Tsitsa P, Tsatsas G, Sandris C
Steroids. 1979 Jan;33(1):23-31. doi: 10.1016/s0039-128x(79)80003-3.
The geometry of the condensation products between ethyl cyanoacetate and 20-ketosteroids (5 alpha-pregnane-20-one, 3 beta-hydroxypregn-5-en-20-one and 3 beta-acetoxypregn-5-en-20-one) was established by NMR spectra. Reduction of these steroid C-20 alkylidene cyanoacetates was shown to afford one of the two possible 20-C epimers, which seen to correspond to the 20 beta-methyl configuration.
通过核磁共振光谱确定了氰基乙酸乙酯与20-酮甾体（5α-孕烷-20-酮、3β-羟基孕-5-烯-20-酮和3β-乙酰氧基孕-5-烯-20-酮）之间缩合产物的几何结构。结果表明，这些甾体C-20亚烷基氰基乙酸酯的还原反应生成了两种可能的20-C差向异构体中的一种，该异构体似乎对应于20β-甲基构型。
