反应详情

A mixture of Example 2A (0.3g, 1.0 mmol) and pyridinium dichromate (0.98 g, 2.6 mmol) in chloroform (20 mL) was heated at reflux with a Dean-Stark trap for 18 h. The reaction mixture was cooled to room temperature and filtered through celite. The filtrate was concentrated in vacuo. Column chromatography on silica (5% →15% ethyl acetate/hexane) afforded the title compound as a white solid (0.18 g, 58%). 1H NMR (300 MHz, CDCl3) δ ppm 0.40(m, 1H), 0.72 (m, 7H), 1.37(m, 1H), 2.36(m, 2H), 3.61 (s, 3H), 3.83(s, 3H), 5.96 (s, 1H), 7.42 (m, 2H), 7.56 (m, 1H), 8.19 (d, J=7.72 Hz, 1H); MS m/z 303.1 (M+H)+.

1. temperatureat reflux with a Dean-Stark trap for 18 h
2. filtrationfiltered through celite
3. concentrationThe filtrate was concentrated in vacuo