Patent ID: 8835679

Claim:
Process for the preparation of 2,4,5-trifluorophenylacetic acid of formula (I) or a salt thereof: comprising the following steps: (a) halogenation of the compound of formula (VII): in which X is a halogen atom, to give the compound of formula (V): in which X and X′ are independently halogen atoms, and/or the compound of formula (VI): in which X and X′ are independently halogen atoms, (b) dehydrohalogenation of the compound/s of formula (V) and/or of formula (VI) obtained in the step (a) to give the compound of formula (IV): in which X is a halogen atom; (c) conversion of the compound of formula (IV) obtained in the step (b) into the compound of formula (II): in which R is a linear or branched C1-C5 alkyl or is an aryl or benzyl group; and/or into the compound of formula (III): in which X is a halogen atom and R is a linear or branched C1-C5 alkyl or is an aryl or benzyl group; (d) hydrolysis of the compound/s of formula (II) and/or of formula (III) obtained in the step (c) to give the compound of formula (I) or salts thereof: or, alternatively to the steps (c) and (d) the following step: (e) direct hydrolysis of the compound of formula (IV) obtained in the step (b) to give the compound of formula (I) or salts thereof.