Acetic Anhydride → 2-Bromoimidazo[5,1-b]thiazole

Participants

Reaction Conditions

Reaction Steps

Acetic anhydride (0.1 ml, 1.06 mmol) was added to a solution of 2-bromoimidazo[5,1-b]thiazole-7-carboxylic acid (38 mg, 0.15 mmol) in 1,2,4-trichlorobenzene (1 ml), and the mixture was stirred at 150° C. for 2 hr. The reaction solution was allowed to cool to room temperature, was diluted with hexane, and was extracted with 1 M hydrochloric acid (2 ml×3). The aqueous layer was neutralized with a 2 M aqueous solution of sodium hydroxide and was then extracted with ethyl acetate (4 ml×3). The organic layer was washed with saturated brine and was dried over anhydrous sodium sulfate. The solvent was then removed by distillation under the reduced pressure, and the residue was purified by column chromatography on silica gel (hexane:ethyl acetate=1:1→1:2) to give 2-bromoimidazo[5,1-b]thiazole (20.5 mg, 66%) as a white solid.

Provenance & Evidence