Acetaldehyde → Ethyl 5-bromo-2-(1-hydroxyethyl)thiophene-3-carboxylate

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Reaction Steps

Ethyl 2,5-dibromothiophene-3-carboxylate (22.3 g) synthesized above was dissolved in tetrahydrofuran (200 mL), and 1.0M isopropylmagnesium bromide-tetrahydrofuran solution (78.0 mL) was added dropwise at −45° C. After stirring under an argon atmosphere for 1 hr, acetaldehyde (19.9 mL) was added dropwise, and the mixture was stirred at −45° C. for 1 hr, and at room temperature for 2 hr. Saturated aqueous ammonium chloride solution was added to quench the reaction, and the mixture was extracted with ethyl acetate. The extract was washed with brine, dried over magnesium sulfate, and concentrated under reduced pressure. The residue was purified by silica gel column chromatography (ethyl acetate:hexane=3:17, volume ratio) to give the title compound (9.63 g, 49%) as a yellow oil.

Provenance & Evidence