The vial was flushed with Ar(g), then THF (5489 μL, 1.098 mmol) and potassium carbonate (1.5 M) (1464 μL, 2.195 mmol) (aq. solution) were added in sequence. The vial was sealed and heated at 110° C. for 2 hours. The mixture was diluted with water and extracted with 10% i-PrOH/EtOAc (3×). The combined organic extracts were dried over sodium sulfate, filtered, and evaporated. The residue was purified by chromatography on a 100-g SNAP column, eluting with 0-100% of a 90:10:1 mixture of DCM/MeOH/NH 4 OH in DCM to provide (S)-3-bromo-7-(pyrimidin-5-yl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine as an off-white solid.

Step 2: Combined (S)-3-bromo-7-(pyrimidin-5-yl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine (99 mg, 0.242 mmol), tetrakis(triphenylphosphine)palladium (28.0 mg, 0.024 mmol), copper(i) iodide (4.61 mg, 0.024 mmol) and THF (969 μL, 0.242 mmol) and DMF (969 μL, 0.242 mmol). Added DIPA (679 μL, 4.85 mmol) then 2-methylbut-3-yn-2-ol (118 μL, 1.211 mmol) and flushed the reaction tube with argon. Sealed and heated at 110° C. for 2 hours. The mixture was diluted with water and extracted with EtOAc (3×). The combined organic extracts were dried over sodium sulfate, filtered, and evaporated. The residue was purified by chromatography on a 25-g SNAP column, eluting with 0-100% of a 90:10:1 mixture of DCM/MeOH/NH 4 OH to give (S)-4-(2′-amino-7-(pyrimidin-5-yl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazole]-3-yl)-2-methylbut-3-yn-2-ol as a white solid after evaporation from DCM/hexane.

Step 3: To a solution of (S)-4-(2′-amino-7-(pyrimidin-5-yl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazole]-3-yl)-2-methylbut-3-yn-2-ol (58 mg, 0.140 mmol) in MeOH (1703 μL, 42.1 mmol) was added methane sulfonic acid (91 μL, 1.403 mmol) in a vial. The vial was sealed and placed in a 70° C. oil bath for 3 hours. The mixture was poured into saturated aqueous sodium bicarbonate solution (20 mL) and extracted with DCM (3×10 mL). The combined organic extracts were dried over sodium sulfate, filtered, and evaporated. The residue was purified by chromatography on a 25-g SNAP column, eluting with 0-70% of a 90:10:1 mixture of DCM/MeOH/NH 4 OH in DCM to give (S)-3-(3-methoxy-3-methylbut-1-ynyl)-7-(pyrimidin-5-yl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine as a white solid after evaporation from DCM/hexane.

Method AA42

Synthesis of 3-(3,3-dimethylbut-1-ynyl)-7-methoxy-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine

3-Bromo-7-methoxy-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine (104186-10-peak 1) (500 mg, 1.381 mmol), tetrakis(triphenylphosphine)palladium (160 mg, 0.138 mmol), copper(i) iodide (52.6 mg, 0.276 mmol) were combined, and to the mixture was added DMF (6903 μL, 1.381 mmol), 3,3-dimethylbut-1-yne (340 mg, 4.14 mmol) and DIPA (4837 μL, 34.5 mmol). The reaction was flushed with argon, sealed and heated at 90° C. for 2 hours. The reaction mixture was diluted with water (100 mL) and poured into a separatory funnel containing EtOAc (100 mL). The layers were separated and the aqueous layer was extracted with EtOAc (3×50 mL). The combined organic layers were washed with water and then brine, dried over sodium sulfate, filtered and concentrated in vacuo to provide a brown oil that was purified by silica gel chromatography (Redi-Sep pre-packed silica gel column (40 g), 0-10% methanol in methylenechloride with 0.1% ammonium hydroxide) to provide the desired product contaminated with triphenylphosphine. The yellow solid was suspended in 25 mL of ether, resulting in the formation of a fine white precipitate. Decanted ether and washed the solid with 10 mL of ether. Dried under reduced pressure to provide 3-(3,3-dimethylbut-1-ynyl)-7-methoxy-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine as a white solid.

Method AA43

Synthesis of (S)-2′-(cyclopropylethynyl)-7′-(2-methoxy-2-methylpropoxy)-5H-spiro[oxazole-4,9′-xanthen]-2-amine

Step 1: A vial was charged with (R)-2-amino-2′-bromo-5H-spiro[oxazole-4,9′-xanthen]-7′-ol (1.00 g, 2.88 mmol), cyclopropyl acetylene (0.732 mL, 8.64 mmol), copper(i) iodide (0.110 g, 0.576 mmol), and DIPA (14.40 mL). Tetrakis(triphenylphosphine)palladium(0) (0.333 g, 0.288 mmol) was added, the vial was flushed with argon, and the reaction was heated to 50° C. and stirred overnight. The reaction was diluted with ethyl acetate and filtered through Celite. The solution was concentrated and purified via column chromatography (RediSep 40 g, gradient elution 0-10% MeOH:DCM) to afford (S)-2-amino-2′-(cyclopropylethynyl)-5H-spiro[oxazole-4,9′-xanthen]-7′-ol as a tan solid.

Step 2: A 2-5 mL microwave vial was charged with (S)-2-amino-2′-(cyclopropylethynyl)-5H-spiro[oxazole-4,9′-xanthen]-7′-ol (0.250 g, 0.752 mmol), cesium carbonate (0.980 g, 3.01 mmol), and DMF (3.01 mL). The mixture was stirred vigorously for 5 min, then 1-iodo-2-methoxy-2-methylpropane (0.303 mL, 2.257 mmol) was added via syringe. The vial was sealed and the reaction was microwaved at 110° C. for two hours. The mixture was diluted with water and EtOAc and the layers were separated, and the aqueous layer was extracted twice with EtOAc. The combined organic extracts were dried over sodium sulfate, filtered, and evaporated. The residue was purified by chromatography on a 12-g Redi-Sep column, eluting with 0-10% MeOH/DCM to provide (S)-2′-(cyclopropylethynyl)-7′-(2-methoxy-2-methylpropoxy)-5H-spiro[oxazole-4,9′-xanthen]-2-amine as an off-white solid.

Method AA44

Step 1: A 100 ml RBF vial was charged with (S)-2′-bromo-7′-iodo-5H-spiro[oxazole-4,9′-xanthen]-2-amine (3.37 g, 7.37 mmol) in dioxane (30 mL), water (15 mL), phenylboronic acid (0.965 g, 7.91 mmol), bis(di-tert-butyl(4-dimethylaminophenyl)phosphine)dichloropalladium(II) (0.106 g, 0.150 mmol), and potassium phosphate-tribasic (3.17 g, 14.93 mmol). The reaction was heated to 100° C. in an oil-bath for 8 hours. The reaction was diluted with ethyl acetate (100 mL), water (25 mL), and the ethyl acetate layer was separated and dried over anhydrous sodium sulfate. Concentration and purification by silica gel flash column chromatography (hexanes/ethyl acetate) provided (R)-2′-bromo-7′-phenyl-5H-spiro[oxazole-4,9′-xanthen]-2-amine

Step 2: A 0.5-2 mL microwave vial charged with (R)-2′-bromo-7′-phenyl-5H-spiro[oxazole-4,9′-xanthen]-2-amine (0.1000 g, 0.246 mmol), Mo(CO) 6 (0.065 g, 0.246 mmol), acetoxy(2-(dio-tolylphosphino)benzyl)palladium (0.012 g, 0.012 mmol), sodium carbonate (0.026 g, 0.246 mmol), cyclopropanamine (0.026 mL, 0.368 mmol), and 1,4-dioxane (0.541 mL, 6.14 mmol) was sealed and heated to 170° C. for 30 min. The mixture was diluted with EtOAc and water. The aqueous phase was extracted with EtOAc three times. The organic layer was dried over Na 2 SO 4 and concentrated in vacuo. The crude was purified by silica gel chromatography (12 g, 2-10% MeOH—CH 2 Cl 2 , then 10-20% MeOH (2 M NH 3 )—CH 2 Cl 2 ). The product was purified again by reverse phase prep HPLC: 15-60% CH 3 CN (0.1% TFA)-water (0.1% TFA) in 26 min. The fractions were combined and neutralized with solid Na 2 CO 3 , extracted three times with CH 2 Cl 2 . The organic layer was dried over Na 2 SO 4 and concentrated in vacuo. The depicted product was obtained as a white solid.

Method AA45

Synthesis of (S)-2-(2-amino-2′-(neopentyloxy)-5H-spiro[oxazole-4,9′-xanthene]-7′-yl)propan-2-ol

To a solution of (S)-methyl 2-amino-7′-(neopentyloxy)-5H-spiro[oxazole-4,9′-xanthene]-2′-carboxylate (50 mg, 0.13 mmol) in THF (1 mL) was added methylmagnesium bromide (Aldrich, 0.76 mL, 0.76 mmol) at 0° C. The cooling bath was removed after the addition. After 1 h, the reaction was quenched with saturated NH 4 Cl. The mixture was extracted with EtOAc three times. The organic phase was dried over Na 2 SO 4 , and concentrated in vacuo. The residue was purified by silica gel chromatography (12 g, 2-10% in 10 min, then 10% MeOH—CH 2 Cl 2 ). The product was obtained as a white solid. MS: 397 (M+1).

Method AA46

Step 1: The mixture of 2′-bromo-7′-(neopentyloxy)-5H-spiro[oxazole-4,9′-xanthen]-2-amine (1.00 g, 2.4 mmol), CH 3 CN (15 mL), di-tert-butyl dicarbonate (Aldrich, 0.63 g, 2.9 mmol), and DMAP (Aldrich, 0.015 g, 0.12 mmol) was heated to 60° C. overnight. LCMS showed the product. di-tert-butyl dicarbonate (70 mg) was added and the reaction was continued overnight. LC didn't show further improvement in conversion. The mixture was diluted with EtOAc and washed with saturated Na 2 CO 3 , water and brine. The organic layer was dried over Na 2 SO 4 and concentrated in vacuo. The residue was purified by silica gel chromatography (40 g, 0-10%, then 10% MeOH—CH 2 Cl 2 ). The Boc-protected 2′-bromo-7′-(neopentyloxy)-5H-spiro[oxazole-4,9′-xanthen]-2-amine was obtained as a white solid. MS: 517, 519, 462 (M+1). The mixture of the above product (70 mg, 0.14 mmol, potassium phosphate (115 mg, 0.54 mmol), dcppHBF 4 (0.41 mg, 0.68 μmol), palladium acetate (0.12 mg, 0.54 μmol), and MeOH (3 mL) was pressurized with carbon monoxide, purged twice with CO gas (40 psi) and then heated to 100° C. (50 psi) overnight. The reaction mixture was concentrated in vacuo. The residue was diluted with EtOAc and water. The aqueous phase was extracted with EtOAc three times. The organic layer was dried over Na 2 SO 4 and concentrated in vacuo. The crude was purified by prep TLC: 8% MeOH—CH 2 Cl 2 . The product was obtained as a white solid. MS: 397 (M+1).

Step 2: To a mixture of methyl 2-amino-7′-(neopentyloxy)-5H-spiro[oxazole-4,9′-xanthene]-2′-carboxylate (33 mg, 83 μmol) and lithium hydroxide hydrate (Aldrich, 7 mg, 166 μmol) was added THF:MeOH:water (3:2:1, 1 mL). The mixture was stirred at RT for 5 h, then at 40° C. for 2 h. The mixture was concentrated in vacuo. The residue was neutralized with 1N HCl (2 mL). Ether was added to the mixture and stirred at RT for 10 min. The solid was filtered, washed with ether and dried in vacuum oven. The product was obtained as a white solid. MS: 383 (M+1).

Step 3: A mixture of 2-amino-7′-(neopentyloxy)-5H-spiro[oxazole-4,9′-xanthene]-2′-carboxylic acid (17 mg, 44 μmol), EDC (Aldrich, 13 mg, 67 μmol), HOBt (Ana Spec, 3 mg, 22 μmol), TEA (Aldrich, 37 μL, 267 μmol), dimethylamine.HCl (Alfa Aesar, 33 mg, 400 μmol) and DMF (0.5 mL) was stirred at RT overnight. The mixture was diluted with EtOAc and washed with saturated Na 2 CO 3 . The organic layer was dried over Na 2 SO 4 and concentrated in vacuo. The crude was purified by silica gel chromatography (4 g, 0-10% MeOH—CH 2 Cl 2 ). The depicted product was obtained as colorless film. MS: 410 (M+1).

Method AA47

Synthesis of 1-((S)-2-amino-2′-(pyridin-3-yl)-5H-spiro[oxazole-4,9′-xanthene]-7′-yloxy)-2-methylbutan-2-ol

Step 1: A 350-mL pressure vessel was charged with (R)-2-amino-2′-bromo-5H-spiro[oxazole-4,9′-xanthen]-7′-ol (4.00 g, 11.52 mmol), 3-pyridylboronic acid (3.54 g, 28.8 mmol), tetrakis(triphenylphosphine)palladium(0) (1.331 g, 1.152 mmol), THF (57.6 mL), and potassium carbonate (2.0M aq. solution) (28.8 mL, 57.6 mmol). The vessel was sealed and heated to 100° C. and stirred for 2 hours. The layers were partitioned between EtOAc (20 mL) and water (20 mL). The layers were separated, and the aqueous layer was extracted with EtOAc (2×20 mL). The combined organic layers were washed with brine (emulsion!), dried over sodium sulfate and filtered with the aid of 10% MeOH/DCM. The filtrate was evaporated to give a yellow solid. This solid was taken up in minimal DCM and sonicated for 5 min. The solid was filtered and washed with DCM (30 mL). Filtering and washing with DCM afforded (S)-2-amino-7′-(pyridin-3-yl)-5H-spiro[oxazole-4,9′-xanthen]-2′-ol as a pale-yellow solid

Step 2: A vial was charged with (S)-2-amino-7′-(pyridin-3-yl)-5H-spiro[oxazole-4,9′-xanthen]-2′-ol (0.300 g, 0.869 mmol), cesium carbonate (0.425 g, 1.303 mmol). DMF (3.47 mL) was added, the vial was sonicated for 30 s, and the mixture was stirred vigorously for 20 min, at which time some white solid still remained. The vial was cooled in an ice-bath for 10 min, then 1-chloroacetone (0.083 mL, 1.042 mmol) was added dropwise and the reaction was stirred over the weekend, during which the bath warmed to RT. The reaction was cooled back to 0° C. and 1-chloroacetone (0.083 mL, 1.042 mmol) was added. The reaction was stirred for two hours before 0.5 equivalents of cesium carbonate and chloroacetone were added at one hour intervals until the reaction was complete. The mixture was partitioned between water and EtOAc. The layers were separated, and the aqueous layer was extracted with EtOAc (2×). The combined organic extracts were dried over sodium sulfate, filtered, and evaporated. The material was purified via column chromatography (RediSep 40 g, gradient elution 0-5% MeOH:DCM) to afford (S)-1-(2-amino-2′-(pyridin-3-yl)-5H-spiro[oxazole-4,9′-xanthene]-7′-yloxy)propan-2-one as a white solid. The remaining fractions were combined and concentrated to afford impure material as an off-white solid.

Step 3: (S)-1-(2-amino-2′-(pyridin-3-yl)-5H-spiro[oxazole-4,9′-xanthene]-7′-yloxy)propan-2-one (0.050 g, 0.125 mmol) was dissolved in THF (1.246 mL) and cooled to 0° C. ethylmagnesium bromide 1.0 M solution in THF (0.374 mL, 0.374 mmol) was added and the reaction was stirred for one hour. Additional ethylmagnesium bromide 1.0 M solution in THF (0.374 mL, 0.374 mmol) was added again and the reaction was stirred overnight at RT. The reaction was diluted with ethyl acetate and washed with water. The aqueous layer was extracted with ethyl acetate, and the combined organic layers were dried with sodium sulfate, filtered, and concentrated. The material was purified via Gilson HPLC (25-90% MeCN:H 2 O). The product fractions were partitioned between DCM and saturated sodium bicarbonate solution. The aqueous layer was extracted with DCM, and the combined organic layers were dried with sodium sulfate, filtered, and concentrated to afford 1-((S)-2-amino-2′-(pyridin-3-yl)-5H-spiro[oxazole-4,9′-xanthene]-7′-yloxy)-2-methylbutan-2-ol as a white solid.

Method AA48

Step 1: To a solution of (S)-2′-bromo-7′-iodo-5H-spiro[oxazole-4,9′-xanthen]-2-amine (0.978 g, 2.140 mmol) in THF (5 mL) was added (2-tert-butoxy-2-oxoethyl)zinc(II) chloride (17.12 mL, 8.56 mmol) and tetrakis(triphenylphosphine)palladium(0) (0.124 g, 0.107 mmol). The resulting mixture was then heated to 85° C. overnight. Saturated ammonium chloride (50 mL) and EtOAc (100 mL) were added and the mixture was stirred at room temperature overnight. The mixture was filtered and the organic layer was collected, dried over MgSO4, and concentrated. The residue was mixed silica gel and the solid mixture was purified by silica gel column chromatography (solid loading, 0%-100% ammonia in methanol 2M/DCM) to give the product as a brown solid.

Step 2: To a solution of (R)-tert-butyl 2-(2-amino-2′-bromo-5H-spiro[oxazole-4,9′-xanthene]-7′-yl)acetate (0.505 g, 1.134 mmol) in 1,2-Dimethoxyethane (7 mL) was added 5-pyrimidinylboronic acid (0.155 g, 1.247 mmol), sodium carbonate monohydrate (0.142 mL, 3.40 mmol), tetrakis(triphenylphosphine)palladium(0) (0.105 g, 0.091 mmol), and H 2 O (1.4 mL). The resulting mixture was then heated to 90° C. for 10 h. The mixture was cooled to room temperature, EtOAc (20 mL) and sat. NaHCO 3 (5 mL) were added. The mixture was stirred at room temperature for 5 minutes then the organic layer was collected, dried over MgSO 4 , and concentrated. The residue was then dissolved in a solution of DMSO (1 mL) and MeOH (1 mL). The solution mixture was then purified by preparative HPLC (0%-90% MeCN 0.1% NH 4 OH/H 2 O 0.1% NH 4 OH) to give the product as a light yellow solid.

Step 3: A solution of (R)-tert-butyl 2-(2-amino-2′-(pyrimidin-5-yl)-5H-spiro[oxazole-4,9′-xanthene]-7′-yl)acetate (14 mg, 0.031 mmol) in 30% TFA in DCM (0.5 mL) was stirred at room temperature for 1 h. A saturated NaHCO 3 solution was added slowly to the mixture at 0° C. to adjust the pH to 7. Then, solvents were removed and the residue was dissolved in a solution of MeOH (0.5 mL), H 2 O (0.1 mL), and DMF (0.3 mL). The solution mixture was then purified by preparative HPLC (0%-100% MeCN 0.1% NH 4 OH/H 2 O 0.1% NH 4 OH) to give the depicted product as a white solid.

Method AA49

A mixture of (R)-2′-bromo-7′-(neopentyloxy)-5H-spiro[oxazole-4,9′-xanthen]-2-amine (0.0500 g, 0.120 mmol), ethanol (2 mL), and palladium 10% on activated carbon (0.013 g, 0.012 mmol) was stirred under 1 atm of H 2 gas overnight. The catalyst was filtered through celite and the filtrate was concentrated in vacuo to provide (S)-2′-(neopentyloxy)-5H-spiro[oxazole-4,9′-xanthen]-2-amine as a white solid.

Method AA50

Synthesis of (S)-1-(2-amino-2′-(pyridin-3-yl)-5H-spiro[oxazole-4,9′-xanthene]-7′-yl)-4-hydroxybutan-1-one

Step 1: A 250 ml RB flask was charged with (R)-2′-bromo-7′-iodo-5H-spiro[oxazole-4,9′-xanthen]-2-amine (4.06 g, 8.88 mmol), pyridin-3-ylboronic acid (1.419 g, 11.55 mmol), tetrakis(triphenylphosphine)palladium(0) (1.026 g, 0.888 mmol). DME (63.4 mL) and sodium carbonate (13.32 mL, 26.6 mmol) (2M solution) were added and the mixture was heated at 70° C. for 15 hrs. The mixture was diluted with water and ethyl acetate, filtered and organic layer was separated and concentrated. The crude material was purified by silica gel chromatography (0-50% gradient of 90/10/1 DCM/MeOH/NH4OH in DCM) to give (S)-2′-bromo-7′-(pyridin-3-yl)-5H-spiro[oxazole-4,9′-xanthen]-2-amine as an off-white solid.

Step: A 2-5 ml microwave vial was charged with (S)-2′-bromo-7′-(pyridin-3-yl)-5H-spiro[oxazole-4,9′-xanthen]-2-amine (96 mg, 0.235 mmol), potassium phosphate (150 mg, 0.705 mmol), 2-(4,5-dihydrofuran-2-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (92 mg, 0.470 mmol) and AmPhos (16.65 mg, 0.024 mmol). 1,4-Dioxane (1176 μL) and water (392 μL) were added and the vial was sealed and heated in microwave reactor for 1 hr at 100° C. The mixture was diluted with ethyl acetate, filtered through celite, and concentrated on 2 g of silica gel. Purification by flash chromatography on 12 g rediSep column using 5-50% gradient of DCM/MeOH/NH 4 OH (90:10:1) in DCM provided (S)-1-(2-amino-2′-(pyridin-3-yl)-5H-spiro[oxazole-4,9′-xanthene]-7′-yl)-4-hydroxybutan-1-one as an off-white solid.

Method AA51

Synthesis of 7-(2-fluoropyridin-3-yl)-3-(2-methoxy-2-methylpropoxy)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine

Step 1: A solution of 2′-amino-7-bromo-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-3-01 (15.00 g, 51.4 mmol) in 100 mL DCM was treated with DBU (9.68 mL, 64.2 mmol) and was allowed to stir for 10 minutes. 3-Bromo-2-methylpropene (5.44 mL, 53.9 mmol) was added, and the reaction mixture was allowed to stir at RT for an additional 1 hour. The reaction mixture was quenched with 200 mL 0.5 N citric acid and was concentrated to remove the organics. The resulting solid was filtered, washed with 1:1 water/acetone, and was dried. The solid was purified by column chromatography yielding 7-bromo-3-(2-methylallyloxy)-5H-chromeno[2,3-b]pyridin-5-one.

Step 2: A suspension of 7-bromo-3-(2-methylallyloxy)-5H-chromeno[2,3-b]pyridin-5-one (4.50 g, 13.00 mmol) in 100 mL MeOH was treated with NIS (5.85 g, 26.0 mmol) and was allowed to stir at room temperature for 48 hours. The reaction mixture was poured into 1:1 water/brine and was extracted with ether and then DCM. The organics were dried over MgSO 4 and concentrated. Purification of the crude residue by column chromatography gave 7-bromo-3-(3-iodo-2-methoxy-2-methylpropoxy)-5H-chromeno[2,3-b]pyridin-5-one as a yellow solid.

Step: A solution of 7-bromo-3-(3-iodo-2-methoxy-2-methylpropoxy)-5H-chromeno[2,3-b]pyridin-5-one (4.10 g, 8.13 mmol) in 100 mL THF was cooled to −40° C. and was treated with methylmagnesium chloride (5.42 mL, 16.27 mmol). After stirring for two hours, the reaction mixture was allowed to warm to room temperature and superhydride (40.7 mL, 40.7 mmol) was added. After stirring for an additional 2 hours the reaction mixture was cooled to 0° C. and was quenched with MeOH. The reaction mixture was poured into saturated NH 4 Cl solution and was extracted with EtOAc. The organics were washed with waer, brine, dried over MgSO4 and concentrated yielding 7-bromo-3-(2-methoxy-2-methylpropoxy)-5-methyl-5H-chromeno[2,3-b]pyridin-5-ol.

Step 4: A solution of 7-bromo-3-(2-methoxy-2-methylpropoxy)-5-methyl-5H-chromeno[2,3-b]pyridin-5-ol (1.780 g, 4.51 mmol) in 50 mL THF was treated with HCl 4N in dioxane (0.113 mL, 0.451 mmol) and was heated to 50° C. for one hour. The reaction mixture was cooled to 0° C. and added to the mixture below. A separate solution of iodine (1.260 g, 4.97 mmol) in 50 mL THF was prepared and cooled to −40° C. Silver cyanate (1.692 g, 11.29 mmol) was added, and the reaction mixture was allowed to stir for one hour. The above solution was then added via cannula and the reaction mixture was allowed to stir for an additional hour before ammonia 2N in IPA (13.54 mL, 27.1 mmol) was added, and the reaction mixture was allowed to warm to room temperature and stir 3 hours. The reaction mixture was quenched with 10% sodium thiosulfate solution, and was allowed to stir at room temperature for one hour. The organics were separated, washed with water, brine, dried over MgSO 4 and concentrated. Purification of the crude residue by column chromatography gave 7-bromo-3-(2-methoxy-2-methylpropoxy)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine.

Step 5: A vial charged with 2-fluoropyridin-3-ylboronic acid (0.156 g, 1.105 mmol), palladiumtetrakis (0.043 g, 0.037 mmol), potassium carbonate (0.255 g, 1.842 mmol), and 7-bromo-3-(2-methoxy-2-methylpropoxy)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine (0.160 g, 0.368 mmol) was dissolved in 3 mL THF and 0.5 mL water and was heated to 110° C. 2 hours. The reaction mixture was diluted with EtOAc and dried over MgSO 4 . The organcis were concentrated then purified directly by column chromatography yielding 7-(2-fluoropyridin-3-yl)-3-(2-methoxy-2-methylpropoxy)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine.

Method AA52

Synthesis of (R)-2-amino-7′-(neopentyloxy)-5H-spiro[oxazole-4,9′-xanthene]-2′-carbonitrile

(S)-2′-bromo-7′-(neopentyloxy)-5H-spiro[oxazole-4,9′-xanthen]-2-amine (250 mg, 0.599 mmol) and CuCN (268 mg, 3.00 mmol) were brought up in NMP (1997 μL) and heated to 200° C. in the microwave. The reactions were cooled to rt, filtered and purified by reverse-phase preparative HPLC using a Gemini NX c!8 column (150*30 mm, 5 um), 0.1% TFA in CH 3 CN/H 2 O, gradient 0% to 70% over 10 min to provide the product. Solvent was removed by evaporation and the product was brought up in sat's aqueous NaHCO 3 and DCM and extracted with DCM. The organic washes were combined, dried over Na 2 SO 4 , filtered and concentrated to give (R)-2-amino-7′-(neopentyloxy)-5H-spiro[oxazole-4,9′-xanthene]-2′-carbonitrile.

Method AA54

Synthesis of (S)-1′-bromo-2′-(neopentyloxy)-7′-(pyridin-3-yl)-5H-spiro[oxazole-4,9′-xanthen]-2-amine

Step 1: A 75-mL pressure vessel was charged with starting material (3.25 g, 9.36 mmol), pyridin-3-ylboronic acid (2.88 g, 23.40 mmol), tetrakis(triphenylphosphine)palladium(0) (1.081 g, 0.936 mmol), THF (46.8 mL), and potassium carbonate (23.40 mL, 46.8 mmol) (as a 2.0 M aq. solution). The vessel was sealed and placed in a 100° C. oil bath for 5 hours. The mixture was partitioned between EtOAc (50 mL) and water (50 mL). The layers were separated, and the aqueous layer was extracted with EtOAc (2×30 mL). The combined mixture was dried over sodium sulfate and filtered with the aid of 10% MeOH/DCM. The filtrate was evaporated to give a yellow solid. This solid was taken up in DCM (80 mL) and sonicated for 5 min. The solid was filtered and washed with DCM (2×40 mL), then air-dried on the filter. The filtrate was evaporated and again taken up in DCM (80 mL). The mixture was sonicated for 10 min, then filtered and washed with DCM (30 mL). The solid was air-dried and combined with the first solid to give (S)-2-amino-7′-(pyridin-3-yl)-5H-spiro[oxazole-4,9′-xanthen]-2′-ol.

Step 2: A 50-mL RBF was charged with (S)-2-amino-7′-(pyridin-3-yl)-5H-spiro[oxazole-4,9′-xanthen]-2′-ol (1.426 g, 4.13 mmol) and TFA (20.65 mL). The mixture was stirred for 30 min and sonicated for 2 min, but it did not become a clear solution. An additional portion of TFA (5 mL) was added, giving an orange mixture. The flask was cooled in an ice-bath for 15 min. n-bromosuccinimide (0.735 g, 4.13 mmol) was added in one portion. After stirring for 2 hour the mixture was diluted with methanol and evaporated in vacuo. The residue was dissolved in methanol and loaded onto a 10-g SCX-2 column. The column was eluted with methanol to remove impurities, then with 2M ammonia in methanol to give the product. The filtrate was evaporated, and the residue was purified by chromatography on a 100-g SNAP column, eluting with 0-100% of a 90:10:1 mix of a DCM/MeOH/NH 4 OH in DCM. The product came out in two peaks which were combined to give (S)-2-amino-1′-bromo-7′-(pyridin-3-yl)-5H-spiro[oxazole-4,9′-xanthen]-2′-ol as an off-white powder. NMR matched that of the product.

Step 3: A vial was charged with (S)-2-amino-1′-bromo-7′-(pyridin-3-yl)-5H-spiro[oxazole-4,9′-xanthen]-2′-ol (163 mg, 0.384 mmol), cesium carbonate (375 mg, 1.152 mmol), and DMF (2.0 mL). The mixture was stirred for 10 min, then 1-iodo-2,2-dimethylpropane (102 μL, 0.768 mmol) was added. The vial was sealed and heated in a Biotage Initiator microwave reactor for 2 h at 110° C. LCMS at this time shows no starting material and mainly desired product. The mixture was partitioned between water and EtOAc. Brine was added to break up the emulsioon that formed and this was partially successful. The aqueous layer was extracted with EtOAc (2×), and the combined organic extracts were dried over sodium sulfate, filtered, and evaporated. The residue was chromatographed on a 50-g SNAP column, eluting with 0-70% of a 90:10:1 mix of DCM/MeOH/NH 4 OH in DCM to give (S)-1′-bromo-2′-(neopentyloxy)-7′-(pyridin-3-yl)-5H-spiro[oxazole-4,9′-xanthen]-2-amine as an off-white solid after evaporation from DCM/hexane.

Method AA55

Synthesis of (S)-2-amino-2′-(neopentyloxy)-7′-(pyridin-3-yl)-5H-spiro[oxazole-4,9′-xanthene]-1′-carbonitrile

A vial was charged with (S)-1′-bromo-2′-(neopentyloxy)-7′-(pyridin-3-yl)-5H-spiro[oxazole-4,9′-xanthen]-2-amine (68.1 mg, 0.138 mmol), dicyanozinc (81 mg, 0.689 mmol), tetrakis(triphenylphosphine)palladium(0) (31.8 mg, 0.028 mmol), and DMF (689 μL). The vial was sealed and placed in a 120° C. oil bath for 12 hours. The mixture was diluted with water and extracted with DCM (3×). The combined organic extracts were dried over sodium sulfate, filtered, and evaporated. The residue was chromatographed on a 25-g SNAP column, eluting with a 90:10:1 mix of DCM/MeOH/NH 4 OH in DCM. This gave ca. 40 mg of a white powder that was impure by HPLC. The solid was combined with 104487-6-2 in DMSO/MeOH and purified by reverse-phase HPLC (10-90% CH 3 CN/H 2 O with 0.1% TFA). The fractions containing product were combined in saturated aq. sodium bicarbonate solution with the aid of methanol and extracted with DCM (3×). The combined organic extracts were dried over sodium sulfate, filtered, and evaporated to give (S)-2-amino-2′-(neopentyloxy)-7′-(pyridin-3-yl)-5H-spiro[oxazole-4,9′-xanthene]-1′-carbonitrile as an off-white powder after evaporation from DCM/hexane.

Method AA56

Step 1: A resealable tube was charged with 1-chloro-8-(pyridin-3-yl)-10H-chromeno[3,2-c]pyridin-10-one (0.500 g, 1.620 mmol) and acetic acid (12.5 mL). Ammonium acetate (1.248 g, 16.20 mmol) was added, the system was purged with argon, and the tube was sealed. The mixture stirred at 65° C. for 20 h. The reaction mixture was filtered and washed with water. The filter cake was concentrated down from heptanes to afford 8-(pyridin-3-yl)-1H-chromeno[3,2-c]pyridine-1,10(2H)-dione as an off-white solid. MS m/z=291.0 [M+H] + . Calcd for C 17 H 10 N 2 O 3 : 290.07.

Step 2: A solution of 8-(pyridin-3-yl)-1H-chromeno[3,2-c]pyridine-1,10(2H)-dione (0.100 g, 0.345 mmol) in THF (3.00 mL) was cooled to 0° C. and methylmagnesium bromide (3.0 M in diethyl ether) (0.345 mL, 1.034 mmol) was added dropwise. The mixture stirred at 0° C. for 1 h. The mixture was quenched at 0° C. with saturated aqueous ammonium chloride solution and diluted with ethyl acetate. The aqueous phase was separated and extracted with ethyl acetate. The combined organic phases were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated to afford a tan solid. The material was dissolved in 1,2-dichloroethane (3.00 mL), pyridinium p-toluenesulfonate (8.66 mg, 0.034 mmol) was added, and the mixture was heated at reflux for 2 h to afford a tan suspension. This mixture was filtered, and the solids were washed with 1,2 dichloroethane and dried to afford 10-methylene-8-(pyridin-3-yl)-2,10-dihydro-1H-chromeno[3,2-c]pyridin-1-one as a tan solid. MS m/z=289.0 [M+H] + . Calcd for C 18 H 12 N 2 O 2 : 288.1.

Step 3: A resealable tube was charged with (1R,2R)-diaminomethylcyclohexane (9.77 mg, 0.069 mmol), copper(I) iodide (8.72 mg, 0.046 mmol), 10-methylene-8-(pyridin-3-yl)-2,10-dihydro-1H-chromeno[3,2-c]pyridin-1-one (0.066 g, 0.229 mmol), 4-iodotoluene (0.055 g, 0.252 mmol), potassium carbonate (0.063 g, 0.458 mmol), and DMSO (2.5 mL). The system was purged with argon and the tube was sealed. The mixture stirred in an Initiator microwave reactor (Personal Chemistry, Biotage AB, Inc., Upssala, Sweden) at 100° C. for 2 h. The reaction mixture was diluted with dichloromethane and filtered through a pad of celite. The filtrate was concentrated and partitioned between dichloromethane and water. The aqueous phase was separated and extracted with dichloromethane. The combined organic phases were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated to afford 10-methylene-8-(pyridin-3-yl)-2-p-tolyl-2,10-dihydro-1H-chromeno[3,2-c]pyridin-1-one. MS m/z=379.0 [M+H] + . Calcd for C 25 H 18 N 2 O 2 : 378.4.

Step 4: A solution of iodine (0.061 g, 0.239 mmol) in THF (2.5 mL) was cooled to −25° C. and silver cyanate (0.102 g, 0.682 mmol) was added. The mixture stirred at −25° C. for 30 min and then a −25° C. solution of 10-methylene-8-(pyridin-3-yl)-2-p-tolyl-2,10-dihydro-1H-chromeno[3,2-c]pyridin-1-one (0.086 g, 0.227 mmol) in THF (2.5 mL) was added via cannula. The mixture stirred at −20° C. for 1 h. The reaction mixture was cooled to −40° C. and ammonia, 2.0 M in 2-propanol (0.568 mL, 1.136 mmol) was added dropwise. The reaction mixture was allowed to warm to RT overnight. The reaction mixture was filtered through celite and washed with ethyl acetate. The filtrate was partitioned between ethyl acetate and saturated aqueous sodium thiosulfate solution. The aqueous phase was separated and extracted with ethyl acetate. The combined organic phases were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated to afford a yellow solid. This material was purified via column chromatography on silica gel (RediSep 40 g column, gradient elution with 50-100% ((90:10:1, dichloromethane/methanol/ammonium hydroxide)-dichloromethane) to afford 2′-amino-8-(pyridin-3-yl)-2-p-tolyl-5′H-spiro[chromeno[3,2-c]pyridine-10,4′-oxazol]-1(2H)-one. MS m/z=437.0 [M+H] + . Calcd for C 26 H 20 N 4 O 3 : 436.2.

Method AA57

Synthesis of (S)-2′-(2-fluoropyridin-3-yl)-7′-(3-methylisoxazol-5-yl)-5H-spiro[oxazole-4,9′-xanthen]-2-amine

A resealable was charged with (S)-2′-bromo-7′-(2-fluoropyridin-3-yl)-5H-spiro[oxazole-4,9′-xanthen]-2-amine (300 mg, 0.704 mmol), 3-methyl-5-(tributylstannyl)isoxazole (786 mg, 2.111 mmol), amphos (18.68 mg, 0.070 mmol) and argon purged dry dioxane (3 mL). The tube was purged with argon, sealed and heated with microwave at 100° C. for 1 h. The solution was concentrated. The crude product was purified via silica gel column chromatography (RediSep 12 g column) using 10-50% 90/10/1 DCM/MeOH/ammonia in DCM to afford (S)-2′-(2-fluoropyridin-3-yl)-7′-(3-methylisoxazol-5-yl)-5H-spiro[oxazole-4,9′-xanthen]-2-amine as a white solid. MS m/z=429.2 [M+H]+. Calcd for C 24 H 17 FN 4 O 3 : 428.42.

Method AA60

Synthesis of (S,E)-methyl 3-(2-amino-2′-bromo-5H-spiro[oxazole-4,9′-xanthene]-7′-yl)acrylate

A mixture of (R)-2′-bromo-7′-iodo-5H-spiro[oxazole-4,9′-xanthen]-2-amine (3.00 g, 6.56 mmol), methyl acrylate (0.621 mL, 6.89 mmol), phosphine, tri-o-tolyl (0.400 g, 1.313 mmol), palladium(ii) acetate (0.295 g, 1.313 mmol), and triethylamine 99.5% (1.826 mL, 13.13 mmol) in DMF (12 mL) in a microwave vial was purged with argon for 5 min, capped, and heated to 120° C. for 40 min in a microwave. The reaction mixture was diluted with EtOAc (100 mL) and washed with water, dried over Na2SO4, and concentrated. The product was purified with ISCO using 0-70% EtOAc in hexanes to give (S,E)-methyl 3-(2-amino-2′-bromo-5H-spiro[oxazole-4,9′-xanthene]-7′-yl)acrylate. MS (ESI pos. ion) m/z: 416.9 (M+1).

Method AA62

Step 1: To a solution of (R)-2′-bromo-7′-iodo-5H-spiro[oxazole-4,9′-xanthen]-2-amine (1.5 g, 3.28 mmol) in THF (7.5 mL) was added (2-tert-butoxy-2-oxoethyl)zinc(II) chloride (21.00 mL, 10.50 mmol) (0.5 M in diethyl ether) and tetrakis(triphenylphosphine)palladium(0) (0.190 g, 0.164 mmol). The resulting mixture was then heated to 85-90° C. for overnight. Then, the mixture was cooled to RT and saturated NaHCO 3 solution (50 mL) was added. The mixture was then extracted with EtOAc (2×50 mL). The combined organic extracts were dried over MgSO 4 and concentrated. The residue was then dissolved in DCM. The solution mixture was then purified by silica gel column chromatography using ISCO instrument (solid loading, 0%-30% MeOH/DCM) to give the product as a light brown solid. MS (ESI, positive ion) m/z: 444.9, 446.9 (M+1).

Step 2: To a solution of (R)-tert-butyl 2-(2-amino-2′-bromo-5H-spiro[oxazole-4,9′-xanthene]-7′-yl)acetate (0.663 g, 1.489 mmol) in 1,2-dimethoxyethane (7 mL) was added 3-pyridineboronic acid (0.220 g, 1.787 mmol), tetrakis(triphenylphosphine)palladium(o) (0.138 g, 0.119 mmol), bisodium carbonate (0.062 mL, 1.489 mmol), and water (2.333 mL). The resulting mixture was then heated to 85-90° C. for 5 h. Then, the mixture was cooled to room temperature and was diluted with EtOAc (10 mL). Then, saturated NaHCO 3 (3 mL) was added and the mixture was stirred at room temperature for 5 min. The organic layer was collected, dried over MgSO 4 , and concentrated. The residue was then dissolved in a solution of DMSO (1 mL) and MeOH (2 mL). The solution mixture was then purified by preparative HPLC (0%-100% MeCN 0.1% TFA/H 2 O 0.1% TFA) to give a desired product in a solution of MeCN/H 2 O 0.1% TFA. The solution mixture was neutralized by saturated NaHCO 3 . The solvent, MeCN was removed and saturated NaHCO 3 (10 mL) was added and the mixture was extracted with EtOAc (2×20 mL). The combined organic extracts were dried over MgSO 4 , concentrated, and dried in vacuo to give the product both as a white solid and as an orange solid (<95% pure). MS (ESI, positive ion) m/z: 444 (M+1).

Step 3: To a solution of (R)-tert-butyl 2-(2-amino-2′-(pyridin-3-yl)-5H-spiro[oxazole-4,9′-xanthene]-7′-yl)acetate (95 mg, 0.214 mmol) in THF (1 mL) at −78° C. was added methyllithium, 1.6M solution in diethyl ether (0.669 mL, 1.071 mmol). The resulting mixture was then stirred at −78° C. for 2 h. Then, the mixture was quenched with saturated ammonium chloride (1 mL). Then, saturated NaHCO 3 (5 mL) and EtOAc (10 mL) were added. The mixture was then extracted with EtOAc (2×10 mL). The combined organic extracts were dried over MgSO 4 and concentrated. The residue was then dissolved in a solution of DMSO (1 mL) and MeOH (1 mL). The solution mixture was then purified by preparative HPLC (0%-100% MeCN 0.1% TFA/H 2 O 0.1% TFA) to give two products: R)-1-(2-amino-2′-(pyridin-3-yl)-5H-spiro[oxazole-4,9′-xanthene]-7′-yl)-2-methylpropan-2-01 and (R)-1-(2-amino-2′-(pyridin-3-yl)-5H-spiro[oxazole-4,9′-xanthene]-7′-yl)propan-2-one in a solution of MeCN/H 2 O 0.1% TFA. The solution was then neutralized by saturated NaHCO 3 . Then, the solvents were removed, and saturated NaHCO 3 (2 mL) and EtOAc (5 mL) were added. The mixture was then stirred at RT for 15 min. The organic layer was collected, dried over MgSO 4 , concentrated, and dried in vacuo to give the depicted product as a white solid. MS (ESI, positive ion) m/z: 402 (M+1).

Method AA63

A solution of (R)-tert-butyl 2-(2-amino-2′-(pyrimidin-5-yl)-5H-spiro[oxazole-4,9′-xanthene]-7′-yl)acetate (14 mg, 0.031 mmol) in 30% TFA in DCM (0.5 mL) was stirred at RT for 1 h. Then, saturated NaHCO 3 solution was added slowly to the mixture at 0° C. until pH=7.0. Then, solvents were removed and the residue was dissolved in a solution of MeOH (0.5 mL), H 2 O (0.1 mL), and DMF (0.3 mL). The solution mixture was then purified by preparative HPLC (0%-100% MeCN 0.1% NH 4 OH/H 2 O 0.1% NH 4 OH) to give the acid adduct as a white solid. MS (ESI, positive ion) m/z: 389 (M+1).

Method AA64

Step 1: A three neck 3-L flask equipped with an overhead stirred was charged with 6-fluoropyridin-3-ylboronic acid (105 g, 745 mmol) and 1 L of THF. The mixture was cooled to 0° C. and NaOH 6N (373 mL, 2235 mmol) was added. To the resulting mixture was added hydrogen peroxide 30% (126 mL, 4098 mmol), dropwise via an addition funnel over the course of 30 minutes. After stirring at 0° C. for 2 hours the mixture was removed from the ice bath and maintained at RT for 30 minutes. The reaction was acidified to pH 7 with 6 N HCl (ca. 300 mL) and diluted with 500 mL of ether. The aqueous layer was extracted with ether (2×1 L) and the combined organic layers were washed with water (1.5 L) then brine before being dried over sodium sulfate. Filtration and concentration of the crude material provided a white solid that was dried on high vac overnight to provide 6-fluoropyridin-3-ol.

Step 2: To a solution of 6-fluoropyridin-3-ol (75 g, 663 mmol) in DMF (265 mL, 663 mmol) were added potassium carbonate (59.7 g, 995 mmol) and iodomethane (108 g, 763 mmol). The resulting slurry was heated at 100° C. for 3 hours. The reaction was diluted with water (1000 mL) and poured into a separatory funnel containing diethyl ether (1000 mL). The layers were separated and the aqueous layer was extracted with diethyl ether (4×500 mL). The combined organic layers were washed with water and then brine, dried over sodium sulfate, filtered and concentrated in vacuo to provide a yellow oil. This oil was diluted with 500 mL of DCM and concentrated to provide a yellow oil with a large amount of an off white precipitate. The mixture was filtered and the derived solid was washed well with DCM. The filtrate was concentrate to provide a mixture consisting of a yellow oil and an off white solid. The solid eas filtered, washing with DCM. Repeat this procedure again and then concentrated the filtrate to provide a yellow oil. The oil was taken up in 100 mL of ether and flashed through a plug of silica gel with 10:1 hexanes:ether to provide 2-fluoro-5-methoxypyridine as a yellow oil.

Step 3: To a solution of DIPA (54.0 mL, 385 mmol) in THF (1101 mL, 385 mmol) at −60° C. was added BuLi, 2.5 M in hexanes (154 mL, 385 mmol) over 5 minutes such that the internal temperature was maintained below −60° C. After stirring for 45 minutes at −65° C. a solution of 2-fluoro-5-methoxypyridine (49 g, 385 mmol) in 200 mL of THF was added over the course of 2 minutes maintaining an internal temperature <−65° C. The reaction was stirred at −70° C. for 1.5 hours then reaction was poured into a 3 L flask containing 1200 g of crushed dry ice. The reaction was allowed to warm to 0° C. and then poured into 1000 mL of water. The organics were removed under reduced pressure and the aqueuous layer was acidified with 1100 mL of 2 N HCl. The resulting thick white slurry was stirred for 1 hour then filtered to provide 2-fluoro-5-methoxynicotinic acid as a white solid.

Step 4: To a slurry of sodium hydride (60% dispersion) (21.74 g, 543 mmol) in DMF (351 mL, 175 mmol) at 0° C. was added 4-bromophenol (60.7 g, 351 mmol) over the course of 5 minutes. Stirred at 0° C. for two minutes then removed from the ice bath and stirred for an additional 5 minutes at room temperature. Added 2-fluoro-5-methoxynicotinic acid (30 g, 175 mmol) portionwise over 10 minutes and heated the resulting slurry at 140° C. After cooling to room temperature the mixture was then poured onto 1 kg of ice and was quenched with acetic acid (50.2 mL, 877 mmol) and then 75 mL of 6 N HCl. Stirred vigorously for 1 hour, leading to the formation of a red slurry containing a very fine white precipitate. Filtered the slurry to provide 2-(4-bromophenoxy)-5-methoxynicotinic acid.

Step 5: A 2 L flask charged with polyphosphoric acid (115% H 3 PO 4 ) (300 g, 89 mmol) was heated to 140° C. at which point 2-(4-bromophenoxy)-5-methoxynicotinic acid (29 g, 89 mmol) was introduced. The thick viscous mixture is slowly stirred while heating at 140° C. After heating for 2.5 hours the solution was cooled to 100° C. and then poured onto 1 kg of ice, leading to the formation of a yellow taffy mixture. The slurry was vigorously stirred for 1 hour leading to the formation of a fine white precipitate. Filtration of this mixture proceeded slowly to provide an off white solid. This solid was washed well with DCM. The filtrate, which contained the desired product, was washed with brine and concentrated to provide 7-bromo-3-methoxy-5H-chromeno[2,3-b]pyridin-5-one as an off-white solid.

Step 6: To a slurry of 7-bromo-3-methoxy-5H-chromeno[2,3-b]pyridin-5-one (23 g, 75 mmol) in THF (751 mL, 75 mmol) at −40° C. was added methylmagnesium chloride, 3.0 M solution in THF (88 mL, 263 mmol) over 2 minutes such that the temperature did not rise above −35° C. The resulting red slurry was maintained at −30° C. After 1 hour the reaction, which was now homogeneous, was quenched with 50 mL of ethyl acetate. The solution was then carefully quenched with 800 mL of 50% ammonium chloride. The mixture was poured into a separatory funnel containing ethyl acetate (100 mL). The layers were separated and the organics were washed with brined, dried over sodium sulfate, filtered and concentrated. The aqueous layer was extracted with ethyl acetate (3×500 mL). The combined organic layers were washed with water and then brine, dried over sodium sulfate, filtered, and combined with the above derived oil. This organic solution was washed with brined, dried over sodium sulfate, fitlered and concentrated to provide 7-bromo-3-methoxy-5-methyl-5H-chromeno[2,3-b]pyridin-5-ol as a yellow solid.

Step 7: To a solution of 7-bromo-3-methoxy-5-methyl-5H-chromeno[2,3-b]pyridin-5-ol (23.5 g, 72.9 mmol) in THF (729 mL, 72.9 mmol) was added HCl (1 M in ether) (0.729 mL, 0.729 mmol). The resulting solution was heated at 45° C. for 1 hour. The light yellow solution was cooled to −25° C. and added to the slurry below.

In a separate 2 L flask was added iodine (20.37 g, 80 mmol) and 400 mL of THF. This solution was cooled to −15° C. and silver cyanate (32.8 g, 219 mmol) was added. The resulting slurry was maintained at −40° C. for 25 minutes before the above solution was added via cannula over 15 minutes maintaining the temperature below −35° C. The derived slurry was maintained at −30° C. for 1 hour at which it was filtered through a pad of celite, washing well with 200 mL of THF. The derived brown solution was cooled to −20° C. and treated with ammonia, 2.0 M solution in 2-propanol (219 mL, 438 mmol). The resulting solution was allowed to slowly warm to rt overnight. To the reaction was added 700 mL of 10% sodium thiosulfate and the resulting light orange solution was stirred for 10 minutes before being poured into a separatory funnel containing 250 mL of ethyl acetate. The layers were separated and the organics were washed with brine and then concentrated in vacuo. This mixture was combined with the organic extracts obtained below.

The aqueous layer was extracted with ethyl acetate (2×500 mL). These organics were combined with the organics obtained and poured into a separatory funnel. The layers were separated and the aqueous layer was extracted with ethyl acetate (2×100 mL). The combined organic layers were washed with brine, dried over sodium sulfate, filtered and concentrated in vacuo to provide 25 g of 7-bromo-3-methoxy-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine as a brown solid.

Synthesis of (S)-3-(3-(azetidin-1-yl)-3-methylbut-1-ynyl)-7-(pyridin-3-yl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine

Step 1: A vial charged with pyridin-3-ylboronic acid (0.295 g, 2.401 mmol), palladiumtetrakis (0.126 g, 0.109 mmol), potassium carbonate (1.509 g, 10.92 mmol), and (S)-3-bromo-7-iodo-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine (1.000 g, 2.183 mmol) was treated with 11 mL dioxane followed by 4.5 mL water. The vial was flushed with argon and was heated to 80° C. for 4 hours. The reaction mixture was diluted with EtOAc and dried over MgSO 4 . The organics were then concentrated, and the crude residue was purified by column chromatography yielding (S)-3-bromo-7-(pyridin-3-yl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine

Step 2: A vial charged with potassium carbonate (0.338 g, 2.444 mmol), (S)-3-bromo-7-(pyridin-3-yl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine (0.100 g, 0.244 mmol), azetidine hydrochloride (0.209 g, 3.67 mmol), copper(i) iodide (4.65 mg, 0.024 mmol), and palladiumtetrakistriphenylphosphine (0.028 g, 0.024 mmol) was treated with 2 mL DMF and was thoroughly degassed with argon gas. 3-chloro-3-methylbut-1-yne (0.125 g, 1.222 mmol) was added, the vial was placed under argon, and was heated to 80° C. for 4 hours. The reaction mixture was poured into water and was extracted with EtOAc. The organics were washed with brine, dried over MgSO 4 and concentrated. Purification of the crude residue by column chromatography gave (S)-3-(3-(azetidin-1-yl)-3-methylbut-1-ynyl)-7-(pyridin-3-yl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine

Method AA65

Synthesis of 1-fluoro-3,7-di(pyridin-3-yl)-5′H-spiro[chromeno[2,3-c]pyridine-5,4′-oxazol]-2′-amine

Step 1: A 500 mL RBF was charged with 2-fluoro-3-hydroxypyridine (3487 mg, 30.8 mmol), 2,5-dibromobenzoic acid (8630 mg, 30.8 mmol), copper (I) trifluoromethane-sulfonate toluene complex (2:1) (399 mg, 0.771 mmol) and cesium carbonate (2.01E+04 mg, 61.7 mmol). To this was added 100 mL of toluene and the mixture was azeotroped to remove about 20 mL of toluene under reduced pressure. Reaction mixture was then flushed with N2 and was heated to 120° C. for 2 hours. LC-MS analysis showed formation of the desired product along with significant impurities. The reaction mixture was cooled to RT and concentrated to give a gummy residue. The residue was taken up in ethyl acetate (100 mL) and water (75 mL). The aqueous layer was neutralized with 1N HCl to pH ˜2.0-3.0. The aqueous layer was extracted with ethyl acetate (2×150 mL), separated, dried over anhydrous sodium sulfate, and concentrated to yield the crude product as a brown solid which was used directly in the next step.

Step 2: A mixture of crude 5-bromo-2-(2-fluoropyridin-3-yloxy)benzoic acid (8.00 g, 25.6 mmol), diethylamine (6.63 mL, 64.1 mmol) and TBTU (8.23 g, 25.6 mmol) in 8 mL of DMF was stirred overnight. The reaction was quenched with Sat. NaHCO3, extracted with EA/H=2:1, washed with brine, dried over Na2SO4, filtered and evaporated to dryness. CC (DCM to DCM/EA 100:5 to 100:10 to 100:20 to 3:1) gave 5-bromo-N,N-diethyl-2-(2-fluoropyridin-3-yloxy)benzamide as a yellow solid.

Step 3: To a solution of 5-bromo-N,N-diethyl-2-(2-fluoropyridin-3-yloxy)benzamide (1.4 g, 3.81 mmol) and urea peroxide (1.076 g, 11.44 mmol) in 10 mL of DCM at 0 C was added dropwise trifluoroacetic anhydride (1.601 mL, 11.44 mmol) and the resulting reaction was stirred overnight. LCMS showed only less than 50% of desired conversion. The mixture was evaporated to dryness, quenched with Sat. NaHCO 3 , extracted with EA, dried over Na 2 SO 4 , filtered and evaporated to dryness. CC (DCM to DCM/EA=3:1 to DCM/MeOH=100:2 to 100:5 to 100:10) gave 3-(4-bromo-2-(diethylcarbamoyl)phenoxy)-2-fluoropyridine 1-oxide as an offwhite solid.

Step 4: To a solution of 3-(4-bromo-2-(diethylcarbamoyl)phenoxy)-2-fluoropyridine 1-oxide (420 mg, 1.096 mmol) in 15 mL of DCM was added dropwise phosphorus oxychloride (301 μL, 3.29 mmol) followed by 2 drops of DMF. After stirring at rt for 1 h, the reaction was quenched with sat. NaHCO 3 , extracted with EA, dried over Na2SO4, filtered and evaporated to dryness. CC (DCM to DCM/EA=10:1 to 5:1 to 3:1) gave 5-bromo-2-(6-chloro-2-fluoropyridin-3-yloxy)-N,N-diethylbenzamide as a colorless gum.

Step 5: To a solution of 5-bromo-2-(6-chloro-2-fluoropyridin-3-yloxy)-N,N-diethylbenzamide (120 mg, 0.299 mmol) in 5 mL of dry THF at −78 C was added dropwise lithium diisopropylamide, 2.0 m heptane/tetrahydrofuran/ethylbenzene (158 μL, 1.195 mmol) (0.6 mL of 2M solution) and the reaction was stirred at −78 C for 3 h. The reaction was quenched at −78 C with sat. NH 4 Cl and was allowed to warm up to RT. The reaction was extracted with EA, dried over Na 2 SO 4 , filtered and evaporated to dryness. CC (hexane to H/DCM=1:1 to DCM) gave 7-bromo-3-chloro-1-fluoro-5H-chromeno[2,3-c]pyridin-5-one as an offwhite solid. MS (M+1): 328.

Step 6: To a solution of 7-bromo-3-chloro-1-fluoro-5H-chromeno[2,3-c]pyridin-5-one (50 mg, 0.152 mmol) in 5 mL of dry THF at −78 C was added methylmagnesium chloride, 3.0 m solution in tetrahydrofuran (16.87 μL, 0.228 mmol) (0.07 mL) and the reaction was slowly warmed up to −30 C. Only half of conversion was detected. To this was added another batch of methylmagnesium chloride, 3.0 m solution in THF (16.87 μL, 0.228 mmol) (0.07 mL). The reaction was quenched at −30 C with sat. NH 4 Cl, extracted with EA, dried over Na 2 SO 4 , filtered and evaporated to dryness. It was then treated with 1 mg of PPTS in DCM at 25 C for 0.5 h. After cooling, 0.1 g of NaHCO 3 was added the solvent was evaporated to dryness to give crude 7-bromo-3-chloro-1-fluoro-5-methylene-5H-chromeno[2,3-c]pyridine which was directly used in the next step.

A solution of iodine (8.23 μL, 0.160 mmol) in THF at −25 C was treated with silver cyanate (22.81 μL, 0.609 mmol). After 30 min, a solution of crude 7-bromo-3-chloro-1-fluoro-5-methylene-5H-chromeno[2,3-c]pyridine in THF was added dropwise. The slurry was maintained at −25 C for 2 h until LCMS showed complete consumption of starting material. The slurry was filtered through celite with ether. The brown solution was concentrated to dryness, taken up in THF, cooled to 0 C and treated with ammonia, 2 m solution in 2-propanol (13.21 μL, 0.609 mmol) (0.4 mL). The reaction was allowed to slowly warm to RT and stirred overnight. Half the solvent was evaporated and the residue was diluted with water, extracted with EA, dried over Na 2 SO 4 , filtered and evaporated to dryness. The residue was filtered, washed with DCM and air dried to give 7-bromo-3-chloro-1-fluoro-5′H-spiro[chromeno[2,3-c]pyridine-5,4′-oxazol]-2′-amine as a yellow solid. MS (M+1): 384.

Step 7: A mixture of 7-bromo-3-chloro-1-fluoro-5′H-spiro[chromeno[2,3-c]pyridine-5,4′-oxazol]-2′-amine (40.0 mg, 0.104 mmol), pyridin-3-ylboronic acid (21.73 mg, 0.177 mmol), bis-(di-tert-butyl(4-dimethylaminophenyl)phosphine)dichloropalladium(ii) (2.95 mg, 4.16 μmol) and potassium phosphate (66.2 mg, 0.312 mmol) in 1.5 ml of dioxane/water=2:1 was heated at 120 C microwave for 20 min. LCMS showed mostly conversion to the mono coupling product. 10 mg of pyridin-3-ylboronic acid (21.73 mg, 0.177 mmol) was added and the reaction was heated at 140 C under microwave for 20 min. The reaction mixture was directly loaded to CC (SiO2, DCM to DCM/MeOH=100:1 to 100:6) to give crude final product which was further purified by prep TLC (DCM/MeOH) to give 1-fluoro-3,7-di(pyridin-3-yl)-5′H-spiro[chromeno[2,3-c]pyridine-5,4′-oxazol]-2′-amine as a white solid. MS (M+1): 426.

Synthesis of (R) and (S)-2′-(neopentyloxy)-7′-(pyrimidin-5-yl)-5H-spiro[thiazole-4,9′-xanthen]-2-amine

Step 1: A 500 ml RB flask was charged with 2-bromo-7-iodo-9H-xanthen-9-one (16.030 g, 40.0 mmol) and THF (150 mL). The mixture was stirred for 10 min at RT and the resulting suspension was placed in water-ice bath for another 10 min. Methylmagnesium bromide, 3.0 M in Et 2 O (20.0 ml, 60.0 mmol) was added dropwise. After 1 hr, the mixture was carefully quenched with sat NH 4 Cl (150 mL) at 0° C. and diluted with EtOAc. The organic layer was washed with brine, dried with sodium sulfate, and concentrated in vacuo. The material was dissolved in 100 mL of methylene chloride, treated with PPTS (0.201 g, 0.800 mmol), and heated to reflux for 2 hr. The mixture was cooled to RT, diluted with methylene chloride, and washed with saturated sodium bicarbonate and brine. The organic fraction was dried over sodium sulfate and concentrated in vacuo to afford crude 2-bromo-7-iodo-9-methylene-9H-xanthene as a light orange solid that was advanced without further purification. MS: MH+=399.0/401.0.

Step 2: A 100 mL flask was charged with iodine (1.002 g, 3.95 mmol) and THF (30 mL) and the resulting solution was cooled to −20° C. in a methanol-ice bath. Thiocyanatosilver (1.872 g, 11.28 mmol) was added in one portion and the resulting mixture was stirred for 0.5 hr at ca. −15° C. Crude 2-bromo-7-iodo-9-methylene-9H-xanthene (1.500 g, 3.76 mmol) was added as a solid in one portion and the resulting mixture was stirred for 5 min @−15° C., then at 0° C. for 1 hr. The yellow mixture was filtered through celite with the aid of THF (5 ml) and to the filtrate was dropwise added 2-methylpropan-2-amine (1.195 mL, 11.28 mmol) at RT. After 20 hrs, the solution was concentrated in vacuo, taken up in CH2Cl2, and adsorbed onto silica gel. The material was purified by silica gel chromatography using 15-30% Hexanes:EtOAc to afford 2′-bromo-N-tert-butyl-7′-iodo-5H-spiro[thiazole-4,9′-xanthen]-2-amine as a yellow solid. MH+=529.8/530.8.

Step 3: To a mixture of sodium carbonate (1.562 g, 14.74 mmol), palladium tetrakistriphenylphosphine (0.454 g, 0.393 mmol), pyrimidin-5-ylboronic acid (0.791 g, 6.39 mmol) and 2′-bromo-N-tert-butyl-7′-iodo-5H-spiro[thiazole-4,9′-xanthen]-2-amine (2.600 g, 4.91 mmol) in a resealable pressure tube, was added DME (15 mL) and water (5 mL) at RT. The tube was sealed and heated to 80° C. After 24 hrs, the mixture was cooled to RT, diluted with EtOAc, and washed with water and brine. The organic fraction was adsorbed onto silica gel and purified by silica gel chromatography using 40% hexanes:EtOAc to afford 2′-bromo-N-tert-butyl-7′-(pyrimidin-5-yl)-5H-spiro[thiazole-4,9′-xanthen]-2-amine MS: MH+=481.0/483.0.

Step 4: A pressure tube was charged with 2′-bromo-N-tert-butyl-7′-(pyrimidin-5-yl)-5H-spiro[thiazole-4,9′-xanthen]-2-amine (0.150 g, 0.312 mmol), 4,4,4′,4′,5,5,5′,5′-octamethyl-2,2′-bi(1,3,2-dioxaborolane) (0.237 g, 0.935 mmol), potassium acetate (0.092 g, 0.935 mmol), XPhos (0.030 g, 0.062 mmol), diacetoxypalladium (7.00 mg, 0.031 mmol), and 1,4-dioxane (3.0 mL, 0.312 mmol). The tube was purged with Argon, sealed, and heated to 100° C. After 18 hrs the dark mixture was filtered over celite with EtOAc. The filtrate was concentrated in vacuo and purified by silica gel chromatography using 25-50% Hexanes:EtOAc to afford N-tert-butyl-2′-(pyrimidin-5-yl)-7′-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-5H-spiro[thiazole-4,9′-xanthen]-2-amine as a white foam. MH+=529.2.

Step 5: To a mixture of N-tert-butyl-2′-(pyrimidin-5-yl)-7′-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-5H-spiro[thiazole-4,9′-xanthen]-2-amine (0.475 g, 0.899 mmol), NaOH solid (0.062 mL, 3.33 mmol), and hydroxyammonium chloride (0.120 mL, 2.88 mmol) was added Ethanol (8 mL). The mixture was stirred at RT. After 48 hrs, the mixture was concentrated in vacuo and the residue partioned between DCM and water. The aqueous layer was acidified to ca. pH=7 and extracted with CH 2 Cl 2 . The combined organic fractions were adsorbed onto silica gel and purified by silica gel chromatography using 40-80% Hexanes:EtOAc to give 2-(tert-butylamino)-7′-(pyrimidin-5-yl)-5H-spiro[thiazole-4,9′-xanthen]-2′-ol as an off-white solid. MS: MH+=419.2.

Step 6: To a solution of 2-(tert-butylamino)-7′-(pyrimidin-5-yl)-5H-spiro[thiazole-4,9′-xanthen]-2′-ol (0.075 g, 0.179 mmol) in DMF (2 mL) was added cesium carbonate (0.175 g, 0.538 mmol) followed by 1-iodo-2,2-dimethylpropane (0.048 mL, 0.358 mmol). The mixture was heated to 100° C. After 6 hrs the mixture was cooled to RT, diluted with EtOAc, and washed with water and brine. The organic fraction was concentrated in vacuo and purified by silica gel chromatography using 40-60% Hexanes:EtOAc to afford N-tert-butyl-2′-(neopentyloxy)-7′-(pyrimidin-5-yl)-5H-spiro[thiazole-4,9′-xanthen]-2-amine as an off-white foam. MS: MH+=489.2.

Step 7: A resealable tube charged with a solution of N-tert-butyl-2′-(neopentyloxy)-7′-(pyrimidin-5-yl)-5H-spiro[thiazole-4,9′-xanthen]-2-amine (0.033 g, 0.068 mmol) in 48% HBr (1.00 mL, 18.42 mmol) was heated to 80° C. After 3 hrs, the solution was cooled and evaporated to dryness with a stream of N2. The residue was treated with CH2Cl2 (2 mL) and TEA (0.1 mL). The solution was loaded onto a silica gel column and purified with 1-5% MeOH:CH2Cl2 w/1% NH4OH (Rf=0.5 in 10% MeOH:CH2Cl2 w/1% NH4OH) to afford racemic material that was resolved by chiral chromatography to give both (R) and (S)-2′-(neopentyloxy)-7′-(pyrimidin-5-yl)-5H-spiro[thiazole-4,9′-xanthen]-2-amine MS Found: MH + =433.2.

A glass microwave reaction vessel was charged with (S)-3-chloro-7-(2-fluoro-5-methylpyridin-3-yl)-5′H-spiro[chromeno[2,3-c]pyridine-5,4′-oxazol]-2′-amine (0.100 g, 0.252 mmol), potassium phosphate (0.160 g, 0.756 mmol), 2-(3,6-dihydro-2H-pyran-4-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (0.106 g, 0.504 mmol) and Bis(di-tert-butyl(4-dimethylaminophenyl)phosphine)dichloropalladium (II) (8.92 mg, 0.013 mmol) in dioxane (1.2 mL) and water (0.40 mL). The reaction mixture was stirred and heated in microwave at 120° C. for 30 minutes before being diluted with EtOAc and saturated Na 2 CO 3 . The organic layer was washed twice with saturated Na 2 CO 3 , dried over Na2SO4 and concentrated in vacuo. The crude was purified by silica gel chromatography (2-10% MeOH—CH 2 Cl 2 ), followed by preparative HPLC (15-60% CH 3 CN (with 0.1% TFA)-water (with 0.1% TFA) in 20 min) to provide (S)-3-(3,6-dihydro-2H-pyran-4-yl)-7-(2-fluoro-5-methylpyridin-3-yl)-5′H-spiro[chromeno[2,3-c]pyridine-5,4′-oxazol]-2′-amine as a white solid (MS: MH + =445).

A vial was charged with (S)-2-amino-4′-fluoro-7′-(2-fluoropyridin-3-yl)-5H-spiro[oxazole-4,9′-xanthen]-2′-ol (45.0 mg, 0.118 mmol), cesium carbonate (57.7 mg, 0.177 mmol), and DMF (787 μL). The mixture was stirred vigorously for 15 min, then 2-cyano-2-methylpropyl trifluoromethanesulfonate (22.56 μL, 0.130 mmol) was added via syringe. The resulting mixture was stirred at room temperature for 19 hours before being diluted with water (10 mL) and EtOAc (10 mL). The layers were separated, and the aqueous layer was extracted with EtOAc (2×10 mL). The combined organic extracts were dried over sodium sulfate, filtered, and evaporated. The residue was purified by chromatography on a 12 g Redi-Sep column, eluting with 5-60% MeOH/DCM to give (S)-3-(2-amino-5′-fluoro-2′-(2-fluoropyridin-3-yl)-5H-spiro[oxazole-4,9′-xanthene]-7′-yloxy)-2,2-dimethylpropanenitrile as an off-white solid. (MS: MH + =463).

A vial was charged with (S)-2′-amino-3-((3-methyloxetan-3-yl)ethynyl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazole]-7-yl trifluoromethanesulfonate (50.0 mg, 0.101 mmol), 2-fluoropyridin-3-ylboronic acid (21.33 mg, 0.151 mmol), potassium carbonate (69.7 mg, 0.505 mmol), and Pd(PPh 3 ) 4 (11.66 mg, 10.09 μmol). The vial was flushed with Ar (g), then dioxane (505 μL) and water (0.25 mL) were added in sequence. The vial was sealed and placed in a 70° C. oil for 1 hour. The mixture was diluted with EtOAc and washed with brine. The organic layer was dried over sodium sulfate, filtered, and evaporated. The residue was chromatographed on a 12-g Redi-Sep column with 0-60% of a 90:10:1 mix of DCM/MeOH/NH 4 OH in DCM to give a pink solid. The solid was dissolved in MeOH and loaded onto a 500-mg SCX-2 column. The column was first eluted with methanol, then with 2N ammonia in methanol to remove the product. The filtrate was evaporated to give (S)-7-(2-fluoropyridin-3-yl)-3-(3-methyloxetan-3-yl)ethynyl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine as pale yellow solid. Found MS: MH+=443.0.

A 25 mL RB flask was charged with (R)-2-amino-2′-(2,2-dimethylmorpholino)-5H-spiro[oxazole-4,9′-xanthene]-7′-yl trifluoromethanesulfonate (270 mg, 0.526 mmol), tetrakis(triphenylphosphine)palladium(0) (60.8 mg, 0.053 mmol), 2-fluoropyridin-3-ylboronic acid (119 mg, 0.841 mmol), DMF (2629 μL) and sodium carbonate (2M solution) (789 μL, 1.577 mmol). The mixture was stirred under argon for 2 hrs at 85° C.

The mixture was diluted with water (2 ml) and extracted with 10 ml of EtOAc. The organic layer was washed with water, brine, passed through plug of Celite and concentrated. Dark residue was purified by silica gel chromatography on a 12 g RediSep column using 5-70% DCM/MeOH/NH 4 OH in DCM to afford (S)-2′-(2,2-dimethylmorpholino)-7′-(2-fluoropyridin-3-yl)-5H-spiro[oxazole-4,9′-xanthen]-2-amine Found MS: MH+=461.

Synthesis of (S)-2′-(3,6-dihydro-2H-pyran-4-yl)-3′-fluoro-7′-(pyrimidin-5-yl)-5H-spiro[oxazole-4,9′-xanthen]-2-amine

A 0.5-2 ml microwave vial was charged with tetrakis(triphenylphosphine)palladium(0) (27.9 mg, 0.024 mmol), 2-(3,6-dihydro-2H-pyran-4-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (86 mg, 0.411 mmol). A solution of (S)-2-amino-6′-fluoro-2′-(pyrimidin-5-yl)-5H-spiro[oxazole-4,9′-xanthene]-7′-yl trifluoromethanesulfonate (120 mg, 0.242 mmol) in DMF (1612 μL) was added followed by sodium carbonate (2M solution) (363 μL, 0.725 mmol). The vial was sealed and heated in microwave reactor at 85° C. for 1 hr. The mixture was diluted with water and extracted with EtOAc. The organic layer was washed with water, brine, filtered through celite and concentrated to leve brown oil. The crude material was purified by silica gel chromatography on 12 g RediSep column using (15-60% DCM/MeOH/NH 4 OH 90:10:1 in DCM) to afford (S)-2′-(3,6-dihydro-2H-pyran-4-yl)-3′-fluoro-7′-(pyrimidin-5-yl)-5H-spiro[oxazole-4,9′-xanthen]-2-amine Found MS: MH+=431.

Synthesis of (S)-4′-fluoro-2′-(2-fluoro-2-methylpropoxy)-7′-(pyrimidin-5-yl)-5H-spiro[oxazole-4,9′-xanthen]-2-amine

A vial was charged with (S)-2-amino-4′-fluoro-7′-(pyrimidin-5-yl)-5H-spiro[oxazole-4,9′-xanthen]-2′-ol (61.0 mg, 0.167 mmol), cesium carbonate (82 mg, 0.251 mmol), and DMF (670 μL). The resulting mixture was stirred vigorously for 10 min, then the vial was placed in large ice-bath for 10 min. 2-fluoro-2-methylpropyl trifluoromethanesulfonate (33.3 μL, 0.201 mmol) was added dropwise and the ice-bath was removed after 5 minutes. The mixture was stirred at for 6 hours, then the mixture was diluted with water (10 mL) and extracted with EtOAc (3×5 mL). The combined organic extracts were dried over sodium sulfate, filtered, and evaporated. The residue was chromatographed on a 12 g Redi-Sep column, eluting with 5-60% gradient of DCM/MeOH/NH4OH (90:10:1) in DCM to give (S)-4′-fluoro-2′-(2-fluoro-2-methylpropoxy)-7′-(pyrimidin-5-yl)-5H-spiro[oxazole-4,9′-xanthen]-2-amine as an off-white solid. Found MS: MH+=439.

Synthesis of (S)-3-(3,6-dihydro-2H-pyran-4-yl)-7-(2-fluoropyridin-3-yl)-5′H-spiro[chromeno[2,3-c]pyridine-5,4′-oxazol]-2′-amine

A glass microwave reaction vessel was charged with (S)-3-chloro-7-(2-fluoropyridin-3-yl)-5′H-spiro[chromeno[2,3-c]pyridine-5,4′-oxazol]-2′-amine (0.075 g, 0.196 mmol), potassium phosphate (0.125 g, 0.588 mmol), 2-(3,6-dihydro-2H-pyran-4-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (0.082 g, 0.392 mmol) and Bis(di-tert-butyl(4-dimethylaminophenyl)phosphine)dichloropalladium (II) (0.014 g, 0.020 mmol) in dioxane (1.2 mL) and water (0.40 mL). The reaction mixture was stirred and heated in microwave at 120° C. for 30 min. The mixture was diluted with EtOAc and saturated Na 2 CO 3 . The organic layer was washed twice with saturated Na 2 CO 3 , dried over Na 2 SO 4 and concentrated in vacuo. The crude was purified by silica gel chromatography (12 g, 2-10% MeOH-DCM, then 10% MeOH-DCM) provided (S)-3-(3,6-dihydro-2H-pyran-4-yl)-7-(2-fluoropyridin-3-yl)-5′H-spiro[chromeno[2,3-c]pyridine-5,4′-oxazol]-2′-amine as a grey solid. Found MS: MH+=431.

Synthesis of (R)-2′-(3,6-dihydro-2H-pyran-4-yl)-4′-fluoro-7′-(pyrimidin-5-yl)-5H-spiro[oxazole-4,9′-xanthen]-2-amine

A vial was charged with 2-amino-2′-(3,6-dihydro-2H-pyran-4-yl)-4′-fluoro-5H-spiro[oxazole-4,9′-xanthene]-7′-yl trifluoromethanesulfonate (150 mg, 0.300 mmol), pyrimidin-5-ylboronic acid (111 mg, 0.899 mmol), and Pd(PPh 3 ) 4 (34.6 mg, 0.030 mmol). The vial was purged with Ar (g), then DMF (2 mL) and potassium carbonate (0.749 mL, 1.499 mmol) (as a 2.0 M aq. solution) were added in sequence. The vial was capped and heated in a Biotage Initiator microwave reactor for 1.5 h at 75° C. The product was purified via Gilson HPLC (gradient elution 20-90% MeCN/H 2 O, 0.1% TFA) to afford (R)-2′-(3,6-dihydro-2H-pyran-4-yl)-4′-fluoro-7′-(pyrimidin-5-yl)-5H-spiro[oxazole-4,9′-xanthen]-2-amine as an off white solid. Found MS: MH+=431.

Synthesis of (S)-7-(5-chloro-2-fluorophenyl)-3-(3,6-dihydro-2H-pyran-4-yl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine

A vial was charged with (S)-2′-amino-3-(3,6-dihydro-2H-pyran-4-yl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazole]-7-yl trifluoromethanesulfonate (0.050 g, 0.103 mmol), 5-chloro-2-fluorophenylboronic acid (0.054 g, 0.310 mmol), and Pd(PPh 3 ) 4 (5.97 mg, 5.17 μmol). The vial was purged with Ar (g). Then, DMF (0.517 mL) and potassium carbonate (0.259 mL, 0.517 mmol) (as a 2.0 M aq. solution) were added in sequence. The vial was sealed and stirred at 70° C. for one hour. The reaction was diluted with ethyl acetate and washed with water. The aqueous layer was extracted with ethyl acetate, and the combined organic layers were dried with sodium sulfate, filtered, and concentrated. The material was purified via column chromatography (RediSep 40 g, gradient elution 0-7% MeOH in DCM) to afford (S)-7-(5-chloro-2-fluorophenyl)-3-(3,6-dihydro-2H-pyran-4-yl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine as a white solid. Found MS: MH+=464.

Synthesis of (R)-2′-(3,6-dihydro-2H-pyran-4-yl)-4′-fluoro-7′-(pyridin-3-yl)-5H-spiro[oxazole-4,9′-xanthen]-2-amine

A vial was charged with 2-amino-2′-(3,6-dihydro-2H-pyran-4-yl)-4′-fluoro-5H-spiro[oxazole-4,9′-xanthene]-7′-yl trifluoromethanesulfonate (150 mg, 0.300 mmol), pyridin-3-ylboronic acid (111 mg, 0.899 mmol), and Pd(PPh 3 ) 4 (34.6 mg, 0.030 mmol). The vial was purged with Ar (g), then DMF (2 mL) and potassium carbonate (0.749 mL, 1.499 mmol) (as a 2.0 M aq. solution) were added in sequence. The vial was capped and heated in a Biotage Initiator microwave reactor for 1.5 h at 75° C. The product was purified via Gilson HPLC (gradient elution 20-90% MeCN/H 2 O, 0.1% TFA) to afford (R)-2′-(3,6-dihydro-2H-pyran-4-yl)-4′-fluoro-7′-(pyridin-3-yl)-5H-spiro[oxazole-4,9′-xanthen]-2-amine as an off white solid. Found MS: MH+=430.

Synthesis of (S)-3-(3,3-dimethylbut-1-ynyl)-7-(2-fluoropyridin-3-yl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine

Combined (S)-3-bromo-7-(2-fluoropyridin-3-yl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine (80 mg, 0.187 mmol), tetrakis(triphenylphosphine)palladium (21.64 mg, 0.019 mmol), copper(i) iodide (3.57 mg, 0.019 mmol) and THF (749 μL, 0.187 mmol) and DMF (749 μL, 0.187 mmol) in a reaction tube. Added DIPA (525 μL, 3.75 mmol) then 3,3-dimethylbut-1-yne (115 μL, 0.936 mmol) and flushed the reaction tube with argon. Sealed and heated at 110° C. for 3 hours. The mixture was partioned between water (10 mL) and EtOAc (10 mL). The layers were separated, and the aqueous layer was extracted with EtOAc (2×10 mL). The combined organic extracts were dried over sodium sulfate, filtered, and evaporated. The residue was purified by chromatography on a 25-g SNAP column, eluting with 0-70% of a 90:10:1 mixture of DCM/MeOH/NH 4 OH in DCM. The derived residue was then purified by reverse-phase HPLC (10-90% CH 3 CN/H 2 O with 0.1% TFA) to give (S)-3-(3,3-dimethylbut-1-ynyl)-7-(2-fluoropyridin-3-yl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine as a white powder after evaporation from DCM/hexane. Found MS: MH+=429.

The following examples in Table I were prepared by methods and Steps analogous to those described in Examples 1-86 above. Provided also is the mass spectral data and BACE enzyme and cell-based assay data (IC 50 's in uM ranges) for each example, where available. Where the name of the exemplified compound, in each of the Tables herein, does not designate a specific (S) or (R) stereoisomer, then the Example was tested as a racemic mixture. Racemic mixture Examples were in many cases, found to be generally close to a 1:1 stereoisomer mixture.

The following are procedures for preparing intermediates, which were used to prepare Examplary compounds, representative of the present invention. The procedures and Methods hereforth were used to prepare the compounds in Table I herein.

Method BB1

Synthesis of 7-(5-chloro-2-fluorophenyl)-3-((2-methyl-1,3-dioxolan-2-yl)methoxy)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine

Step 1: A solution of 2′-amino-7-bromo-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-3-ol (0.570 g, 1.637 mmol) in 5 mL DMF was treated with potassium carbonate (0.283 g, 2.047 mmol) and was allowed to stir at RT for 15 minutes. The reaction mixture was then cooled to 0° C. and 1-chloropropan-2-one (0.151 g, 1.637 mmol) was added as a solution in 1 mL THF. After stirring for one hour the reaction mixture was allowed to warm to RT and stir for 4 hours. The reaction mixture was poured into 1:1 water/brine, extracted with EtOAc (3×25 mL). The combined organics were dried over MgSO 4 and concentrated. Purification of the crude residue by column chromatography provided 1-(2′-amino-7-bromo-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazole]-3-yloxy)propan-2-one. MS m/z=404.0 [M+H].

Step 2: A vial charged with 5-chloro-2-fluorophenylboronic acid (0.431 g, 2.474 mmol), palladiumtetrakis (0.057 g, 0.049 mmol), potassium carbonate (0.684 g, 4.95 mmol), and 1-(2′-amino-7-bromo-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazole]-3-yloxy)propan-2-one (0.400 g, 0.990 mmol) was treated with 5 mL dioxane followed by 1 mL water. The vial was flushed with argon and was heated to 80° C. for 3 hours. The reaction mixture was diluted with EtOAc (25 mL) and dried over MgSO 4 . The organic layers were combined and concentrated, and the crude residue was purified by column chromatography yielding 1-(2′-amino-7-(5-chloro-2-fluorophenyl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazole]-3-yloxy)propan-2-one. MS m/z=454.0 [M+H].

Step 3: To a vial charged with 1-(2′-amino-7-(5-chloro-2-fluorophenyl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazole]-3-yloxy)propan-2-one (0.140 g, 0.308 mmol), p-toluenesulfonic acid (0.159 g, 0.925 mmol), and 4 Angstrom molecular seives was added 3 mL toluene. The resulting mixture was treated with ethylene glycol (0.022 mL, 0.401 mmol) and was heated to reflux. After stirring for 10 hours, copper(ii) sulfate (0.059 g, 0.617 mmol) was added followed by an additional portion of ethylene glycol (0.022 mL, 0.401 mmol). The reaction mixture was heated to reflux for an additional 4 hours before being allowed to cool to RT. The mixture was poured into saturated NaHCO 3 (25 mL) solution and extracted with EtOAc (3×25 mL). The organics were washed with brine, dried over MgSO 4 and concentrated. Purification of the crude residue by column chromatography gave 7-(5-chloro-2-fluorophenyl)-3-((2-methyl-1,3-dioxolan-2-yl)methoxy)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine. MS m/z=498.0 [M+H].

Method BB2

Synthesis of (S)-4′-fluoro-N7′-(3-methoxyphenyl)-2′-morpholino-5H-spiro[oxazole-4,9′-xanthene]-2,7′-diamine

Step 1: A vial was charged with (S)-2-amino-7′-bromo-4′-fluoro-5H-spiro[oxazole-4,9′-xanthen]-2′-ol (400 mg, 1.095 mmol), di-tert-butyl(2′,4′,6′-triisopropylbiphenyl-2-yl)phosphine (81 mg, 0.192 mmol), Pd 2 dba 3 (50.2 mg, 0.055 mmol), sodium tert-butoxide (316 mg, 3.29 mmol) and 3-methoxyaniline (245 μL, 2.191 mmol). Toluene (2191 μL) was added and the vial was flushed with argon, sealed and shaken to combine all the components. The resulting dark mixture was heated at 100° C. for 16 hrs. The mixture was diluted with water (5 ml) and ethyl acetate (15 ml) and neutralized with saturated NH 4 Cl solution. The organic layer was loaded onto a 5 g SCX column and washed with EtOAc and MeOH. The material was recovered from the column by washing with 2M NH 3 in MeOH. Concentration and separated by silica gel chromatography (10-80% CH 2 Cl 2 /MeOH/NH 4 OH in CH 2 CO provided (S)-2-amino-4′-fluoro-7′-(3-methoxyphenylamino)-5H-spiro[oxazole-4,9′-xanthen]-2′-ol (230 mg, 0.565 mmol, 51.5% yield). MS m/z=408.0 [M+H].

Step 2: To a solution of (S)-2-amino-4′-fluoro-7′-(3-methoxyphenylamino)-5H-spiro[oxazole-4,9′-xanthen]-2′-ol (230 mg, 0.565 mmol) in CH 2 Cl 2 (2823 μL), triethylamine (157 μL, 1.129 mmol) and 1,1,1-trifluoro-N-phenyl-N-(trifluoromethylsulfonyl)methanesulfonamide (323 mg, 0.903 mmol) were added and the mixture was left at RT for 1 hr. The mixture was directly loaded to 12 g RediSep column and purified by silica gel chromatography using 0-50% CH 2 Cl 2 /MeOH/NH 4 OH in CH 2 Cl 2 to afford (S)-2-amino-5′-fluoro-2′-(3-methoxyphenylamino)-5H-spiro[oxazole-4,9′-xanthene]-7′-yl trifluoromethanesulfonate. MS m/z=540.0 [M+H].

Step 3: A vial was charged with morpholine (0.062 mL, 0.706 mmol), (S)-2-amino-5′-fluoro-2′-(3-methoxyphenylamino)-5H-spiro[oxazole-4,9′-xanthene]-7′-yl trifluoromethanesulfonate (127 mg, 0.235 mmol), Pd 2 dba 3 (10.78 mg, 0.012 mmol), (8.43 mg, 0.028 mmol). The tube was flushed with argon and LiHMDS (1M in THF) (0.942 mL, 0.942 mmol) was added and the vial sealed and heated at 110° C. in microwave reactor for 1 hr. The mixture was quenched with 1 ml of water, diluted with EtOAc, and loaded onto 2 g SCX-2 column. The column was washed with EtOAc and MeOH. The material was flushed from the column using 2M ammonia in MeOH. The derived solution was purified by silica gel chromatography to afford (S)-4′-fluoro-N7′-(3-methoxyphenyl)-2′-morpholino-5H-spiro[oxazole-4,9′-xanthene]-2,7′-diamine MS m/z=477.0 [M+H].

Method BB3

Synthesis of (5S)-7-(2,4-difluoro-3-pyridinyl)-3-(3,6-dihydro-2H-pyran-4-yl)spiro[chromeno[2,3-c]pyridine-5,4′-[1,3]oxazol]-2′-amine

Step 1: A mixture (S)-7-bromo-3-chloro-5′H-spiro[chromeno[2,3-c]pyridine-5,4′-oxazol]-2′-amine (1.00 g, 2.73 mmol, prepared as described in Method BB41), bis(pinacolato)diboron (0.831 g, 3.27 mmol), dichloro(1,1-bis(diphenylphosphinoferrocene))palladium(ii) complex with DCM (0.111 g, 0.136 mmol), and KOAc (0.512 mL, 8.18 mmol) of in dioxane (10 mL) was purged with nitrogen for 10 minutes and heated in a microwave at 120° C. for 1 h. The reaction was diluted with water and extracted with EtOAc (2×25 mL). The organic phase was washed with brine, dried over NaSO 4 , and concentrated under vacuum to give the desired product (S)-3-chloro-7-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-5′H-spiro[chromeno[2,3-c]pyridine-5,4′-oxazol]-2′-amine (0.42 g, 1.015 mmol, 37.2% yield) which was carried on without further purification.

Step 2: A 20 mL glass microwave reaction vessel was charged with (S)-3-chloro-7-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-5′H-spiro[chromeno[2,3-c]pyridine-5,4′-oxazol]-2′-amine (0.251 g, 0.608 mmol), potassium phosphate (0.269 g, 1.266 mmol), 2,4-difluoro-3-iodopyridine (0.122 g, 0.506 mmol) and bis(di-tert-butyl(4-dimethylaminophenyl)phosphine)dichloropalladium (II) (0.036 g, 0.051 mmol) in dioxane (3.2 mL) and water (0.8 mL). The reaction mixture was heated at 100° C. for 30 min in microwave reactor. After cooling the rt the mixture was diluted with EtOAc and water. The aqueous layer was washed twice with saturated Na 2 CO 3 . The organic layer was dried over Na 2 SO 4 and concentrated in vacuo. The crude residue was purified by silica gel chromatography (2-10% MeOH—CH 2 Cl 2 ) to provide the desired product as a brown residue.

Step 3: A glass microwave reaction vessel was charged with (S)-3-chloro-7-(2,4-difluoropyridin-3-yl)-5′H-spiro[chromeno[2,3-c]pyridine-5,4′-oxazol]-2′-amine (0.190 g, 0.474 mmol), potassium phosphate (0.302 g, 1.422 mmol), 2-(3,6-dihydro-2H-pyran-4-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (0.169 g, 0.806 mmol) and bis(di-tert-butylphenylphosphine)dichloropalladium (II) (0.029 g, 0.047 mmol) in dioxane (4 mL) and water (1.2 mL). The reaction mixture was heated in microwave at 110° C. for 30 min. The mixture was diluted with EtOAc and saturated Na 2 CO 3 . The organic layer was washed twice with saturated Na 2 CO 3 , dried over Na 2 SO 4 and concentrated in vacuo. The crude residue was purified by silica gel chromatography (2-10% MeOH—CH 2 Cl 2 ) to provide a residue that was purified by HPLC to provide the titled compound as a white solid. MS m/z=449.2 [M+H] + . Calculated for C 24 H 18 F 2 N 4 O 3 : 448.13.

1 H NMR (400 MHz, CHLOROFORM-d) δ ppm 2.54-2.75 (m, 2 H) 3.95 (t, J=5.38 Hz, 2 H) 4.36-4.43 (m, 4 H) 4.63-4.81 (m, 1 H) 6.63 (br. s., 1 H) 7.07 (dd, J=8.02, 5.67 Hz, 1H) 7.29 (s, 1 H) 7.39 (s, 1 H) 7.46 (d, J=8.02 Hz, 1 H) 7.56 (s, 1 H) 8.16 (dd, J=7.82, 5.67 Hz, 1 H) 8.49 (s, 1 H)

Method BB4

Synthesis of (5S)-7-bromo-2-fluoro-3-(trimethylsilyl)spiro[chromeno[2,3-b]pyridine-5,4′-[1,3]oxazol]-2′-amine

Step 1: 2,6-Difluoro-5-(trimethylsilyl)pyridine-3-carboxylic acid (1.17 g, 5.05 mmol) was dissolved in a mixture of DCM (20 mL) and MeOH (5 mL) and treated with (trimethylsilyl)diazomethane (2.0 m in diethyl ether, 5.0 mL, 10.00 mmol). [2,6-Difluoro-5-(trimethylsilyl)pyridine-3-carboxylic acid was synthesized according to M. Schlosser and T. Rausis, Eur. J. Org. Chem., 2004, pp 1018-1024]. The derived solution was maintained at rt for 1 hour. Evaporation under reduced pressure and purification using the by silica gel chromatography (hexane to ethyl actetate gradient) gave the desired methyl 2,6-difluoro-5-(trimethylsilyl)nicotinate.

Step 2: Methyl 2,6-difluoro-5-(trimethylsilyl)nicotinate (1.19 g, 4.85 mmol), 4-bromo-2-iodophenol (1.450 g, 4.85 mmol), and silver trifluoromethanesulfonate (1.496 g, 5.82 mmol) were dissolved in dry THF (40 mL) and treated with potassium carbonate (1.006 g, 7.28 mmol). The mixture was heated to 60° C. for 10 hours before being cooled to rt and filtered through a pad of celite. Water (100 mL) and diethyl ether (100 mL) were added to the filtrate and the phases were separated. The organics were dried with magnesium sulfate, filtered and evaporated to dryness under reduced pressure. Purification using silica chromatography (hexane to DCM gradient) gave the desired methyl 2-(4-bromo-2-iodophenoxy)-6-fluoro-5-(trimethylsilyl)nicotinate.

Step 3: Methyl 2-(4-bromo-2-iodophenoxy)-6-fluoro-5-(trimethylsilyl)nicotinate (2.04 g, 3.89 mmol) was dissolved in dry THF (80 mL) and cooled in a dry ice bath to −78° C. Isopropylmagnesium chloride (2.0 M solution in diethyl ether, 3.89 mL (7.78 mmol) was added and the solution stirred for 15 minutes. The mixture was removed from the cold bath and allowed to slowly warm to RT. Water (100 mL), saturated ammonium chloride (10 mL), and EtOAc (200 mL) were added and the phases mixed and separated. The organics were dried with magnesium sulfate and evaporated to dryness under reduced pressure. The crude was purified using silica chromatography (hexane to ethyl acetate gradient) to give 7-bromo-2-fluoro-3-(trimethylsilyl)-5H-chromeno[2,3-b]pyridin-5-one.

Step 4: 7-bromo-2-fluoro-3-(trimethylsilyl)-5H-chromeno[2,3-b]pyridin-5-one (1.05 g, 2.9 mmol) was dissolved in dry THF (30 mL) and treated with methylmagnesium bromide (3.0 M in diethyl ether, 2.0 mL, 6.00 mmol). After 15 minutes 5N HCl (30 mL) was added followed by EtOAc (100 mL) and water (100 mL). The phases were mixed and separated and the organics were dried with magnesium sulfate before evaporating to dryness under reduced pressure. Purification using silica chromatography (hexane to dichloromethane gradient) gave the desired 7-bromo-2-fluoro-5-methylene-3-(trimethylsilyl)-5H-chromeno[2,3-b]pyridine.

Step 5: Iodine (0.364 g, 1.435 mmol) was dissolved in dry THF (30 mL) under nitrogen and cooled to −78° C. Silver cyanate (0.615 g, 4.10 mmol) was added in one portion and the mixture was stirred for 5 minutes. This slurry was transferred to a −30° C. bath and it was stirred for another 10 minutes. A solution of 7-bromo-2-fluoro-5-methylene-3-(trimethylsilyl)-5H-chromeno[2,3-b]pyridine (0.498 g, 1.367 mmol) in dry tetrahydrofuran (10 mL) was added and the reaction stirred for 1 hour maintaining the bath temperature between −25 and −15° C. The reaction was diluted with diethyl ether (10 mL) and filtered through a pad of celite. The solids were washed with 1:1 THF:ether (20 mL) then the filtrate was cooled in a −20° C. bath under nitrogen. Ammonia (2.0 M solution in MeOH, 3.5 mL, 7.00 mmol) was added and the flask sealed. The solution was allowed to warm slowly over the next 10 hours. The reaction mixture was evaporated to dryness under reduced pressure and the crude purified using silica chromatography (0-10% methanol in dichloromethane gradient) to give 7-bromo-2-fluoro-3-(trimethylsilyl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine

Step 6: 7-Bromo-2-fluoro-3-(trimethylsilyl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine (0.137 g, 0.324 mmol), bis-(di-tert-butyl(4-dimethylaminophenyl)phosphine)dichloropalladium(ii) (0.011 g, 0.016 mmol), 2-fluoropyridin-3-ylboronic acid (0.055 g, 0.389 mmol), and potassium acetate (0.127 g, 1.298 mmol) were suspended in a mixture of ethanol (30 mL) and water (5 mL) and heated to 80° C. After 20 minutes the solution was cooled to rt and concentrated under reduced pressure to ˜10 mL. This solution was then diluted with water (100 mL) and EtOAc (100 mL). The phases were mixed and separated and the organics were dried with magnesium sulfate before filtered and evaporated to dryness under reduced pressure. Purification using silica chromatography (0-10% methanol in DCM gradient followed by a second column using dichloromethane to EtOAc gradient) gave the desired 2-fluoro-7-(2-fluoropyridin-3-yl)-3-(trimethylsilyl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine

Method BB5

Step 1: A mixture of cesium carbonate (3.20 mL, 40.0 mmol), 5-bromosalicylic acid (4.34 g, 20.00 mmol) and 2,6-difluoropyridine (5.52 g, 48.0 mmol) in 8 mL of DMSO was stirred at 110° C. for 3 h. After cooling to rt, the reaction mixture was dissolved in water and the pH was adjusted to ˜3 with 1 N HCl. The reaction mixture was extracted with EtOAC (3×25 mL), washed with brine and evaporated to dryness to give crude 5-bromo-2-(6-fluoropyridin-2-yloxy)benzoic acid which was used directly in the next step.

Step 2: To mixture of 5-bromo-2-(6-fluoropyridin-2-yloxy)benzoic acid (16 g, 51.3 mmol) and TBTU (16.46 g, 51.3 mmol) in 15 mL of DMF was added diethylamine (13.26 mL, 128 mmol). The resulting solution was allowed to stir at rt overnight. The reaction was quenched with saturated NaHCO 3 , extracted with a 2:1 mixture of EtOAc and hexanes (3×50 mL). The combined organics were washed with brine, and evaporated to dryness. Purification by silica gel chromatography (hexane to CH 2 Cl 2 to CH 2 Cl 2 /EA=20:1 to 10:1 to 5:1) provided 5-bromo-N,N-diethyl-2-(6-fluoropyridin-2-yloxy)benzamide as a off-white solid.

Step 3: To a solution of 5-bromo-N,N-diethyl-2-(6-fluoropyridin-2-yloxy)benzamide (2.90 g, 7.90 mmol) in 50 mL of dry THF at −78° C. was added dropwise lithium diisopropylamide (2.0 M heptane/THF/ethylbenzene, 11.8 mL, 23.69 mmol) and the reaction was stirred at −78° C. for 2 hours. The reaction quenched at −78° C. with 30 mL of 1 N HCl in ether. After warming to rt, the reaction was further quenched with saturated NH 4 Cl (250 mL) extracted with ethyl acetate (3×250 mL). The combined organics were washed with brine, and evaporated to dryness. Purification by silica gel chromatography (hexane to hexane/CH 2 Cl 2 =1:1 to CH 2 Cl 2 to CH 2 Cl 2 /EA=10:1) gave 7-bromo-2-fluoro-5H-chromeno[2,3-b]pyridin-5-one as a white solid and 7-bromo-2-(diethylamino)-5H-chromeno[2,3-b]pyridin-5-one as a white solid.

Step 4: A solution of 7-bromo-2-fluoro-5H-chromeno[2,3-b]pyridin-5-one (150 mg, 0.510 mmol) in 5 mL of dry THF at −78° C. was added to methylmagnesium chloride, 3.0 M solution in THF (0.33 mL, 1.020 mmol) (0.33 mL) and the reaction was slowly warmed up to −30 C. At this temperature additional methylmagnesium chloride 3.0 M solution in THF (0.3 mL, 1.020 mmol) was added and stirring was continued for 1 hour. The reaction was quenched at −30° C. with saturated NH 4 Cl (150 mL) and extracted with EtOAc (3×150 mL). The combined organics were dried over sodium sulfate, filtered and evaporated to dryness. The derived residue was treated with 1 mg of PPTS in CH 2 Cl 2 at 25° C. for 0.5 h. This mixture was quenched with 0.1 g of NaHCO 3 and the solvent was evaporated to dryness to give crude 7-bromo-2-fluoro-5-methylene-5H-chromeno[2,3-b]pyridine which was directly used in the next step. A solution of iodine (27.6 μL, 0.536 mmol) in THF at −25° C. was treated with silver cyanate (76 μL, 2.040 mmol). After 30 min, a solution of the above derived olefin (7-bromo-2-fluoro-5-methylene-5H-chromeno[2,3-b]pyridine) in 20 mL of THF was added dropwise. The slurry was maintained at −25° C. for 2 h at which point the slurry was filtered through celite, washing well with ether. The brown filtrate was concentrated to dryness, taken up in THF (10 mL), cooled to 0° C. and treated with ammonia (2 M solution in 2-propanol, 1.1 mL, 2.040 mmol). The reaction was allowed to slowly warm to rt and stirred overnight. Half of the solvent was evaporated in vacuo and the residue was diluted with water (50 mL) and extracted with ethyl acetate (3×50 mL). The combined organics were dried over sodium sulfate, filtered and evaporated to dryness. Purification by silica gel chromatography (CH 2 Cl 2 to CH 2 Cl 2 /EA=3:1 to 2:1 to 1:1 to 1:2) afforded 7-bromo-2-fluoro-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine as a yellow solid.

Step 5: A mixture of 7-bromo-2-fluoro-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine (26.0 mg, 0.074 mmol), 2-fluoro-3-pyridineboronic acid (16.74 mg, 0.119 mmol), bis-(di-tert-butyl(4-dimethylaminophenyl)phosphine)dichloropalladium(ii) (2.103 mg, 2.97 μmol) and potassium phosphate (47.3 mg, 0.223 mmol) in a 2:1 mixture of dioxane and water (1.5 ml) was heated at 110° C. in the microwave for 20 minutes. The reaction mixture was subjected to purification by silica gel chromatography (SiO2, CH 2 Cl 2 to CH 2 Cl 2 /MeOH=100:1 to 100:6) to give 2-fluoro-7-(2-fluoropyridin-3-yl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine as a white solid. MS m/z=367.0 [M+H].

Method BB6

Synthesis of (S)-4-(2-amino-5′-fluoro-2′-(2-fluoropyridin-3-yl)-5H-spiro[oxazole-4,9′-xanthene]-7′-yl)-2-methylbutan-2-ol

Step 1: A 500 mL RBF was charged with (S)-2-amino-7′-bromo-4′-fluoro-5H-spiro[oxazole-4,9′-xanthen]-2′-ol (20.00 g, 54.8 mmol), 2-fluoropyridin-3-ylboronic acid (13.89 g, 99 mmol) and sodium carbonate (23.22 g, 219 mmol). DMF (130 mL) was added and the mixture was stirred for 1 minute before tetrakis(triphenylphosphine) palladium (4.43 g, 3.83 mmol) and water (52.2 mL) were added. The mixture was capped with argon, equipped with a reflux condenser and heated at 85° C. for 16 hrs. The mixture was cooled to RT and the resulting yellow precipitate was filtered. The filtrate was diluted with water (200 mL) and saturated ammonium chloride (200 mL), leading to the formation of a white precipitate and a brown semisolid. The precipitate was filtered and the semisolid was triturated with water (˜200 mL) to provide a brown solid which was also filtered and washed with water. The combined solids were washed excessively with water and dried overnight under a stream of air to afford (S)-2-amino-4′-fluoro-7′-(2-fluoropyridin-3-yl)-5H-spiro[oxazole-4,9′-xanthen]-2′-ol as tan solid which was used without further purification. MS m/z=382.0 [M+H].

Step 2: To a suspension of (S)-2-amino-4′-fluoro-7′-(2-fluoropyridin-3-yl)-5H-spiro[oxazole-4,9′-xanthen]-2′-ol (1.2 g, 3.15 mmol) in CH 2 Cl 2 (15.73 mL) were added triethylamine (0.877 mL, 6.29 mmol) and 1,1,1-trifluoro-N-phenyl-N-(trifluoromethylsulfonyl)methanesulfonamide (1.799 g, 5.03 mmol). The mixture was maintained at RT for 48 hours. to afford clear yellow solution LCMS 110110-4-2 showed ˜90% conversion. The mixture was diluted with CH 2 Cl 2 (15 mL) and washed sequentially with NaHCO 3 (25 mL) and brine. Filtration and concentration provided a solid that was purified by silica gel chromatography (0-40% CH 2 Cl 2 /MeOH/NH 4 OH in CH 2 Cl 2 ) to afford (S)-2-amino-5′-fluoro-2′-(2-fluoropyridin-3-yl)-5H-spiro[oxazole-4,9′-xanthene]-7′-yl trifluoromethanesulfonate as yellow foam. MS m/z=514.0 [M+H].

Step 3: A 15 ml resealable tube was charged with (S)-2-amino-5′-fluoro-2′-(2-fluoropyridin-3-yl)-5H-spiro[oxazole-4,9′-xanthene]-7′-yl trifluoromethanesulfonate (300 mg, 0.584 mmol), tetrakis(triphenylphosphine)palladium(0) (67.5 mg, 0.058 mmol), copper(i) iodide (11.13 mg, 0.058 mmol), DMF (2922 μL), 2-methylbut-3-yn-2-ol (114 μL, 1.169 mmol) and diisopropylamine (416 μL, 2.92 mmol). The mixture was capped with argon, sealed and heated at 85° C. for 1 hr. Concentration and purification of the crude residue by silica gel chromatography (10-60% CH 2 Cl 2 /MeOH/NH 4 OH 90:10:1 in CH 2 Cl 2 ) afforded (S)-4-(2-amino-5′-fluoro-2′-(2-fluoropyridin-3-yl)-5H-spiro[oxazole-4,9′-xanthene]-7′-yl)-2-methylbut-3-yn-2-ol. MS m/z=448.0 [M+H].

Step 4: A 100 ml flask was charged with (S)-4-(2-amino-5′-fluoro-2′-(2-fluoropyridin-3-yl)-5H-spiro[oxazole-4,9′-xanthene]-7′-yl)-2-methylbut-3-yn-2-ol (120 mg, 0.268 mmol) ethanol (4 ml). Palladium on carbon (86 mg, 0.080 mmol) was added under argon and the resulting mixture was hydrogenated under 1 atm of hydrogen gas for 1 hr. The mixture was filtered through celite and concentrated in vacuo to provide (S)-4-(2-amino-5′-fluoro-2′-(2-fluoropyridin-3-yl)-5H-spiro[oxazole-4,9′-xanthene]-7′-yl)-2-methylbutan-2-ol. MS m/z=454.0 [M+H].

Method BB7

Synthesis of (S)-3-(2-amino-5′-fluoro-2′-(pyrazin-2-yl)-5H-spiro[oxazole-4,9′-xanthene]-7′-yloxy)-2,2-dimethylpropanenitrile

Step 1: To a flask charged with potassium iodide (273 mg, 1.643 mmol), 2-cyano-2-methylpropyl trifluoromethanesulfonate (1140 mg, 4.93 mmol), cesium carbonate (3212 mg, 9.86 mmol), and (S)-2-amino-7′-bromo-4′-fluoro-5H-spiro[oxazole-4,9′-xanthen]-2′-ol (1200 mg, 3.29 mmol) was added 10 ml of DMF. The resulting slurry was heated for 1 hour at 60° C. The solution was quenched with water (20 mL). The aqueous layer was extracted with CH 2 Cl 2 (3×25 mL) and the combined organic layers were washed with brine and dried over anhydrous sodium sulfate. After being filtered and concentrated, the derived residue was purified via silica gel column chromatography using 15-70% 90/10/1 (CH 2 Cl 2 /MeOH/ammonia) in CH 2 Cl 2 to afford (S)-3-(2-amino-2′-bromo-5′-fluoro-5H-spiro[oxazole-4,9′-xanthene]-7′-yloxy)-2,2-dimethylpropanenitrile as a brown solid. MS m/z=446.0 [M+H].

Step 2: To a flask charged with Pd(PPh 3 ) 4 (8.82 mg, 0.034 mmol), 2-(tributylstannyl)pyrazine (248 mg, 0.672 mmol), and (S)-3-(2-amino-2′-bromo-5′-fluoro-5H-spiro[oxazole-4,9′-xanthene]-7′-yloxy)-2,2-dimethylpropanenitrile (150 mg, 0.336 mmol) was added 3 ml of DMF. The resulting mixture was heated in the microwave at 100° C. for one hour. The solution was concentrated in vacuo and the derived residue was purified by HPLC (gradient elution 10-90% MeCN/H 2 O, 0.1% TFA) to afford (S)-3-(2-amino-5′-fluoro-2′-(pyrazin-2-yl)-5H-spiro[oxazole-4,9′-xanthene]-7′-yloxy)-2,2-dimethylpropanenitrile as a white solid. MS m/z=446.0 [M+H].

Method BB8

Synthesis of (S)-2′-((2R,6S)-2,6-dimethylmorpholino)-4′-fluoro-7′-(pyrazin-2-yl)-5H-spiro[oxazole-4,9′-xanthen]-2-amine

Step 1: Pd(PPh 3 ) 4 (0.506 g, 0.438 mmol), (S)-2-amino-7′-bromo-4′-fluoro-5H-spiro[oxazole-4,9′-xanthen]-2′-ol (1.6 g, 4.38 mmol), and 2-(tributylstannyl)pyrazine (2.426 g, 6.57 mmol) were combined in 10 ml of DMF and heated in the microwave at 110° C. for two hours. The solution was diluted with ethyl acetate (50 mL) and washed twice with water. The organic layer was washed with brine and dried over anhydrous sodium sulfate, filtered and concentrated. The product was purified via silica gel column chromatography (RediSep 40 g column) using 10-100% 90/10/1 (CH 2 Cl 2 /MeOH/ammonia) in CH 2 Cl 2 to afford (S)-2-amino-4′-fluoro-7′-(pyrazin-2-yl)-5H-spiro[oxazole-4,9′-xanthen]-2′-ol as a white solid. MS m/z=365.0 [M+H].

Step 2: (S)-2-amino-4′-fluoro-7′-(pyrazin-2-yl)-5H-spiro[oxazole-4,9′-xanthen]-2′-ol (600 mg, 1.647 mmol) and TEA (0.459 ml, 3.29 mmol) were combined in 25 ml of CH 2 Cl 2 , and 1,1,1-trifluoro-N-phenyl-N-(trifluoromethylsulfonyl)methanesulfonamide (706 mg, 1.976 mmol) was added. The resulting solution was stirred at RT overnight. The solution was loaded directly on a silica gel column. The product was purified via silica gel column chromatography (RediSep 40 g column) using 10-70% 90/10/1 (CH 2 Cl 2 /MeOH/ammonia) in CH 2 Cl 2 to afford (S)-2-amino-5′-fluoro-2′-(pyrazin-2-yl)-5H-spiro[oxazole-4,9′-xanthene]-7′-yl trifluoromethanesulfonate as a yellow solid solid. MS m/z=496.9 [M+H].

Step 3: A microwave vial was charged with (S)-2-amino-5′-fluoro-2′-(pyrazin-2-yl)-5H-spiro[oxazole-4,9′-xanthene]-7′-yl trifluoromethanesulfonate (150 mg, 0.302 mmol), Pd 2 (dba) 3 (13.84 mg, 0.015 mmol), biphenyl-2-yldi-tert-butylphosphine (10.82 mg, 0.036 mmol) and (2R,6S)-2,6-dimethylmorpholine (104 mg, 0.907 mmol) and capped under argon. LiHMDS (1 M in THF) (1.511 mL, 1.511 mmol) was added and the mixture was heated in the microwave at 110° C. for 1 hr. To the reaction was added 1 ml of water and the mixture was concentrated in vacuo. The product was purified via Gilson HPLC (gradient elution 20-70% MeCN/H 2 O, 0.1% TFA) and freebased with sodium bicarbonte to afford (S)-2′-((2R,6S)-2,6-dimethylmorpholino)-4′-fluoro-7′-(pyrazin-2-yl)-5H-spiro[oxazole-4,9′-xanthen]-2-amine as an off white solid. MS m/z=462.0 [M+H].

Method BB9

Synthesis of (5S)-3-(3,3-difluoro-1-pyrrolidinyl)-7-((3-methyl-3-oxetanyl)ethynyl)spiro[chromeno[2,3-c]pyridine-5,4′-[1,3]oxazol]-2′-amine

Step 1: Pd(PPh 3 ) 4 (0.315 g, 0.273 mmol), copper(i) iodide (0.055 mL, 1.637 mmol) and (S)-7-bromo-3-chloro-5′H-spiro[chromeno[2,3-c]pyridine-5,4′-oxazol]-2′-amine (1.00 g, 2.73 mmol) were combined in a heating tube which was degassed with argon gas. Sequential addition of DMF (10 mL), DIPA (5.73 mL, 40.9 mmol) and trimethyl ((3-methyloxetan-3-yl)ethynyl)silane (0.505 g, 3.00 mmol) to the mixture provided a brown slurry. The reaction vessel was sealed and heated at 90° C. for 24 h. The reaction mixture was poured into water and extracted with EtOAc (3×25 mL). The combined organic layers were washed with water, brine, dried over sodium sulfate, filtered and concentrated. The crude material ws purified by column chromatography with 30-70% EA/HX to give the desired product.

Step 2: Tris(dibenzylideneacetone)dipalladium (0) (0.012 g, 0.013 mmol), 2-(dicyclohexylphosphino)-2′-(n,n-dimethylamino)biphenyl (0.015 g, 0.039 mmol), 3,3-difluoropyrolidine HCl, 98% (0.113 g, 0.786 mmol) and (S)-3-chloro-7-((3-methyloxetan-3-yl)ethynyl)-5′H-spiro[chromeno[2,3-c]pyridine-5,4′-oxazol]-2′-amine (0.100 g, 0.262 mmol) were combined and degassed with nitrogen. LHMDS (1.06 m solution in THF) (1.571 mL, 1.571 mmol) was added and the mixture was stirred at 90° C. overnight. The solvent was removed and the crude material was purified by column chromatography with 0-5% 2M NH 3 in MeOH/CH 2 Cl 2 to provide the desired product as an off white solid. MS m/z=452.9 [M+H].

Method BB10

Synthesis of (R)-4-(2-amino-3′-fluoro-2′-(pyrimidin-5-yl)-5H-spiro[oxazole-4,9′-xanthene]-7′-yl)-2-methylbutan-2-ol

Step 1: A vial charged with (S)-2-amino-7′-bromo-3′-fluoro-5H-spiro[oxazole-4,9′-xanthen]-2′-ol (0.225 g, 0.616 mmol), Pd(PPh 3 ) 4 (0.071 g, 0.062 mmol), and copper(i) iodide (0.012 g, 0.062 mmol), was treated with 3 mL DMF followed by DIPA (1.317 mL, 9.24 mmol). The solution was purged with argon for 2 minutes then 2-methylbut-3-yn-2-ol (0.301 mL, 3.08 mmol) was added and the vial was sealed and heated to 80° C. overnight. The reaction mixture was poured into saturated NH 4 Cl (50 mL) and was extracted with EtOAc (3×25 mL). The combined organics were washed with brine, dried over MgSO 4 and concentrated. Purification of the crude residue by column chromatography [0-100% (9:1:0.1—CH 2 Cl 2 :MeOH:NH4OH)/CH 2 Cl 2 ] provided (R)-2-amino-3′-fluoro-7′-(3-hydroxy-3-methylbut-1-ynyl)-5H-spiro[oxazole-4,9′-xanthen]-2′-ol. MS m/z=369.3 [M+H].

Step 2: A solution of (R)-2-amino-3′-fluoro-7′-(3-hydroxy-3-methylbut-1-ynyl)-5H-spiro[oxazole-4,9′-xanthen]-2′-ol (0.240 g, 0.652 mmol) in 6 mL DMF was treated with cesium carbonate (0.318 g, 0.977 mmol). The resulting slurry was allowed to stir for 15 minutes before being cooled to −10° C. and treated with 1,1,1-trifluoro-N-phenyl-N-(trifluoromethylsulfonyl)methanesulfonamide (0.244 g, 0.684 mmol). After stirring for an additional hour the reaction mixture was loaded directly only a column and purified by column chromatography [0-100% (9:1:0.1—CH 2 Cl 2 :MeOH:NH4OH)/CH 2 Cl 2 ] to provide (R)-2-amino-6′-fluoro-2′-(3-hydroxy-3-methylbut-1-ynyl)-5H-spiro[oxazole-4,9′-xanthene]-7′-yl trifluoromethanesulfonate. MS m/z=501.0 [M+H].

Step 3: A solution of (R)-2-amino-6′-fluoro-2′-(3-hydroxy-3-methylbut-1-ynyl)-5H-spiro[oxazole-4,9′-xanthene]-7′-yl trifluoromethanesulfonate (0.317 g, 0.633 mmol), pyrimidin-5-ylboronic acid (0.157 g, 1.267 mmol), Pd(PPh 3 ) 4 (0.037 g, 0.032 mmol), and potassium carbonate (0.438 g, 3.17 mmol) in 1.5 mL dioxane was treated with 0.5 mL water and was heated to 100° C. overnight. The reaction mixture was cooled to rt and diluted with EtOAc. The layers were separated and the organic layer was dried over MgSO 4 filtered and concentrated. Purification of the crude residue by column chromatography [0-80% (9:1:0.1—CH 2 Cl 2 :MeOH:NH4OH)/CH 2 Cl 2 ] gave (R)-4-(2-amino-3′-fluoro-2′-(pyrimidin-5-yl)-5H-spiro[oxazole-4,9′-xanthene]-7′-yl)-2-methylbut-3-yn-2-ol. MS m/z=431.0 [M+H].

Step 4: A vial charged with (R)-4-(2-amino-3′-fluoro-2′-(pyrimidin-5-yl)-5H-spiro[oxazole-4,9′-xanthene]-7′-yl)-2-methylbut-3-yn-2-ol (0.050 g, 0.116 mmol) and 10% Pd/C (1.236 mg, 0.012 mmol) was taken up in 5 mL MeOH thoroughly degassed then placed under 50 psi H 2 overnight. The reaction mixture was filtered through celite and concentrated in vacuo to provide an off white solid. Purification of the crude residue by column chromatography [0-80% (9:1:0.1—CH 2 Cl 2 :MeOH:NH 4 OH)/CH 2 Cl 2 ] gave (R)-4-(2-amino-3′-fluoro-2′-(pyrimidin-5-yl)-5H-spiro[oxazole-4,9′-xanthene]-7′-yl)-2-methylbutan-2-ol. MS m/z=435.0 [M+H].

Method BB12

Synthesis of (S)-3-(3,6-dihydro-2H-pyran-4-yl)-7-(2-fluoropyridin-3-yl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-thiazol]-2′-amine

Step 1: 3-bromo-7-iodo-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-thiazol]-2′-amine (0.770 g, 1.624 mmol; prepared as described in Method BB26) was dissolved in dioxane (8 mL). 8 mL of saturated sodium bicarbonate solution was added, followed by boc-anhydride (3.77 mL, 16.24 mmol). The reaction was stirred overnight at RT. The reaction was diluted with EtOAc and washed with water. The aqueous layer was extracted with EtOAc, and the combined organic layers were dried with sodium sulfate, filtered, and concentrated. The material was purified via silica gel chromatography (gradient elution 0-25% EtOAc:Hex) to afford tert-butyl 3-bromo-7-iodo-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-thiazole]-2′-ylcarbamate as a yellow solid. MS m/z=576.0. Calc'd for C 19 H 17 BrIN 3 O 3 S: 574.23.

Step 2: A vial was charged with tert-butyl 3-bromo-7-iodo-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-thiazole]-2′-ylcarbamate (0.454 g, 0.791 mmol), 2-fluoropyridin-3-ylboronic acid (0.167 g, 1.186 mmol), potassium carbonate (0.546 g, 3.95 mmol), and tetrakis(triphenylphosphine)palladium(0) (0.091 g, 0.079 mmol). The vial was flushed with Ar (g), then Dioxane (5.27 mL) and water (2.64 mL) were added in sequence. The vial was sealed and heated at 80° C. for one hour. The reaction was diluted with EtOAc and washed with water. The aqueous layer was extracted with EtOAc, and the combined organic layers were dried with sodium sulfate, filtered, and concentrated. The material was purified via silica gel chromatography (gradient elution 0-50% EtOAc:Hex) to afford tert-butyl 3-bromo-7-(2-fluoropyridin-3-yl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-thiazole]-2′-ylcarbamate as a light yellow solid. MS m/z=545.1. Calc'd for C 24 H 20 BrFN 4 O 3 S: 543.41

Step 3: A vial was charged with tert-butyl 3-bromo-7-(2-fluoropyridin-3-yl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-thiazole]-2′-ylcarbamate (0.105 g, 0.193 mmol), 2-(3,6-dihydro-2H-pyran-4-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (0.122 g, 0.580 mmol), potassium carbonate (0.134 g, 0.966 mmol), and bis(di-tert-butyl(4-dimethylaminophenyl)phosphine)dichloropalladium(II) (0.014 g, 0.019 mmol). The vial was flushed with Ar (g), then dioxane (1.288 mL) and water (0.644 mL) were added in sequence. The vial was sealed and heated at 80° C. overnight. The reaction was diluted with ethyl acetate and washed with water. The aqueous layer was extracted with ethyl acetate, and the combined organic layers were dried with sodium sulfate, filtered, and concentrated. The material was purified via silica gel chromatography (gradient elution 0-100% EtOAc:Hex) to afford tert-butyl 3-(3,6-dihydro-2H-pyran-4-yl)-7-(2-fluoropyridin-3-yl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-thiazole]-2′-ylcarbamate as an off-white solid. MS m/z=547.2. Calc'd for C 29 H 27 FN 4 O 4 S: 546.61.

Step 4: A RBF was charged with tert-butyl 3-(3,6-dihydro-2H-pyran-4-yl)-7-(2-fluoropyridin-3-yl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-thiazole]-2′-ylcarbamate (0.091 g, 0.166 mmol). The material was dissolved in 0.5 mL of CH 2 Cl 2 and TFA (0.149 mL, 1.932 mmol) was added. The reaction was heated to 50° C. and stirred for one hour. The reaction was concentrated, diluted with CH 2 Cl 2 and washed with saturated sodium bicarbonate solution. The aqueous layer was extracted with CH 2 Cl 2 , and the combined organic layers were washed with brine, dried with sodium sulfate, filtered, and concentrated to afford (S)-3-(3,6-dihydro-2H-pyran-4-yl)-7-(2-fluoropyridin-3-yl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-thiazol]-2′-amine as an off-white solid. MS m/z=447.3 [M+H] + . Calculated for C 24 H 19 FN 4 O 2 S: 446.12.

1 H NMR (400 MHz, DMSO-d 6 ) δ=8.40 (d, J=2.5 Hz, 1 H), 8.28-8.21 (m, 1 H), 8.14-8.04 (m, 1 H), 7.83 (d, J=2.5 Hz, 1 H), 7.66-7.61 (m, 2 H), 7.49 (ddd, J=1.8, 5.0, 7.3 Hz, 1 H), 7.42 (d, J=9.1 Hz, 1 H), 7.06 (s, 2 H), 6.29 (td, J=1.3, 2.7 Hz, 1 H), 4.25 (q, J=2.6 Hz, 2 H), 3.85 (t, J=5.5 Hz, 2 H), 3.48-3.41 (m, 2 H), 2.48-2.42 (m, 2 H)

Method BB13

Synthesis of (S)-tert-butyl 7-(2-fluoropyridin-3-yl)-3-((3-methyloxetan-3-yl)ethynyl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-thiazole]-2′-ylcarbamate

Step 1: 3-bromo-7-iodo-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-thiazol]-2′-amine (770 g, 1.624 mmol) was dissolved in dioxane (8 mL). 8 mL of saturated sodium bicarbonate solution was added, followed by boc-anhydride (3.77 mL, 16.24 mmol). The reaction was stirred overnight at RT. The reaction was diluted with EtOAc and washed with water. The aqueous layer was extracted with EtOAc, and the combined organic layers were dried with sodium sulfate, filtered, and concentrated. The material was purified via silica gel chromatography (gradient elution 0-25% EtOAc:Hex) to afford tert-butyl 3-bromo-7-iodo-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-thiazole]-2′-ylcarbamate as a yellow solid. MS m/z=576.0. Calc'd for C 19 H 17 BrIN 3 O 3 S: 574.23.

Step 2: A vial was charged with tert-butyl 3-bromo-7-iodo-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-thiazole]-2′-ylcarbamate (0.454 g, 0.791 mmol), 2-fluoropyridin-3-ylboronic acid (0.167 g, 1.186 mmol), potassium carbonate (0.546 g, 3.95 mmol), and tetrakis(triphenylphosphine)palladium(0) (0.091 g, 0.079 mmol). The vial was flushed with Ar (g), then dioxane (5.27 mL) and water (2.64 mL) were added in sequence. The vial was sealed and heated at 80° C. for one hour. The reaction was diluted with EtOAc and washed with water. The aqueous layer was extracted with EtOAc, and the combined organic layers were dried with sodium sulfate, filtered, and concentrated. The material was purified via silica gel chromatography (gradient elution 0-50% EtOAc:Hex) to afford tert-butyl 3-bromo-7-(2-fluoropyridin-3-yl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-thiazole]-2′-ylcarbamate as a light yellow solid. MS m/z=545.1. Calc'd for C 24 H 20 BrFN 4 O 3 S: 543.41.

Step 3: A vial was charged with (5)-tert-butyl 3-bromo-7-(2-fluoropyridin-3-yl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-thiazole]-2′-ylcarbamate (0.181 g, 0.333 mmol), copper(i) iodide (0.013 g, 0.067 mmol), and bis(di-tert-butyl(4-dimethylaminophenyl)phosphine)dichloropalladium(II) (0.024 g, 0.033 mmol). The vial was flushed with Ar (g), then DMF (1.665 mL), DIPA (0.712 mL, 5.00 mmol), and trimethyl((3-methyloxetan-3-yl)ethynyl)silane (0.201 mL, 0.999 mmol) were added in sequence. The reaction was heated to 90° C. and stirred for three hours. The reaction was diluted with EtOAc and washed with water. The aqueous layer was extracted with EtOAc, and the combined organic layers were dried with sodium sulfate, filtered, and concentrated. The material was purified via silica gel chromatography (gradient elution 0-50% EtOAc:Hex) to afford (S)-tert-butyl 7-(2-fluoropyridin-3-yl)-3-((3-methyloxetan-3-yl)ethynyl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-thiazole]-2′-ylcarbamate as a yellow solid. MS m/z=559.2. Calc'd for C 30 H 27 FN 4 O 4 S: 558.62.

Step 4: A RBF was charged with (5)-tert-butyl 7-(2-fluoropyridin-3-yl)-3-((3-methyloxetan-3-yl)ethynyl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-thiazole]-2′-ylcarbamate (0.101 g, 0.181 mmol). The material was dissolved in 1.5 mL of CH 2 Cl 2 and TFA (0.256 mL, 3.33 mmol) was added. The reaction was heated to 40° C. and stirred for four hours. The reaction was diluted with CH 2 Cl 2 and washed with saturated sodium bicarbonate solution. The aqueous layer was extracted with CH 2 Cl 2 , and the combined organic layers were dried with sodium sulfate, filtered, and concentrated. The material was purified via column chromatography (gradient elution 0-5% MeOH:CH 2 Cl 2 ) to afford (S)-tert-butyl 7-(2-fluoropyridin-3-yl)-3-((3-methyloxetan-3-yl)ethynyl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-thiazole]-2′-ylcarbamate as a white solid. MS m/z=459.3. Calc'd for C 25 H 19 FN 4 O 2 S: 458.51.

Method BB14

Synthesis of (4′S)-3-(2-methylbutylthio)-7-(pyridin-3-yl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine

Step 1: A vial was charged with (S)-3-bromo-7-iodo-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine (906 mg, 1.978 mmol), pyridin-3-ylboronic acid (267 mg, 2.176 mmol), potassium carbonate (1367 mg, 9.89 mmol), and tetrakis(triphenylphosphine)palladium(0) (114 mg, 0.099 mmol). The vial was flushed with argon and dioxane (9.89 mL) and water (5.1 mL) were added in sequence. The vial was sealed and placed in an 80° C. oil bath for 4 h. The mixture was cooled to rt, diluted with EtOAc (45 mL), and brine (45 mL). The layers were separated, and the aq. layer was extracted with EtOAc (2×35 mL). The combined organic extracts were dried over sodium sulfate, filtered, and concentrated. The residue was purified by chromatography on a 40-g Redi-Sep column, eluting with 0-60% of a 90:10:1 mix of CH 2 Cl 2 /MeOH/NH 4 OH in CH 2 Cl 2 to give (S)-3-bromo-7-(pyridin-3-yl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine as an off-white solid.

Step: A mixture of (S)-3-bromo-7-(pyridin-3-yl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine (53 mg, 0.130 mmol), 2-methylbutane-1-thiol (14.21 mg, 0.130 mmol), tris(dibenzylideneacetone)dipalladium (5.93 mg, 6.48 μmol), (9,9-dimethyl-9H-xanthene-4,5-diyl)bis(diphenylphosphine) (3.75 mg, 6.48 μmol), N,N-diethyl-N-isopropylpropan-2-amine (45.1 μL, 0.259 mmol), and dry 1,4-dioxane (0.5 mL) was irradiated in microwave glass vessel at 160° C. for 35 minutes. The whole was cooled to rt and the resulting solid was filtered off and washed with MeOH (3 mL). The filtrates were combined, concentrated, and purified with reverse phase HPLC. Fractions containing the product were combined, and concentrated. TFA was removed using catch and release with strong cation exchange with 2 g SCX columns. First, the material was loaded in the column with MeOH. The column washed with MeOH to remove the TFA, then with 2M NH 3 in MeOH to collect the product. The basic wash was collected and dried to afford (4′S)-3-(2-methylbutylthio)-7-(pyridin-3-yl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine as a white solid.

Method BB15

Step 1: To a solution of (S)-2-amino-2′-bromo-4′-fluoro-5H-spiro[oxazole-4,9′-xanthen]-7′-ol (1.0 g, 2.74 mmol) in 1,4-dioxane (13.5 mL) and water (4.50 mL) were added potassium phosphate (1.744 g, 8.22 mmol), and bis(di-tert-butyl(4-dimethylaminophenyl)phosphine)dichloropalladium(II) (0.097 g, 0.137 mmol). A 2:1 mixture of 2-(6,6-dimethyl-3,6-dihydro-2H-pyran-4-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane and 2-(2,2-dimethyl-3,6-dihydro-2H-pyran-4-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (652 mg, 2.74 mmol) was added and the resulting mixture was heated to 85° C. for 4 hours. The mixture was cooled to RT and diluted with EtOAc (25 mL). The layers were separated and the aqueous layer was extracted with EtOAc (2×100 mL). The combined organic extracts were dried over MgSO 4 and silica gel was added. The solvents were removed and the solid mixture was purified by silica gel column chromatography using (solid loading, 0%-20% MeOH/CH 2 Cl 2 ) to provide a mixture of (S)-2-amino-2′-(6,6-dimethyl-3,6-dihydro-2H-pyran-4-yl)-4′-fluoro-5H-spiro[oxazole-4,9′-xanthen]-7′-ol and (S)-2-amino-2′-(2,2-dimethyl-3,6-dihydro-2H-pyran-4-yl)-4′-fluoro-5H-spiro[oxazole-4,9′-xanthen]-7′-ol as a light yellow solid. MS m/z=576.0 [M+H].

Step 2: To a solution of (S)-2-amino-2′-(6,6-dimethyl-3,6-dihydro-2H-pyran-4-yl)-4′-fluoro-5H-spiro[oxazole-4,9′-xanthen]-7′-ol and (S)-2-amino-2′-(2,2-dimethyl-3,6-dihydro-2H-pyran-4-yl)-4′-fluoro-5H-spiro[oxazole-4,9′-xanthen]-7′-ol (0.760 g, 1.917 mmol) in EtOH (6 mL) and MeOH (1 mL) was added palladium hydroxide (100 mg). The mixture was stirred at RT under H 2 (42 psi) overnight. The mixture was filtered through celite, washing well with methanol. The combined filtrates were concentrated and the residue was dissolved in MeOH (20 mL). Silica gel was added and the solvent was removed in vacuo. The derived solid mixture was purified by silica gel column chromatography using (solid loading, 0%-100% EtOAc/hexane, then 5%-20% MeOH/CH 2 Cl 2 ) to provide a mixture of 1:1 mixture of (S)-2-amino-2′-((S)-2,2-dimethyltetrahydro-2H-pyran-4-yl)-4′-fluoro-5H-spiro[oxazole-4,9′-xanthen]-7′-ol and (S)-2-amino-2′-((R)-2,2-dimethyltetrahydro-2H-pyran-4-yl)-4′-fluoro-5H-spiro[oxazole-4,9′-xanthen]-7′-ol as a light yellow solid.

Step 3: Individual diastereomers (S)-2-amino-2′-((S)-2,2-dimethyltetrahydro-2H-pyran-4-yl)-4′-fluoro-5H-spiro[oxazole-4,9′-xanthen]-7′-ol and (S)-2-amino-2′-((R)-2,2-dimethyltetrahydro-2H-pyran-4-yl)-4′-fluoro-5H-spiro[oxazole-4,9′-xanthen]-7′-ol were separated by SFC and each were processed individually.

Step 4: To a solution of (S)-2-amino-2′-((S)-2,2-dimethyltetrahydro-2H-pyran-4-yl)-4′-fluoro-5H-spiro[oxazole-4,9′-xanthen]-7′-ol (0.143 g, 0.359 mmol) in CH 2 Cl 2 (2.5 mL) at 0° C. was added n-phenyltrifluoromethanesulfonimide (0.192 g, 0.538 mmol) and triethylamine (0.100 mL, 0.718 mmol). After the addition was complete, the mixture was stirred at RT for 5 h. The mixture was loading directly onto a column and was purified by silica gel column chromatography (0%-20% MeOH/CH 2 Cl 2 ) to give the product of step 3 as a yellow solid.

Step 5: To a solution of (S)-2-amino-2′-((S)-2,2-dimethyltetrahydro-2H-pyran-4-yl)-4′-fluoro-5H-spiro[oxazole-4,9′-xanthene]-7′-yl trifluoromethanesulfonate (0.152 g, 0.287 mmol) in DMF (1.9 mL) was added copper(i) iodide (0.971 μL, 0.029 mmol), lithium chloride (0.059 mL, 2.87 mmol), tetrakis(triphenylphosphine)palladium(0) (0.033 g, 0.029 mmol), and 2-(tributylstannyl)pyrazine (0.271 mL, 0.860 mmol). The resulting mixture was then subjected to a microwave irradiation at 120° C. for 20 min. The solution was cooled to rt filtered through a plug of celite. The filtrate was purified by preparative HPLC (0%-100% MeCN 0.1% TFA/H 2 O 0.1% TFA) to give a desired product as TFA salt. The derived salt was dissolved in MeOH (4 mL) and passed through a PL-HCO3 MP resin 200 mg/6 mL tube and the resin was washed with MeOH (2×5 mL). The filtrate was concentrated and dried in vacuo to give the depicted compound as a light yellow solid.

Method BB16

Synthesis of (S)-4′-fluoro-7′-(2-fluoropyridin-3-yl)-2′-(2-(3-methyloxetan-3-yl)ethyl)-5H-spiro[oxazole-4,9′-xanthen]-2-amine

Step 1: A 500 mL RBF was charged with (S)-2-amino-7′-bromo-4′-fluoro-5H-spiro[oxazole-4,9′-xanthen]-2′-ol (20.00 g, 54.8 mmol), 2-fluoropyridin-3-ylboronic acid (13.89 g, 99 mmol) and sodium carbonate (23.22 g, 219 mmol). DMF (130 mL) was added and the mixture was stirred for 1 minute before tetrakis(triphenylphosphine) palladium (4.43 g, 3.83 mmol) and water (52.2 mL) were added. The mixture was capped with argon, equipped with a reflux condenser and heated at 85° C. for 16 hrs. The mixture was cooled to room temperature and the resulting yellow precipitate was filtered. The filtrate was diluted with water (200 mL) and saturated ammonium chloride (200 mL), leading to the formation of a white precipitate and a brown semisolid. The precipitate was filtered and the semisolid was triturated with water (˜200 mL) to provide a brown solid which was also filtered and washed with water. The combined solids were washed excessively with water and dried overnight under a stream of air to afford (S)-2-amino-4′-fluoro-7′-(2-fluoropyridin-3-yl)-5H-spiro[oxazole-4,9′-xanthen]-2′-ol as tan solid which was used without further purification.

Step 2: To a reaction vessel charged with (S)-2-amino-4′-fluoro-7′-(2-fluoropyridin-3-yl)-5H-spiro[oxazole-4,9′-xanthen]-2′-ol (365 mg, 0.957 mmol) in dry CH 2 Cl 2 (2.5 mL) was added TEA (0.266 mL, 1.914 mmol). The resulting solution was stirred for several minutes at room temperature before 1,1,1-trifluoro-N-phenyl-N-(trifluoromethylsulfonyl)methanesulfonamide (513 mg, 1.436 mmol) was added in one portion. The mixture was maintained at rt for 1 hour before being washed sequentially with saturated NaHCO 3 , water and brine. The organics were filtered through the pad of celite and concentrated in vacuo. The crude material was absorbed onto a plug of silica gel and purified by silica gel chromatography (40-50% EtOAc in hexane then 50% CH 2 Cl 2 :MeOH:NH4OH (90:10:1) in EtOAc to provide (S)-2-amino-5′-fluoro-2′-(2-fluoropyridin-3-yl)-5H-spiro[oxazole-4,9′-xanthene]-7′-yl trifluoromethanesulfonate as off white solid. MS m/z=513.8 [M+H].

Step 3: A glass microwave reaction vessel was charged with (S)-2-amino-5′-fluoro-2′-(2-fluoropyridin-3-yl)-5H-spiro[oxazole-4,9′-xanthene]-7′-yl trifluoromethanesulfonate (120 mg, 0.234 mmol), trans-dichlorobis(triphenyl-phosphine)palladium (19.69 mg, 0.028 mmol), triphenylphosphine (36.8 mg, 0.140 mmol), lithium chloride (0.041 mL, 1.987 mmol) and (E)-tributyl(2-(3-methyloxetan-3-yl)vinyl)stannane (136 mg, 0.351 mmol). DMF (2.5 mL) was added and the reaction mixture was purged with argon for several minutes. The vessel was sealed and heated in a Initiator microwave reactor (Personal Chemistry, Biotage AB, Inc., Upssala, Sweden) at 120° C. for 10 mins. The mixture was cooled to rt and portioned between saturated KF (7 mL) and CH 2 Cl 2 (20 mL). The organics were washed with brine, dried over sodium sulfate filtered and concentrated. The crude material was absorbed onto a plug of silica gel and purified by chromatography through a Redi-Sep pre-packed silica gel column (40 g; 0-50% ethyl acetate in hexanes then 50% CH 2 Cl 2 : MeOH: NH 4 OH in EtOAc) to provide (S,E)-4′-fluoro-7′-(2-fluoropyridin-3-yl)-2′-(2-(3-methyloxetan-3-yl)vinyl)-5H-spiro[oxazole-4,9′-xanthen]-2-amine as light-yellow solid. MS m/z=462.2 [M+H].

Step 4: To a reaction vessel charged with (S,E)-4′-fluoro-7′-(2-fluoropyridin-3-yl)-2′-(2-(3-methyloxetan-3-yl)vinyl)-5H-spiro[oxazole-4,9′-xanthen]-2-amine (38 mg, 0.082 mmol) and Pd/C (5%) (30 mg, 0.082 mmol) was added EtOH (1.5 mL). The reaction mixture was purged with hydrogen gas for 5 minutes and then maintained under 1 atm of hydrogen gas for 4 hours. The mixture was filtered through celite and the derived filtrate concentrated to provide (S)-4′-fluoro-7′-(2-fluoropyridin-3-yl)-2′-(2-(3-methyloxetan-3-yl)ethyl)-5H-spiro[oxazole-4,9′-xanthen]-2-amine as white solid.

MS m/z=464.2 [M+H].

Method BB17

Synthesis of 7-(2-fluoropyridin-3-yl)-3-(neopentyloxy)-5′H-spiro[chromeno[2,3-c]pyridine-5,4′-oxazol]-2′-amine 2,2,2-trifluoroacetate

Step 1: A vial was charged with 7-bromo-3-chloro-5H-chromeno[2,3-c]pyridin-5-one (3 g, 9.66 mmol), 2-fluoropyridin-3-ylboronic acid (1.497 g, 10.63 mmol), bis(di-tert-butyl(4-dimethylaminophenyl)phosphine)dichloropalladium(H) (0.684 g, 0.966 mmol), and KOAc (1.510 mL, 24.15 mmol). The vial was evacuated and backfilled with nitrogen (this procedure was repeated twice). ACN (20 mL), dioxane (30 mL) and water (3 mL) were added, and the vial was sealed and the reaction mixture was heated to 120° C. for 4 h. The reaction mixture was cooled to RT. Upon addition of EtOAc, a solid precipitated which was filtered off and dried under vacuum to provide 3-Chloro-7-(2-fluoropyridin-3-yl)-5H-chromeno[2,3-c]pyridin-5-one as a tan solid.

Step 2: A vial was charged with 3-chloro-7-(2-fluoropyridin-3-yl)-5H-chromeno[2,3-c]pyridin-5-one (275 mg, 0.842 mmol), neopentyl alcohol (297 mg, 3.37 mmol), Pd 2 dba 3 (38.5 mg, 0.042 mmol), racemic-2-(di-t-butylphosphino)-1,1′-binaphthyl (67.1 mg, 0.168 mmol) and cesium carbonate (686 mg, 2.104 mmol). The vial was evacuated and backfilled with nitrogen (procedure was repeated twice). Toluene (1.7 mL) was added, the vial was sealed and the reaction mixture was heated to 95° C. in an oilbath overnight. The reaction mixture was cooled to RT and partitioned between EtOAc and water. The organic phase was separated and dried over MgSO 4 . The solvent was removed under reduced pressure and the residue was purified by flash chromatography (10-100% EtOAc/hexanes). 7-(2-Fluoropyridin-3-yl)-3-(neopentyloxy)-5H-chromeno[2,3-c]pyridin-5-one (60 mg) was obtained as a yellow powder.

Step 3: A solution of 7-(2-fluoropyridin-3-yl)-3-(neopentyloxy)-5H-chromeno[2,3-c]pyridin-5-one (60 mg, 0.159 mmol) in THF (2 mL) was cooled to −78° C. and ((trimethylsilyl)methyl)lithium (1.0 M solution in pentane, 0.634 mL, 0.634 mmol) was added dropwise. After 15 minutes, aqueous diluted acetic acid was added. The cold bath was removed and the reaction mixture was allowed to warm to RT. The reaction mixture was quenched with aqueous saturated bicarbonate solution and extracted with EtOAc. The organic phase was washed with saturated ammonium chloride solution and dried over MgSO 4 . The solvent was removed under reduced pressure and the yellow residue was dissolved in THF (1 mL). This solution was added to a mixture of iodine (44.3 mg, 0.174 mmol) and silver cyanate (71.3 mg, 0.476 mmol) in THF (1 mL) which was prestirred for 1 h at −20° C. The reaction was allowed to warm to 0° C. After 2 h at room temperature the reaction mixture was filtered through a pad of celite. The celite was washed with THF. Ammonia (2.0M solution in isopropanol; 3.17 mL, 6.34 mmol) was added dropwise and the reaction mixture was allowed to stir overnight. The solvent was removed under reduced pressure and the remaining residue was purified by preparative HPLC. The combined fractions were concentrated to afford 7-(2-fluoropyridin-3-yl)-3-(neopentyloxy)-5′H-spiro[chromeno[2,3-c]pyridine-5,4′-oxazol]-2′-amine 2,2,2-trifluoroacetate as a light-yellow solid. (ESI, pos. ion) m/z: 435.2 [M+H].

Method BB18

Synthesis of 4′-fluoro-2′-methoxy-7′-(pyrazin-2-yl)-5H-spiro[thiazole-4,9′-xanthen]-2-amine

Step 1: A 10 ml resealable tube was charged with tert-butyl 7′-bromo-4′-fluoro-2′-methoxy-5H-spiro[thiazole-4,9′-xanthene]-2-ylcarbamate (300 mg, 0.606 mmol), tetrakis(triphenylphosphine)palladium (70.0 mg, 0.061 mmol) and DMF (3.03 ml) and 2-(tributylstannyl)pyrazine (402 mg, 1.090 mmol). The mixture was stirred for 3 hr at 110° C. The mixture was partitioned between EtOAc and water. The organic layer was washed twice with water, filtered through celite and concentrated under reduced pressure. The solids were triturated with hexane to remove excess tin residue before being filtered. Purification by silica gel chromatography (10-80% CH 2 Cl 2 /MeOH/NH4OH in CH 2 Cl 2 ) to provide tert-butyl 4′-fluoro-2′-methoxy-7′-(pyrazin-2-yl)-5H-spiro[thiazole-4,9′-xanthene]-2-ylcarbamate.

Step 2: A solution of the derived carbamate in 3 mL of CH 2 Cl 2 was treated with TFA (1 ml, 12.98 mmol). The solution was allowed to stir at RT overnight before being concentrated in vacuo. The derived material was neutralized with NaHCO 3 (25 mL) and extracted with EtOAc (3×25 mL). The combined organic layers were combined, filtered through celite and concentrated to afford 4′-fluoro-2′-methoxy-7′-(pyrazin-2-yl)-5H-spiro[thiazole-4,9′-xanthen]-2-amine. MS m/z=395.0 [M+H].

Method BB19

Synthesis of (S)-7-(4-fluoropyridin-3-yl)-3-((3-methyloxetan-3-yl)ethynyl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine

Step 1: A sealable tube was charged with (S)-2′-amino-3-bromo-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-7-ol (3.00 g, 8.62 mmol), tetrakis(triphenylphosphine)palladium (0.996 g, 0.862 mmol), copper(i) iodide (0.164 g, 0.862 mmol). To this was added trimethyl((3-methyloxetan-3-yl)ethynyl)silane (2.90 g, 17.23 mmol) followed by tetra-n-butylammonium fluoride (1 M in THF) (25.9 mL, 25.9 mmol). The resulting brown solution was flushed with argon and heated at 70° C. for 5 hours. The reaction was cooled to rt and diluted with 250 mL of water. The slurry was poured into a separatory funnel containing EtOAc (500 mL). The layers were separated and the aqueous layer was extracted with EtOAc (3×250 mL). In the first extraction a slight emulsion formed, this was cleared upon the addition of 50 mL of brine. The aqueous layer was then extracted with CH 2 Cl 2 (3×200 mL). The organic layers were washed with brine, dried over sodium sulfate, filtered and concentrated in vacuo to provide a brown foam that was purified by silica gel chromatography (Redi-Sep pre-packed silica gel column (330 g), 0-100% CH 2 Cl 2 to 10:1 methanol in methylenechloride with 0.1% ammonium hydroxide) to provide (S)-2′-amino-3-((3-methyloxetan-3-yl)ethynyl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-7-ol as a brown foam.

Step 2: A solution of the derived alcohol was taken up in 85 mL of CH 2 Cl 2 and treated sequentially with DIPEA (2.402 mL, 17.23 mmol) and n-phenyltrifluoromethane-sulfonimide (3.08 g, 8.62 mmol). The resulting solution was maintained at rt for 1.5 hours. The mixture was cooled to room temperature and concentrated to a brown oil that was purified by silica gel chromatography (Redi-Sep pre-packed silica gel column (330 g), 0-100% ethyl acetate in hexanes) to provide (S)-2′-amino-3-((3-methyloxetan-3-yl)ethynyl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazole]-7-yl trifluoromethanesulfonate as a yellow solid. MS m/z=495.9 [M+H].

Step 3: A solution of potassium acetate (0.210 g, 2.140 mmol), PdCl 2 (dppf)-CH 2 Cl 2 adduct (0.022 g, 0.027 mmol), (S)-2′-amino-3-((3-methyloxetan-3-yl)ethynyl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazole]-7-yl trifluoromethanesulfonate (0.265 g, 0.535 mmol), and bis(pinacolato)diboron (0.143 g, 0.562 mmol) in 5 mL DMF was heated to 100° C. for 3 hours. Pd(PPh 3 ) 4 (0.031 g, 0.027 mmol) was added, followed by 3-bromo-4-fluoropyridine (0.141 g, 0.802 mmol), potassium carbonate (0.296 g, 2.140 mmol), and 2 mL water. The reaction mixture was capped with argon and was heated to 100° C. for 2 hours. After cooling to RT, the reaction mixture was diluted with EtOAc and was washed sequentially with water and brine. The organics were dried over MgSO 4 and concentrated. Purification of the crude residue by column chromatography [0-100% (9:1 CH 2 Cl 2 :MeOH)/CH 2 Cl 2 ] then HPLC (10-90% MeCN/H 2 O) provided (S)-7-(4-fluoropyridin-3-yl)-3-(3-methyloxetan-3-yl)ethynyl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine. MS m/z=443.0 [M+H].

Method BB20

Synthesis of 2-(3,6-dihydro-2H-pyran-4-yl)-4-fluoro-8-(2-fluoropyridin-3-yl)-5′H-spiro[chromeno[3,2-b]pyridine-10,4′-oxazol]-2′-amine

Step 1: To a solution of methyl 5-bromosalicylate (5.78 g, 25.00 mmol) in 30 mL of dry THF was added slowly sodium hydride (0.600 g, 25.00 mmol, 60 wt %) and the solution was stirred at rt for 15 minutes. The solvent was evaporated and the residue was dissolved in 10 mL of dry DMF. To this was added 3-bromo-4-nitropyridine 1-oxide (4.38 g, 20.00 mmol) and the reaction mixture was stirred at 50° C. for 4 h and 40° C. overnight. Water was added and the resulting solid was washed with water, filtered and dried under vacuum. Purification of the crude residue by column chromatography (CH 2 Cl 2 to CH 2 Cl 2 /EA=10:1 to 5:1 to 3:1 to 1:1 to pure EA) gave 3-(4-bromo-2-(methoxycarbonyl)phenoxy)-4-nitropyridine 1-oxide as a yellow solid.

Step 2: To a solution of 3-(4-bromo-2-(methoxycarbonyl)phenoxy)-4-nitropyridine 1-oxide (369 mg, 1.000 mmol) in 20 mL of dry THF at −78° C. was added dropwise lithium diisopropylamide (2M, 1.99 mL, 1.999 mmol) and the reaction was stirred at −78° C. for 3 h. The reaction was quenched at this temperature with 15 mL of 1 M HCl in ether and the whole was allowed to warm up to rt. The reaction was extracted with ethyl acetate (3×100 mL). The combined organics were dried over sodium sulfate, filtered and evaporated to dryness. Purification of the crude residue by column chromatography (hexane to H/CH 2 Cl 2 =1:1 to CH 2 Cl 2 ) gave 8-bromo-4-nitro-10-oxo-10H-chromeno[3,2-b]pyridine 1-oxide (20 mg, 0.059 mmol, 5.94% yield) as an offwhite solid and 8-bromo-4-nitro-10H-chromeno[3,2-b]pyridin-10-one as an light yellow solid.

Step 3: To a suspension of urea hydrogen peroxide (58.6 mg, 0.623 mmol) in 5 mL of CH 2 Cl 2 at 0° C. was added dropwise trifluoroacetic anhydride (87 μL, 0.623 mmol). After stirring for 5 min at 0° C., a solution of 8-bromo-4-nitro-10H-chromeno[3,2-b]pyridin-10-one (80 mg, 0.249 mmol) in CH 2 Cl 2 (5 mL) was added and the resulting reaction was stirred at rt for 1.5 h. The mixture was carefully quenched with saturated NaHCO 3 and extracted with ethyl acetate (5×5 mL). The combined organics were dried over sodium sulfate, filtered and evaporated to dryness. Purification of the crude residue by column chromatography (CH 2 Cl 2 to CH 2 Cl 2 /EA=10:1 to 5:1) gave 8-bromo-4-nitro-10-oxo-10H-chromeno[3,2-b]pyridine 1-oxide as an light yellow solid.

Step 4: A suspension of 8-bromo-4-nitro-10-oxo-10H-chromeno[3,2-b]pyridine 1-oxide (90 mg, 0.267 mmol) in 1 mL of dry DMF was added dropwise to a solution of phosphorus oxychloride (44.0 μL, 0.481 mmol) in 0.2 mL of DMF and 0.5 mL of toluene at 0° C. After stirring at 0° C. for 0.5 h, the reaction was quenched with saturated NaHCO 3 and extracted with ethyl acetate (5×5 mL). The combined organics were dried over sodium sulfate, filtered and evaporated to dryness. Purification of the crude residue by column chromatography (CH 2 Cl 2 to CH 2 Cl 2 /EA=100:3) gave 8-bromo-2-chloro-4-nitro-10H-chromeno[3,2-b]pyridin-10-one as a light yellow solid.

Step 5: To a solution of 8-bromo-2-chloro-4-nitro-10H-chromeno[3,2-b]pyridin-10-one (80 mg, 0.225 mmol) in 0.8 mL of DMF at 0° C. was added tetrabutylammonium fluoride (1M in THF, 0.45 mL, 0.450 mmol) dropwise. After 15 minutes, the reaction was quenched with saturated NH 4 Cl (20 mL) and extracted with ethyl acetate (2×10 mL). The combined organics were dried over sodium sulfate, filtered and evaporated to dryness. Purification of the crude residue by column chromatography (SiO2, CH 2 Cl 2 to CH 2 Cl 2 /EA=100:3) gave 8-bromo-2-chloro-4-fluoro-10H-chromeno[3,2-b]pyridin-10-one as an off white solid.

Step 6: To a solution of 8-bromo-2-chloro-4-fluoro-10H-chromeno[3,2-b]pyridin-10-one (44 mg, 0.134 mmol) in 10 mL of dry THF was added dropwise methylmagnesium chloride (3M in THF, 0.12 mL, 0.335 mmol) in at −78° C. The reaction was slowly warmed up to 0° C. over 2 hours. The reaction was quenched at 0° C. with saturated NH 4 Cl (20 mL) and extracted with EtOAc (2×10 mL). The combined organics were dried over sodium sulfate, filtered and evaporated to dryness. The derived tertiary alcohol was taken up in 10 mL of CH 2 Cl 2 treated with 1 mg of PPTS. After stirring for 30 minutes the mixture was cooled to 0° C. and 0.1 g of NaHCO 3 was added. The solvent was evaporated to dryness to give crude 8-bromo-2-chloro-4-fluoro-10-methylene-10H-chromeno[3,2-b]pyridine which was directly used in the next step. A solution of iodine (7.24 μL, 0.141 mmol) in THF at −25° C. was treated with silver cyanate (20.07 μL, 0.536 mmol). After stirring for 30 minutes, a solution of the derived olefin (8-bromo-2-chloro-4-fluoro-10-methylene-10H-chromeno[3,2-b]pyridine) in THF (10 mL) was added dropwise. The slurry was maintained at −25° C. for 2 h at which point the slurry was filtered through celite. The brown solution was concentrated to dryness, taken up in 10 mL THF, cooled to 0° C. and treated with ammonia (2M in 2-propanol (0.3 mL, 0.536 mmol). The reaction was allowed to slowly warm to rt and stirred overnight. The solvent was evaporated and the residue was purified by flash column (CH 2 Cl 2 to CH 2 Cl 2 /EA=2:1 to 1:1 to CH 2 Cl 2 /MeOH=100:5) to give 8-bromo-2-chloro-4-fluoro-5′H-spiro[chromeno[3,2-b]pyridine-10,4′-oxazol]-2′-amine as an off white solid.

Step 7: A mixture of 8-bromo-2-chloro-4-fluoro-5′H-spiro[chromeno[3,2-b]pyridine-10,4′-oxazol]-2′-amine (27.0 mg, 0.070 mmol), bis-(di-tert-butyl(4-dimethylaminophenyl)phosphine)dichloropalladium(ii) (2.486 mg, 3.51 μmol), 2-fluoropyridine-3-boronic acid (10.8 mg, 0.077 mmol) and potassium phosphate (29.8 mg, 0.140 mmol) in a 2:1 mixture of dioxane and water (1.2 mL) was heated at 105° C. in the microwave for 35 min. The reaction mixture was purified by column chromatography (SiO2, CH 2 Cl 2 to CH 2 Cl 2 /EA=2:1 to 1:1 to 3:4 to 1:2 to 1:3 to pure EA) to give 2-chloro-4-fluoro-8-(2-fluoropyridin-3-yl)-5′H-spiro[chromeno[3,2-b]pyridine-10,4′-oxazol]-2′-amine as an off white solid.

Step 8: A mixture of 2-chloro-4-fluoro-8-(2-fluoropyridin-3-yl)-5′H-spiro[chromeno[3,2-b]pyridine-10,4′-oxazol]-2′-amine (19.00 mg, 0.047 mmol), 2-(3,6-dihydro-2H-pyran-4-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (24.90 mg, 0.119 mmol), bis-(di-tert-butyl(4-dimethylaminophenyl)phosphine)dichloropalladium(ii) (1.678 mg, 2.370 μmol) and potassium phosphate (22.14 mg, 0.104 mmol) in a 2:1 mixture of dioxane and water (1.5 mL was heated at 135° C. in the microwave for 25 minutes. The reaction mixture was purified by column chromatography (SiO2, CH 2 Cl 2 to CH 2 Cl 2 /EA=3:1 to 2:1 to 1:1 to pure EA to EA/MeOH=100:5) to give 2-(3,6-dihydro-2H-pyran-4-yl)-4-fluoro-8-(2-fluoropyridin-3-yl)-5′H-spiro[chromeno[3,2-b]pyridine-10,4′-oxazol]-2′-amine as a off white solid.

Method BB21

Synthesis of (S)-4-(2-amino-2′-((3-methyloxetan-3-yl)methoxy)-7′-(pyridin-3-yl)-5H-spiro[oxazole-4,9′-xanthene]-1′-yl)-2-methylbut-3-yn-2-ol

Step 1: A 75-mL pressure vessel was charged with (R)-2-amino-2′-bromo-5H-spiro[oxazole-4,9′-xanthen]-7′-ol (3.25 g, 9.36 mmol), pyridin-3-ylboronic acid (2.88 g, 23.40 mmol), tetrakis(triphenylphosphine)palladium(0) (1.081 g, 0.936 mmol), THF (46.8 mL), and potassium carbonate (23.40 mL, 46.8 mmol) (as a 2.0 M aq. solution). The vessel was sealed and placed in a 100° C. oil bath for 6 hours. The mixture was partitioned between EtOAc (50 mL) and water (50 mL). The layers were separated, and the aqueous layer was extracted with EtOAc (2×30 mL. The combined mixture was dried over sodium sulfate and filtered with the aid of 10% MeOH/CH 2 Cl 2 . The filtrate was evaporated to give a yellow solid. This solid was taken up in CH 2 Cl 2 (80 mL) and sonicated for 5 min. The solid was filtered and washed with CH 2 Cl 2 (2×40 mL), then air-dried on the filter. The filtrate was evaporated and again taken up in CH 2 Cl 2 (80 mL). The mixture was sonicated for 10 min, then filtered and washed with CH 2 Cl 2 (30 mL). The solid was air-dried and combined with the first solid to give (S)-2-amino-7′-(pyridin-3-yl)-5H-spiro[oxazole-4,9′-xanthen]-2′-ol. MS m/z=346.0 [M+H].

Step 2: A 100-mL round-bottom flask was charged with (S)-2-amino-7′-(pyridin-3-yl)-5H-spiro[oxazole-4,9′-xanthen]-2′-ol (1100 mg, 3.19 mmol) and TFA (1.59E+04 μL). The mixture was sonicated for 1 minute and then the flask was submerged in an ice-bath and the resulting red solution was treated with n-bromosuccinimide (567 mg, 3.19 mmol). After stirring at 0° C. for 15 minutes the mixture was diluted with 15 mL of MeOH and evaporated in vacuo. The residue was dissolved in methanol and loaded onto a 10-g SCX-2 column. The column was eluted with methanol to remove impurities, then with 2M ammonia in methanol to give the product as a light yellow solid that was carried on without further purification. MS m/z=424.0 [M+H].

Step 3: To a slurry of (S)-2-amino-1′-bromo-7′-(pyridin-3-yl)-5H-spiro[oxazole-4,9′-xanthen]-2′-ol (710 mg, 1.674 mmol), cesium carbonate (1091 mg, 3.35 mmol) and potassium iodide (306 mg, 1.841 mmol) in DMF (6694 μL, 1.674 mmol) at 0° C. was added 3-(bromomethyl)-3-methyloxetane (304 mg, 1.841 mmol). The reaction was removed from the ice bath and allowed to warm to rt. Reaction was allowed to stir at rt overnight before being diluted with water (250 mL) and poured into a separatory funnel containing ethyl acetate (100 mL). The layers were separated and the aqueous layer was extracted with ethyl acetate (2×100 mL). The combined organic layers were washed with brine, dried over sodium sulfate, filtered and concentrated in vacuo to provide a red oil that was purified by silica gel chromatography (Redi-Sep pre-packed silica gel column (40 g), 0-100% CH 2 Cl 2 to 10:1 methanol in methylenechloride with 0.1% ammonium hydroxide) to provide (S)-1′-bromo-2′-((3-methyloxetan-3-yl)methoxy)-7′-(pyridin-3-yl)-5H-spiro[oxazole-4,9′-xanthen]-2-amine as an off white solid. MS m/z=508.0 [M+H].

Step 4: A resealable tube was charged with (S)-1′-bromo-2′-((3-methyloxetan-3-yl)methoxy)-7′-(pyridin-3-yl)-5H-spiro[oxazole-4,9′-xanthen]-2-amine (300 mg, 0.590 mmol), 2-methyl-3-butyn-2-ol (248 mg, 2.95 mmol), tetrakis(triphenylphosphine)palladium (68.2 mg, 0.059 mmol) and copper(i) iodide (22.48 mg, 0.118 mmol). To this were added DMF (1180 μL, 0.590 mmol) and diisopropylamine (1241 μL, 8.85 mmol). The reaction was flushed with argon, sealed and heated at 90° C. for 1.5 hours. The reaction was diluted with water (100 mL) and poured into a separatory funnel containing EtOAc (50 mL). The layers were separated and the aqueous layer was extracted with ethyl acetate (3×25 mL). The combined organic layers were washed with brine, dried over sodium sulfate, filtered and concentrated in vacuo to provide a brown oil that was purified by silica gel chromatography (Redi-Sep pre-packed silica gel column (40 g), 0-100% CH 2 Cl 2 to 10:1 methanol in methylenechloride with 0.1% ammonium hydroxide) to provide (S)-4-(2-amino-2′-((3-methyloxetan-3-yl)methoxy)-7′-(pyridin-3-yl)-5H-spiro[oxazole-4,9′-xanthene]-1′-yl)-2-methylbut-3-yn-2-ol as a light yellow solid. MS m/z=512.2 [M+H].

Method BB22

Synthesis of (S)-2′-amino-3,7-di(pyridin-3-yl)-5′H-spiro[chromeno[2,3-c]pyridine-5,4′-oxazol]-1(2H)-one

Step 1: A solution of (S)-1-fluoro-3,7-di(pyridin-3-yl)-5′H-spiro[chromeno[2,3-c]pyridine-5,4′-oxazol]-2′-amine (40 mg, 0.094 mmol) and sodium methoxide (52.4 μL, 0.940 mmol) in 15 mL of MeOH was heated to 65° for 5 h. After cooling to rt, the reaction was evaporated to dryness and was partitioned between water (100 mL) and EtOAc (100 mL). The layers were separated and the organics were dried over sodium sulfate, filtered and evaporated to dryness. Flash column (CH 2 Cl 2 to CH 2 Cl 2 /MeOH=100:5 to 100:10 to 100:20) gave (S)-1-methoxy-3,7-di(pyridin-3-yl)-5′H-spiro[chromeno[2,3-c]pyridine-5,4′-oxazol]-2′-amine as an off white solid.

Step 2: To a solution of (S)-1-methoxy-3,7-di(pyridin-3-yl)-5′H-spiro[chromeno[2,3-c]pyridine-5,4′-oxazol]-2′-amine (15 mg, 0.034 mmol) in 5 mL of dry CH 2 Cl 2 at rt was added boron tribromide (1 M in CH 2 Cl 2 , 1.0 m in DCM (0.34 mL, 0.343 mmol) and the resulting suspension was stirred at rt for 2 h. The reaction was quenched with half saturated NaHCO 3 (50 mL) and extracted with EtOAc (3×25 mL). The combined organics were dried over sodium sulfate, filtered and evaporated to dryness. Purification by silica gel chromatography (CH 2 Cl 2 /MeOH=100:10 to 100:12 to 100:15 to 4:1) gave (S)-2′-amino-3,7-di(pyridin-3-yl)-5′H-spiro[chromeno[2,3-c]pyridine-5,4′-oxazol]-1(2H)-one.

Method BB24

Synthesis of (4′R)-8-fluoro-7-(2-fluoropyridin-3-yl)-3-((3-methyloxetan-3-yl)ethynyl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine; and (4′S)-8-fluoro-7-(2-fluoropyridin-3-yl)-3-((3-methyloxetan-3-yl)ethynyl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine

Step 1: A solution of n-butyllithium (150 mL, 375 mmol) in 950 mL THF was cooled to −10° C. and treated with a solution of 2,2,6,6-tetramethylpiperidine (72.7 mL, 428 mmol) in 50 mL THF. After stirring for 15 min, the solution was cooled to −78° C. and 2-fluoro-5-iodopyridine (80 g, 357 mmol) was added as a solution in 400 mL THF dropwise via addition funnel over 60 minutes. After stirring for an additional 30 min, CO 2 was bubbled through the red solution for 10 minutes. The cooling bath was removed, and CO 2 was bubbled through the reaction mixture for an additional hour. The reaction mixture was concentrated in vacuo, triturated with hexanes and again concentrated in vacuo. The crude residue was taken up in 360 mL DMF and was treated with 4-bromo-3-fluorophenol (68.1 g, 357 mmol) followed by potassium carbonate (61.6 g, 446 mmol). The resulting mixture was heated to 120° C. for 18 h. The reaction mixture was cooled to rt and filtered through celite. The filtrate was diluted with EtOAc (500 mL) and was acidified to pH 3 with 6 N HCl. The organics were washed with water, brine, dried over MgSO 4 and concentrated in vacuo. The crude residue was triturated with ether/hexanes, and the derived solid was dried under a stream of nitrogen to provide 2-(4-bromo-3-fluorophenoxy)-5-iodonicotinic acid (108.93 g, 249 mmol) as a brown solid.

Step 2: A flask charged with 2-(4-bromo-3-fluorophenoxy)-5-iodonicotinic acid (109 g, 249 mmol) and phosphorus pentoxide (70.6 g, 497 mmol) was treated with methanesulfonic acid (484 mL, 7460 mmol). After stirring for 30 minutes at room temperature, the reaction mixture was heated to 120° C. for 18 h. The reaction mixture was allowed to cool to room temperature and was poured into 1 L of ice water. After stirring for one hour, the resulting solid was filtered and subsequently washed sequentially with water and MeOH. The solid was dried to provide a 1:4 mixture of 7-bromo-6-fluoro-3-iodo-5H-chromeno[2,3-b]pyridin-5-one and 7-bromo-8-fluoro-3-iodo-5H-chromeno[2,3-b]pyridin-5-one (81.92 g, 195 mmol, 78% yield) as an off white solid.

Step 3: A suspension of 7-bromo-6-fluoro-3-iodo-5H-chromeno[2,3-b]pyridin-5-one and 7-bromo-8-fluoro-3-iodo-5H-chromeno[2,3-b]pyridin-5-one (1:4 mixture) (76 g, 182 mmol) in 1 L dioxane was placed under argon and was heated with a heat gun until it became a homogenous solution. The solution was allowed to cool to room temperature and stir 72 hours. The reaction mixture was then cooled to −10° C. and was treated with methylmagnesium chloride (106 mL, 319 mmol) dropwise with stirring over 30 min. After stirring for an additional 60 min, the reaction mixture was quenched with MeOH (25 mL). Water (250 mL) was added, followed by concentrated NH 4 Cl solution (250 mL). The reaction mixture was concentrated in vacuo to remove most of the organics. The remaining aqueous solution was extracted with EtOAc (3×500 mL). The organics were washed with brine, dried over MgSO 4 and concentrated. The crude residue was taken up in ˜300 mL CH 2 Cl 2 and was again concentrated. This process was repeated 3×. The crude black solid was triturated with MeOH and was again dried to provide a 1:10 mixture of 7-bromo-6-fluoro-3-iodo-5-methylene-5H-chromeno[2,3-b]pyridine and 7-bromo-8-fluoro-3-iodo-5-methylene-5H-chromeno[2,3-b]pyridine (59.200 g, 142 mmol, 78% yield). This material was used without purification.

Step 4: A solution of 7-bromo-8-fluoro-3-iodo-5-methylene-5H-chromeno[2,3-b]pyridine (59.2 g, 136 mmol) in 500 mL THF was treated with HCl 4 N in dioxane (3.39 mL, 13.57 mmol) and was allowed to stir at RT for one hour at which point the reaction mixture was cooled to 0° C. A separate flask charged with a solution of iodine (37.9 g, 149 mmol) in 500 mL THF was cooled to −40° C. and treated with silver cyanate (50.8 g, 339 mmol). This mixture was allowed to stir for one hour before being treated with the solution of 7-bromo-8-fluoro-3-iodo-5-methylene-5H-chromeno[2,3-b]pyridine (59.2 g, 136 mmol) in 500 mL THF. The resulting orange slurry was maintained at 0° C. for 1 hour at which point ammonia 2 N in IPA (407 mL, 814 mmol) was added, and the reaction mixture was allowed to warm to room temperature and stir for 18 hours. The reaction mixture was filtered through celite, washing well with THF. The filtrate was quenched with saturated sodium thiosulfate solution (500 mL) and was allowed to stir for 72 hours. The reaction mixture was diluted with water (500 mL) and extracted with EtOAc (5×250 mL). The organics were washed with water then brine. The organics were dried over MgSO 4 and concentrated in vacuo. The crude residue was triturated with EtOAc and filtered. The remaining solid was triturated with CH 2 Cl 2 and again filtered. The resulting tan solid was collected and dried under a stream of nitrogen to provide 7-bromo-8-fluoro-3-iodo-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine (37.90 g, 80 mmol).

Step 5: A vial charged with Pd(PPh 3 ) 4 (0.73 g, 0.63 mmol), copper(I) iodide (0.48 g, 2.52 mmol), 7-bromo-8-fluoro-3-iodo-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine (3.0 g, 6.30 mmol), trimethyl((3-methyloxetan-3-yl)ethynyl)silane (1.06 g, 6.30 mmol) and 13 mL DMF was degassed with argon and treated with DIPA (4.49 mL, 31.5 mmol). The resulting slurry was allowed to stir at RT for 18 h at which point an additional portion of copper(I) iodide (0.48 g, 2.52 mmol) was added. After stirring for an additional 4 h the reaction mixture was poured into water (50 mL) and was extracted with EtOAc (3×100 mL). The resulting suspension was filtered through a glass frit and the filtrate was dried over MgSO 4 and concentrated in vacuo. Purification of the crude residue by column chromatography [0-50% (9:1 CH 2 Cl 2 :MeOH)/CH 2 Cl 2 ] provided 7-bromo-8-fluoro-3-((3-methyloxetan-3-yl)ethynyl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine (1.18 g, 2.66 mmol).

Step 6: A solution of Pd(PPh 3 ) 4 (0.077 g, 0.066 mmol), 2-fluoropyridin-3-ylboronic acid (0.19 g, 1.33 mmol), 7-bromo-8-fluoro-3-((3-methyloxetan-3-yl)ethynyl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine (0.30 g, 0.66 mmol), and potassium carbonate (0.46 g, 3.32 mmol) in 4.5 mL dioxane was treated with 1.8 mL water and was heated to 80° C. overnight. The reaction mixture cooled to rt and diluted with EtOAc (50 mL). The layers were separated and the organics were dried over MgSO 4 , and concentrated in vacuo. Purification of the crude residue by column chromatography [0-80% (9:1 CH 2 Cl 2 :MeOH)/CH 2 Cl 2 ] gave 8-fluoro-7-(2-fluoropyridin-3-yl)-3-((3-methyloxetan-3-yl)ethynyl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine (0.067 g, 0.146 mmol). Chiral separation provided (4′R)-8-fluoro-7-(2-fluoropyridin-3-yl)-3-((3-methyloxetan-3-yl)ethynyl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine (0.022 g, 0.048 mmol, peak 1) and (4′S)-8-fluoro-7-(2-fluoropyridin-3-yl)-3-((3-methyloxetan-3-yl)ethynyl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine (0.022 g, 0.048 mmol, peak 2).

Method BB25

Synthesis of 7-bromo-3-chloro-9-fluoro-5′H-spiro[chromeno[2,3-c]pyridine-5,4′-oxazol]-2′-amine

Step 1: Bromine (3.65 mL, 70.9 mmol) in Chloroform (250 mL) was added dropwise via an addition funnel to a suspension of 2-amino-3-fluorobenzoic acid (10 g, 64.5 mmol) in chloroform (400 mL) at RT. The solution was stirred for 12 hours at which point the resulting slurry was filtered. The solid was washed well with CH 2 Cl 2 and dried under a stream of nitrogen to afford 2-amino-5-bromo-3-fluorobenzoic acid HBr.

MS m/z=233.9 [M+H].

Step 2: Sulfuric acid (47.0 mL, 882 mmol) was added to a mixture of 2-amino-5-bromo-3-fluorobenzoic acid hydrobromide (16.34 g, 51.9 mmol) and HCl (12.45 mL, 156 mmol) at 0° C. The resulting slurry was stirred at 0° C. and sodium nitrite (3.58 g, 51.9 mmol) in water (20 mL) was added dropwise over 10 minutes. The reaction was stirred 40 minutes at 0° C. before a solution of potassium iodide (17.23 g, 104 mmol) in water (20.00 mL) was added dropwise. The solution was stirred allowed to warm to RT, leading to the formation of a viscous mixture. After 1 hour at ambient temperature, the reaction was poured into ice water (500 mL) and the resulting precipitate was filtered. The black solid was washed with well water to give a dark brown solid which was dried in a vacuum oven at 50° C. for 12 hours to afford 5-bromo-3-fluoro-2-iodobenzoic acid as an orange/tan solid. MS m/z=344.8 [M+H].

Step 3: A flask was charged with 5-bromo-3-fluoro-2-iodobenzoic acid (25.5 g, 73.9 mmol), 6-chloropyridin-3-ol (11.51 g, 88.9 mmol), and cesium carbonate (48.2 g, 148 mmol). The flask was evacuated and flushed with nitrogen twice before copper (i) trifluoromethanesulfonate toluene complex (0.488 g, 0.942 mmol) was added. Toluene (181 mL) (degassed 10 minutes by bubbling nitrogen through the solution prior to use) and ethyl acetate (0.263 mL, 2.68 mmol) were added and the mixture was heated at 115° C. for 12 hrs. The reaction was cooled to rt and poured into water (250 mL). The layers are separated and the organic layer was extracted with water (3×100 mL). The combined aqueous layers are washed with diethyl ether and then the pH of the aqueous layer was brought to a pH=3-4 with 1 N HCl. The aqueous layer was then extracted with ethyl acetate (3×250 mL). The combined organic extracts were washed with saturated aqueous sodium chloride and dried over sodium sulfate. The solution was filtered and concentrated in vacuo to provide the desired product which was used directly for the next reaction without further purification. MS m/z=348.1 [M+H].

Step 4: (N,N,N′,N′-tetramethyl-o-(1H-benzotriazol-1-yl)uronium tetrafluoroborate (53.1 g, 165 mmol) was added to a solution of 5-bromo-2-(6-chloropyridin-3-yloxy)-3-fluorobenzoic acid (38.2 g, 110 mmol) and diethylamine (63.3 mL, 606 mmol) in CH 2 Cl 2 (500 mL) at 0° C. After stirring 5 hours at RT, the reaction was quenched with saturated aqueous sodium bicarbonate (250 mL) at RT and diluted with water (100 mL) and the organics was removed in vacuo. The mixture was diluted with EtOAc (250 mL) and the layers were separated and the aqueous layer was extracted with EtOAc (3×100 mL). The combined organic extracts were washed with saturated aqueous sodium bicarbonate, water, 1N HCl, water, brine, and dried over sodium sulfate. The solution was filtered and concentrated in vacuo to provide a residue that was purified by filtering through a pad of silica gel by eluting with 1:2 EtOAc in hexane to provide 5-bromo-2-(6-chloropyridin-3-yloxy)-N,N-diethyl-3-fluorobenzamide.

Step 5: n-Butyllithium, 2.5 M (44.8 mL, 112 mmol) was added slowly to a solution of diisopropylamine (19.16 mL, 134 mmol) in THF (400 mL) at −78° C. The resulting solution was stirred at 0° C. for 15 minutes before cooling to −78° C. A solution of 5-bromo-2-(6-chloropyridin-3-yloxy)-N,N-diethyl-3-fluorobenzamide (30 g, 74.7 mmol) in THF (400 mL), cooled to −78° C., was added dropwise via cannula under positive pressure. The resulting solution was stirred 3 hours at −78° C. before being quenched with saturated ammonium chloride (200 mL). The reaction mixture was diluted with water (20 mL) and extracted with EtOAc (3×250 mL). The combined organic extracts were washed with saturated aqueous ammonium chloride, water, saturated aqueous sodium chloride, and dried over sodium sulfate. The solution was filtered and concentrated in vacuo to provide an off white solid that was triturated with methanol. The derived solid was dried under a stream of nitrogen to provide 7-bromo-3-chloro-9-fluoro-5H-chromeno[2,3-c]pyridin-5-one. MS m/z=330.1 [M+H].

Step 6: Methyl magnesium chloride, 22 wt % in tetrahydrofuran (6.14 mL, 18.26 mmol) was added to a solution of 7-bromo-3-chloro-9-fluoro-5H-chromeno[2,3-c]pyridin-5-one (3.0 g, 9.13 mmol) in THF (40 mL) at 0° C. After 2 hours, the reaction was quenched with saturated aqueous ammonium chloride (250 mL) and diluted with water (100 mL) and extracted with EtOAc (3×200 mL). The combined organic extracts were washed with saturated aqueous ammonium chloride, water, saturated aqueous sodium chloride, and dried over sodium sulfate. The solution was filtered and concentrated in vacuo to give the crude product 7-bromo-3-chloro-9-fluoro-5-methyl-5H-chromeno[2,3-c]pyridin-5-ol which was used directly in the next reaction. MS m/z=346.0 [M+H].

Step 7: Pyridinium p-toluene-sulfonate (2.53 g, 10.06 mmol) was added to a solution of 7-bromo-3-chloro-9-fluoro-5-methyl-5H-chromeno[2,3-c]pyridin-5-ol (3.15 g, 9.14 mmol) in DCE (91 mL) at 55° C. The reaction was stirred 2.5 hours at which time TLC analysis (10:1 Hex/EtOAc) showed the reaction to be complete. The reaction was poured into saturated aqueous sodium bicarbonate (150 mL) and the layers were separated. The aqueous layer was extracted with CH 2 Cl 2 (4×150 mL). The combined organic extracts were washed with saturated aqueous sodium chloride, and dried over sodium sulfate. The solution was filtered and concentrated in vacuo to give the crude product 7-bromo-3-chloro-9-fluoro-5-methylene-5H-chromeno[2,3-c]pyridine which was concentrated and used without further purification. MS m/z=327.9 [M+H].

Step 8: To a solution of iodine (2.56 g, 10.07 mmol) in THF (23 mL) at −20° C. was added silver cyanate (4.12 g, 27.5 mmol) and the mixture was stirred at −20° C. for 1 hour. To this slurry was added a solution of 7-bromo-3-chloro-9-fluoro-5-methylene-5H-chromeno[2,3-c]pyridine (2.99 g, 9.16 mmol) in THF (23.00 mL) dropwise over 5 minutes. The reaction was maintained at 0° C. for 2.5 hours at which point it was filtered through a bed of celite. The filtrate was cooled to 20° C. and treated with a 2 M solution of ammonia in i-PrOH (13.73 mL, 27.5 mmol). The resulting dark solution was allowed to warm to rt and stir for 12 hours. The reaction mixture was diluted with saturated aqueous sodium bicarbonate (200 mL) and saturated aqueous sodium thiosulfate (200 mL) and extracted with CH 2 Cl 2 (3×250 mL). The combined organic extracts were washed with water, saturated aqueous sodium chloride, and dried over sodium sulfate. The solution was filtered and concentrated in vacuo to provide a residue that was purified by silica gel chromatography (100% CH 2 Cl 2 followed by 1:20 MeOH in CH 2 Cl 2 to provide 7-bromo-3-chloro-9-fluoro-5′H-spiro[chromeno[2,3-c]pyridine-5,4′-oxazol]-2′-amine. MS m/z=386.0 [M+H].

Method BB26

Synthesis of 3-bromo-7-iodo-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-thiazol]-2′-amine

Step 1: A RBF was charged with 3-bromo-7-iodo-5H-chromeno[2,3-b]pyridin-5-one (12 g, 29.9 mmol) and THF (149 mL). The mixture was cooled to −78° C. using an acetone/dry ice bath. Methylmagnesium chloride (3.0M in THF) (21.89 mL, 65.7 mmol) was added dropwise and the reaction was stirred for two hours at −78° C. The reaction was quenched with saturated ammonium chloride solution (150 mL) and warmed to RT.

The biphasic solution was extracted three times with EtOAc, and the combined organic layers were dried with sodium sulfate, filtered, and concentrated to afford crude 3-bromo-7-iodo-5-methyl-5H-chromeno[2,3-b]pyridin-5-ol as a light yellow solid. MS m/z=420.0. Calc'd for C 13 H 9 BrINO 2 : 418.02.

Step 2: 3-bromo-7-iodo-5-methyl-5H-chromeno[2,3-b]pyridin-5-ol (12.09 g, 28.9 mmol) was taken up in CH 2 Cl 2 (116 mL) and ppts (0.100 g, 0.578 mmol) was added. The reaction was heated to 55° C. and stirred for two hours. The reaction was concentrated to afford crude 3-bromo-7-iodo-5-methylene-5H-chromeno[2,3-b]pyridine as an orange solid. The material was used immediately in the next step.

Step 3: A RBF was charged with iodine (7.71 g, 30.4 mmol), which was dissolved in 150 mL of THF and cooled to −40° C. in a dry ice/acetonitrile bath. Silver thiocyanate (14.40 g, 87 mmol) was added and the slurry was stirred for 30 minutes. In a separate flask, 3-bromo-7-iodo-5-methylene-5H-chromeno[2,3-b]pyridine (11.57 g, 28.9 mmol, 100% yield) was dissolved in minimal THF. The olefin solution was added dropwise to the iodine slurry via cannula, maintaining the internal temperature below −30° C. The reaction was stirred for 30 minutes. Ammonia (2.0 M in IPA) (72.3 mL, 145 mmol) was added and the reaction was stirred for 18 hours, during which the reaction warmed to RT. The reaction was filtered and the solids were washed with ethyl acetate and THF. The filtrate was diluted with ethyl acetate and saturated sodium thiosulfate solution was added. The biphasic solution was stirred for ten minutes, after which the layers were separated and the aqueous layer was extracted with ethyl acetate. The combined organic layers were dried with sodium sulfate, filtered, and concentrated. The material was purified via silica gel chromatography (gradient elution 0-10% EtOAc: CH 2 Cl 2 ) to afford 3-bromo-7-iodo-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-thiazol]-2′-amine as a light yellow solid. MS m/z=476.1. Calc'd for C 14 H 9 BrIN 3 OS: 474.11.

Method BB27

Synthesis of 4,4-difluoro-2′-(neopentyloxy)-7′-(pyrimidin-5-yl)-3,4-dihydrospiro[pyrrole-2,9′-xanthen]-5-amine

Step 1: Methyl magnesium chloride, 22 wt % in THF (5.0 mL, 14.88 mmol), was added to a solution of 2-(neopentyloxy)-7-(pyrimidin-5-yl)-9H-xanthen-9-one (2.2 g, 6.10 mmol) in THF (61.0 mL) at 0° C. After 2 hours, the reaction mixture was quenched with saturated aqueous ammonium chloride (200 mL) and extracted with EtOAc (3×200 mL). The combined organic extracts were washed with saturated aqueous ammonium chloride, water, saturated aqueous sodium chloride, and dried over sodium sulfate. The solution was filtered and concentrated in vacuo to afford 9-methyl-2-(neopentyloxy)-7-(pyrimidin-5-yl)-9H-xanthen-9-ol which used directly for the next reaction without further purification. Pyridinium p-toluene-sulfonate (0.140 g, 0.558 mmol) was added to a solution of 9-methyl-2-(neopentyloxy)-7-(pyrimidin-5-yl)-9H-xanthen-9-ol (0.200 g, 0.531 mmol) in DCE (2 mL) at 65° C. The reaction was monitored by and TLC analysis (1:1 Hex/EtOAc) and after 2 hours the solution was allowed to cool and was poured into saturated aqueous sodium bicarbonate (25 mL) and the layers were separated. The aqueous layer was extracted with CH 2 Cl 2 (3×15 mL). The combined organic extracts were washed with saturated aqueous sodium chloride, and dried over sodium sulfate. The solution was filtered and concentrated in vacuo to give the crude material which was taken up in toluene and concentrated twice to remove residual pyridine. The product was used without further purification. MS m/z=359.2 [M+H].

Step 2: Ethyl 2,2-difluoro-2-iodoacetate (0.062 mL, 0.418 mmol) was added to a mixture of copper (0.013 g, 0.209 mmol) and 5-(9-methylene-7-(neopentyloxy)-9H-xanthen-2-yl)pyrimidine (0.150 g, 0.418 mmol) in DMSO (4 mL) (degassed 10 minutes with nitrogen prior to use) at 55° C. The reaction was stirred over 12 hours. After cooling, the reaction mixture was diluted with water and a 10:1 mixture of saturated aqueous ammonium chloride/ammonium hydroxide and extracted with CH 2 Cl 2 (3×15 mL). The combined organic extracts were washed with a 10:1 mixture of saturated aqueous ammonium chloride/ammonium hydroxide, water, saturated aqueous sodium chloride, and dried over sodium sulfate. The solution was filtered and concentrated in vacuo to provide a residue that was purified by silica gel chromatography (1:1.5 EtOAc in hexane) to provide ethyl 2,2-difluoro-3-(9-hydroxy-2-(neopentyloxy)-7-(pyrimidin-5-yl)-9H-xanthen-9-yl). The procedure of step 2 is also described in Yang et al, J. Org. Chem ., Vol. 56, No. 17, 1991 pp. 5125-5132.

Step 3: Ammonia, as a 2 M solution in iPrOH (15 mL, 30.0 mmol), was added to ethyl 2,2-difluoro-3-(9-hydroxy-2-(neopentyloxy)-7-(pyrimidin-5-yl)-9H-xanthen-9-yl)propanoate (0.100 g, 0.201 mmol) at room temperature. After 30 minutes of stirring at RT the solution was concentrated to afford 2,2-difluoro-3-(9-hydroxy-2-(neopentyloxy)-7-(pyrimidin-5-yl)-9H-xanthen-9-yl)propanamide. M=470.3 [M+H].

Step 4: Ammonium acetate (0.131 g, 1.704 mmol) was added to a solution of 2,2-difluoro-3-(9-hydroxy-2-(neopentyloxy)-7-(pyrimidin-5-yl)-9H-xanthen-9-yl)propanamide (0.04 g, 0.085 mmol) in 2-Propanol (0.852 mL) and the reaction was heated to 90° C. After 30 minutes the reaction was diluted with water and saturated aqueous sodium bicarbonate (50 mL) and extracted with CH 2 Cl 2 (3×25 mL). The combined organic extracts were washed with water, saturated aqueous sodium chloride, and dried over sodium sulfate. The solution was filtered and concentrated in vacuo to afford a residue that was purified by silica gel chromatography (1:1 EtOAc in hexane) to provide 4,4-difluoro-2′-(neopentyloxy)-7′-(pyrimidin-5-yl)spiro[pyrrolidine-2,9′-xanthen]-5-one. M=452.1 [M+H].

Step 5: Lawesson's reagent (6.72 mg, 0.017 mmol) was added to a solution of 4,4-difluoro-2′-(neopentyloxy)-7′-(pyrimidin-5-yl)spiro[pyrrolidine-2,9′-xanthen]-5-one (0.015 g, 0.033 mmol) in toluene (0.665 mL) and the reaction was heated at 90° C. for 2.5 hours before being concentrated. The crude material was purified by dissolving in a minimal amount of CH 2 Cl 2 and filtering through a pad of silica gel eluting with 1:4 EtOAc in hexane followed by 1:1 EtOAc in hexane, to provide 4,4-difluoro-2′-(neopentyloxy)-7′-(pyrimidin-5-yl)spiro[pyrrolidine-2,9′-xanthene]-5-thione. M=468.1 [M+H].

Step 6: Ammonia gas was bubbled through a solution of 4,4-difluoro-2′-(neopentyloxy)-7′-(pyrimidin-5-yl)spiro[pyrrolidine-2,9′-xanthene]-5-thione (0.013 g, 0.028 mmol) in THF (0.350 mL) at 55° C. for 2 minutes. Mercury(II) chloride (0.011 g, 0.042 mmol) was added in one portion and ammonia gas was bubbled through for 3 more minutes while heating at 55° C. (THF solution replenished as necessary to maintain a volume of ˜0.2-0.3 mL). The resulting reaction was stirred at 55° C. under nitrogen atmosphere for 14 hours. After cooling, the reaction was partitioned between CH 2 Cl 2 (25 mL) and water (10 mL). The reaction mixture was diluted with a 10:1 mixture of saturated aqueous ammonium chloride/ammonium hydroxide, the layers were separated and the aqueous layer was extracted with CH 2 Cl 2 (3×25 mL). The combined organic extracts were washed with a 10:1 mixture of saturated aqueous ammonium chloride/ammonium hydroxide, water, saturated aqueous sodium chloride, and dried over sodium sulfate. The solution was filtered and concentrated in vacuo to provide a residue that was purified by filtering through a pad of silica gel by eluting with 1:10 MeOH 2 M ammonia solution in CH 2 Cl 2 followed by further purification by preparative thin layer chromatography (20:1 CHCl 3 /MeOH) to provide 4,4-difluoro-2′-(neopentyloxy)-7′-(pyrimidin-5-yl)-3,4-dihydrospiro[pyrrole-2,9′-xanthen]-5-amine as a white solid after triturating with pentane. MS m/z=451.2 [M+H]. This procedure is analogous to that described in Foloppe et al, Tetrahedron Letters, 33, 20, pp. 2803-2804, 1992.

Method BB28

Synthesis of (5S)-4′,4′-difluoro-3,7-di-3-pyridinyl-3′,4′-dihydrospiro[chromeno[2,3-b]pyridine-5,2′-pyrrol]-5′-amine

Step 1: Methyl magnesium chloride, 22 wt % in THF (4.67 mL, 13.90 mmol) was added to a solution of 3-bromo-7-methoxy-5H-chromeno[2,3-b]pyridin-5-one (2.66 g, 8.69 mmol) in THF (100 mL) at 0° C. After 2 hours, the reaction was quenched with saturated aqueous ammonium chloride (200 mL) and diluted with water and extracted with EtOAc (3×150 mL). The combined organic extracts were washed with saturated aqueous ammonium chloride, water, saturated aqueous sodium chloride, and dried over sodium sulfate. The solution was filtered and concentrated in vacuo to give the crude material which was used directly for the next reaction. MS m/z=324.0 [M+H]. Pyridinium p-toluene-sulfonate (0.078 g, 0.310 mmol) was added to a solution of 3-bromo-7-methoxy-5-methyl-5H-chromeno[2,3-b]pyridin-5-ol (0.100 g, 0.310 mmol) in DCE (3 mL) at 55° C. The reaction was stirred 60 minutes before LC/MS analysis showed the reaction to be complete and the reaction was poured into saturated aqueous sodium bicarbonate (100 mL) and the layers were separated. The aqueous layer was extracted with CH 2 Cl 2 (3×50 mL). The combined organic extracts were washed with saturated aqueous sodium chloride, and dried over sodium sulfate. The solution was filtered and concentrated in vacuo to give the crude material which was dried under vacuum and then used directly for the next reaction. MS m/z=306.1 [M+H].

Step 2: This procedure was followed in accordance with that described in Yang et al, J. Org. Chem ., Vol. 56, No. 17, 1991 pp. 5125-5132.

Copper (0.303 g, 4.77 mmol) and ethyl 2,2-difluoro-2-iodoacetate (0.771 mL, 5.24 mmol) were added to a solution of 3-bromo-7-methoxy-5-methylene-5H-chromeno[2,3-b]pyridine (1.45 g, 4.77 mmol) in DMSO (50 mL) (degassed 10 minutes by bubbling in nitrogen through the solvent prior to use) and the reaction was heated to 55° C. After 6 hours the reaction was allowed to cool to RT. The reaction was diluted with diethyl ether (50 mL) and washed with 10:1 saturated aqueous ammonium chloride/aqueous ammonium hydroxide, water, saturated aqueous sodium chloride, and dried over magnesium sulfate. The solution was filtered and concentrated in vacuo to give the crude material which was dissolved in ammonia, 2 M solution in i-PrOH (40 mL, 80 mmol), and stirred 12 hours before being concentrated. The crude material was purified by silica gel chromatography (1:1 EtOAc in hexanes followed by 1:20 MeOH in CH 2 Cl 2 ) to provide 3-(3-bromo-5-hydroxy-7-methoxy-5H-chromeno[2,3-b]pyridin-5-yl)-2,2-difluoropropanamide. MS m/z=417.2 [M+H].

Step 3: 3-(3-bromo-5-hydroxy-7-methoxy-5H-chromeno[2,3-b]pyridin-5-yl)-2,2-difluoropropanamide (0.120 g, 0.289 mmol) was added to a saturated solution of ammonium acetate (2.228 g, 28.9 mmol) in 2-propanol (20 mL) and the mixture was heated to reflux. After 2.5 hours the reaction was allowed to cool to rt and the 2-propanol was removed in vacuo. The derived residue was partitioned between CH 2 Cl 2 (50 mL) and water (50 mL). The layers were separated and the aqueous layer was extracted with CH 2 Cl 2 (3×25 mL) and EtOAc (3×25 mL). The combined organic layers were washed with saturated sodium bicarbonate, water, brine, dried over sodium sulfate, and concentrated. The product was precipitated from 1:1 chloroform and diethyl ether to afford 3-bromo-4′,4′-difluoro-7-methoxyspiro[chromeno[2,3-b]pyridine-5,2′-pyrrolidin]-5′-one as a gold solid. MS m/z=397.1 [M+H].

Step 4: Tribromoborane, as a 1 M solution in DCM (1.057 mL, 1.057 mmol) was added to a solution of 3-bromo-4′,4′-difluoro-7-methoxyspiro[chromeno[2,3-b]pyridine-5,2′-pyrrolidin]-5′-one (0.070 g, 0.176 mmol) at 0° C. After stirring 1.5 hours at 0° C. the reaction was allowed to warm to RT and stir for an additional 1.5 hours. At this point the reaction was cooled to 0° C. and quenched with 9:1 saturated aqueous ammonium chloride/ammonium hydroxide. This mixture was diluted with water and extracted with CH 2 Cl 2 (3×25 mL) and the EtOAc (3×25 mL). The combined organic extracts were washed with 9:1 saturated aqueous ammonium chloride/ammonium hydroxide, water, saturated aqueous sodium chloride, and dried over sodium sulfate. The solution was filtered and concentrated in vacuo to give the crude material which was used directly for the next reaction. MS m/z=383.0 [M+H].

Step 5: N-phenyltrifluoromethanesulfonimide (0.045 g, 0.125 mmol) was added to a mixture of 3-bromo-4′,4′-difluoro-7-hydroxyspiro[chromeno[2,3-b]pyridine-5,2′-pyrrolidin]-5′-one (0.040 g, 0.104 mmol) and cesium carbonate (0.041 g, 0.125 mmol) in DMF (0.522 mL) at 0° C. The reaction was stirred at RT for 1.5 hours when LC/MS analysis showed the reaction to be nearly complete. The reaction was poured into water (20 mL) and extracted with EtOAc (3×15 mL). The combined organic extracts were washed with water, saturated aqueous sodium chloride, and dried over sodium sulfate. The solution was filtered and concentrated in vacuo to give the crude material. The crude material was purified by dissolving in a minimal amount of DCM and filtering through a pad of silica gel eluting with 100% CH 2 Cl 2 followed by 1:10 MeOH in CH 2 Cl 2 , to provide 3-bromo-4′,4′-difluoro-5′-oxospiro[chromeno[2,3-b]pyridine-5,2′-pyrrolidine]-7-yl trifluoromethanesulfonate. MS m/z=516.9 [M+H].

Step 6: Pd(PPh 3 ) 4 (10.77 mg, 9.32 mmol) was added to a degassed (nitrogen) solution of 3-bromo-4′,4′-difluoro-5′-oxospiro[chromeno[2,3-b]pyridine-5,2′-pyrrolidine]-7-yl trifluoromethanesulfonate (0.048 g, 0.093 mmol) and 3-pyridylboronic acid (0.034 g, 0.279 mmol) in dioxane (0.900 mL) and a 2 M sodium carbonate aqueous solution (0.300 mL, 0.600 mmol). The reaction was heated at 90° C. for 1.5 hours before being cooled to rt and diluted with water (10 mL) and 9:1 saturated aqueous ammonium chloride/ammonium hydroxide (10 mL) and extracted with EtOAc (3×20 mL). The combined organic extracts were washed with 9:1 saturated aqueous ammonium chloride/ammonium hydroxide, water, saturated aqueous sodium chloride, and dried over sodium sulfate. The solution was filtered and concentrated in vacuo to give the crude material which was used directly for the next reaction without further purification. MS m/z=443.1 [M+H].

Step 7: 4′,4′-difluoro-3,7-di(pyridin-3-yl)spiro[chromeno[2,3-b]pyridine-5,2′-pyrrolidin]-5′-one (0.041 g, 0.093 mmol) as the crude product from the previous reaction was dissolved in toluene (1.5 mL) along with enough CH 2 Cl 2 to form a homogenous solution. The solution was placed in an oil bath at 90° C. and the CH 2 Cl 2 was allowed to boil off before the reaction was capped with a septum and placed under a nitrogen atmosphere. Lawesson's reagent (0.019 g, 0.046 mmol) was added and the reaction was stirred at 90° C. for 4 hours. After cooling to rt, the reaction was poured into water (10 mL) and extracted with CH 2 Cl 2 (3×25 mL) and a 2:1 chloroform/i-PrOH mixture (2×10 mL).

The combined organic extracts were washed with saturated aqueous sodium chloride and concentrated in vacuo to provide a residue that was purified by silica gel chromatography (1:20 followed by 1:10 MeOH in CH 2 Cl 2 ) to provide 4′,4′-difluoro-3,7-di(pyridin-3-yl)spiro[chromeno[2,3-b]pyridine-5,2′-pyrrolidine]-5′-thione as a orange solid. MS m/z=459.1 [M+H].

Step 8: Ammonia gas was bubbled through a solution of 4′,4′-difluoro-3,7-di(pyridin-3-yl)spiro[chromeno[2,3-b]pyridine-5,2′-pyrrolidine]-5′-thione (0.019 g, 0.041 mmol) in THF (0.691 mL) at 55° C. for 2 minutes. Mercuric chloride (0.019 g, 0.070 mmol) was added in one portion and ammonia gas was bubbled through for 5 more minutes while heating at 55° C. (THF solution replenished as necessary to maintain a volume of ˜0.6 mL). The resulting reaction was stirred at 55° C. under nitrogen atmosphere for 12 hours to completion. After cooling, the reaction was filtered with CH 2 Cl 2 , MeOH, and 2:1 mixture of CHCl 3 /i-PrOH. The filtrate was diluted with a 10:1 mixture of saturated aqueous ammonium chloride/ammonium hydroxide (10 mL), the layers were separated and the aqueous layer was extracted with a 2:1 mixture of CHCl 3 /i-PrOH (3×20 mL). The combined organic extracts were washed with a 10:1 mixture of saturated aqueous ammonium chloride/ammonium hydroxide, water, saturated aqueous sodium chloride, and dried over sodium sulfate. The solution was filtered and concentrated in vacuo to afford a residue that was purified by silica gel chromatography (1:20 MeOH in CH 2 Cl 2 , followed by 1:10 2 M ammonia MeOH solution in CH 2 Cl 2 ) to provide 4′,4′-difluoro-3,7-di(pyridin-3-yl)-3′,4′-dihydrospiro[chromeno[2,3-b]pyridine-5,2′-pyrrol]-5′-amine as an off-white solid after triturating with diethyl ether and pentane. MS m/z=442.0 [M+H].

Synthesis of (S,E)-7-(6-fluoropyridin-3-yl)-3-(2-(3-methyloxetan-3-yl)vinyl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine

Step 1: A vial was charged with (S)-2′-amino-3-bromo-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-7-ol (715 mg, 2.054 mmol) and dichloro 1,1′-bis(diphenylphosphino)ferrocene palladium(II) (168 mg, 0.205 mmol). The vial was flushed with Ar (g), then DMF (1 mL) and (E)-tributyl(2-(3-methyloxetan-3-yl)vinyl)stannane (1080 μL, 3.08 mmol) were added in sequence. The vial was sealed and heated in a Biotage Initiator microwave reactor for 2.5 h at 120° C. The mixture was loaded onto a 25-g SCX-2 ion exchange column and eluted with methanol to remove impurities. The product was then eluted with 2N ammonia in MeOH. The filtrate was concentrated under vacuum, and the residue was purified by chromatography on silica gel with 0-100% of a 90:10:1 mixture of CH 2 Cl 2 /MeOH/NH 4 OH in CH 2 Cl 2 to give (S,E)-2′-amino-3-(2-(3-methyloxetan-3-yl)vinyl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-7-01 as a brown oil. MS m/z=366.2. Calc'd for C 20 H 20 N 3 O 4 : 366.2.

Step 2: A 100-mL RBF was charged with (S,E)-2′-amino-3-(2-(3-methyloxetan-3-yl)vinyl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-7-01 (355 mg, 0.972 mmol), CH 2 Cl 2 (9.7 mL), triethylamine (271 μL, 1.943 mmol), resulting in a clear, pale brown solution. 1,1,1-Trifluoro-N-phenyl-N-(trifluoromethylsulfonyl)methanesulfonamide (364 mg, 1.020 mmol) was added, and the resulting mixture was stirred for 16 h. An additional portion of 1,1,1-trifluoro-N-phenyl-N-(trifluoromethylsulfonyl)methanesulfonamide (40 mg) was added, and the mixture was stirred for an additional 2 h. The mixture was concentrated under vacuum, and the residue was purified by chromatography on an silica gel, eluting with 0-5% MeOH/CH 2 Cl 2 to give (S,E)-2′-amino-3-(2-(3-methyloxetan-3-yl)vinyl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazole]-7-yl trifluoromethanesulfonate as an off-white solid. MS m/z=498.0. Calc'd for C 21 H 19 F 3 N 3 O 6 S: 498.1.

Step 3: Similar to a Suzuki reaction, a vial was charged with (S,E)-2′-amino-3-(2-(3-methyloxetan-3-yl)vinyl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazole]-7-yl trifluoromethanesulfonate (80 mg, 0.161 mmol), 6-fluoropyridin-3-ylboronic acid (68.0 mg, 0.482 mmol), potassium carbonate (111 mg, 0.804 mmol), and dichloro 1,1′-bis(diphenylphosphino)ferrocene palladium(II) (1.313 mg, 1.608 μmol). The vial was flushed with Ar (g), then dioxane (1 mL) and water (0.5 mL) were added. The vial was sealed and heated to 80° C. for 4 h. The reaction mixture was cooled to RT, partitioned between water and EtOAc, and the aq. layer was extracted with EtOAc (2×). The combined organic extracts were dried over sodium sulfate, filtered, and concentrated under vacuum. The residue was purified by chromatography on silica gel eluting with 0-80% of a 90:10:1 mixture of CH 2 Cl 2 /MeOH/NH 4 OH in CH 2 Cl 2 to give ca. 55 mg of an light orange solid. The solid was dissolved in MeOH and purified by reverse-phase HPLC (10-70% CH 3 CN/H 2 O with 0.1% TFA). The fractions containing product were poured onto a 2-g SCX-2 ion exchange column and eluted with methanol to remove impurities.

The product was eluted with 2N ammonia in MeOH. The filtrate was concentrated under vacuum to give 29 mg of a white solid. The solid was repurified by chromatography on silica gel as before to give (S,E)-7-(6-fluoropyridin-3-yl)-3-(2-(3-methyloxetan-3-yl)vinyl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine as a white solid. MS m/z=445.2. Calc'd for C 25 H 22 FN 4 O 3 : 445.2.

Synthesis of (S)-4′-fluoro-7′-(2-fluoropyridin-3-yl)-2′-(6-methylpyridazin-3-yl)-5H-spiro[oxazole-4,9′-xanthen]-2-amine

Step 1: Sodium carbonate (saturated, 2 mL), Pd(PPh 3 ) 4 (0.237 g, 0.205 mmol), (S)-2-amino-7′-bromo-4′-fluoro-5H-spiro[oxazole-4,9′-xanthen]-2′-ol (0.75 g, 2.054 mmol), and 2-fluoropyridine-3-boronic acid (310 mg, 2.18 mmol) were combined in DMF (5 mL). The solution was heated at 85° C. overnight before being cooled to rt. The solution was diluted with water (25 ml) and filtered. The solids were triturated with MeOH and dried under vacuum to afford (S)-2-amino-4′-fluoro-7′-(2-fluoropyridin-3-yl)-5H-spiro[oxazole-4,9′-xanthen]-2′-ol as a tan solid. MS m/z=382.0 [M+H].

Step 2: (S)-2-amino-4′-fluoro-7′-(2-fluoropyridin-3-yl)-5H-spiro[oxazole-4,9′-xanthen]-2′-ol (900 mg, 2.360 mmol) and TEA (0.658 ml, 4.72 mmol) were combined in 25 ml of CH 2 Cl 2 , and 1,1,1-trifluoro-N-phenyl-N-(trifluoromethylsulfonyl)methanesulfonamide (1012 mg, 2.83 mmol) was added. The derived solution was stirred at RT overnight. The solution was loaded directly on a silica column. The product was purified via silica gel column chromatography (RediSep 40 g column) eluting with 10-70% 90/10/1 (CH 2 Cl 2 /MeOH/ammonia) in CH 2 Cl 2 to afford (S)-2-amino-5′-fluoro-2′-(2-fluoropyridin-3-yl)-5H-spiro[oxazole-4,9′-xanthene]-7′-yl trifluoromethanesulfonate as a yellow solid solid. MS m/z=514.0 [M+H].

Step 3: A 15 mL resealable tube was charged with (S)-2-amino-5′-fluoro-2′-(2-fluoropyridin-3-yl)-5H-spiro[oxazole-4,9′-xanthene]-7′-yl trifluoromethanesulfonate (1.07 g, 2.084 mmol), Cl 2 Pd(dppf)-CH 2 Cl 2 complex (0.170 g, 0.208 mmol), bis-pinacolatodiboron (0.900 g, 3.54 mmol), KOAc (0.614 g, 6.25 mmol) and dioxane (6.95 mL). The vial was sealed and heated at 100° C. overnight. The mixture was cooled to rt and filtered through celite. The filtrate was partitioned between ethyl acetate (50 mL) and water (25 mL). The organic layer was washed with brine, filtered through celite and concentrated in vacuo. The derived residue was redissolved in EtOAc (6 mL) and ˜10 ml of hexane was added. The resulting light yellow solution was decanted from the black oil and concentrated in vacuo to give a tan solid. This solid was then triturated with 200 mL hexane and the resulting precipitate was filtered and dried in vacuo to afford (S)-4′-fluoro-7′-(2-fluoropyridin-3-yl)-2′-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-5H-spiro[oxazole-4,9′-xanthen]-2-amine as a beige solid.

Step 4: Sodium carbonate (saturated, 1 mL), Pd(PPh 3 ) 4 (23.52 mg, 0.020 mmol), (S)-4′-fluoro-7′-(2-fluoropyridin-3-yl)-2′-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-5H-spiro[oxazole-4,9′-xanthen]-2-amine (200 mg, 0.407 mmol), and 3-bromo-6-methylpyridazine (141 mg, 0.814 mmol) were combined in DMF (5 mL). The solution was heated at 85° C. overnight. The solution was filtered through celite and the derived residue was purified via Gilson HPLC (gradient elution 25-65% MeCN/H 2 O, 0.1% TFA) to afford (S)-4′-fluoro-7′-(2-fluoropyridin-3-yl)-2′-(6-methylpyridazin-3-yl)-5H-spiro[oxazole-4,9′-xanthen]-2-amine as an off white solid. MS m/z=458.0 [M+H].

Synthesis of (4′R)-8-fluoro-7-(2-fluoropyridin-3-yl)-3-(3-methoxy-3-methylbut-1-ynyl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine (115a) and (4′S)-8-fluoro-7-(2-fluoropyridin-3-yl)-3-(3-methoxy-3-methylbut-1-ynyl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine (115b)

Step 1: A vial charged with Pd(PPh 3 ) 4 (0.485 g, 0.420 mmol), copper(i) iodide (0.080 g, 0.420 mmol), 7-bromo-8-fluoro-3-iodo-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine (2.000 g, 4.20 mmol), 2-methylbut-3-yn-2-ol (0.353 g, 4.20 mmol) and 9 mL DMF was degassed with argon and treated with DIPA (2.99 mL, 21.01 mmol). The resulting black mixture was allowed to stir at RT for 3 hours. The reaction mixture was then poured into water (25 mL) and extracted with EtOAc (3×30 mL). The organics were dried over MgSO 4 and concentrated in vacuo. Purification of the crude residue by column chromatography [0-50% (9:1 CH 2 Cl 2 :MeOH)/CH 2 Cl 2 ] provided 4-(2′-amino-7-bromo-8-fluoro-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazole]-3-yl)-2-methylbut-3-yn-2-ol.

Step 2: A solution of 4-(2′-amino-7-bromo-8-fluoro-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazole]-3-yl)-2-methylbut-3-yn-2-ol (0.580 g, 1.342 mmol) in 10 mL MeOH was treated with methanesulfonic acid (0.871 mL, 13.42 mmol). The resulting solution was allowed to stir at RT for 72 hours and was then heated at 85° C. for 3 hours. The reaction mixture was poured into saturated NaHCO 3 (50 mL) and was extracted with EtOAc (3×25 mL). The organics were washed with brine, dried over MgSO 4 and concentrated in vacuo. Purification of the crude residue by column chromatgraphy [0-100% (95:5 EtOAc/MeOH)/CH 2 Cl 2 ] afforded 7-bromo-8-fluoro-3-(3-methoxy-3-methylbut-1-ynyl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine

Step 3: A solution of Pd(PPh 3 ) 4 (0.064 g, 0.055 mmol), 2-fluoropyridin-3-ylboronic acid (0.155 g, 1.102 mmol), 7-bromo-8-fluoro-3-(3-methoxy-3-methylbut-1-ynyl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine (0.246 g, 0.551 mmol), and potassium carbonate (0.381 g, 2.76 mmol) in 5 mL dioxane was treated with 2 mL water and was heated to 80° C. overnight. The reaction mixture was cooled to rt and diluted with EtOAc (25 mL). The mixture was dried over MgSO 4 and concentrated. Purification of the crude residue by column chromatography [0-80% (9:1 CH 2 Cl 2 :MeOH)/CH 2 Cl 2 ] provided a mixture of (4′R)-8-fluoro-7-(2-fluoropyridin-3-yl)-3-(3-methoxy-3-methylbut-1-ynyl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine and (4′S)-8-fluoro-7-(2-fluoropyridin-3-yl)-3-(3-methoxy-3-methylbut-1-ynyl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine (0.132 g, 0.285 mmol). Chiral separation of this material provided (4′R)-8-fluoro-7-(2-fluoropyridin-3-yl)-3-(3-methoxy-3-methylbut-1-ynyl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine (peak 1) and (4′S)-8-fluoro-7-(2-fluoropyridin-3-yl)-3-(3-methoxy-3-methylbut-1-ynyl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine (peak 2).

Synthesis of -bromo-3-chloro-8-fluoro-5′H-spiro[chromeno[2,3-c]pyridine-5,4′-oxazol]-2′-amine

Step 1: Sulfuric acid (19.36 mL, 363 mmol) was added to a solution of 2-amino-5-bromo-4-fluorobenzoic acid (5.00 g, 21.37 mmol) in concentrated HCl (5.13 mL, 64.1 mmol) at 0° C. To this was added a solution of sodium nitrate (1.816 g, 21.37 mmol) in water (9 mL). The reaction was stirred for 40 minutes at 0° C. before potassium iodide (7.09 g, 42.7 mmol) in water (9.00 mL) was added dropwise. The solution was stirred at rt for 1 hour, at which point it had become a viscous oil. The mixture was poured into a mixture of ice water (250 mL) with EtOAc (200 mL). The layers were separated and the aqueous layer was extracted with EtOAc (3×100 mL). The combined organic extracts were washed with 1N HCl, 1 N aqueous sodium sulfite, and dried over sodium sulfate. The solution was filtered and concentrated in vacuo to give 5-bromo-4-fluoro-2-iodobenzoic acid.

Step 2: A flask was charged with 5-bromo-4-fluoro-2-iodobenzoic acid (4.00 g, 11.60 mmol), 6-chloropyridin-3-ol (1.803 g, 13.92 mmol), and cesium carbonate (7.56 g, 23.19 mmol). The flask was evacuated and flushed with nitrogen twice before copper (I) trifluoromethanesulfonate toluene complex (0.156 g, 0.302 mmol) was added. Toluene (58.0 mL) (degassed 10 minutes by bubbling nitrogen through the solution prior to use) and ethyl acetate (0.084 mL, 0.858 mmol) were added and the mixture was heated at 115° C. After 2 hours, the reaction was allowed to cool to RT and the mixture was diluted with water (50 mL) and stirred vigorously for 15 minutes. After diluting with ether (200 mL), the layers were separated and the organic layer was extracted with 10% sodium carbonate. The pH of the combined aqueous layers was adjusted to pH ˜2 and extracted with ethyl acetate. The combined organic layers were washed with saturated sodium chloride, dried over sodium sulfate, filtered, and concentrated to afford 5-bromo-2-(6-chloropyridin-3-yloxy)-4-fluorobenzoic acid as a solid. MS m/z=347.9 [M+H].

Step 3: (N,N,N′,N′-Tetramethyl-o-(1h-benzotriazol-1-yl)uronium tetrafluoroborate (6.95 g, 21.64 mmol) was added to a solution of 5-bromo-2-(6-chloropyridin-3-yloxy)-4-fluorobenzoic acid (5.00 g, 14.43 mmol) and diethylamine (8.00 mL, 77 mmol) in DMF (70 mL) at 0° C. The reaction was stirred 1.5 hours before being quenched with saturated sodium bicarbonate (100 mL). The reaction mixture was diluted with water (50 mL) and extracted with EtOAc (3×50 mL). The combined organic extracts were washed with saturated aqueous ammonium chloride, water, 10% aqueous sodium carbonate, saturated aqueous sodium chloride, and dried over sodium sulfate. The solution was filtered and concentrated in vacuo to provide a residue that was purified by silica gel chromatography (1:2 EtOAc in hexane) to provide 5-bromo-2-(6-chloropyridin-3-yloxy)-N,N-diethyl-4-fluorobenzamide. MS m/z=403.0 [M+H].

Step 4: n-Butyl lithium (3.14 mL, 7.84 mmol) was added to a solution of diisopropylamine (1.341 mL, 9.41 mmol) in THF (40 mL) at −78° C. The resulting solution was stirred at 0° C. for 15 minutes before being added dropwise via cannula to a solution of 5-bromo-2-(6-chloropyridin-3-yloxy)-N,N-diethyl-4-fluorobenzamide (2.1 g, 5.23 mmol) in THF (40.0 mL) cooled to −78° C. under positive pressure. The resulting solution was stirred 3 hours at −78° C. before being quenched with saturated ammonium chloride (100 mL). The reaction mixture was diluted with water (50 mL) and extracted with EtOAc (3×75 mL). The combined organic extracts were washed with saturated aqueous NH 4 Cl, water, saturated aqueous NaCl, and dried over sodium sulfate. The solution was filtered and concentrated in vacuo to give the crude material. The crude material was purified by dissolving in a minimal amount of CH 2 Cl 2 and filtering through a pad of silica gel by eluting with 1:10 EtOAc in hexane, to provide 7-bromo-3-chloro-8-fluoro-5H-chromeno[2,3-c]pyridin-5-one as a off-white solid. MS m/z=330.0 [M+H].

Step 5: Methylmagnesium chloride, 3.0 M solution in THF (0.958 mL, 2.87 mmol) was added to a solution of 7-bromo-3-chloro-8-fluoro-5H-chromeno[2,3-c]pyridin-5-one (0.590 g, 1.796 mmol) in THF (6 mL) at 0° C. After 1.5 hours the reaction was quenched with saturated aqueous ammonium chloride (50 mL) and extracted with EtOAc (2×50 mL). The combined organic extracts were washed with water, saturated aqueous sodium chloride, and dried over sodium sulfate. The solution was filtered and concentrated in vacuo to give the crude material which was used directly for the next reaction without further purification.

Step 6: Pyridinium p-toluenesulfonate (0.023 g, 0.090 mmol) was added to a solution of 7-bromo-3-chloro-8-fluoro-5-methyl-5H-chromeno[2,3-c]pyridin-5-ol (0.619 g, 1.796 mmol) in DCE (7.19 mL) at 65° C. After 1.5 hours, the reaction was judged complete by LC/MS analysis and the solution was allowed to cool to rt and was poured into saturated sodium bicarbonate (50 mL). The layers were separated and the aqueous layer was extracted with CH 2 Cl 2 (3×25 mL). The combined organic extracts were washed with saturated aqueous sodium chloride, and dried over sodium sulfate. The solution was filtered and concentrated in vacuo to afford 7-bromo-3-chloro-8-fluoro-5-methylene-5H-chromeno[2,3-c]pyridine which was used directly for the next reaction without further purification. MS m/z=327.9 [M+H].

Step 7: To a solution of iodine (0.502 g, 1.977 mmol) in THF (4 mL) at −20° C. was added silver cyanate (0.202 mL, 5.39 mmol) and the mixture was stirred at −20° C. for 1 hour. 7-bromo-3-chloro-8-fluoro-5-methylene-5H-chromeno[2,3-c]pyridine (0.587 g, 1.798 mmol) as a solution in THF (5.00 mL) was added slowly by syringe and the mixture was stirred at 0° C. for 2.5 hours. The whole was then filtered through Celite with the aid of THF (˜6 mL). A 2 M ammonia solution in i-PrOH (2.70 mL, 5.39 mmol) was added slowly to the filtrate and the resulting solution was stirred at RT for 3.5 hours. The reaction mixture was diluted with saturated aqueous sodium bicarbonate and saturated aqueous NaHSO 3 (25 mL) and extracted with CH 2 Cl 2 (3×25 mL). The combined organic extracts were washed with water, saturated aqueous sodium chloride, and dried over sodium sulfate. The solution was filtered and concentrated in vacuo to afford 7-bromo-3-chloro-8-fluoro-5′H-spiro[chromeno[2,3-c]pyridine-5,4′-oxazol]-2′-amine. MS m/z=386.0 [M+H].

Synthesis of 7-bromo-3-chloro-1-fluoro-5′H-spiro[chromeno[2,3-c]pyridine-5,4′-oxazol]-2′-amine

Step 1: DIPA (6.0 mL, 42.8 mmol) was dissolved in dry THF (20 mL) and cooled under nitrogen in a dry ice bath. n-Butyllithium solution (2.5 M in hexanes, 17 mL, 42.5 mmol) was added and after stirring for a few minutes a solution of 2-chloro-6-fluoropyridine (5.0 g, 38.0 mmol) in dry THF (20 mL) was added dropwise. The solution was stirred for 50 minutes then a solution of triisopropyl borate (8.72 mL, 38.0 mmol) in dry tetrahydrofuran (10 mL) was added dropwise. The reaction was stirred for 10 minutes. Water (80 mL) was added and the reaction concentrated under reduced pressure until water began to distill. The solution was treated with aqueous sodium hydroxide (10.0 N, 11.40 mL, 114 mmol) and hydrogen peroxide (30% by wt, 4.66 mL, 45.6 mmol) and stirred at RT for 90 minutes. Additional hydrogen peroxide (0.75 mL) was added. After stirring for 30 minutes, ice (˜100 mL), water (100 mL) and HCl (2N, 60 mL) were added followed by EtOAc (200 ml). The phases were mixed and separated and the organic dried with magnesium sulfate before evaporating to dryness under reduced pressure. The crude intermediate was dissolved in acetone (100 mL) and treated with potassium carbonate (6.30 g, 45.6 mmol) and chloromethyl methyl ether (2.89 mL, 38.0 mmol). The mixture was heated in a 60° C. oil bath and monitored by TLC. The reaction was complete within 2 hours and was concentrated under reduced pressure to ˜30 mL. Water (100 mL) and diethyl ether (100 ml) were added and the phases mixed and separated. The organic was dried with magnesium sulfate and evaporated to dryness under reduced pressure. The crude oil was found to be 6-chloro-2-fluoro-3-(methoxymethoxy)pyridine and did not required purification.

Step 2: DIPA (0.750 mL, 5.35 mmol) was dissolved in dry THF (20 mL) under nitrogen and cooled in a dry ice bath to −78° C. Butyllithium solution (2.5 M in hexanes, 2.0 mL, 5.00 mmol) was added and the solution was stirred for a few minutes. A solution of 6-chloro-2-fluoro-3-(methoxymethoxy)pyridine (0.864 g, 4.51 mmol) in dry THF (10 mL) was added slowly and the resulting solution stirred for 40 minutes. A solution of 5-bromo-2-fluorobenzaldehyde (1.02 g, 5.05 mmol) in dry THF (1 mL) was added dropwise. After 10 minutes saturated ammonium chloride (10 mL), water (100 mL) and EtOAc (100 mL) were added and the phases mixed and separated. The organic was dried with magnesium sulfate and evaporated to dryness under reduced pressure. Purification using silica chromatography (hexane to EtOAc gradient) gave the desired (5-bromo-2-fluorophenyl)(6-chloro-2-fluoro-3-(methoxymethoxy)pyridin-4-yl)methanol.

Step 3: (5-Bromo-2-fluorophenyl)(6-chloro-2-fluoro-3-(methoxymethoxy)pyridin-4-yl)methanol (1.008 g, 2.55 mmol) and 4-methylmorpholine n-oxide (0.898 g, 7.66 mmol) were dissolved in DCM (60 mL) and treated with tetrapropylammonium perruthenate (0.045 g, 0.128 mmol). When the oxidation was complete by TLC (EA/hexane) it was passed through a short silica column using 1:1 EtOAc:DCM to wash off the desired ketone. Evaporation under reduced pressure gave the intermediate as a clear oil that crystallized on standing. It was dissolved in DCM (60 mL) under nitrogen and cooled in an ice bath. Boron tribromide (0.5 mL, 5.29 mmol) was added and the solution turned red. After 5 minutes additional DCM (80 mL) was added followed by ice (˜50 mL) and water (100 mL). The phases were mixed and separated and the organic dried with magnesium sulfate before evaporating to dryness under reduced pressure. The crude material was dissolved in dioxane (50 mL) and treated with cesium carbonate (0.246 mL, 3.07 mmol). The reaction was heated to reflux for 30 minutes. It was cooled and water (100 mL) and EtOAc (100 mL) were added. The phases were mixed and separated and the organic dried with magnesium sulfate before evaporating to dryness under reduced pressure. The crude product was purified using silica chromatography (hexane to ethyl acetate gradient) to give 7-bromo-3-chloro-1-fluoro-5H-chromeno[2,3-c]pyridin-5-one as a white solid.

Step 4: 7-Bromo-3-chloro-1-fluoro-5H-chromeno[2,3-c]pyridin-5-one (21.5 g, 65.4 mmol) was suspended in dry THF (300 mL) under nitrogen in an ice bath. Methylmagnesium bromide (3.0 M in diethyl ether, 36 mL, 108 mmol) was added in ˜12 mL portions allowing 10-15 minutes between additions. The mixture was stirred for a 15 minutes after the final addition. Saturated ammonium chloride (50 mL) was added carefully followed by diethyl ether (200 mL), ethyl aceate (200 mL), water (400 mL) and 2 N HCl (50 mL). The phases were mixed and separated and the organic dried with magnesium sulfate before evaporating to dryness under reduced pressure. The crude alcohol was dissolved in dry THF (300 mL) and treated with HCl (4.0 M solution in 1,4-dioxane, 16 mL, 64.0 mmol). The mixture was heated to 50° C. and stirred for 30 minutes. The crude reaction mixture was evaporated to dryness under reduced pressure. The crude tar was triturated with diethyl ether (200 mL) and stirred in an ice bath. A cream coloured solid precipitated within a few minutes. After 10 minutes the mixture was filtered through a sintered glass frit and dried under high vacuum to give the desired 7-bromo-3-chloro-1-fluoro-5-methylene-5H-chromeno[2,3-c]pyridine.

Step 5: 7-Bromo-3-chloro-1-fluoro-5-methylene-5H-chromeno[2,3-c]pyridine (14.2 g, 43.5 mmol) was dissolved in dry THF (400 mL) under nitrogen and cooled in an ice bath. Silver cyanate (19.55 g, 130 mmol) was added followed by slow addition of a solution of iodine (11.04 g, 43.5 mmol) in dry THF (80 mL) over 30 minutes. It was stirred for another 30 minutes then it was filtered through a pad of celite. The filtrate was treated with ammonia (2.0 M solution in MeOH, 250 mL, 500 mmol) and capped. The solution was stirred for 10 hours. The crude reaction was concentrated under reduced pressure to ˜100 mL then diluted with DCM (300 mL). The solution was washed with aqueous sodium sulfite to remove iodine then evaporated to dryness under reduced pressure. DCM/MeOH (60:40, 300 mL) were added to the solids and the crude was triturated for 10 minutes before filtering through a pad of celite. The solution was evaporated to dryness under reduced pressure to give 7-bromo-3-chloro-1-fluoro-5′H-spiro[chromeno[2,3-c]pyridine-5,4′-oxazol]-2′-amine.

Chiral separation of the racemic mixture provides the individual (R) and (S) enantiomers, which may be used to prepare compounds of the invention.

Synthesis of 2-fluoro-7-(2-fluoropyridin-3-yl)-3-iodo-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine

Step 1: DIPA (8.0 mL, 56.6 mmol) was dissolved in dry THF (40 mL) under nitrogen and cooled in a dry ice bath to −78°. n-Butyllithium solution, 2.5 m in hexanes (23.0 mL, 57.5 mmol) was added and the solution stirred for a few minutes prior to dropwise addition of 2,6-difluoropyridine (5.0 mL, 55.1 mmol) in dry THF (10 mL) via an addition funnel over 10 minutes. The pale yellow solution was stirred for 30 minutes then additional dry THF (70 mL) was added dropwise via an addition funnel. Solid 5-bromo-2-methoxybenzaldehyde (11.85 g, 55.1 mmol) was added in one portion and the reaction stirred for 5 minutes. Additional dry THF (100 mL) was added dropwise to keep the mixture stirring freely. After 15 minutes saturated ammonium chloride (20 mL) was added to quench followed by ethyl acetate (200 mL) and water (200 mL). The phases were mixed and separated and the organic dried with magnesium sulfate before evaporating to dryness under reduced pressure. Purification using silica chromatography (hexane to DCM gradient) gave (5-bromo-2-methoxyphenyl)(2,6-difluoropyridin-3-yl)methanol.

Step 2: (5-Bromo-2-methoxyphenyl)(2,6-difluoropyridin-3-yl)methanol (13.77 g, 41.7 mmol) and imidazole (3.41 g, 50.1 mmol) were dissolved in dry DMF (20 mL) under nitrogen. t-Butyl(chloro)dimethylsilane (6.92 g, 45.9 mmol) was added and the solution heated to 70° C. After 1 hour the mixture was cooled to RT. Water (200 mL) and diethyl ether (200 mL) were added and the phases mixed and separated. The organic was washed with water (200 mL) one more time then dried with magnesium sulfate and evaporated to dryness under reduced pressure. Purification using silica chromatography (hexane to 1:1 DCM: hexane gradient) gave 3-((5-bromo-2-methoxyphenyl)(tert-butyldimethylsilyloxy)methyl)-2,6-difluoropyridine as a thick oil that solidified on standing.

Step 3: DIPA (1.2 mL, 8.49 mmol) (freshly distilled) was dissolved in dry THF (40 mL) under nitrogen and cooled in a dry ice bath to −78°. N-butyllithium solution (2.5 m in hexanes, 3.0 mL, 7.50 mmol) was added and the solution stirred for a few minutes. A solution of 3-((5-bromo-2-methoxyphenyl)(tert-butyldimethylsilyloxy)methyl)-2,6-difluoropyridine (3.20 g, 7.20 mmol) in dry THF (20 mL) was added dropwise via an addition funnel and the solution stirred for 1 hour. Tributyltin chloride (2.0 mL, 7.37 mmol) was added to the pale yellow solution and it was stirred for 10 minutes. The reaction was quenched by addition of saturated ammonium chloride (10 mL). Water (100 mL) and diethyl ether (200 mL) were added and the phases mixed and separated. The organic was dried with magnesium sulfate and evaporated to dryness under reduced pressure. Purification using silica chromatography (2-15% diethyl ether in hexane gradient) gave 3-((5-bromo-2-methoxyphenyl)(tert-butyldimethylsilyloxy)methyl)-2,6-difluoro-5-(tributylstannyl)pyridine.

Step 4: 3-((5-Bromo-2-methoxyphenyl)(tert-butyldimethylsilyloxy)methyl)-2,6-difluoro-5-(tributylstannyl)pyridine (1.17 g, 1.595 mmol) was dissolved in dry THF (10 mL). Tetrabutylammonium fluoride (2.2 mL, 2.200 mmol) was added and the reaction stirred for 5 minutes. Water (100 mL), diethyl ether (100 mL) and saturated ammonium chloride (10 mL) were added. The phases were mixed and separated and the organic dried with magnesium sulfate before evaporating to dryness under reduced pressure. The crude alcohol was dissolved in DCM (50 mL) and treated with 4-methylmorpholine n-oxide (0.467 g, 3.99 mmol) followed by tetrapropylammonium perruthenate (0.056 g, 0.160 mmol). The dark yellow solution was stirred for 15 minutes until it turned black. The solution was diluted with DCM (50 mL) and water (100 mL). The phases were mixed, filtered through a pad of celite and separated and the organic dried with magnesium sulfate before evaporating to dryness under reduced pressure. The crude was purified using silica chromatography (hexane to DCM gradient) to give (5-bromo-2-methoxyphenyl)(2,6-difluoro-5-(tributylstannyl)pyridin-3-yl)methanone.

Step 5: (5-Bromo-2-methoxyphenyl)(2,6-difluoro-5-(tributylstannyl)pyridin-3-yl)methanone (6.48 g, 10.50 mmol) was dissolved in DCM (60 mL) under nitrogen and cooled in a dry ice bath to −78° C. 9-Bromo-9-borabicyclo[3.3.1]nonane, (1 M in DCM, 11.02 mL, 11.02 mmol) was added dropwise over 5 minutes and the reaction stirred for another 5 minutes. The flask was removed from the cold bath and stirred at ambient temperature for 20 minutes then saturated sodium bicarbonate (50 mL) was added to quench. Water (200 mL) and dichloromethane (100 mL) were added and the phases mixed and separated. The organic was dried with magnesium sulfate and evaporated to dryness under reduced pressure. Purification using silica chromatography (hexane to dichloromethane gradient) gave 7-bromo-2-fluoro-3-(tributylstannyl)-5H-chromeno[2,3-b]pyridin-5-one.

Step 6: 7-Bromo-2-fluoro-3-(tributylstannyl)-5H-chromeno[2,3-b]pyridin-5-one (0.240 g, 0.412 mmol), AmPhos (0.015 g, 0.021 mmol), potassium acetate (0.077 mL, 1.235 mmol), and 2-fluoro-3-pyridineboronic acid (0.070 g, 0.494 mmol) were suspended in a mixture of EtOH (20 mL) and water (2 mL) and heated to 85° C. After 30 minutes water (250 mL) and ethyl acetate (200 mL) were added and the phases mixed and separated. The organic was washed with 10% saturated sodium bicarbonate (100 mL) then dried with magnesium sulfate and evaporated to dryness under reduced pressure. The crude was purified using silica chromatography (hexane to ethyl acetate gradient) to give 2-fluoro-7-(2-fluoropyridin-3-yl)-3-(tributylstannyl)-5H-chromeno[2,3-b]pyridin-5-one.

Step 7: 2-Fluoro-7-(2-fluoropyridin-3-yl)-3-(tributylstannyl)-5H-chromeno[2,3-b]pyridin-5-one (1.79 g, 2.99 mmol) was dissolved in dry THF (50 mL) and cooled in an ice bath under nitrogen to 0°. Methylmagnesium bromide (3.0 M in diethyl ether, 3.2 mL, 9.60 mmol) was added slowly. After 15 minutes saturated ammonium chloride was added carefully to quench followed by diethyl ether (200 mL) and water (200 mL). The phases were mixed and separated and the organic dried with magnesium sulfate before evaporating to dryness under reduced pressure. The crude alcohol was dissolved in acetonitrile (100 mL) and treated with iodine (0.154 mL, 2.99 mmol). It was stirred for 30 minutes at RT. Water (200 mL) and ethyl acetate (200 mL) were added and the phases mixed and separated. The organic was washed with aqueous sodium sulfite then dried with magnesium sulfate and evaporated to dryness under reduced pressure. The crude was purified using column chromatography (hexane to EtOAc gradient). The purified alcohol was dissolved in dry THF (200 mL) and treated with a catalytic amount of hydrogen chloride in dioxane (4 M, 0.25 mL). It was stirred for 15 minutes. Saturated sodium bicarbonate (30 mL), water (200 mL) and ethyl acetate (300 mL) were added and the phases mixed and separated. The organic was dried with magnesium sulfate and evaporated to dryness under reduced pressure. The crude 2-fluoro-7-(2-fluoropyridin-3-yl)-3-iodo-5-methylene-5H-chromeno[2,3-b]pyridine (1.14 g, 2.63 mmol, 88% yield) was used without purification.

Step 8: 2-Fluoro-7-(2-fluoropyridin-3-yl)-3-iodo-5-methylene-5H-chromeno[2,3-b]pyridine (1.14 g, 2.63 mmol) was dissolved in ACN (50 mL) and treated with silver cyanate (1.181 g, 7.88 mmol). The suspension was stirred under nitrogen in an ice bath and a solution of iodine (0.666 g, 2.63 mmol) in dry THF (10 mL) was added dropwise. After stirring for 15 minutes, the reaction was filtered through a pad of celite and the filtrate treated with ammonia (2.0 M solution in methanol, 10 mL, 20.00 mmol). The reaction was sealed and stirred for 10 hours then it was concentrated under reduced pressure. The crude was partitioned between water (200 mL) and ethyl acetate (200 mL). The organic was dried with magnesium sulfate and evaporated to dryness under reduced pressure. Purification using silica chromatography (0-6% methanol in DCM gradient) gave 2-fluoro-7-(2-fluoropyridin-3-yl)-3-iodo-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine

Synthesis of 3-(3,6-dihydro-2H-pyran-4-yl)-2-fluoro-7-(2-fluoropyridin-3-yl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine

Step 1: 2-Fluoro-7-(2-fluoropyridin-3-yl)-3-iodo-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine (0.151 g, 0.307 mmol), 2-(3,6-dihydro-2H-pyran-4-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (0.150 g, 0.71 mmol), tetrakis(triphenylphosphine)palladium (0.177 g, 0.153 mmol), and potassium phosphate (0.102 mL, 1.227 mmol) were suspended in dioxane (2 mL) and water (0.5 mL) and sealed in a microwave vessel under argon. The mixture was heated to 120° C. for 20 minutes. The reaction mixture was concentrated under reduced pressure and partitioned between water (80 mL) and ethyl acetate (80 mL). The organic was dried with magnesium sulfate and evaporated to dryness under reduced pressure. Purification using silica chromatography (1-4% methanol in dichloromethane gradient) gave 3-(3,6-dihydro-2H-pyran-4-yl)-2-fluoro-7-(2-fluoropyridin-3-yl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine.

Synthesis of 2-Fluoro-7-(2-fluoropyridin-3-yl)-3-((3-methyloxetan-3-yl)ethynyl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine

Step 1: 3-(2,2-dibromovinyl)-3-methyloxetane (0.156 g, 0.609 mmol) was dissolved in a mixture of diethyl ether (10 mL) and dry THF (10 mL) and cooled in a dry ice bath under nitrogen. Butyllithium solution, 2.5 m in hexanes (0.528 mL, 1.321 mmol) was added dropwise and the mixture stirred for 40 minutes before removing from the cold bath and quenching with saturated ammonium chloride. Water (100 mL) and diethyl ether (100 mL) were added and the phases mixed and separated. The organic layer was dried with magnesium sulfate and concentrated to ˜20 mL under reduced pressure using a 40° C. water bath. The crude alkyne was combined with 2-fluoro-7-(2-fluoropyridin-3-yl)-3-iodo-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine (0.250 g, 0.508 mmol), copper(i) iodide (0.097 g, 0.508 mmol), trans-dichlorobis(triphenyl-phosphine)palladium (ii) (7.13 mg, 10.16 μmol), and diisopropylethylamine (1.00 mL, 5.75 mmol) in dry dimethylformamide (5 mL) and heated to 90° C. After 2 hours DIPA (2 mL) was added and it was stirred at 60° C. overnight.

Another equivalent of the alkyne was prepared and added. After sealing and heating at 80° C. for another 3 hours the mixture was cooled to rt and partitioned between water (100 mL) and ethyl acetate (100 mL). The organic was dried with magnesium sulfate and evaporated to dryness under reduced pressure. Purification by silica gel chromatography (0-5% methanol in DCM gradient) followed by reverse phase HPLC and free basing gave the desired 2-fluoro-7-(2-fluoropyridin-3-yl)-3-((3-methyloxetan-3-yl)ethynyl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine

Synthesis of (5S)-7-(2,4-difluoro-3-pyridinyl)-3-(3,3-dimethyl-1-butyn-1-yl)spiro[chromeno[2,3-c]pyridine-5,4′-[1,3]oxazol]-2′-amine

Step 1: A mixture of (S)-7-bromo-3-chloro-5′H-spiro[chromeno[2,3-c]pyridine-5,4′-oxazol]-2′-amine (2.03 g, 5.54 mmol), 4,4,4′,4′,5,5,5′,5′-octamethyl-2,2′-bi(1,3,2-dioxaborolane) (2.81 g, 11.07 mmol), Cl 2 Pd(dppf)-CH 2 Cl 2 adduct (0.452 g, 0.554 mmol) and potassium acetate (1.630 g, 16.61 mmol) were combined a reaction vessel. To this mixture was added dioxane (26 mL) and the resulting slurry was purged with nitrogen, sealed and heated at 100° C. overnight. The mixture was filtered through a pad of celite. The filtrate was concentrated, diluted with water (50 mL) and extracted with EtOAc (3×50 mL). The combined organic layers were washed with brine, dried over magnesium sulfate, filtered and concentrated. The crude material was purified by column chromatography with 0-10% MeOH/DCM, then purified again with 30-60% EtOAc/DCM to provide the desired product.

Step 2: A 20 mL glass microwave reaction vessel was charged with (S)-3-chloro-7-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-5′H-spiro[chromeno[2,3-c]pyridine-5,4′-oxazol]-2′-amine (0.506 g, 1.223 mmol), potassium phosphate tribasic (0.230 mL, 2.78 mmol), 2,4-difluoro-3-iodopyridine (0.2680 g, 1.112 mmol), dioxane (4.8 mL) and water (1.2 mL). The vessel was flushed with argon, sealed and heated at 100° C. in a microwave for 30 minutes. The mixture was partitioned between EtOAc (50 mL) and water (50 mL). The aqueous layer was washed twice with saturated Na 2 CO 3 . The organic layer was dried over sodium sulfate and concentrated in vacuo. The crude residue was purified by silica gel chromatography (100% EtOAc) to provide the desired product.

Step 3: Tetrakis(triphenylphosphine)palladium (0.029 g, 0.025 mmol), copper(i) iodide (5.50 μL, 0.162 mmol) and (S)-3-chloro-7-(2,4-difluoropyridin-3-yl)-5′H-spiro[chromeno[2,3-c]pyridine-5,4′-oxazol]-2′-amine (0.100 g, 0.250 mmol) were combined in a heating tube that was subsequently purged with argon. DMF (1.5 mL), DIPA (0.533 mL, 3.74 mmol) and 3,3-dimethylbut-1-yne (0.031 g, 0.374 mmol) were added in sequence and the reaction vessel was sealed and heated at 90° C. for 16 h. The reaction mixture was poured into water (25 mL) and extracted with EtOAc (3×20 mL).

The combined organic layers were washed with water and then brine, dried over sodium sulfate, filtered and concentrated. The crude material was purified by column chromatography with 80-100% EtOAc/hexanes, then 5% 2M NH 3 in MeOH/CH 2 Cl 2 to provide the desired product. MS m/z=458.0 [M+H].

Synthesis of (S)-2′-bromo-3′,5′-difluoro-7′-methoxy-5H-spiro[oxazole-4,9′-xanthen]-2-amine and (R)-2′-bromo-3′,5′-difluoro-7′-methoxy-5H-spiro[oxazole-4,9′-xanthen]-2-amine

Step 1: A 2 L RB flask was charged with 2-fluoro-4-methoxyphenol (49.6 g, 349 mmol), 2,5-dibromo-4-fluorobenzoic acid (80 g, 269 mmol), ethyl acetate (1.316 mL, 13.43 mmol), cesium carbonate (192 g, 591 mmol) and toluene (1200 mL). To the mixture at was added copper(I) triflate toluene complex (2:1) (1.713 g, 8.06 mmol) and it was stirred at room temperature for 20 minutes. The solution was then heated to 75° C. for 16 hours at which point the toluene was removed under reduced pressure. The solution was dissolved in 1.5 liters of water and washed with 250 ml of EtOAc. The aqeuous layer was acidified to pH 1 with concentrated HCl and the resulting precipitant was collected by filtration and washed with water. The derived solid was washed with a 1:1 solution of ethyl acetate and hexane, then dried under vacuum to afford 5-bromo-4-fluoro-2-(2-fluoro-4-methoxyphenoxy)benzoic acid as a light brown solid. MS m/z=358.8 [M+H].

Step 2: To a flaske charged with polyphosphoric acid (396 g, 4038 mmol) was added 5-bromo-4-fluoro-2-(2-fluoro-4-methoxyphenoxy)benzoic acid (58 g, 162 mmol) and the viscous mixture was heated at 140° C. for 2 hours. The viscous solution was cooled slightly and diluted with ice-water (1 L). After 15 min of stirring, EtOAc (1 L) was added and the aqueous fraction extracted with EtOAc (3×200 mL). The combined organic fractions were dried over sodium sulfate and concentrated. The solids were washed with 6 N NaOH, then water. The solids were then sequentially triturated with methanol and ethyl acetate. The resulting solid was dried under vacuum to afford 2-bromo-3,5-difluoro-7-methoxy-9H-xanthen-9-one (41 g, 120 mmol, 74.4% yield).

Step 3: A mixture of 2-bromo-3,5-difluoro-7-methoxy-9H-xanthen-9-one (40 g, 117 mmol) and THF (300 mL) was cooled to 0° C. and treated with methylmagnesium chloride (58.6 mL, 176 mmol) (3M in THF). After stirring at this temperature for 20 minutes, the reaction was quenched by the addition of sataturated NH 4 Cl (500 mL). Brine was added and the mixture was extracted with EtOAc (3×100 mL). The combined organic extracts were dried with sodium sulfate, filtered and concentrated in vacuo to afford crude 2-bromo-3,5-difluoro-7-methoxy-9-methyl-9H-xanthen-9-ol as a brown solid that was carried on without further purification. MS m/z=339.0 [M+1−H 2 O].

Step 4: To a 1000 mL RBF charged with 2-bromo-3,5-difluoro-7-methoxy-9-methyl-9H-xanthen-9-ol (38 g, 106 mmol) and THF (200 mL) was added HCl (4 M in dioxane) (1.330 mL, 5.32 mmol). This solution was stirred at rt for 15 minutes before being added to the mixture below.

Separately, to a mixture of iodine (28.4 g, 112 mmol) in 300 mL of THF at −30° C. was added silver cyanate (9.97 mL, 266 mmol) and the slurry was stirred for 30 minutes. To this mixture was added the solution of the olefin derived above. The mixture was stirred for one hour at −30° C. at which point ammonia (2M in isopropanol, 266 mL, 532 mmol) was then added and the black mixture was stirred at room temperature for 24 hours. The mixture was filtered through celine and concentrated in vacuo. The solution was diluted with CH 2 Cl 2 (300 mL) and 10 ml of MeOH and filtered. The filtrated was treated with p-toluenesulfonic acid monohydrate (24.29 g, 128 mmol). After 20 min of stirring, the resulting precipitate was collected by filtration. The solid was stirred with saturated NaHCO 3 (500 mL) and EtOAc (500 mL). The organic fraction was washed with brine, dried with sodium sulfate, filtered and concentrated in vacuo to afford (S)-2′-bromo-3′,5′-difluoro-7′-methoxy-5H-spiro[oxazole-4,9′-xanthen]-2-amine as an off-white/tan solid. MS m/z=398.8 [M+H].

Chiral separation provided (S)-2′-bromo-3′,5′-difluoro-7′-methoxy-5H-spiro[oxazole-4,9′-xanthen]-2-amine and (R)-2′-bromo-3′,5′-difluoro-7′-methoxy-5H-spiro[oxazole-4,9′-xanthen]-2-amine, both as off white solids. MS m/z=398.8 [M+H].

Synthesis of (R)-2-amino-2′-bromo-1′-fluoro-5H-spiro[oxazole-4,9′-xanthen]-7′-ol and (S)-2-amino-2′-bromo-1′-fluoro-5H-spiro[oxazole-4,9′-xanthen]-7′-ol

Step 1: A 1 L 3-neck flask equipped with a reflux condenser and overhead stirrer was charged with cesium carbonate (99 g, 303 mmol), 4-bromo-3-fluorophenol (34.7 g, 182 mmol), 2-bromo-5-methoxybenzoic acid (35 g, 151 mmol) and 100 mL of toluene. To this slurry were added EtOAc (0.741 mL, 7.57 mmol) and copper (i) trifluoromethanesulfonate toluene complex (1.959 g, 3.79 mmol). The resulting blue slurry was then heated at 120° C. After heating for 10 minutes the slurry went from blue to a greenish color. The reaction was maintained at 120° C. for 20 hours before being cooled rt and poured into 1 L of water. 1 L of ethyl acetate was added and the mixture was acidified to pH 2 with 3 N HCl. The layers were separated and the aqueous layer was extracted with EtOAc (3×500 mL). The combined organics were washed with brine, dried over sodium sulfate, filtered and concentrated to provide a light brown solid that was carried on without further purification.

Step 2: To a 1 L flask charged with 2-(4-bromo-3-fluorophenoxy)-5-methoxybenzoic acid (100 g, 293 mmol) was added sulfuric acid (391 mL, 7329 mmol). The resulting slurry was heated to 80° C. for 2 hours. The reaction was removed from the oil bath, cooled to rt and poured into a 3 L flask containing 2 L of ice water. The derived slurry was vigorously stirred for 2 hours before being filtered. The derived solid was washed well with water (3×500 mL), 3 N NaOH (2×500 mL) and water (2×500 mL). The wet solid was then washed with ether (2×250 mL) and dried under a vacuum at 50° C. overnight. The solid was then azeotropped from toluene (3×100 mL) to provide 41 g of a 4:1 mixture of 2-bromo-1-fluoro-7-methoxy-9H-xanthen-9-one:2-bromo-3-fluoro-7-methoxy-9H-xanthen-9-one (40.0 g, 123.9 mmol, 42.2% yield). A portion of this material (10 g) was slurried in hot IPA (200 mL) and placed in the refrigerator overnight. The derived solid was filtered and purified by silica gel chromatography (100% CH 2 Cl 2 ) to provide 2-bromo-1-fluoro-7-methoxy-9H-xanthen-9-one (4.1 g) and 2-bromo-3-fluoro-7-methoxy-9H-xanthen-9-one (0.95 g) both as light white solids.

Step 3: To a solution of 2-bromo-1-fluoro-7-methoxy-9H-xanthen-9-one (0.79 g, 2.445 mmol) in THF (30.6 mL, 2.445 mmol) at −25° C. was added methylmagnesium chloride, (3.0 M solution in THF, 0.937 mL, 2.81 mmol). After stirring for 5 minutes at −25° C. the reaction was removed from the cold bath and allowed to warm to rt. Once at rt another 1 equivalent of methylmagnesium chloride was added to the reaction mixture and stirting was continued for another 1 hour. TLC showed complete conversion to a lower Rf product (eluent 100% CH 2 Cl 2 ). The reaction was diluted with water (50 mL; reaction became colorless) and poured into a separatory funnel containing EtOAc (100 mL). The layers were separated and the aqueous layer was extracted with EtOAc (3×50 mL). The combined organic layers were washed with brine, dried over sodium sulfate, filtered and concentrated in vacuo to provide the desired alcohol as a colorless oil. MS m/z=321.0 [M+H−H 2 O].

Step 4: To a solution of 2-bromo-1-fluoro-7-methoxy-9-methyl-9H-xanthen-9-ol (0.85 mg, 2.44 mmol) in 20 mL of THF was added HCl (4.0 M solution in 1,4-dioxane, 0.031 mL, 0.122 mmol). After stirring for 10 minutes at rt, TLC showed complete conversion to a higher Rf spot (10% EA in hexanes). This solution was added directly to the slurry below.

To a solution of iodine (0.621 g, 2.445 mmol) in 10 mL of THF at −25° C. was added silver cyanate (1.099 g, 7.33 mmol). This mixture was stirred at −25° C. for 20 minutes then a solution of the above derived olefin was added in one portion. The resulting orange mixture was maintained at −20° C. for 1 hour before being filtered through celite. The filtrate was cooled to −10° C. and treated with ammonia (2.0 M solution in 2-propanol, 2.445 mL, 4.89 mmol). Once the addition was compete, the reaction was removed from cold bath and allowed reaction to warm to rt overnight. The reaction was diluted with 10% sodium thiosulfate (100 mL) and poured into a separatory funnel containing EtOAc (100 mL). The layers were separated and the aqueous layer was extracted with EtOAc (2×100 mL). The combined organic layers were washed with brine, dried over sodium sulfate, filtered and concentrated in vacuo to provide a light yellow solid. The solid was suspended in 50 mL of EtOAc and filtered. The filtrate was concentrated and purified by silica gel chromatography (0-100% CH 2 Cl 2 to 10:1 MeOH in CH 2 Cl 2 with 0.1% ammonium hydroxide) to provide 2′-bromo-1′-fluoro-7′-methoxy-5H-spiro[oxazole-4,9′-xanthen]-2-amine as a light yellow foam. MS m/z=378.8 [M+H].

Step 5: To a solution of 2′-bromo-1′-fluoro-7′-methoxy-5H-spiro[oxazole-4,9′-xanthen]-2-amine (0.575 g, 1.516 mmol) in 15 mL of CH 2 Cl 2 at −15° C. was added boron tribromide (1.0 M in CH 2 Cl 2 , 4.55 mL, 4.55 mmol). The mixture was slowly allowed to warm to 0° C. over the course of 1.25 hours at which point the reaction was carefully quenched with 2 mL of MeOH and saturated sodium bicarbonate (100 mL). This mixture was poured into a separatory funnel containing EtOAc (100 mL). The layers were separated and the aqueous layer was extracted with EtOAc (2×100 mL). The combined organic layers were washed with brine, dried over sodium sulfate, filtered and concentrated in vacuo to provide 2-amino-2′-bromo-1′-fluoro-5H-spiro[oxazole-4,9′-xanthen]-7′-ol as a glassy red solid. MS m/z=365.1 [M+H].

Chiral separation provided (R)-2-amino-2′-bromo-1′-fluoro-5H-spiro[oxazole-4,9′-xanthen]-7′-ol and (S)-2-amino-2′-bromo-1′-fluoro-5H-spiro[oxazole-4,9′-xanthen]-7′-ol, both as off white solids. MS m/z=365.1 [M+H].

Synthesis of (S)-7′-bromo-4′-fluoro-2′-methoxy-5H-spiro[oxazole-4,9′-xanthen]-2-amine and (R)-7′-bromo-4′-fluoro-2′-methoxy-5H-spiro[oxazole-4,9′-xanthen]-2-amine

Step 1: A three-neck RBF equipped with a reflux condenser and overhead stirrer was charged with 2-fluoro-4-methoxyphenol (14.24 g, 100 mmol), 2,5-dibromobenzoic acid (25.5 g, 91 mmol), EtOAc (0.446 mL, 4.55 mmol), copper (I) triflate toluene complex (2:1) (0.484 g, 2.27 mmol) and toluene (300 mL). Cesium carbonate (59.4 g, 182 mmol) was carefully added portion-wise. The mixture was stirred for 10 minutes at RT then heated at 95° C. for 3 hours. The toluene was cooled to RT then extracted twice with 300 ml of water. The combined water extracts were acidified with 6 N HCl at which time a precipitate formed. The mixture was extracted with EtOAc (3×500 mL) and the combined organic fractions were dried over sodium sulfate and concentrated in vacuo. The resulting solid was triturated with minimal 1:1 Hexanes:EtOAc and filtered. The collected solid was dried in vacuo to afford 5-bromo-2-(2-fluoro-4-methoxyphenoxy)benzoic acid as a grey solid. The mother liquors were set aside for later recrystallizatio. MS m/z=341.0 [M+H].

Step 2: 5-bromo-2-(2-fluoro-4-methoxyphenoxy)benzoic acid (28.5 g, 84 mmol) and polyphosphoric acid (205 g, 2089 mmol) were combined and heated at 125° C. for two hours. The solution was diluted with water (1 L) and filtered. The solids were washed well with 2N NaOH, then with water. The solids were then dried under vacuum to afford 7-bromo-4-fluoro-2-methoxy-9H-xanthen-9-one as an off white solid. MS m/z=323.0 [M+H].

Step 3: 7-bromo-4-fluoro-2-methoxy-9H-xanthen-9-one (22 g, 68.1 mmol) was dissolved in 300 ml of THF and cooled to −30° C. in a dry ice ACN bath. Methylmagnesium chloride (34.0 mL, 102 mmol) (3M in THF) was added to the slurry maintaining temperature less than −15° C. The solution was allowed to warm to RT (undissolved solids went into solution), then quenched with saturated NH 4 Cl (250 mL). The aqueous layer was extracted with EtOAc (3×200 mL) and the combined organic layers were washed with brine and dried over anhydrous sodium sulfate, filtered and concentrated to afford 7-bromo-4-fluoro-2-methoxy-9-methyl-9H-xanthen-9-ol as a brown liquid that was used without further purification.

Step 4: 7-Bromo-4-fluoro-2-methoxy-9-methyl-9H-xanthen-9-ol (24 g, 70.8 mmol) was slurried in THF (100 mL) and HCl (4 M in dioxane) (0.354 mL, 1.415 mmol) was added. The solution was warmed to 50° C. for 1.5 hours. In a separate RB charged with a mixture of iodine (18.86 g, 74.3 mmol) and 300 ml of THF at −30° C. was added silver cyanate (7.95 mL, 212 mmol). This mixture was maintained for 30 minutes, at which point the ofefin derived above was added in one portion. The solution was stirred for another 30 minutes at −30° C. at which time ammonia (2M in iPrOH, 177 mL, 354 mmol) was added. The dark mixture was allowed to warm to rt and stir for 20 hours. The solution was filtered and 200 ml of saturated aqueous sodium thiosulfate was added and the solution was stirred for 30 minutes. The aqueous layer was separated and the organics were washed with water, brine, then dried over sodium sulfate and concentrated. The solids were triturated with IPA, filtered, and dried under vacuum to give 10 g of the desired product as a first crop. The filtrate was concentrated and purified via silica gel column chromatography (0-100% ethyl acetate in hexane). The solid obtained was triturated with IPA, filtered, then dried under vacuum to give 2 g of a second crop which was combined with the first crop to afford 7′-bromo-4′-fluoro-2′-methoxy-5H-spiro[oxazole-4,9′-xanthen]-2-amine as an off white solid. MS m/z=379.0 [M+H].

Chiral separation provided (S)-7′-bromo-4′-fluoro-2′-methoxy-5H-spiro[oxazole-4,9′-xanthen]-2-amine and (R)-7′-bromo-4′-fluoro-2′-methoxy-5H-spiro[oxazole-4,9′-xanthen]-2-amine, both as off white solids. MS m/z=379.0 [M+H].

Synthesis of (S)-7-bromo-3-chloro-5′H-spiro[chromeno[2,3-c]pyridine-5,4′-oxazol]-2′-amine and (R)-7-bromo-3-chloro-5′H-spiro[chromeno[2,3-c]pyridine-5,4′-oxazol]-2′-amine

Step 1: To a 5 L of three necks bottle was charged 200 g (0.715 mol) of 2,5-dibromobenzoic acid, 111.07 g (0.857 mol) of 5-hydroxyl-2-chloropyridine and 469.52 g (1.43 mol) of cesium carbonate. (The solid was fleshed for 20 min with nitrogen gas then Copper (I) trifloromethanesulfonate toluene complex (9.62 g, 18.59 mmol) and 2500 mL of toluene and 5.24 mL (53.62 mmol) of ethyl acetate were added. The resulting suspension was heated to 105° C. (oil-bath: 115° C.) stirred for 1.5 hrs. Cooled to RT and the toluene was removed by simple poured. To this residue, was added 1.5 L of water and 500 mL of EtOAc and stirred until whole solid was dissolved. The EtOAc was separate and the aqueous was neutralized with 6N HCl till the pH2-3. Extracted with EtOAc (800 mL×3) and combined organic layers was dried on Na 2 SO 4 . Filtered and concentrated to get the brown solid which did not purify and used to next step reaction directly. The above derived 5-bromo-2-(6-chloropyridin-3-yloxy)benzoic acid obtained above was dissolved in 2.5 L of DCM and then 229.6 g (0.715 mol) of TBTU was added. 148.6 mL (1.43 mol) of diethylamine was added dropwise. The resulting dark solution was stirred at RT for overnight. 500 mL of sat. NH 4 Cl and 500 mL of water was added. After stirred for 15 min, the aqueous layer was separated. The organic layer was washed one time with 1000 mL of sat. NaCO 2 solution then dried on Na 2 SO 4 . Filtered and 400 g of silica gel was added. Concentrated the organic layers to a crude material, which was loaded on a column (Column size: 7″×16″, Silica gel: 3 kg) and eluted with hexane/EtOAc (20:1 to 5:1, Rf of product: 0.6, TLC solvent: hexane: EtOAc/3:1) to give the desired product.

Step 2: 5-Bromo-2-(6-chloropyridin-3-yloxy)-N,N-diethylbenzamide (290 g, 0.756 mol) of was dissolved in dry THF (2000 mL) and cooled to −78 C. To this solution was added a solution of LDA (preparation with 392.6 ml (2.778 mol) of diisopropylamine and 1058 mL of BuLi (2.5 M in hexane) 700 mL of dry THF). After the addition was complete the solution was stirred for 30 min at −78° C., then the dry ice acetone bath was removed and the reaction was quenched slowly with 2 L of Sat NH 4 Cl. Separated the layers and the aqueous layer was extracted with ethyl acetate (2×500 mL). The combined organic layers were dried and past through a pad of silica gel to provide the desired product as a light yellow solid (110 g, 50% yield, three steps).

Step 3: To a solution of compound 7-bromo-3-chloro-5H-chromeno[2,3-c]pyridin-5-one (400 g, 1.288 mol) in dry THF (5 L) was added drop wise a solution of methylmagnesium chloride (2M in THF, 1.5 L) at 0° C. After the addition was complete the reaction was stirred at rt overnight. The mixture was cooled to 0° C. and quenched with saturated NH 4 Cl (3 L). 2 L of ethyl acetate were added, the phases were separated and the aqueous layer was extracted one time with EtOAc (1 L). The combined organic layers were past through a pad of silica gel to provide the desire product as a light yellow solid.

Step 3: To a solution of 7-bromo-3-chloro-5-methyl-5H-chromeno[2,3-c]pyridin-5-ol (450 g, 1.28 mol) in dichloroethane (5.5 L) at rt was added PPTS (18 g, 71.6 mmol). The resulting solution was heated to 70° C. for 6 hours and was then allowed to cool to rt. The mixture was concentrated to 10% of the original volume and was then purified by silica gel chromatography (Column size: 7″×16″, Silica gel: 2.5 kg, DCM) to provide the desired product as a light pink solid (46%, two steps).

Step 4: To a solution of iodine (181.2 g, 0.714 mol) in dry THF (5 L) was added silver cyanate (291.48 g, 1.95 mol) at −20° C. The resulting slurry was maintained at this temperature for 1 hr. To this suspension was added a solution of 7-bromo-3-chloro-5-methylene-5H-chromeno[2,3-c]pyridine (200 g, 0.6482 mol) in 1 L of THF and the mixture was stirred at 0° C. for 3 hours. The mixture was then filtered through a pad of celite, washing well with THF. The filtrate was cooled to 10° C. and treated with a solution of ammonia in i-PrOH (2M, 972.3 mL). The resulting dark solution was stirred at rt overnight at which point 1 L of saturated sodium thio sulfate and 1.5 L of saturated sodium bicarbonate were added. The mixture was stirred 1 hour then the phases were separated and the aqueous phase was extracted with ethyl acetate (1 L). The combined organic layers were dried over sodium sulfate, filtered and evaporated. The derived solid was triturated with 1 L of DCM and 1 L of water before being filtered to provide 7-bromo-3-chloro-5′H-spiro[chromeno[2,3-c]pyridine-5,4′-oxazol]-2′-amine as yellow solid.

Chiral separation provided (S)-7-bromo-3-chloro-5′H-spiro[chromeno[2,3-c]pyridine-5,4′-oxazol]-2′-amine and (R)-7-bromo-3-chloro-5′H-spiro[chromeno[2,3-c]pyridine-5,4′-oxazol]-2′-amine, both as light yellow solids.

Synthesis of (R)-7′-bromo-3′-fluoro-2′-methoxy-5H-spiro[oxazole-4,9′-xanthen]-2-amine and (S)-7′-bromo-3′-fluoro-2′-methoxy-5H-spiro[oxazole-4,9′-xanthen]-2-amine

Step 1: A mixture of 2-bromo-4-fluoro-5-methoxybenzoic acid 1 (1.0 kg, 4.02 mol), 4-bromophenol (4.41 mol, 1.05 equiv, 729.5 g) and Cs 2 CO 3 (12.06 mol, 3 equiv. 3.92 kg) in anhydrous DMF (12 L) was degassed with N 2 for 30 min. To this mixture was added copper (I) triflate toluene complex (2:1) (0.04 equiv. 83.12 g) and the mixture was further degassed again with N 2 for 15 min. The resulting mixture was heated at 110° C. for 4 days. The reaction mixture was cooled to ambient temperature and poured onto 5 L of ice water. The pH was adjusted to 1 with concentrated HCl and the aqueous layer was extracted with EtOAc (3×4 L). The combined extracts were washed with brine (2×2 L). The organic layer was separated, dried over Na 2 SO 4 , filtered and concentrated under reduced pressure to provide a thick brown oil. The brown oil was triturated with a 5% IPA/water mixture (5 L) at ambient temp to obtain a brown solid. The solid was filtered, washed with water and hexane and dried overnight under vacuum to afford 2-(4-bromophenoxy)-4-fluoro-5-methoxybenzoic acid (1.3 kg, 95% yield) as a brown solid.

Step 2: A 3 neck 22 L RBF equipped with a mechanical stirrer, temperature probe and N 2 inlet was charged with concentrated H 2 SO 4 (2.7 L) and heated to 60° C. To this mixture was added 2-(4-bromophenoxy)-4-fluoro-5-methoxybenzoic acid (1.3 kg, 3.81 mol) in portions such that the internal temp remained below 70° C. The resulting mixture was stirred at 60° C. for 1 hour at which point the reaction mixture was cooled to 0° C. and slowly poured onto ice water. The resulting solids were removed by filtration, washed with water and triturated with EtOAc (3 L). The solid was then washed with EtOAc, hexane and dried under vacuum at 30° C. to afford 7-bromo-3-fluoro-2-methoxy-9H-xanthen-9-one as an off white solid.

Step 3: To a suspension of 7-bromo-3-fluoro-2-methoxy-9H-xanthen-9-one (25 g, 73.4 mmol) in THF (500 mL) was added MeMgCl (2.0 equiv. 146.75 mmol, 48.9 mL, 3.0 M solution in THF) at −20° C. (internal temp) slowly over 30 minutes. The resulting mixture was allowed to reach ambient temperature where it was maintained for 12 hours. The reaction was quenched by adding saturated NH 4 Cl. The phases were separated and the aqueous layer was extracted with EtOAc (2×300 mL). The combined organic extracts were washed with brine, dried over Na 2 SO 4 , filtered and concentrated to afford 25 g of 7-bromo-3-fluoro-2-methoxy-9-methyl-9H-xanthen-9-ol that was used in the next step without further purification. A solution of the derived alcohol (25 g) was dissolved in DCM (300 mL) and pPTS (250 mg, 0.995 mmol) was added. The mixture was heated to reflux for 2 hours at which time the reaction was cooled to rt and washed with NaHCO 3 (100 mL). The layers were separated and the organic layer was washed with brine, dried over Na 2 SO 4 , filtered and concentrated. The resulting residue was purified via chromatography (hexanes/DCM, 3:1) to provide 7-bromo-3-fluoro-2-methoxy-9-methylene-9H-xanthene as an orange solid.

Step 4: A solution of iodine (306 g, 1.20 mol, 1.05 eq) in THF (1.2 L) was cooled to −20° C. and treated with silver cyanate (515 g, 3.48 mol, 3.0 eq). The mixture was stirred for 30 minutes at −10° C. and then cooled down to −30° C. Once at this temperature a solution of 7-bromo-3-fluoro-2-methoxy-9-methylene-9H-xanthene as an orange solid (368 g, 1.146 mol) in THF (4.0 L) was added over to the above mixture, keeping the internal temperature, <−10° C. (˜20 min). The reaction mixture was slowly warmed up to 0° C. and stirred for 30 minutes. The reaction mixture was cooled down again to −30° C. and a solution of ammonium in IPA (2.0M) was added slowly, keeping internal temperature <−10° C. After the addition, the mixture was stirred for overnight at room temperature. The mixture was filtered through a pad of celite, washed with THF. The filtrate was diluted with EtOAc (˜4 L) and washed sequentially with aqueous Na 2 S 2 O 4 (2 L) and brine. Thd solution was dried over Na 2 SO 4 , filtered and concentrated to provide a residue was triturated with ethyl ether. The resulting solid was filtered and washed with cold ether to afford 7′-bromo-3′-fluoro-2′-methoxy-5H-spiro[oxazole-4,9′-xanthen]-2-amine (260 g) as a white solid. The filtrate was concentrated and purified via chromatography (ethyl acetate/hexanes (1:3) to (1:1)) to afford 180 g of 7′-bromo-3′-fluoro-2′-methoxy-5H-spiro[oxazole-4,9′-xanthen]-2-amine.

Chiral separation provided (R)-7′-bromo-3′-fluoro-2′-methoxy-5H-spiro[oxazole-4,9′-xanthen]-2-amine and (S)-7′-bromo-3′-fluoro-2′-methoxy-5H-spiro[oxazole-4,9′-xanthen]-2-amine, both as off white solids.

A glass microwave reaction vessel was charged with (S)-3-chloro-7-(2,4-difluoropyridin-3-yl)-5′H-spiro[chromeno[2,3-c]pyrid