反应详情

iii)—A solution of (3β,20S)-3-[(1-ethoxyethyl)oxy]pregn-5-en-20-ol (compound 3a; 56.9 g) in a mixture of dry pyridine (144 ml) and acetic anhydride (72.4 ml) was stirred at room temperature for 18 h. Water (482 ml) was added and stirring was continued for another 1 h. The product was extracted into ethyl acetate; the combined organic phases were washed with a saturated aqueous solution of sodium hydrogen carbonate and with brine, dried over sodium sulfate, and concentrated under reduced pressure to give (3β,20S)-3-[(1-ethoxyethyl)oxy]pregn-5-en-20-ol acetate (compound 4a; 66.1 g) which was used in the following step without further purification.

1. stirringstirring
2. waitwas continued for another 1 h
3. extractionThe product was extracted into ethyl acetate
4. washthe combined organic phases were washed with a saturated aqueous solution of sodium hydrogen carbonate and with brine
5. dry with materialdried over sodium sulfate
6. concentrationconcentrated under reduced pressure