反应详情

A 250-mL single-neck round-bottomed flask equipped with a magnetic stirrer was charged with 251c (1.14 g, 3.10 mmol), methylene chloride (10 mL) and trifluoroacetic acid (5 mL). The reaction mixture was stirred at room temperature for 2 h. After this time, the mixture was concentrated under reduced pressure. The resulting residue was diluted with methylene chloride (100 mL) and washed with saturated aqueous sodium bicarbonate (50 mL). The aqueous layer was extracted with methylene chloride (2×50 mL) and the combined organic extracts were dried over sodium sulfate, filtered and concentrated to afford a 92% yield (1.10 g) of 251d as a colorless oil. This compound was used directly for the next step without any purification: 1H NMR (500 MHz, DMSO-d6) d 8.65 (s, 1H), 8.55 (d, 1H, J=2.5 Hz), 7.82 (d, 1H, J=3.0 Hz), 7.48 (d, 1H, J=2.5 Hz), 7.30 (d, 1H, J=9.0 Hz), 7.21 (m, 1H), 4.95 (t, 1H, J=6.0 Hz), 3.76 (m, 1H), 3.48 (m, 5H); MS (ESI+) m/z 353.0 (M+H).

1. customA 250-mL single-neck round-bottomed flask equipped with a magnetic stirrer
2. concentrationAfter this time, the mixture was concentrated under reduced pressure
3. additionThe resulting residue was diluted with methylene chloride (100 mL)
4. washwashed with saturated aqueous sodium bicarbonate (50 mL)
5. extractionThe aqueous layer was extracted with methylene chloride (2×50 mL)
6. dry with materialthe combined organic extracts were dried over sodium sulfate
7. filtrationfiltered
8. concentrationconcentrated