Reaktion #42653

Reaktionsgleichung

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

HCl

→

(11β,16β)-9-fluoro-11,21-dihydroxy-16-methyl-3,20-dioxopregna-1,4-dien-17-yl ethylcarbamate

Ausbeute 50.0%

Lösungsmittel

—

pre-mixed solution

methanol chloroform

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.WAITAfter 5 hours more
2. 2
   Sonstigethe solution was partitioned between ethyl acetate and water
3. 3
   WaschenThe organic phase was washed successively with sat. NaHCO3, water, and brine
4. 4
   TrocknenThe organic layer was dried over Na2SO4
5. 5
   Filtrationfiltered
6. 6
   Sonstigeevaporated in vacuo
7. 7
   Sonstigeto give a pale yellow oil
8. 8
   SonstigePurification by flash chromatography through a column of 500 g of silica gel
9. 9
   Wascheneluting with hexane/ethyl acetate/dichloromethane/methanol (3:3:3:1)

Vorschrift

Solid (11β,16β)-21-(acetyloxy)-9-fluoro-16-methyl-3,20-dioxo-11-[(trimethylsilyl)oxy]-pregna-1,4-dien-17-yl ethylcarbamate (2.22 g, 3.84 mmol) was dissolved in 128 mL of a pre-mixed solution of methanol/chloroform/6N HCl (10:2:1) and stirred at room temperature. After 16 hours, an additional 2 mL of 6N HCl was added. After 5 hours more, the solution was partitioned between ethyl acetate and water. The organic phase was washed successively with sat. NaHCO3, water, and brine. The organic layer was dried over Na2SO4, filtered and evaporated in vacuo to give a pale yellow oil. Purification by flash chromatography through a column of 500 g of silica gel, eluting with hexane/ethyl acetate/dichloromethane/methanol (3:3:3:1) yielded 0.890 g of (11β,16β)-9-fluoro-11,21-dihydroxy-16-methyl-3,20-dioxopregna-1,4-dien-17-yl ethylcarbamate as a white powder.

Quelle