Perchloric Acid → Acetoacetic Acid

Participants

Reaction Steps

(VI) or triamcinolone is reacted with an acetylalkanoic acid in a solution of dichloromethane in the presence of catalytic amount of perchloric acid to produce the corresponding 16α,17-carboxycyclic acetal pregnane derivatives, e.g., when triamcinolone and acetylacetic acid are used the product is (XVI) 9α-fluoro-11β,21-dihydroxy-3,20-dioxo-16α, 17-(methyl, carboxylicmethyl)methylenedioxy-1,4-pregnadiene; when triamcinolone and acetylbutyric acid are used the product is (XVII) 9α-fluoro-11β,21-dihydroxy-3,20-dioxo-16α,17-(methyl, carboxylic-n-propyl)methylenedioxy-1,4-pregnadiene; (XVII) is reacted with diazomethane to produce same (VIII);

Provenance & Evidence