Hydroxy-steroids. Part IX. The nuclear magnetic resonances of angular methyl groups in steroid ketones

Abstract

The signals of the angular methyl groups in twenty-four mono-, di-, and tri-oxo-steroids, free from other substituents, have been examined in carbon tetrachloride, deuteriochloroform, benzene, and pyridine. Benzene induces the largest shifts, and the Δ₁³ values (τC₆H₆-τCCl₄) of the methyl groups vary characteristically with the position of the ketonic groups. With 6-ketones the Δ₁³ value appears to be greater for the C-18 than for the C-19 protons; unexpectedly, the shifts are almost equal in 5α- and 5β-6-ketones.

The methyl resonances of deuteriochloroform solutions of di- and tri-oxo-5α-androstanes show remarkably good agreement with the figures predicted from Zürcher's survey, and the observed Δ₁³ values are close to those calculated from the shifts of the corresponding monoketones.