Ethyl 6-methoxybenzo[b]thiophene-2-carboxylate → Ethyl 6-hydroxybenzo[b]thiophene-2-carboxylate

Participants

Reaction Steps

To a solution of ethyl 6-methoxy-1-benzothiophene-2-carboxylate (5.58 g, 23.6 mmol) in methylene chloride (50 mL) was added dropwise 1 M boron tribromide methylene chloride solution (71 mL, 70.8 mmol) at −20° C., and the mixture was stirred at room temperature for 3 hr. The reaction mixture was poured into ice, and the mixture was extracted twice with ethyl acetate. The extract was washed with saturated brine and dried over anhydrous sodium sulfate. The solvent was evaporated under reduced pressure, and the obtained residue was purified by silica gel column chromatography (hexane to hexane:ethyl acetate=3:2) to give the title compound (1.76 g, yield 34%) as a white solid.

Provenance & Evidence