17,21-Dihydroxy-5β-pregn-2-ene-1,11,20-trione, a new analogue of cortisone. Methods for distinguishing between Δ2-1-oxo- and Δ1-3-oxo-steroids

Abstract

17,21-Dihydroxy-5β-pregn-2-ene-1,11,20-trione (9), a new analogue of cortisone, has been prepared from 1β,3α,17,20β,21-pentahydroxy-5β-pregnan-11-one, and compared with known analogues, namely ‘isocortisone’(11) and ‘Δ¹-allocortisone’(2). The chief characteristic of the new analogue is its instability, which is attributed to interaction between the C-1 and C-11 carbonyl groups with resulting conformational distortion.

A study has been made of the u.v. and i.r. absorption and rotational characteristics of eleven matched pairs of Δ²-1-oxo-Δ¹-oxo-steroids in order to better characterise and differentiate them. Significant and consistent differences were noted in their extinction coefficients, in the CC stretching bands of their i.r. spectra, and in their M_D values. Examples of C-1 carbonyl : C-10 methyl and C-1 carbonyl : C-11 carbonyl group interactions, derived from M_D considerations, also were encountered.