Reacción #42651

Ecuación de reacción

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

Rendimiento 73.9%

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

Rendimiento 73.9%

Disolventes

tetrahydrofuran

THF

Condiciones de reacción

Tratamiento posterior

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

Procedimiento

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.

Fuente