反应详情

A mixture of Example 178A (0.3 g, 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 product as a white solid (0.18 g, 58%). 1H NMR (300 MHz, CDCl3) 8 ppm 0.40 (m, 1 H), 0.72 (m, 7 H), 1.37 (m, 1 H), 2.36 (m, 2 H), 3.61 (s, 3 H), 3.83 (s, 3 H), 5.96 (s, 1 H), 7.42 (m, 2 H), 7.56 (m, 1 H), 8.19 (d, J=7.72 Hz, 1 H); 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