Patent ID: 6919450

Claim:
A process for the production of benazepril hydrochloride of Formula (II), comprising the steps of (i)treating ethyl (R)-2-hydroxy-4-phenylbutyrate of Formula (Ill) with trifluoromethane sulphonic anhydride of Formula (IV) F 3 C—SO 2 —O—SO 2 —CF 3 FORMULA IV in an inert solvent in the presence of a base and purifying it by passing through a column to obtain trifluoromethane sulfonic ester of ethyl(R)-2-hydroxy-4-phenyl butyrate of Formula (I); and (ii) further condensing said compound of formula I with 1-tert-butoxycarbonylmethyl-3-5-amino-2, 3, 4, 5,-tetrahydro-1H-(1)-enzazepin-2-one of Formula V in the presence of an organic solvent and an acid acceptor at a temperature from about 0 to 50° C. for about 1 to 5 hours followed by a suitable work up.