反应详情

In 5 ml of acetone was dissolved 24.3 mg (0.05 mmole) of 20-(5,5-dimethyl-1,3-dioxan-2-yl)-1α,2α;6α,7α- diepoxypregn-4-en-3β-yl acetate, followed by addition of 2.5 mg (0.01 mmole) of pyridinium p-toluenesulfonate. The mixture was refluxed for 2 hours. The reaction mixture thus obtained was cooled to room temperature and the solvent was distilled off under reduced pressure. To the residue was added methylene chloride and the mixture was washed successively with saturated aqueous sodium hydrogen carbonate solution and saturated aqueous sodium chloride solution and dried 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=1:5, v/v) to recover 9.6 mg of 3β-acetoxy-1α,2α;6α,7α-diepoxypregn-4-ene-20-carbaldehyde (yield: 48%).

1. temperatureThe mixture was refluxed for 2 hours
2. customThe reaction mixture thus obtained
3. distillationthe solvent was distilled off under reduced pressure
4. additionTo the residue was added methylene chloride
5. washthe mixture was washed successively with saturated aqueous sodium hydrogen carbonate solution and saturated aqueous sodium chloride solution
6. dry with materialdried over magnesium sulfate
7. distillationThe solvent was then distilled off under reduced pressure
8. customthe residue was purified by silica gel chromatography (eluent
9. customethyl acetate-hexane=1:5, v/v) to recover 9.6 mg of 3β-acetoxy-1α,2α