反应详情

To a stirred solution of 4-bromo-5-methylthiophene-2-carboxylic acid (45 g, 204 mmol) in methanol (225 mL) was added concentrated H2SO4 (4.0 g, 41 mmol). The reaction mixture was heated to reflux overnight, cooled to room temperature, poured into saturated NaHCO3 (800 mL), and left to stir for 30 min. The precipitate was filtered, washed with water, and dried under high-vacuum to afford the title compound. 1H NMR (500 MHz, CDCl3) δ 7.61 (s, 1H); 3.88 (s, 3H); 2.45 (s, 3H). LRMS (APCI) calc'd for (C7H8BrO2S) [M+H]+, 234.9. found 234.9.

1. temperatureThe reaction mixture was heated
2. temperatureto reflux overnight
3. waitleft
4. filtrationThe precipitate was filtered
5. washwashed with water
6. customdried under high-vacuum