1976 年 96 巻 7 号 p. 863-879
In the oxidation reactions of 3-oxo-steroids with oxygen in a basic solution, the effect of various substituents in B and C rings was examined by product analyses and by ESR measurements. 3-Oxo-5α-steroids themselves produced only 2, 3-diketones although Δ3-semidiones were observed along with Δ2-semidiones in the ESR spectra. Introduction of 11-oxo, 11-methylene, 11β-methyl, Δ7 (8), or Δ9 (11) group into 3-oxo-5α-steroids gave 3, 4-diketones together with 2, 3-diketones, but the substituent effect of 11α-hydroxyl 11α-methyl-11β-hydroxyl, Δ9 (11)-11-methyl, Δ6 (7), Δ11 (12), Δ11 (12)-12-methyl, or 12-meth-ylene group was not observed significantly. 25D.5β-Spirostan-3-one (XLVIII) afforded only the 3, 4-diketone and no substituent effect was observed by introducing an oxo group into the C-11 position of (XLVIII). In the ESR measurements the concentrations of Δ2-semidiones and Δ3-semidiones changed with time and the ratios of the maximum concentration corresponded to the product ratios. The long range effect of these substituents can be interpreted in terms of"conformational transmission"based on the direction of enolation in the A rings.