Hydrogen Bromide → 5-Bromothiophene-3-carboxylic acid

Participants

Reaction Steps

Thiophene-3-formic acid (12.6 g) and AcOH (96 ml) are added to a reaction flask (250 ml), to dissolved after stirred at room temperature, HBr solution (8 ml) is then added to the reaction flask, and the reaction is rapidly changed to a light yellow. Pyridinium bromide perbromide (27 g) is then added to the flask in batches at room temperature. After addition, the reaction is stirred at room temperature, and the reaction is tracked by HPLC. The above mixture is poured into ice-water after reaction, stirred for about 30 minutes, filtered to form a white powder solid, the white powder solid is crystallized with hot water, filtered and dried to obtain a crystal of 5-bromo-thiophene-3-formic acid (10.8 g), content of 92% measured by HPLC.

Provenance & Evidence