Ethanol → Ethyl 5-bromothiophene-3-carboxylate

Participants

Reaction Steps

5-bromo-thiophene-3-carboxylic acid (18.2 g, 0.09 mol) was dissolved in absolute ethanol (150 ml) and H2SO4 (5 ml), and the mixture was refluxed for 5 hours. The mixture was concentrated under vacuum to give a yellow oil, then diluted with a mixture of ethyl acetate (100 ml) and saturated brine (200 ml), and mixed, let standing for layer separation. The aqueous layer was washed with ethyl acetate (25 ml twice). The extract and the organic layer was adjusted with Na2CO3 (10%) to pH=8, and the organic phase was separated and washed with saturated brine to pH=7, dried over anhydrous Na2SO4 over night. The organic layer was concentrated under reduced pressure to give 5-bromo-thiophene-3-carboxylic acid ethyl ester as yellow oil (15 g).

Provenance & Evidence