反应详情

A solution of 2β-ethoxy-3α-hydroxy-5α-androstane-11,17-dione (8 g) in chloroform (80 ml) containing ethylene glycol (13 ml), ethyl orthoformate (8.3 ml) and p-toluene sulphonic acid (160 mg) was kept at room temperature overnight. The reaction mixture was washed with sodium bicarbonate solution and water, dried (Na2SO4) and evaporated in vacuo. Purification of the residual froth (8.6 g) by preparative thin layer chromatography over silica (acetone-petroleum ether 3:7) and crystallization from ethyl acetate-petroleum ether afforded the title compound m.p. 142°-145°, [α]D +18.2°.

1. washThe reaction mixture was washed with sodium bicarbonate solution and water
2. dry with materialdried (Na2SO4)
3. customevaporated in vacuo
4. customPurification of the residual froth (8.6 g) by preparative thin layer chromatography
5. customover silica (acetone-petroleum ether 3:7) and crystallization from ethyl acetate-petroleum ether