TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Process: The process comprises (a5) preparing a solution of prasugrel in a solvent, (b5) adding a solution of hydrogen chloride dissolved in a solvent to the solution of step (a5), (c5) optionally, adding a seed crystal of prasugrel hydrochloride to the reaction mass prepared in step (b5), (d5) isolating the precipitated prasugrel hydrochloride, and (e5) optionally, purifying prasugrel hydrochloride to obtain a more purified prasugrel hydrochloride. The process comprises (a6) measuring the level of 3-fluoro phenyl acetic acid in one or more batches of 2-fluoro phenyl acetic acid, (b6) selecting a batch having less than 0.1% of 3-fluoro phenyl acetic acid, and (c6) synthesizing prasugrel or its salt, having less than 0.1% of 5-((1RS)-2-cyclopropyl-1-(3-fluorophenyl)-2-oxoethyl)-4,5,6,7-tetrahydrothieno(3,2-c)pyridin-2-yl acetate from the batch of step (b6). The process-1 further comprises converting the 2-bromo-1-cyclopropyl-2-(2-fluorophenyl)ethanone into prasugrel or its salt. In the process, the step (b) is carried out without isolating (I) obtained in step (a). Preferred Components: The solvent of step (a) is an ether solvent, ketone solvent, ester solvent, alcohol solvent, nitrile solvent, amide solvent, sulfoxide solvent and/or water. The acetylating agent of the step (b) is acetic anhydride. ACTIVITY - Cardiant; Vasotropic.    MECHANISM OF ACTION - None given.    EXAMPLE - 2-Bromo-1-cyclopropyl-2-(2-fluorophenyl)ethanone (7.5 g) and acetonitrile (25 ml) were charged into a flask at 26 degrees C. Sodium carbonate (6.06 g) was added to the reaction mass at 26 degrees C. 5,6,7,7a-Tetrahydrothieno(3,2-c)pyridin-2(4H)-one (5 g) was added to the reaction mass at 26 degrees C and stirred for 28 hours. The reaction mass was filtered and washed with acetonitrile (10 ml) and charged into a flask at 27 degrees C and cooled to 4 degrees C. N-Methylmorpholine (5.25 g) and 4-dimethylaminopyridine (0.0349 g) was added to the filtrate at 4 degrees C. Acetic anhydride (3.981 g) was added by drops to the reaction mass at 4 degrees C and stirred for 3 hours at 4 degrees C. Water (35 ml) was added by drops to the reaction mass at 4 degrees C in 15 minutes. The reaction mass was stirred at 4 degrees C for 1 hour 30 minutes to obtain prasugrel. The prasugrel (100 g) and acetone (800 ml) was charged into a round bottom flask at 25 degrees C. The reaction mass was heated to 35 degrees C and stirred to obtain a clear solution. Basic carbon (0.2 g) was added to the reaction mass at 36 degrees C, stirred for 30 minutes and filtered under vacuum and washed with acetone (200 ml). The filtrate was charged into the flask at 27 degrees C and heated to 48 degrees C for 30 minutes. An isopropyl alcohol solution of hydrochloric acid (99.7 ml) was added to the reaction mass at 48 degrees C in 10 minutes to obtain prasugrel hydrochloride (yield: 99.3 g).