反应详情

2α,3α-Epoxy-5α-pregnane-11,20-dione (1 g.) was dissolved in 2-chloroethanol (50 ml.) and concentrated sulphuric acid (6 drops) added to the solution. The mixture was stirred at room temperature for 1 hour, neutralised with sodium bicarbonate solution and poured into water (500 ml.). The precipitate formed was extracted into ether (2 × 100 ml.) and the combined extracts washed with water (2 × 100 ml.). The organic layer was dried over anhydrous sodium sulphate and evaporated to a yellow oil (1.5 g.) which was purified by preparative tlc using ethyl acetatepetroleum ether, 1/1 run 3 times. The main band (RF ~0.2 - 0.3) gave the title compound (640 mg.) as an off-white foam identical with a previously prepared sample.

1. customThe precipitate formed
2. extractionwas extracted into ether (2 × 100 ml.)
3. washthe combined extracts washed with water (2 × 100 ml.)
4. dry with materialThe organic layer was dried over anhydrous sodium sulphate
5. customevaporated to a yellow oil (1.5 g.) which
6. customwas purified by preparative tlc