Water → 5-Acetoxymethylimidazo[5,1-b]thiazole

To a solution of 0.231 g (1.50 mmol) of the 5-Hydroxymethylimidazo[5,1-b]thiazole prepared in Preparation 10 in 8 ml of dichloromethane was added 0.156 ml (1.65 mmol) of acetic anhydride with ice-cooling, and the mixture was stirred at room temperature for 20 hours. To the reaction solution were added water and a saturated aqueous solution of sodium hydrogencarbonate, and the mixture was extracted with dichloromethane. The organic layer was dried over anhydrous magnesium sulfate, and concentrated to dryness under reduced pressure. The residue was purified by flash column chromatography using silica gel, eluting with a 30:1 mixture of chloroform and methanol to give 0.237 g (yield 81%) of the title compound.