反应详情

Ethanol (20 ml) was added to (20S)-7α-hydroxy-pregn-4-en-3-one-20-carbaldehyde (2.00 g, 5.81 mmol) obtained in the same manner as in Example 1 and the mixture was ice-cooled with stirring. Sodium borohydride (0.11 g, 2.91 mmol) was added to the obtained solution and the mixture was stirred under ice-cooling for 1 hr. 3% Hydrochloric acid was added to the obtained reaction mixture for neutralization, and ethanol was evaporated under reduced pressure. Ethyl acetate (100 ml) and water (20 ml) were added to wash the residue, and the aqueous layer was separated. The organic layer was dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure to give (20S)-7α,21-dihydroxy-20-methyl-pregn-4-en-3-one (1.77 g, yield 88%) having the following property.

1. customobtained in the same manner as in Example 1
2. temperaturecooled
3. stirringthe mixture was stirred under ice-
4. temperaturecooling for 1 hr
5. customwas evaporated under reduced pressure
6. additionEthyl acetate (100 ml) and water (20 ml) were added
7. washto wash the residue
8. customthe aqueous layer was separated
9. dry with materialThe organic layer was dried over anhydrous sodium sulfate
10. filtrationfiltered
11. concentrationconcentrated under reduced pressure