Abstract
When epitestosterone (17α-hydroxyandrost-4-en-3-one) (I) was heated with formic acid, 17-methyl-18-norandrosta-4, 13 (17)-dien-3-one (III) and 17-methyl-18-norandrosta-4, 13 (14)-dien-3-one (IV) were formed, besides the 17α-formate of I. Kagi-Miescher reaction of I, III, and IV gave almost identical absorption spectra (Fig. 3). The olefinic products, III and IV, were, contrary to the original substrate (I), so sensitive that the bathochromic absorption was noticeable already at the first stage of this reaction without any heating. Although any increase in intensity was never observed on boiling in this case, a remarkable hyperchromic change at the wave-length (580 nm) of the maximum absorption was noticed at the second stage of the reaction, in which bromine molecules are the regular additive. It seems in the Kagi-Miescher chromogenic reaction that the possible intermediates, III and IV, including their protonated carbonium ions are oxidized mainly by bromine molecule to produce the characteristic chromophore in an acid medium.
