反应详情

To a mixture of 0.084 g (0.189 mmole) of 20-(5,5-dimethyl-1,3-dioxan-2-yl )-1α,260 ;6α,7α-diepoxypregn- 4-en-3β-ol, 0.5 ml (6.18 mmoles) of dry pyridine and 5 ml of methylene chloride was gradually added 0.1 ml (1.06 mmoles) of acetic anhydride dropwise at a temperature of 0° C. and the solution was stirred at room temperature for 8 hours. The reaction mixture thus obtained was diluted with methylene chloride and washed with saturated aqueous copper (II) sulfate solution. The aqueous layer (washings) was extracted with methylene chloride and the extract was combined with the organic layer. The resulting mixture was washed with water and aqueous sodium chloride solution in that order and dired over magnesium sulfate. The solvent was then distilled off under reduced pressure and the residue was purified by silica gel chromatography (eluent: ethyl acetate-hexane: 1:10, v/v) to recover 0.083 g of 20-(5,5-dimethyl-1,3-dioxan-2-yl)-1α,2α;6α,7α-diepoxypregn-4-en-3β -yl acetate (yield: 90%).

1. additionTo a mixture of 0.084 g (0.189 mmole) of 20-(5,5-dimethyl-1,3-dioxan-2-yl )-1α,260
2. customdropwise at a temperature of 0° C.
3. customThe reaction mixture thus obtained
4. washwashed with saturated aqueous copper (II) sulfate solution
5. extractionThe aqueous layer (washings) was extracted with methylene chloride
6. washThe resulting mixture was washed with water and aqueous sodium chloride solution in that order
7. distillationThe solvent was then distilled off under reduced pressure
8. customthe residue was purified by silica gel chromatography (eluent
9. customethyl acetate-hexane: 1:10, v/v) to recover 0.083 g of 20-(5,5-dimethyl-1,3-dioxan-2-yl)-1α,2α