A PROCESS FOR THE PREPARATION OF CRYSTALLINE FORM 1 OR CLOPIDOGREL HYDROGEN SULFATE

摘要

The crystalline Form 1 of methyl (S)-clopidogrel hydrogen sulfate is prepared by precipitating the salt formed in the reaction of the optically active base, methyl (S) - (+) -alpha- (2-chlorophenyl) -4, 5, 6, 7-tetrahydrothieno[3,2-c]pyridine-5-acetate with concentrated sulfuric acid, using a precipitating solvent selected from a group comprising aliphatic and cyclic ethers and isobutyl methyl ketone. Methyl (S) - (+) -alpha- (2-chlorophenyl) -4,5,6,7- tetrahydrothieno[3,2-c]pyridine-5-acetate hydrogen sulfate is useful in the treatment and prevention of thrombosis, by acting as a platelet aggregation inhibitor and an anticoagulant.