反应详情

A solution of 14.0 g of 21-acetoxy-6α-chloro-11β-hydroxy-16α-methyl-1,4-pregnadiene-3,20-dione in 29 ml of collidine and 90 ml of DMF is combined with 11 ml of methanesulfonic acid chloride containing 3% sulfur dioxide and agitated at room temperature. After 15 minutes, 15 ml of water is added under ice cooling. The thus-obtained precipitate is filtered off, washed with water, and dried in the open air. The crude product is chromatographed on silica gel. With 33-61% ethyl acetate-hexane, 12.1 g of 21-acetoxy-6α-chloro-16α-methyl-1,4,9(11)-pregnatriene-3,20-dione is obtained. A sample, recrystallized from ethyl acetate-hexane, melts at 181° C. [α]D25 =+22° (chloroform).

1. filtrationThe thus-obtained precipitate is filtered off
2. washwashed with water
3. customdried in the open air
4. customThe crude product is chromatographed on silica gel