Phenylpiperazines

Preparation of Compound a,i (See Scheme i)

Step 1 (scheme i): To a solution of chloronitrocatechol (6.45 g, 34 mmol) in dry DMSO (50 ml) was added powdered NaOH (2.72 g, 68 mmol). After stirring for 30 minutes a solution was added of R-glycerolketal mesylate (8.0 g, 38 mmol) in DMSO (20 ml) and this mixture was heated at 80° C. during 24 hours. After cooling to room temperature the reaction mixture was poured into water (200 ml), acidified with 1 N HCl and extracted with methyl t-butylether. The organic fraction was washed with water and dried on MgSO 4 . After removal of the drying agent and the solvent in vacuo, the resulting oil was subjected to flash chromatografy (SiO 2 , eluent PE/aceton=3/1). Yield 9.29 g (90%) of the S-ketal.

Step 2 (scheme i): To a solution of the S-ketal (31 g, 102 mmol) in acetic acid (120 ml) was added 35% HBr in acetic acid (80 ml) and this mixture was rotated for 2 hours on a rotavapor in a waterbath of 50° C. The reaction mixture was diluted with ethanol (96%, 250 ml), cooled in a salt/ice mixture and then NaOH (50% in water, 250 ml) was added slowly, keeping the temperature below 15° C. After adding ethanol (250 ml) and water (250 ml) the reaction mixture was stirred at room temperature for 16 hours. Then concentrated HCl (about 300 ml) and water were added and the mixture extracted with ethyl acetate. After washing the organic fraction with 5% NaHCO 3 (4×500 ml), the solvent was removed in vacuo and the resulting oil was subjected to flash chromatografy (SiO 2 , eluent PE/aceton=3/1). Yield 20.5 g (81%) of the R-benzodioxane as a yellow oil.

Step 3 (scheme i): To a solution of R-benzodioxane (20 g, 81 mmol) in DMF (200 ml) was added KOH (4.56 g, 81 mmol). After cooling the red solution in ice/aceton dimethyl sulfate (23 ml) was added and the reaction mixture was stirred for 1.5 hours at room temperature. Then more KOH (4.56 g, cooling) was added and the mixture was stirred at room temperature for 16 hours. After adding water (700 ml), the product was extracted with ethyl acetate. The ethyl acetate was removed in vacuo and the resulting oil was subjected to flash chromatografy (SiO 2 , eluent PE/aceton=4/1) yielding R-methoxymethylbenzodioxane (12.3 g, 58%) as a yellow oil. [α] D 25 =−97° (methanol).

Step 4 (scheme i): To a solution of R-methoxymethylbenzodioxane (5 g, 19 mmol) in ethanol (100 ml) and ethyl acetate (50 ml) was added a catalytic amount of 10% Pd/C and the solution was shaken under atmospheric H 2 pressure at room temperature. After the calculated amount of H 2 was taken up by the reaction mixture, the catalyst was removed by filtration and the filtrate was concentrated in vacuo. Yield 3.7 g (100%) of the corresponding anilino-compound.

Step 5 (scheme i): The anilino-compound (4 g, 2 mmol) and BCEA, i.e. HN(CH 2 CH 2 Cl) 2 .HCl (3.7 g, 2 mmol) were dissolved in chlorobenzene (100 ml). The mixture was heated to 150° C. for 16 hours, concentrated in vacuo and purified by flash chromatografy (SiO 2 , dichloromethane/methanol/ammonium hydroxide=92/7.5/0.5). Yield 3.67 g (68%) of the piperazine a,i.

Preparation of Compound No. 126

The route is described above, i.e. reaction of compound (II) with compound (III). The mesylates of formula (III) were prepared from the corresponding alcohols by standard procedures, e.g. with MsCl/Et 3 N.

A mixture of the piperazine a,i (3,6 g, 13,6 mmol), the 5-fluoro indole-mesylate (4,1 g, 15,1 mmol), triethylamine (2 ml) and a catalytic amount of KI in CH 3 CN (100 ml) was heated under reflux during 18 hours after which the reaction mixture was concentrated in vacuo and purified by chromatografy (SiO 2 , dichloromethane/methanol/ammonium hydroxide=92/7.5/0.5). Yield 3,77 of the free base (oil). The free base was dissolved in ethanol and 1 equivalent of fumaric acid in ethanol was added. After removal of the solvent compound no. 126 was obtained (4,3 g, 57%). [α] D 25 =−2° (methanol)

Preparation of Compound b,ii (See Scheme ii)

Step 1 (scheme ii): A solution of the aminophenol (37.3 g, 198 mmol), S-lactic acid methyl ester (20 ml) and triphenylphosphine (58 g, 220 mmol) in THF (2000 ml) was cooled in ice/salt (temperature<10° C.). Then a solution of azodicarboxic acid ester (DIAD, 43 ml, 218 mmol) in THF (400 ml) was added slowly. After stirring at room temperature for 18 hours the reaction mixture was concentrated in vacuo and ethanol (500 ml) and 36% HCl (125 ml) were added to the residue. The mixture was heated to 100° C. (development of gas). After cooling the compound was isolated by filtration and washed with 96% ethanol (about 100 ml). Yield 42 g (87%).

Step 2 (scheme ii): This step is similar to step 4 described in scheme i.

Step 3 (scheme ii): This step is similar to step 5 described in scheme i, resulting in the formation of the piperazine b,ii.

Preparation of Compound No. 89

The route is described above, i.e. reaction of compound (II) with compound (III). The reaction is carried out as described in example 2, starting with the piperazine b,ii. Yield 58% of compound no. 89, [α] D 25 =−24° (methanol).

Preparation of Coumpound c,iii (See Scheme iii)

Step 1 (scheme iii): A solution of the benzomorpholinone (10 g, 41 mmol; see scheme ii, step 1) and powdered KOH (2.3 g, 41 mmol) in DMF (100 ml) was cooled in ice (temperature<10° C.). After adding 1 equivalent of MeI (2.55 ml, 41 mmol) the reaction mixture was stirred at room temperature for about 1.5 hours and then poured into water. The precipitate was filtered off, washed with water and dried. Yield 10 g (95%) of the NCH 3 -compound, mp. 191–192; [α] D 25 =+7.5° (in THF)

Step 2 (scheme iii): This step is similar to step 4 described in scheme i.

Step 3 (scheme iii): This step is similar to step 5 described in scheme i, resulting in the formation of the piperazine c,iii.

Preparation of Compound No. 121

The route is described above, i.e. reaction of compound (II) with compound (III). The reaction is performed as described in example 2, starting with the piperazine c,iii. Yield 44% of compound no. 121, [α] D 25 =−28° (methanol).

Preparation of Compound d,iv (See Scheme iv)

Step 1 (scheme iv): Pyridine (81 ml, 1 mol) was added to a solution of 2-hydroxy-5-chloroaniline (143.5 g, 1 mol) in dry CH 2 Cl 2 . The mixture was cooled in ice (temperature<10° C.) and then a solution of 2-bromo-2-methyl-propionylbromide (163 ml, 1 mol) in CH 2 Cl 2 (100 ml) was added slowly. The mixture was stirred at room temperature for 18 hours and was poured into CH 2 Cl 2 (5000 ml) and water (2000 ml). The organic layer was washed with water, dried and concentrated in vacuo till about 1 liter. The precipitate was filtered off, washed with CH 2 Cl 2 and dried. Yield 231 g (79%) of the bromocompound, mp. 172° C.

Step 2 (scheme iv): To a suspension of the bromocompound (60 g, 205 mmol) in water (95 ml) was added slowly under ice cooling concentrated sulfuric acid (7 ml) followed by 70% HNO 3 (16 ml) and stirring was continued for 2 hours at room temperature. After cooling in ice water the precipitate was filtered off, washed with water and purified by chromatografy (SiO 2 , methyl t-butylether). Yield 49 g (71%) of the nitrocompound.

Step 3 (scheme iv): To a solution of the nitrocompound (49 g, 145 mmol) in DMF (500 ml) was added K 2 CO 3 . This mixture was heated for one hour at 150° C., then cooled and poured into a mixture water/ethyl acetate. The organic fraction was washed with sodium bicarbonate (5% in water) HCl (2N) and water respectively. The solvent was removed in vacuo and the residue was purified by flash chromatografy (SiO 2 , methyl t-butylether/PE=1/1). Yield 23 g (62%).

Step 4 (scheme iv): This step is similar to step 4 described in scheme i.

Step 5 (scheme iv): This step is similar to step 5 described in scheme i, leading to the formation of the piperazine d,iv.

Preparation of Compound No. 115

The route is described above, i.e. reaction of compound (II) with compound (III). The reaction is performed as described in example 2, starting with the piperazine d,iv. Yield 20% of compound no. 115.

The compounds listed in the following tables have been prepared according to the method of the above examples.