Patent ID: 6521760
Filing Date: 2003-02-18
Classification: A61P,C07D

Abstract:
A process for the preparation of polymorph A of zofenopril calcium salt in substantially pure form, which comprises:a) reaction of S(âˆ’)-3-benzoylthio-2-methylpropanoic acid chloride with cis-4-phenylthio-L-proline in water at pH ranging from 9.0 to 9.5 and recovery of zofenopril in the acidic form; b) salification of acid zofenopril with a potassium salt in alcoholic solution, and recovery of the resulting potassium salt; c) conversion of the potassium salt to calcium salt by addition of a zofenopril potassium salt aqueous solution to a CaCl2 aqueous solution at a temperature of 70-90Â° C. with simultaneous seeding to promote the precipitation of polymorph A.