反应详情

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).

1. temperaturethe mixture heated
2. temperatureat reflux for 14 hours
3. customThe reaction was quenched
4. additionby adding a solution of saturated aqueous sodium bicarbonate
5. custommost of the solvent was removed by evaporation under vacuum
6. additionThe mixture was then diluted with a solution of saturated aqueous sodium bicarbonate
7. extractionthe product extracted with DCM
8. dry with materialThe organic solution was dried over sodium sulphate
9. filtrationfiltered
10. customthe solvent removed by evaporation