2-および3-オキソステロイドの酸素酸化反応(第2報) : 3-オキソステロイド類の塩基性溶液中における酸素酸化反応

抄録

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, Δ^{7 (8)}, or Δ^{9 (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, Δ^{9 (11)}-11-methyl, Δ^{6 (7)}, Δ^{11 (12)}, Δ^{11 (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.