反应详情

To a solution of 2 g p-toluene sulfonic acid in 100 ml isopropenylacetate was added 20 g of 9β,11β-epoxy-21-acetoxy-17-hydroxypregna-1,4-diene-3,20-dione and the mixture was kept at 80°-85° C. for 2.5 hr with exclusion of moisture. The resulting solution was cooled, neutralized with pyridine (3 ml) and evaporated under high vacuum to give crude 9β,11β-epoxy-3,17,21-triacetoxy-pregna-1,3,5-trien-20-one as a hard gum (25 g) which could not be induced to crystallize (λmax 301 nm ε=5400).

1. temperatureThe resulting solution was cooled
2. customevaporated under high vacuum