Hydrochloric Acid → 2-Amino-5-(5-trifluoromethylpyridin-2-ylthio)thiazole

Participants

Reaction Steps

A mixture of 2-acetylamino-5-(5-trifluoromethylpyridin-2-ylthio)thiazole (3.2 g) in a mixture of ethanol (60 ml), tetrahydrofuran (30 ml) and aqueous 6N-hydrochloric acid (10 ml) was refluxed for 3 hours with stirring. The reaction mixture was concentrated under reduced pressure and the residue was dissolved in water. The solution was adjusted to pH 8.5 using aqueous sodium bicarbonate and extracted with mixture of tetrahydrofuran and ethyl acetate (1:1) and dried over magnesium sulfate. The solvent was concentrated under reduced pressure to give solid. The solid was subjected to column chromatography on silica gel (silica gel 60, 70-230 mesh; Merck: 150 g) and eluted with a mixture of chloroform and methanol (10:1). The fractions containing the objective compound were combined and concentrated under reduced pressure to give 2-amino-5-(5-trifluoromethylpyridin-2-ylthio)thiazole (2.1 g, yield: 75.8%). mp: 135°-138° C.

Provenance & Evidence