Synthesis of n,n-dimethyl-3-(4-methyl) benzoyl propionamide, a key intermediate of zolpidem

摘要

The present invention relates to an improved and industrially advantageous process for the preparation of N,N-dimethyl-3-(4-methyl)benzoyl propionamide of Formula I, which is a key intermediate in the synthesis of zolpidem hemitartrate, a non-benzodiazepine hypnotic agent. The process includes reacting 3-(4-methyl)-benzoyl propionic acid of Formula IV, with alkyl chloroformate or pivaloyl chloride to get a mixed anhydride of Formula V; and reacting the mixed anhydride of Formula V with dimethylamine of Formula VI to get the N,N-dimethyl-3-(4-methyl)benzoyl propionamide of Formula I.