NOVELTY - Preparing clopidogrel comprises: e.g. (i) providing 2-(2-chlorophenyl)-2-(6,7-dihydrothieno(3,2-c)pyridine-5(4H)-yl)acetic acid by condensation of 4,5,6,7-tetrahydrothieno(3,2-c)pyridine hydrochloride with 2-bromo-2-(2-chlorophenyl)acetic acid; (ii) optically resolving 2-(2-chlorophenyl)-2-(6,7-dihydrothieno(3,2-c)pyridine-5(4H)-yl)acetic acid, using di-O-benzyl-L-tartaric acid and obtaining corresponding L-di-O-benzoyl tartaric acid salt; (iii) converting (S)-2-(2-chlorophenyl)-2-(6,7-dihydrothieno(3,2-c)pyridine-5(4H)-yl)acetic acid L-di-O-benzoyl tartaric acid salt, into clopidogrel.    USE - The process is useful for preparing clopidogrel or its salt. The (S)- 2-(2-chlorophenyl)-2-(6,7-dihydrothieno(3, 2-c)pyridine-5(4H)-yl)acetic acid L-di-O-benzoyl tartaric acid salt is useful for the preparation of clopidogrel or its salts (all claimed), where clopidogrel is used for preventing platelet aggregation, and reducing thrombotic events (e.g. strokes and ischemic attacks). No biological data given.    ADVANTAGE - The process: is cost-effective for large scale production of high purity clopidogrel besylate in high yield; and utilizes lees time, mild and safer reaction conditions that helps protect the environment and the personnel.    DETAILED DESCRIPTION - Preparing clopidogrel or its salt (e.g. clopidogrel besylate), comprises: (i) providing 2-(2-chlorophenyl)-2-(6,7-dihydrothieno(3,2-c)pyridine-5(4H)-yl)acetic acid by condensation of 4,5,6,7-tetrahydrothieno(3,2-c)pyridine hydrochloride with 2-bromo-2-(2-chlorophenyl)acetic acid in water; (ii) optically resolving the obtained 2-(2-chlorophenyl)-2-(6,7-dihydrothieno(3,2-c)pyridine-5(4H)-yl)acetic acid, using di-O-benzyl-L-tartaric acid and obtaining the dextro-rotary enantiomer (S)- 2-(2-chlorophenyl)-2-(6,7-dihydrothieno(3,2-c)pyridine-5(4H)-yl)acetic acid L-di-O-benzoyl tartaric acid salt; (iii) converting the obtained (S)-2-(2-chlorophenyl)-2-(6,7-dihydrothieno(3,2-c)pyridine-5(4H)-yl)acetic acid L-di-O-benzoyl tartaric acid salt, into clopidogrel or its salts (e.g. clopidogrel besylate); and (iv) de-salting the remaining material from the optical resolution process of step (ii) and racemization to obtain 2-(2-chlorophenyl)-2-(6,7-dihydrothieno(3,2-c)pyridine-5(4H)-yl)acetic acid with chiral purity of less than 60%.