TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Process: The preparation of (III) comprises: (a1) protecting amino functional group of 4,5,6,7-tetrahydrothieno(3,2-c)-pyridine or its salt with a tritylchloride in the presence of base and solvent followed by crystallization to provide 5-trityl-4,5,6,7-tetrahydro-thieno(3,2-c)pyridine (V); (a2) oxidizing (V) into 5-trityl-5,6,7,7a-tetrahydro-4H-thieno(3,2-c)pyridin-2-one (VI) by reacting it with n-butyl lithium, trimethyl borate and then treating with hydrogen peroxide borate in a solvent followed by crystallization; (a3) deprotecting amino group in (VI) by treating it with hydrochloride or weak acid in the presence of a solvent to provide hydrochloride salt of 5,6,7,7a-tetrahydro-4H-thieno(3,2-c)pyridin-2-one (VII); and (a4) reacting (VII) with tert-butyldimethylsilylchloride in the presence of base to obtain (III). Preferred Components: The acetylating agent is acetyl chloride and solvent is acetic acid and/or toluene. The organic base is trimethyl amine, triethyl amine (preferred), tributyl amine, pyridine, 4-dimethylaminopyridine, and N-methyl morpholine, diisopropylethyl amine, ammonia or ammonium bicarbonate. The solvent is benzene, toluene or xylene, dichloromethane, chloroform, methylene chloride, ethylene chloride, methyl isobutyl ketone, acetone, ethyl methyl ketone, ethyl acetate, isopropyl acetate, dimethylformamide, dimethyl sulfoxide, methanol, ethanol, isopropyl alcohol and/or tert-butanol. In step (a) the solvent is toluene and/or tetrahydrofuran, preferably mixture of toluene and tetrahydrofuran. In step (b), the solvent is ethyl acetate (preferred), dichloromethane, chloroform and/or carbon tetrahydrochloride. In step (a1): the base is diisopropylethylamine, triethylamine or ammonia; and the solvent is hexane, diisopropyl ether and/or methanol (preferred). In step (a2): solvent for reaction is toluene and/or tetrahydrofuran, preferably the mixture of toluene and tetrahydrofuran; and the solvent for crystallization is methanol (preferred), hexane and/or diisopropyl ether. In step (a3): the solvent is acetone (preferred) and/or tetrahydrofuran methanol; and the weak acid is an inorganic acid including hydrochloric acid, or organic acid including benzene sulfonic acid or para-toluene sulfonic acid. In step (a4), the base is diisopropyl ethyl amine, triethyl amine (preferred), ammonia or ammonium bicarbonate. EXAMPLE - 2-(Tert-butyldimethylsilyloxy)-5-( alpha -cyclopropylcarbonyl-2-fluoro-benzyl)-4,5,6,7- tetrahydrothieno-(3,2-c)-pyridine (100 g) was suspended in mixture of toluene (400ml) and acetic acid (100 ml) under nitrogen atmosphere at 20 plus minus 5 degrees C and stirred for 10-20 minutes in a 4-necked flask (equipped with a thermometer and mechanical stirrer). Then a solution of acetyl chloride (30 g) was slowly added in acetic acid (140 ml) at 20 plus minus 2 degrees C and the reaction mass was stirred for 4-6 hours at 20 plus minus 2 degrees C. Then acetyl chloride (180 g) was slowly added in reaction mass at 20 plus minus 2 degrees c and stirred for 12-16 hours. The reaction mass was then quenched into 30% sodium bicarbonate solution to obtain the product. The resultant product was extracted with ethyl acetate (2x 500 ml), and an organic layer was washed with sodium chloride solution and water, and dried over sodium sulfate. Then the solvent was recovered under vacuum and crystallized in methanol, ethyl acetate and/or hexane. The product was then filtered and the obtained slurry was washed with methanol, ethyl acetate and/or hexane. Then the resultant material was dried at atmospheric pressure at 40-45 degrees C, to give prasugrel (80 g).