反应详情

Hydrocortisone or prednisolone with 20-hydroxy and 21-acetoxy groups are known, e.g., (I) (20R)-21-acetoxy-11β, 17,20-trihydroxy-3-oxo-1,4-pregnadiene; and (I) is reacted with an alkyl acetylalkanoate in the presence of perchloric acid to produce the corresponding 17,20-carboxycyclic acetal pregnane derivatives, e.g., when methyl acetylbutyrate is used the product is (II) (20R)-21-acetoxy-11β-hydroxy-3-oxo-17,20-(methyl,methoxycarbonyl-n-propyl)methylenedioxy-1,4-pregnadiene;