[Cl:1][C:2]1[CH:16]=[CH:15][CH:14]=[CH:13][C:3]=1[CH2:4][NH:5][CH2:6][CH2:7][C:8]1[S:9][CH:10]=[CH:11][CH:12]=1.Cl[CH2:18]SC.O>CS(C)=O>[ClH:1].[Cl:1][C:2]1[CH:16]=[CH:15][CH:14]=[CH:13][C:3]=1[CH2:4][N:5]1[CH2:6][CH2:7][C:8]2[S:9][CH:10]=[CH:11][C:12]=2[CH2:18]1To 52 g (0.2 M) N-(2-chloro-benzyl)-2-(2-thienyl)ethylamine dissolved in 60 ml dimethylsulfoxide and heated at 60° C. are added, over 30 minutes, 51 g (0.3 M) crude chloromethylmethylthioether prepared in step (a) above. The temperature of the reaction medium increases gradually and it is maintained at 80°-85° C, throughout the addition step, by cooling with water. When addition of chloromethyl methylthioether is completed, the medium is cooled to 6° C. The desired product precipitates out readily. After filtration and washing with 2×70 ml acetone, there are obtained 44.1 g 5-(2-chloro-benzyl)-4,5,6,7-tetrahydro-thieno[3,2-c]pyridine hydrochloride (Yield: 73.5%). Treatment of the filtrates provides another 10 g of the desired product (Yield: 90% M.p.=190° C.). The resulting crude product contains 1-2% impurities and may be made analytically pure by recrystallization from ethanol.
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