Opening of ring f in delta 22,23 solanidane - alkaloids (i) to give new androstane

摘要

Opening of ring F in delta-22,23 solanidane alkaloids (I) to give new androstane pyrrolidones (II) where X, Y represent " 0; = NOH; = NNR12; OR", OR"; H, OR"', H.; R' = H, alkyl or aryl; R" = alkyl or aryl; R"' = H, acyl or aliphatic, araliphatic or aromatic carboxylic acid. Also corresponding delta 4,5 compounds unless X, Y = H, OR"' or OR"', H. During work up e.g. with H2SO4, 3-acyloxy groups are hydrolysed. (I) is formed in situ from the corresponding delta 22, N immonium salt (contaminated with the delta 16, N isomer) which is the starting material obtained from natural products. Useful degradative step en route to pregnane derivatives.