反应详情

A mixture of 3α-hydroxy-16α-methyl-5α-pregnane-11,20-dione (1.00 g), benzene (50 ml), ethylene glycol (5 ml) and toluene-4-sulphonic acid monohydrate (50 mg) was brought to reflux under a Dean and Stark water separator and refluxed for 5 hr, then poured into saturated aqueous sodium hydrogen carbonate (50 ml) and the layers separated. The aqueous portion was extracted with additional benzene (50 ml) and the combined organic portions washed with water (2×50 ml), dried and evaporated to a white foam (1.12 g). A portion of this material (1.00 g) was crystallised from ether-petroleum ether (b.p. 60°-80°) to afford the title compound (581 mg), m.p. 122°-124°, [α]D +37.2°.

1. temperaturerefluxed for 5 hr
2. customthe layers separated
3. extractionThe aqueous portion was extracted with additional benzene (50 ml)
4. washthe combined organic portions washed with water (2×50 ml)
5. customdried
6. customevaporated to a white foam (1.12 g)
7. customA portion of this material (1.00 g) was crystallised from ether-petroleum ether (b.p. 60°-80°)