反应详情

A solution of crude 33 (3.96 mol) in toluene (150 mL) was treated with p-toluenesulfonic acid (100 mg) and refluxed under a Dean-Stark trap for 3 hr. After cooling, the reaction mixture was diluted with ethyl acetate (80 mL) and washed with saturated sodium bicarbonate (80 mL) and water (2×80 mL). The organic extract was dried over sodium sulfate and filtered. The solvent was removed in a rotary evaporator and the crude product was purified by chromatography on silica (80 g) with 2% ethyl acetate in heptane (2 L) to afford 34 (1.15 g, 62%).

1. temperaturerefluxed under a Dean-Stark trap for 3 hr
2. temperatureAfter cooling
3. washwashed with saturated sodium bicarbonate (80 mL) and water (2×80 mL)
4. extractionThe organic extract
5. dry with materialwas dried over sodium sulfate
6. filtrationfiltered
7. customThe solvent was removed in a rotary evaporator
8. customthe crude product was purified by chromatography on silica (80 g) with 2% ethyl acetate in heptane (2 L)