Method for producing tetrazole-substituted anthranilic acid diamide derivatives by reacting pyrazolic acids with anthranilic acid esters

This application is a §371 National Stage Application of PCT/EP2012/063169, filed Jul. 5, 2012, which claims priority to European Application No. 11173325.9, filed Jul. 8, 2011, and claims benefit of U.S. Provisional Application No. 61/506,265, filed Jul. 11, 2011.

1. Field of the Invention

The present invention relates to a process for preparing tetrazole-substituted anthranilic acid diamide derivatives of the formula (I)

by reacting N-aryl- and N-hetaryl-substituted pyrazole acids containing methylenetetrazole radicals with anthranilic esters and amines.

2. Description of Related Art

It has already been described in the literature that tetrazole-substituted anthranilic acid diamide derivatives can be prepared by reacting tetrazole-substituted N-aryl- and N-hetaryl-substituted pyrazole acids with anthranilamides (cf. WO2010/069502). It is also possible to obtain tetrazole-substituted anthranilic acid diamide derivatives by reacting tetrazole-substituted benzoxazinones with amines (WO 2010/069502). Both processes afford a good, but in some cases only moderate, yield; in particular, the proportion of regioisomers where the tetrazole ring Q is attached in two different positions may vary. Accordingly, it is an object of the present invention to provide novel economical processes for preparing tetrazole-substituted anthranilic acid diamide derivatives of the formula (I) in higher purity and high quality which, in particular, afford a constant ratio of the two possible regioisomers.

The object was achieved in accordance with the present invention by a process for preparing anthranilic acid diamide derivatives of the general formula (I)

in which

R 1 , R 3 independently of one another represent hydrogen, or represent C 1 -C 6 -alkyl, C 1 -C 6 -alkoxy, C 2 -C 6 -alkenyl, C 2 -C 6 -alkynyl or C 3 -C 6 -cycloalkyl which are each optionally mono- or polysubstituted by identical or different halogen or nitro substituents, preferably represent (C 1 -C 5 )-alkyl, particularly preferably represent methyl, ethyl or tert-butyl, very particularly preferably represent methyl,

R 2 represents C 1 -C 6 -alkyl, C 3 -C 6 -cycloalkyl, C 1 -C 6 -haloalkyl, C 1 -C 6 -halocycloalkyl, C 2 -C 6 -alkenyl, C 2 -C 6 -haloalkenyl, C 2 -C 6 -alkynyl, C 2 -C 6 -haloalkynyl, C 1 -C 4 -alkoxy, C 1 -C 4 -haloalkoxy, C 1 -C 4 -alkylthio, C 1 -C 4 -alkylsulphinyl, C 1 -C 4 -alkylsulphonyl, C 1 -C 4 -haloalkylthio, C 1 -C 4 -haloalkylsulphinyl, C 1 -C 4 -haloalkylsulphonyl, halogen, cyano, nitro, alkylamino, dialkylamino, cycloalkylamino or C 3 -C 6 -trialkylsilyl, preferably represents halogen or C 1 -C 6 -alkyl, particularly preferably represents fluorine or chlorine, very particularly represents chlorine,

R 4 represents hydrogen, halogen, cyano, nitro C 1 -C 4 -alkyl, C 1 -C 4 -haloalkyl, C 2 -C 6 -alkenyl, C 2 -C 6 -haloalkenyl, C 2 -C 6 -alkynyl, C 1 -C 4 -alkoxy, C 1 -C 4 -haloalkoxy, SF 5 , C 1 -C 4 -alkylthio, C 1 -C 4 -alkylsulphonyl, C 1 -C 4 -haloalkylthio, C 1 -C 4 -haloalkylsulphinyl, C 1 -C 4 -haloalkylsulphonyl, C 1 -C 4 -alkylamino, di-(C 1 -C 4 -alkyl)amino, C 3 -C 6 -cycloalkylamino, (C 1 -C 4 -alkoxy)imino, (C 1 -C 4 -alkyl)(C -C 4 -alkoxy)imino, (C 1 -C 4 -haloalkyl)(C -C 4 -cyano, nitro, alkoxy)imino or C 3 -C 6 -trialkylsilyl, preferably represents hydrogen, chlorine or cyano, particularly preferably represents chlorine or cyano, very particularly preferably represents cyano,

Q represents a tetrazole ring which is monosubstituted by R 5 , preferably represents a tetrazole ring which is monosubstituted by R 5 and selected from the group consisting of

particularly preferably represents Q-1, also particularly preferably represents Q-2,

R 5 represents C 1 -C 5 -alkyl which may be mono- to trisubstituted by halogen, preferably represents C 1 -C 3 -perfluoroalkyl, particularly preferably represents CF 3 or C 2 F 5 , very particularly preferably represents CF 3 ,

Z represents CH or N, preferably represents N,

the compounds of the general formula (I) furthermore include N-oxides and salts, characterized in that tetrazole-substituted pyrazole acids of the formula (II)

in which R 2 , Q and Z have the meanings given above, are reacted with anthranilic acid esters of the formula (III)

in which

R represents alkyl, cycloalkyl, alkoxyalkyl, arylalkyl, thioalkyl, alkylthioalkyl, alkylsulphonylalkyl, cyanoalkyl, haloalkyl, nitroalkyl or aryl, preferably represents methyl, ethyl, (C 5 -C 12 )-alkyl or aryl, particularly preferably represents methyl, ethyl, pentyl, hexyl or 2-ethylhexyl, R 3 , R 4 have the meanings given above,

to give compounds of the formula (IV)

in which R, R 2 , R 3 , R 4 , Q and Z have the meanings given above,

and these compounds of the general formula (IV) are reacted with amines of the general formula (V)

R 1 NH 2 (V)

in which R 1 has the meanings given above, to give anthranilamides of the formula (I),

in which R 1 , R 2 , R 3 , R 4 , Q and Z have the meanings given above.

The process according to the invention provides the compounds of the formula (1) in a purity of >90%, preferably 91%-97%, particularly preferably 95% to 97%, where the isomer ratio of the two possible regioisomers remains constant at from 90:10 to 96:4 (main isomer A, where Q represents Q-1: minor isomer B, where Q represents Q-2).

The process according to the invention can be illustrated by Scheme (I) below:

in which R, R 1 , R 2 , R 3 , R 4 , Q and Z have the general meanings indicated above.

General Definitions:

In the context of the present invention, the term halogens (X) comprises, unless defined otherwise, elements selected from the group consisting of fluorine, chlorine, bromine and iodine, with fluorine, chlorine and bromine being preferred and fluorine and chlorine being particularly preferred. Substituted groups may be mono- or polysubstituted, where in the case of polysubstitution the substituents can be identical or different.

Alkyl groups substituted by one or more halogen atoms (−X) (=haloalkyl groups) are, for example, selected from trifluoromethyl (CF 3 ), difluoromethyl (CHF 2 ), CCl 3 , CFCl 2 , CF 3 CH 2 , ClCH 2 , CF 3 CCl 2 .

In the context of the present invention, alkyl groups are, unless defined otherwise, straight-chain or branched hydrocarbon groups. In the context of the present invention, alkyl groups can be mono- or polysubstituted by further groups; for example, cyanoalkyl groups are selected from cyanomethyl, cyanoethyl, etc., nitroalkyl groups are selected, for example, from nitromethyl, nitroethyl, etc.

Alkoxyalkyl groups are alkyl groups substituted by alkoxy; specifically this comprises, for example, the meanings methoxymethyl, ethoxymethyl, propoxyethyl, etc.

The definitions alkyl and C 1 -C 12 -alkyl include, for example, the meanings methyl, ethyl, n-, isopropyl, n-, iso-, sec- and t-butyl, n-pentyl, n-hexyl, 1,3-dimethylbutyl, 3,3-dimethylbutyl, n-heptyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl.

In the context of the present invention, cycloalkyl groups are, unless defined otherwise, cyclic saturated hydrocarbon groups.

In the context of the present invention, aryl radicals are, unless defined otherwise, aromatic hydrocarbon radicals which may have one, two or more heteroatoms selected from O, N, P and S and may optionally be substituted by further groups.

In the context of the present invention, arylalkyl groups and arylalkoxy groups are, unless defined otherwise, alkyl and alkoxy groups, respectively, which are substituted by aryl groups and may have an alkylene chain. Specifically, the definition arylalkyl includes, for example, the meanings benzyl- and phenylethyl; the definition arylalkoxy includes, for example, the meaning benzyloxy.

In the context of the present invention, alkylaryl groups (alkaryl groups) and alkylaryloxy groups are, unless defined otherwise, aryl groups and aryloxy groups, respectively, which are substituted by alkyl groups and may have a C 1-8 -alkylene chain and may have one or more heteroatoms selected from O, N, P and S in the aryl skeleton or aryloxy skeleton.

If appropriate, the compounds according to the invention may be present as mixtures of various possible isomeric forms, in particular of stereoisomers, such as, for example, E and Z, threo and erythro, and also optical isomers, and, if appropriate, also of tautomers. What are disclosed are both the E and the Z isomers, and also the threo and erythro, and the optical isomers, any mixtures of these isomers and the possible tautomeric forms.

The compounds of the formula (IV) are obtained by reacting tetrazole-substituted pyrazole acids of the formula (II) with anthranilic esters of the formula (III).

Anthranilic esters of the formula (III) are known (cf. WO 2008/070158). Pyrazole acids of the formula (II) are likewise known (cf. WO2007/144100). Pyrazole acids of the formula (II) can be prepared, for example, from halomethylpyrazole esters of the formula (VI) and perfluoroalkyltetrazoles of the formula (VII) in two steps a and b (cf. Scheme (II) and Preparation Examples). Here, the compounds of the formula (VIII) formed are converted by basic hydrolysis (step b) into the pyrazole acids of the formula (II).

Halomethylpyrazole esters of the formula (VI) are likewise known and can be prepared as described in WO 2011/7073101. Perfluoroalkyltetrazoles of the formula (VII) are known; some of them are even commercially available, or they can be obtained by known processes (cf., for example, WO2004/020445; William P. Norris, J. Org. Chem., 1962, 27 (9), 3248-3251; Henry C. Brown, Robert J. Kassal, J. Org. Chem., 1967, 32 (6), 1871-1873; Dennis P Curran, Sabine Hadida, Sun-Young Kim, Tetrahedron, 1999, 55 (29), 8997-9006; L. D. Hansen, E. J. Baca, P. Scheiner, Journal of Heterocyclic Chemistry, 1970, 7, 991-996, JACS V.27, p. 3248).

As a basic principle, Step 1 is carried out in the presence of a base. Suitable bases are, for example, sodium hydroxide, potassium carbonate, sodium carbonate, caesium carbonate, sodium methoxide. Preference is given to organic bases such as trialkylamines, pyridines, alkylpyridines, phosphazenes and 1,8-diazabicyclo[5.4.0]undecene (DBU). Particular preference is given to pyridines, alkylpyridines such as β-picoline, 2,6-dimethylpyridine, 2-methyl-5-ethylpyridine, 2,3-dimethylpyridine. When carrying out Process Step 1 according to the invention, preferably from 1.5 mol to 4 mol, particularly preferably from 1.5 to 3 equivalents, of the base are employed per mole of the pyrazole of the formula (II). Step 1 is carried out in the presence of a condensing agent. Suitable for this purpose are all agents customary for such coupling reactions. Examples which may be mentioned are acid halide formers such as phosgene, phosphorus tribromide, phosphorus trichloride, phosphorus pentachloride, phosphorus oxychloride or thionyl chloride; anhydride formers such as ethyl chloroformate, methyl chloroformate, isopropyl chloroformate, isobutyl chloroformate or methanesulphonyl chloride, p-toluenesulphonyl chloride; carbodiimides such as N,N′-dicyclohexylcarbodiimide (DCC) or other customary condensing agents such as phosphorus pentoxide, polyphosphoric acid, 1,1′-carbonyldiimidazole, 2-ethoxy-N-ethoxycarbonyl-1,2-dihydroquinoline (EEDQ), triphenylphosphine/carbon tetrachloride, bromotripyrrolidinophosphonium hexafluorophosphate, bis(2-oxo-3-oxazolidinyl)phosphinic chloride or benzotriazol-1-yloxytris(dimethylamino)phosphonium hexafluorophosphate. Polymer-supported reagents such as, for example, polymer-bound cyclohexylcarbodiimide may also be used. Particularly suitable are methanesulphonyl chloride (mesyl chloride) and phosgene. When carrying out Process Step 1 according to the according to the invention, preferably from 1 mol to 3 mol, particularly preferably from 1.5 to 2.5 mol, of the condensing agent are employed per mole of the pyrazole of the formula (II).

The process step according to the invention is preferably carried out within a temperature range of from 0° C. to +80° C., particularly preferably at temperatures of from 10° C. to +50° C.

When carrying out the process step according to the invention, an equimolar amount of the compound of the formula (III) is employed per mole of the pyrazole acid of the formula (II).

The Process Step (1) according to the invention is generally carried out under atmospheric pressure. However, it is alternatively also possible to operate under reduced pressure or under elevated pressure.

The reaction time is not critical and may be chosen in a range between one and a plurality of hours, depending on the batch size, on the substituent R 5 and on the temperature.

Suitable solvents are, for example, aliphatic, alicyclic or aromatic hydrocarbons such as, for example, petroleum ether, n-hexane, n-heptane, cyclohexane, methylcyclohexane, benzene, toluene, xylene or decalin, and halogenated hydrocarbons such as, for example, chlorobenzene, dichlorobenzene, dichloromethane, chloroform, carbon tetrachloride, dichloroethane or trichloroethane, ethers such as diethyl ether, diisopropyl ether, methyl tert-butyl ether, methyl tert-amyl ether, dioxane, tetrahydrofuran, 1,2-dimethoxyethane, 1,2-diethoxyethane or anisole; nitriles such as acetonitrile, propionitrile, n- or isobutyronitrile or benzonitrile; amides such as N,N-dimethylformamide, N,N-dimethylacetamide, N-methylformanilide, N-methylpyrrolidone or hexamethylphosphoric triamide; sulphoxides such as dimethyl sulphoxide or sulphones such as sulpholane, alcohols such as methanol, ethanol, isopropanol, or solvent mixtures. Particular preference is given to using acetone, acetonitrile, toluene, methyl tert-butyl ether, THF. Particularly suitable are acetonitrile, THF, DMF and NMP.

The compounds of the formula (IV) formed in Step 1 are converted into anthranilic acid diamide derivatives of the formula (I):

Surprisingly, it has now been found that the compounds of the formula (IV) react selectively and under very mild conditions to give anthranilic acid diamide derivatives of the formula (I). Very mild conditions are to be understood, for example, as meaning the following conditions; however, this is not limiting:

The reaction is generally carried out under atmospheric pressure. However, it is alternatively also possible to operate under elevated pressure (for example reaction with MeNH 2 in an autoclave).

Depending on the batch size and temperature, the reaction time can be chosen in a range between 1 hour and a plurality of hours.

The reaction step is preferably carried out in a solvent. Suitable solvents are, for example, selected from the group consisting of water, alcohols such as methanol, ethanol, isopropanol or butanol, aliphatic and aromatic hydrocarbons such as, for example, n-hexane, benzene or toluene which may be substituted by fluorine and chlorine atoms, such as methylene chloride, dichloroethane, chlorobenzene or dichlorobenzene; ethers such as, for example, diethyl ether, diphenyl ether, methyl tert-butyl ether, isopropyl ethyl ether, dioxane, diglyme, dimethyl glycol, dimethoxyethane (DME) or THF; nitriles such as methyl nitrile, acetonitrile, butyl nitrile or phenyl nitrile; amides such as dimethylformamide (DMF) or N-methylpyrrolidone (NMP), or mixtures of such solvents, with water, acetonitrile, dichloromethane and alcohols (ethanol) being particularly suitable. Particular preference is given to THF, acetonitrile, alcohols.

What are used are the compounds of the formula (V) where R 1 preferably represents (C 1 -C 6 )-alkyl.

The exchange may additionally be accelerated by addition of bases or acids. Suitable bases are alkali metal hydroxides such as, for example, lithium hydroxide, sodium hydroxide or potassium hydroxide, alkali metal carbonates such as, for example, Na 2 CO 3 , K 2 CO 3 , and acetates such as, for example, NaOAc, KOAc, LiOAc and alkali metal alkoxides such as, for example, NaOMe, NaOEt, NaOt-Bu, KOt-Bu, and organic bases such as trialkylamines, alkylpyridines, phosphazenes and 1,8-diazabicyclo[5.4.0]undecene (DBU). Preference is given to organic bases such as pyridines, alkylpyridines.

Suitable acids are CH 3 COOH, CF 3 COOH, p-TSA, HCl, H 2 SO 4 .

The Process Step (2) according to the invention is preferably carried out within a temperature range of from 0° C. to +100° C., particularly preferably at temperatures of from 10° C. to +80° C., very particularly preferably at 10-60° C.

The Process Step (2) according to the invention is generally carried out under atmospheric pressure. However, it is alternatively also possible to operate under reduced pressure or under elevated pressure in an autoclave.

Depending on the batch size and the temperature, the reaction time can be chosen in a range between 1 hour and a plurality of hours.

The following Preparation Examples illustrate the invention without limiting it.