反应详情

温度

-10 °C

i)—A solution of (20S)-3-oxopregn-4-ene-20-carboxaldehyde (125 g) in dry ethanol (1250 ml) was cooled to −10° C., whereupon a solution of sodium borohydride (4.4 g) in dry ethanol (80 ml) was added in 30 min. After stirring the mixture for 2 h at −10° C., the reaction was quenched by adding a 50% aqueous solution of acetic acid. The reaction mixture was concentrated under reduced pressure to 25% of its original volume and then poured into ice-water (5 l). The resulting suspension was stirred overnight and filtered. The residue was washed with water and dried to give (20S)-21-hydroxy-20-methylpregn-4-en-3-one (124 g) which was used in the following step without further purification.

1. additionwas added in 30 min
2. customthe reaction was quenched
3. additionby adding a 50% aqueous solution of acetic acid
4. concentrationThe reaction mixture was concentrated under reduced pressure to 25% of its original volume
5. additionpoured into ice-water (5 l)
6. stirringThe resulting suspension was stirred overnight
7. filtrationfiltered
8. washThe residue was washed with water
9. customdried