2-Thiophenecarboxylic acid, tetrahydro-3-oxo-, methyl ester → 2-(3-chlorophenyl)-6,7-dihydro-1H-thieno[3,2-d]pyrimidin-4-one

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Reaction Conditions

Reaction Steps

To a solution of 3-chlorobenzimidamide (4.8 g, 31.2 mmol) in ethanol (150 mL) was added methyl 3-oxotetrahydrothiophene-2-carboxylate (5.0 g, 31.2 mmol) and sodium methoxide (1.7 g, 31.2 mmol). The mixture was stirred at 85° C. for 16 h. The mixture was concentrated after which ethanol (10 mL) was added and the suspension was chilled to 0° C. HCl (2 M, 50 mL) was added and the suspension was filtered and washed with water. The solid was purified by column chromatography (silica, dichloromethane/methanol) to afford the title compound (1.9 g, 23%) as a brown solid. MW=264.73. 1H NMR (DMSO-d6, 500 MHz) δ 12.85 (s, 1H), 8.13 (s, 1H), 8.07-8.01 (m, 1H), 7.63-7.59 (m, 1H), 7.56-7.51 (m, 1H), 3.41-3.24 (m, 4H); APCI MS m/z 265 [M+H]+.

Provenance & Evidence