Mass-spectrometric Determination of the Configuration of Steroid Alcohols

A large number of epimeric secondary alcohols of the 3-, 11-, 12-, 14-, 15-, 16-, 17-, 20-, and 24-hydroxy-steroid series, derivatives of androstane, pregnane, or cholestane, and also tertiary alcohols of the oestrane series which are epimeric at C(17) show that, in all cases in which the hydroxyl is situated in a conformationally sufficiently rigid part of the steroid skeleton, mass spectrometry can be used to establish the configuration of the steroid alcohols. The main conclusions can be drawn on the basis that, in most cases of electron impact an axial hydroxyl is split off more readily than is an equatorial hydroxyl, as a consequence of the possibility of a mechanism of 1,3- or 1,4-cis-diaxial elimination of the elements of water. A list of 31 references is included.