Cyanamide → 4H,6H,7H-pyrano(4,3-d)(1,3)thiazol-2-amine

Participants

Reaction Steps

To a solution of tetrahydro-4H-pyran-4-one (Aldrich) (7.22 g, 72.11 mmol) in cyclohexane (70 mL) were added pyrrolidine (6.26 mL, 7.57 mmol) and p-toluenesulfonic acid monohydrate (13.72 mg, 0.07 mmol). The reaction mixture was refluxed for 3 hours with a Dean-Stark trap, cooled and concentrated. The residue was dissolved in methanol (20 mL) and then sulfur (2.31 g, 72.11 mmol) was added followed by a solution of cyanamide (3.03 g, 72.11 mmol) in methanol (5 mL) at 0° C. The reaction mixture was stirred at room temperature overnight, filtered, concentrated and purified by column chromatography using an Analogix® Intelliflash280™ (SiO2, 0-5% methanol in dichloromethane) to afford the title compound. MS (ESI+) m/z 157 (M+H)+.

Provenance & Evidence