Boron tribromide → (6-Hydroxy-benzo[b]thiophen-3-yl)-acetic acid ethyl ester

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Reaction Steps

To a solution of (6-Methoxy-benzo[b]thiophen-3-yl)-acetic acid ethyl ester (2.4 g, 9.6 mmol) in methylene chloride (60 mL) is added BBr3 (1.0 M, heptane, 29.4 mL, 29.4 mmol) at −20˜−30° C. The reaction mixture is allowed to warm to room temperature over 2 hrs, and TLC indicated clean conversion. The reaction is quenched by ice water, extracted with methylene chloride, dried over sodium sulfate, concentrated. Column chromatography on silica gel eluted with hexanes/ethyl acetate yields the title compound (2.2 g).

Provenance & Evidence