Ethyl 4-[(3-methoxyphenyl)sulfanyl]-3-oxobutanoate → 4-Methoxy-benzo[b]thiophen-3-yl-acetic acid ethyl ester

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Reaction Steps

4-(3-Methoxy-phenylsulfanyl)-3-oxo-butyric acid ethyl ester (10.0 g) is added to pre-cooled methanesulfonic acid (60 mL) at 0˜5° C., then the reaction mixture is allowed to warm to room temperature. After 1 h, the mixture is diluted with ice water and extracted with ethyl acetate. The combined organics are washed with brine, dried over Na2SO4, concentrated. Chromatography on silica gel elited with hexanes and ethyl acetate yields (6-methoxy-benzo[b]thiophen-3-yl)-acetic acid ethyl ester (4.8 g) and (4-methoxy-benzo[b]thiophen-3-yl)-acetic acid ethyl ester (0.8 g)

Provenance & Evidence