Methanol → Methyl 5-bromothiophene-3-carboxylate

Participants

Reaction Steps

5-Bromo-thiophene-3-carboxylic acid (13 g, 64 mmol) was dissolved in methanol (140 mL). Concentrated sulphuric acid (6.5 mL) was added and the mixture heated at reflux for 14 hours. The reaction was quenched by adding a solution of saturated aqueous sodium bicarbonate and most of the solvent was removed by evaporation under vacuum. The mixture was then diluted with a solution of saturated aqueous sodium bicarbonate and the product extracted with DCM. The organic solution was dried over sodium sulphate, filtered and the solvent removed by evaporation to give a white crystalline solid (13.2 g). 1H NMR (400 MHz, CDCl3): δ 8.0 (s, 1H), 7.5 (s, 1H), 3.85 (s, 3H).

Provenance & Evidence