Reacción #981684

Ecuación de reacción

3β, 17β-di(trifluoroacetoxy)-5α-androstane

nitrobenzene

sodium trifluoroacetate

trifluoromethyl hypofluorite

→

3β,17β-di(trifluoroacetoxy)-9α-fluoro-5α-androstane

Rendimiento 39.4%

Disolventes

fluorotrichloromethane

Condiciones de reacción

Tratamiento posterior

1. 1
   OtroThereafter the solution was purged with nitrogen
2. 2
   Otrothe solvent was removed in vacuo
3. 3
   workup.DISSOLUTIONThe residue was dissolved in chloroform
4. 4
   Lavadothe resulting solution was washed with aqueous sodium bicarbonate and water
5. 5
   Otrowas then dried, whereafter the product
6. 6
   Otrowas chromatographed on silica gel (125 g)
7. 7
   LavadoElution with chloroform:hexane (3:7)
8. 8
   Otrogave unreacted
9. 9
   Lavadowhile subsequent elution with chloroform:hexane (7:13)

Procedimiento

A well-stirred solution of 3β, 17β-di(trifluoroacetoxy)-5α-androstane (2.5 g, 5.15 mmole, prepared by treatment of 5α-androstane-3β,17β-diol with trifluoroacetic anhydride in pyridine), nitrobenzene (800 mg, 6.5 mmole) and sodium trifluoroacetate (10 g, 73.5 mmole) in fluorotrichloromethane (45 ml) was treated with trifluoromethyl hypofluorite (8.5 mmole) at -20° for 2.5 hours, air being admitted to the reaction vessel during this time. Thereafter the solution was purged with nitrogen and the solvent was removed in vacuo. The residue was dissolved in chloroform and the resulting solution was washed with aqueous sodium bicarbonate and water and was then dried, whereafter the product was chromatographed on silica gel (125 g). Elution with chloroform:hexane (3:7) gave unreacted starting material (308 mg), while subsequent elution with chloroform:hexane (7:13) gave 3β,17β-di(trifluoroacetoxy)-9α-fluoro-5α-androstane (1.02 g), which crystallised from hexane as prisms (917 mg) m.p. 140°-142°; [α] D24 -22° (c 1.47, CHCl3). (Found C,55.10; H,5.78; F,26.35%;m/e 502. C33H29O4F7 requires C,54.97; H,5.82; F,26.47%; M+ 502).

Fuente