Реакция #42651

Уравнение реакции

acetic acid

(11β,16β)-9-fluoro-16-methyl-3,20-dioxo-11,17-bis[(trimethylsilyl)oxy]pregna-1,4-dien-21-yl acetate

tetra-n-butylammonium fluoride

→

title compound

Выход 73.9%

(11β,16β)-9-fluoro-17-hydroxy-16-methyl-3,20-dioxo-11-[(trimethylsilyl)oxy]-pregna-1,4-dien-21-yl acetate

Выход 73.9%

Растворители

tetrahydrofuran

THF

Условия реакции

Обработка

1. 1
   Другоеthe ice bath was removed
2. 2
   Температураto warm to room temperature
3. 3
   workup.STIRRINGstir for an additional 16 hours
4. 4
   ДругоеMost of the THF was removed by rotary evaporation in vacuo
5. 5
   Другоеthe residue was partitioned between ethyl acetate and water
6. 6
   ПромывкаThe organic layer was washed successively with water, sat. NH4Cl, water, sat. NaHCO3, water and brine
7. 7
   СушкаThe organic layer was dried over Na2SO4
8. 8
   Фильтрацияfiltered
9. 9
   Другоеevaporated under vacuum
10. 10
    Другоеto give an off-white solid
11. 11
    ДругоеPurification by flash chromatography through a 1.6 kg column of silica gel eluting with 4% MeOH in dichloromethane

Методика

A solution of (11β,16β)-9-fluoro-16-methyl-3,20-dioxo-11,17-bis[(trimethylsilyl)oxy]pregna-1,4-dien-21-yl acetate (26 g, ˜43 mmol) in 430 mL of tetrahydrofuran (THF) was cooled to 0° C. and neat acetic acid (4.95 mL, 86.5 mmol) was added followed by dropwise addition of a 1.0 M solution of tetra-n-butylammonium fluoride in THF (43.3 mL, 43.3 mmol). After stirring at 0° C. for 4 hours, the ice bath was removed and the reaction was allowed to warm to room temperature and stir for an additional 16 hours. Most of the THF was removed by rotary evaporation in vacuo and the residue was partitioned between ethyl acetate and water. The organic layer was washed successively with water, sat. NH4Cl, water, sat. NaHCO3, water and brine. The organic layer was dried over Na2SO4, filtered and evaporated under vacuum to give an off-white solid. Purification by flash chromatography through a 1.6 kg column of silica gel eluting with 4% MeOH in dichloromethane provided 16.1 g of the title compound as a white solid.

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