Piperazine → 4-(3-Fluoro-benzyl)-5-oxo-7-piperazin-1-yl-4,5-dihydro-thieno[3,2-b]pyridine-6-carboxylic acid ethyl ester

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Reaction Steps

7-Chloro-4-(3-fluoro-benzyl)-5-oxo-4,5-dihydro-thieno[3,2-b]pyridine-6-carboxylic acid ethyl ester (17) (10 g, 27.39 mmol) was added slowly to a solution of piperazine (9.42 g, 109 mmol) in dichloromethane. The solution was stirred at room temperature for 3 h. The solvent was evaporated under vacuum. The residue was suspended in water, stirred vigorously at room temperature, and filtered. The solids were again dissolved in dichloromethane and washed by water. The organic phase was dried over MgSO4 and concentrated to yield 9.63 g (84%) of 4-(3-fluoro-benzyl)-5-oxo-7-piperazin-1-yl-4,5-dihydro-thieno[3,2-b]pyridine-6-carboxylic acid ethyl ester. 1H-NMR (DMSO-d6) δ 1.29 (m, 3H), 2.81 (m, 4H), 3.21 (m, 4H), 4.25 (m, 2H), 5.35 (s, 2H), 7.12 (m, 3H), 7.30 (m, 2H), 7.97 (m, 1H); EIMS m/z 416 (M+1).

Provenance & Evidence