反应详情

In 5 ml of pyridine was dissolved 400 mg of 20-(1,3-dioxolan-2-yl)pregn-6-ene-1α,3β,5α-triol. To this solution was added 0.11 ml of acetic anhydride at a temperature of -10°-0° C. and the mixture was stirred under ice-cooling for 2 hours. The reaction mixture thus obtained was poured in ice-water and stirred at room temperature for 30 minutes. This mixture was then extracted with ether and the extracts were pooled, washed successively with water, cold diluted hydrochloric acid, water, aqueous sodium hydrogen carbonate solution and aqueous sodium chloride solution and dried over magnesium sulfate, followed by concentration under reduced pressure. Finally the concentrate was purified by silica gel chromatography to give 420 mg of 20-(1,3-dioxolan-2-yl)-3β-acetoxypregn-6-ene-1α,5α-diol showing the following properties.

1. temperaturecooling for 2 hours
2. customThe reaction mixture thus obtained
3. stirringstirred at room temperature for 30 minutes
4. extractionThis mixture was then extracted with ether
5. washwashed successively with water, cold diluted hydrochloric acid, water, aqueous sodium hydrogen carbonate solution and aqueous sodium chloride solution
6. dry with materialdried over magnesium sulfate
7. concentrationfollowed by concentration under reduced pressure
8. customFinally the concentrate was purified by silica gel chromatography