Reacción #42652

Ecuación de reacción

t-butyl methyl ether hexane chloroform

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

ethyl isocyanate

→

title compound

Rendimiento 62.5%

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

Rendimiento 62.5%

Disolventes

toluene

Condiciones de reacción

Tratamiento posterior

1. 1
   Temperaturathe mixture was refluxed for 48 hours
2. 2
   Otroevaporated under vacuum
3. 3
   Otroto leave a slightly gummy solid

Procedimiento

To a mixture of (11β,16β)-9-fluoro-17-hydroxy-16-methyl-3,20-dioxo-11-[(trimethyl-silyl)oxy]-pregna-1,4-dien-21-yl acetate (3.11 g, 6.15 mmol) in 41 mL of toluene was added neat ethyl isocyanate (20.5 mL, 259 mmol) and the mixture was refluxed for 48 hours. The resulting solution was cooled to room temperature and evaporated under vacuum to leave a slightly gummy solid. Flash chromatography through a 1 kg column of silica gel eluting with t-butyl methyl ether/hexane/chloroform (1:1:1) gave 2.22 g of the title compound as a white solid.

Fuente