3-Chloro-benzamidine → 2-(3-chlorophenyl)-1,6,7,8-tetrahydrothiopyrano[3,2-d]pyrimidin-4-one

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Reaction Steps

A 100-mL round bottomed flask was charged with methyl 3-oxotetrahydrothiopyran-2-carboxylate (1.5 g, 8.6 mmol, 1.47 eq.), 3-chlorobenzamidine (HCl salt, 1.1 g, 5.75 mmol, 1 eq.) and ethanol (20 ml). The resulting mixture was stirred under reflux for 48 hrs. After cooling to room temperature, the volatile material was removed under reduced pressure and the residue was treated with hydrochloric acid (2N, 10 ml) and water (20 ml). The precipitate was collected by filtration and washed with water (3×10 ml) followed by ether (3×10 ml). After drying, the title compound was obtained as white solid (1.15 g, 72% yield).

Provenance & Evidence