IMPROVED PROCESS FOR PREPARATION OF CLOPIODOGREL BISULFATE CRYSTALLINE FORM-1

摘要

An improved process for preparing crystalline form-1 of (S)-methyl 2-(2-chlorophenyl)-2-{6,7-dihydrothieno[3,2-c]pyridine-5(4H)-yl}acetate bisulfate (clopidogrel bisulfate) of formula I is provided The preparation comprises the straight conversion of an uncyclized material of (S)-methyl 2-[2-(thiophen-2-yl)ethylamino]-2-(2-chlorophenyl) acetate hydrochloride into clopidogrel bisulfate crystalline form-1 without any degradation of clopidogrel base