反应详情

A 25-mL single-neck round-bottomed flask equipped with a reflux condenser and magnetic stirrer was purged with nitrogen and charged with 32 (210 mg, 0.89 mmol), ethanol (6 mL), iron powder (−325 mesh, 491 mg, 8.93 mmol) and 2N hydrochloric acid (0.70 mL, 1.40 mmol), and the mixture was heated at reflux for 30 min. After this time, the reaction was cooled to room temperature, and powdered potassium carbonate (3.03 g, 22.0 mmol) was added. The resulting suspension was filtered and the filter cake washed with ethanol (4×10 mL). The filtrate was concentrated under reduced pressure to afford 33 in 100% yield (185 mg) as a white solid: mp 153-154° C.; 1H NMR (300 MHz, DMSO-d6) δ 7.74 (d, 1H, J=2.7 Hz), 6.90 (d, 2H, J=8.4 Hz), 6.47 (d, 2H, J=8.4 Hz), 4.95 (bs, 2H), 3.45 (m, 1H), 3.42 (s, 1H), 3.14 (m, 1H), 2.89 (m, 1H), 2.44 (m, 1H), 2.02 (s, 3H); MS (ESI+) m/z 206 (M+H).

1. customA 25-mL single-neck round-bottomed flask equipped with a reflux condenser and magnetic stirrer
2. customwas purged with nitrogen
3. temperaturethe mixture was heated
4. temperatureat reflux for 30 min
5. filtrationThe resulting suspension was filtered
6. washthe filter cake washed with ethanol (4×10 mL)
7. concentrationThe filtrate was concentrated under reduced pressure