反应详情

3α-(Tetrahydropyran-2ξ- yloxy)-5α-pregnane-11,20-dione (0.9 g) in boiling diethyl carbonate (12 ml) under nitrogen was treated with 1 drop of ethanol and then sodium hydroxide (0.17 g). The mixture was refluxed for 20 minutes, then cooled and the excess sodium hydride was destroyed with ethanol. The reaction mixture was partitioned between water and ether. The organic layer was washed with water, dried (MgSO4) and evaporated. The residue (1.0 g) was purified by preparative t.l.c. to give the ester (0.59 g) This ester in ethanol (5 ml) was treated with 2N hydrochloric acid (0.5 ml) and after ca 6 hours the reaction mixture was partitioned between water and ether. The organic layer was washed with water, dried (MgS04) and evaporated. The residue (0.6 g) was subjected to preparative t.l.c. (ethyl acetate/petrol 1:2). The more polar fraction (0.29 g) gave after crystallisation from ispropyl ether the title compound (0.08 g), m.p. 120-121°, [α]D + 120.5°, λmax. 249 nm. (ε 4,250).

1. temperatureThe mixture was refluxed for 20 minutes
2. temperaturecooled
3. customthe excess sodium hydride was destroyed with ethanol
4. customThe reaction mixture was partitioned between water and ether
5. washThe organic layer was washed with water
6. dry with materialdried (MgSO4)
7. customevaporated
8. customThe residue (1.0 g) was purified by preparative t.l.c