BigPatents India

A simple, efficient and industrially feasible process for the preparation of crystalline quinapril hydrochloride in high purity and good yield is disclosed. A solution of benzyl ester of quinapril hydrochloride is prepared with an alkyl nitrile and is subjected to catalytic hydrogenolysis, after pH adjustment of the solution to o.8 to 1 by adding 3 to 17/% solution of hydrogen chloride in dry ether or dry alkyl nitrile. The molar ratio of the benzyl ester of quinapril and hydrogen chloride is selected to be 1.0:1.15: to 1.0:1.35. Catalytic hydrogenolysis is carried out with hydrogen in the presence of Pd/C catalyst at a pressure of 40 to 150 psi and a temperature of 10-40Û&The solvent is distilled out to 50 to 70% of its volume to obtain crystalline quinapril hydrochloride, which is washed with n-pentane and dried. Drawing : NIL Total Pages: 15