反应详情

2α,3α-Epoxy-5α-pregnane-11,20-dione (2 g), dry ether (50 ml) and 2-cyanoethanol (10 ml.) were sirred at room temperature until the solid had dissolved. Boron trifluoride diethyl etherate (10 drops) was added. After 2 hours at room temperature a further quantity of etherate (10 drops) was added. After 1 hour further etherate (10 drops) was added and after a further hour, the mixture was neutralised with saturated sodium bicarbonate solution, ethyl acetate (50 ml.) added and the organic layer washed with water (3 × 200 ml.). The washed solution was dried over anhydrous sodium sulphate and evaporated to a white foam which was purified by preparative T.L.C. using ethyl acetate. The main band (Rf 0.4) gave the title compound (740 mg;) m.p. 194°-196°C. [α]D + 85° .

1. customwere sirred at room temperature until the solid
2. dissolutionhad dissolved
3. additionAfter 2 hours at room temperature a further quantity of etherate (10 drops) was added
4. additionAfter 1 hour further etherate (10 drops) was added and after a further hour
5. additionadded
6. washthe organic layer washed with water (3 × 200 ml.)
7. dry with materialThe washed solution was dried over anhydrous sodium sulphate
8. customevaporated to a white foam which
9. customwas purified by preparative T.L.C