When 16β-hydroxy-5α-androstan-17-one (2a) and its 16α-deuterio derivative (2a-16-d) were separately treated with H2SO4 or NaOH, compound 2a was rearranged to the 17β-hydroxy-16-oxo isomer (3a) with a marked kinetic deuterium isotope effect at the 16-position (kH/kD= 4.5 or 3.0). The product 3a obtained from compound 2a-16-d retained deuterium at C-17 to the extent of 16-65% while no significant loss of the isotope from the substrate was observed during the reaction. Isotope-labeling experiments showed that the intramolecular 1, 2-hydride shift is principally involved in the ketol rearrangement, and that the 16-oxo function of compound 3a enolizes preferentially toward the C-17 position rather than the C-15 position under the above conditions.
当16β-羟基-5α-
雄甾烷-17-酮(2a)及其16α-
氘代衍
生物(2a-16-d)分别用
硫酸或
氢氧化钠处理时,化合物2a重排为17β-羟基-16-氧代异构体(3a),并在16位显示出显著的动力学
氘同位素效应(kH/kD= 4.5或3.0)。从化合物2a-16-d获得的产物3a在C-17上保留了16-65%的
氘,而在反应过程中没有观察到来自底物的同位素显著损失。同位素标记实验表明,酮醇重排主要涉及分子内的1, 2-氢迁移,并且在上述条件下,化合物3a的16-氧代功能优先在C-17位而不是C-15位发生烯醇化。