Patent ID: 8722893

Claim:
A process for preparing a compound of formula (VI), wherein Z is hydrogen or halogen; Z 1 is hydrogen, halogen, cyano or nitro; R 1 is C 1 -C 4 alkyl; R 2 is C 1 -C 4 alkyl, C 3 -C 6 cycloalkyl or R 1 and R 2 , when taken together with the atom to which they are attached, represent a C 3 -C 6 cycloalkyl group optionally substituted with methyl, and R 3 is hydrogen or a cation, comprising the steps of: (i) reacting a compound of formula (II), with a chlorinating agent, optionally in the presence of a radical initiator in a solvent selected from halogenated hydrocarbons, to obtain a compound of formula (I) wherein Z is hydrogen or halogen; Z 1 is hydrogen, halogen, cyano or nitro; (ii) crystallising the compound of formula (I) formed in step (i) from a solvent selected from 1,2-dichloroethane, chlorobenzene, 1,2-dichlorobenzene, 1,3-dichlorobenzene, 1,4-dichlorobenzene, trichloromethane, dichloromethane, toluene, xylenes, mesitylenes, alkyl acetates, methyl tert.-butyl ether, diisopropylether, cyclopentyl methyl ether, and mixtures thereof; (iii) reacting compound (I) in methanol with MOH or MOCH 3 , where M is an alkali metal cation, followed by acidification, to form compound (VIII) (iv) treating compound (VIII) with a dehydrating agent to form anhydride (IX), and either (v-a1) reacting anhydride (IX) with aminonitrile (V), H 2 N—CR 1 R 2 —CN (V) to obtain nitrile compound (X), (v-a2) hydrolyzing the nitrile group in compound (X) to obtain amide (XI), or (v-b) reacting anhydride (IX) with an amino carboxamide (IV) H 2 N—CR 1 R 2 —CONH 2 (IV) to obtain amide (XI), and (vi) condensing of amide (XI) to yield the compound of formula (VI).