Process for phenylacetic acid derivatives

摘要

A process for the preparation of compounds of formula I, wherein: R is methyl or ethyl, R1 is chloro or fluoro, R2 is hydrogen of fluoro, R3 is hydrogen, fluoro, chloro, methyl, ethyl, methoxy, ethoxy or hydroxy, R4 is hydrogen or fluoro, and R5 is chloro, fluoro, trifluoromethyl or methyl, provided that R1, R2, R4 and R5 are not all fluoro when R is ethyl and R3 is H, the process comprising cleaving a lactam of formula II.