反应详情

A solution of crude 27 (5 mmol) in toluene (120 mL) was treated with p-toluene sulfonic acid (0.2 g) and refluxed under a Dean-Stark trap for 2 hr. After cooling the reaction mixture was diluted with ethyl acetate (100 mL) and washed with saturated sodium bicarbonate (80 mL) and water (2×80 mL). The organic layer was dried over sodium sulfate, filtered and the solvent was removed on a rotary evaporator. The crude product was purified by chromatography on silica (80 g) with hexane (4 L). Pure 28 (1.3 g, 58% over 2 steps) was isolated.

1. temperaturerefluxed under a Dean-Stark trap for 2 hr
2. temperatureAfter cooling the reaction mixture
3. washwashed with saturated sodium bicarbonate (80 mL) and water (2×80 mL)
4. dry with materialThe organic layer was dried over sodium sulfate
5. filtrationfiltered
6. customthe solvent was removed on a rotary evaporator
7. customThe crude product was purified by chromatography on silica (80 g) with hexane (4 L)
8. customPure 28 (1.3 g, 58% over 2 steps) was isolated