反应详情

A 3-L three-necked flask equipped with a mechanical stirrer, addition funnel, and Ar-inlet tube was charged with 60.1 g (199 mmol) of (1α,3β)-1,3-dihydroxyandrosta-5,7-dien-17-one, 40.7 g (598 mmol) of imidazole, and 400 mL of dichloromethane. After cooling with an ice-water bath for 5 min., 50.7 mL (257 mmol) of thexyldimethylsilyl chloride was added over 12 min. The cold bath was removed, and the mixture was stirred at room temperature for 5 hr. After cooling again with an ice-water bath. 36.8 mL (219 mmol) of triethylsilyl chloride was added over 10 min. After stirring at room temperature overnight, 220 mL of hexane was added. After 15 min, the precipitate was removed by filtration and washed with 2×120 mL of hexane. The combined filtrate and washes were concentrated, and the residual hexane was removed by co-evaporation with 120 mL of methanol, and the suspension was stirred for 2 hr in order to obtain a powdery material. After the suspension was stored in a refrigerator overnight, the precipitate was filtered and washed with 2×160 mL of 95% methanol. Drying under high vacuum afforded 96.8 g of (1α,3β)-3-[[dimethyl(1,1,2-trimethylpropyl)silyl]oxy]-1-[(triethylsilyl)oxy]androsta-5,7-dien-17-one as a beige solid.

1. customA 3-L three-necked flask equipped with a mechanical stirrer, addition funnel
2. temperatureAfter cooling with an ice-water bath for 5 min.
3. customThe cold bath was removed
4. temperatureAfter cooling again with an ice-water bath
5. stirringAfter stirring at room temperature overnight
6. waitAfter 15 min
7. customthe precipitate was removed by filtration
8. washwashed with 2×120 mL of hexane
9. concentrationThe combined filtrate and washes were concentrated
10. customthe residual hexane was removed by co-evaporation with 120 mL of methanol
11. stirringthe suspension was stirred for 2 hr in order
12. customto obtain a powdery material
13. customwas stored in a refrigerator overnight
14. filtrationthe precipitate was filtered
15. washwashed with 2×160 mL of 95% methanol
16. customDrying under high vacuum