Patent ID: 8193358

Claim:
A method for producing prasugrel hydrochloride of the formula: with a reduced content of OXTP, comprising preparing free prasugrel of the formula: containing OXTP; dissolving the free prasugrel represented by the formula (I) in an inert solvent, and adding hydrochloric acid optionally dropwise to the solution; wherein the method of preparing free prasugrel comprises the steps of: (i) chlorinating cyclopropyl 2-fluorobenzylketone by blowing chlorine gas thereto in dichloromethane while keeping the solution temperature at 0° C. and stirring at same temperature to synthesize 2-fluoro-α-cyclopropylcarbonylbenzylchloride; (ii) reacting 2-fluoro-α-cyclopropylcarbonylbenzylchloride with the product, which is obtained from reacting 5,6,7,7a-tetrahydro-4H-thieno[3,2-c]pyridine-2-on p-toluenesulfonate and tert-butyldimethylchlorosilane in dichloromethane in the presence of triethylamine and sodium iodide to synthesize 2-(tert-butyldimethylsilyloxy)-5-(α-cyclopropylcarbonyl-2-fluorobenzyl)-4,5,6,7-tetrahydrothieno[3,2-c]pyridine, and recrystallizing thereof; (iii) acetylating 2-(tert-butyldimethylsilyloxy)-5-(α-cyclopropylcarbonyl-2-fluorobenzyl)-4,5,6,7-tetrahydrothieno[3,2-c]pyridine by reacting acetic anhydride therewith in acetonitrile in the presence of triethylamine and 4-dimethylaminopyridine at −15° C.