It is shown that the ozonolysis of Δ9(11)-12-keto steroids with a trans fusion of rings A and B proceeds in better yields than the corresponding opening of ring C in the sterically more hindered A/B-cis series. The syntheses of 23ξ-bromo-3β-hydroxy-9-oxo-9,12-seco-25-iso-5α,22β-spirostan-12-oic acid and some of its derivatives as well as of 3β,20α-dihydroxy-9-oxo-9,12-seco-12-pregnanoic acid and some
结果表明,在空间位阻更大的 A/B-顺式系列中,Δ9(11)-12-
酮类固醇的
臭氧分解与环 A 和 B 的融合相比,环 C 的相应开口以更好的产率进行。23ξ-bromo-3β-hydroxy-9-oxo-9,12-seco-25-iso-5α,22β-spirostan-12-oic酸及其部分衍
生物以及3β,20α-dihydroxy-的合成9-oxo-9,12-seco-12-pregnanoic acid 及其一些酯衍
生物已被报道。结果表明,在
四氢呋喃中用
氢化铝锂还原 12,20-二酮主要产生 12β,20α-二羟基衍
生物,与 12α-乙酰氧基-20-酮的还原形成对比,后者主要提供 20β -
酒精。