Nuclear magnetic resonance and infrared spectra of delta-24- and C-24 saturated steroids.

The infrared (IR) and nuclear magnetic resonance (NMR) spectra of eight Delta(24)-steroids and nine C-24 saturated steroids were examined. NMR spectra allow unambiguous assignment of the biologically important Delta(24)-bond; introduction of a Delta(24)-bond causes the appearance of peaks at Delta 1.60 and 1.68 associated with the C-26, C-27 isopropylidene methyls, while C-24 saturated steroids of the cholestane series possess peaks at Delta 0.82 and 0.91 associated with the C-26, C-27 gem-dimethyls. IR spectra show a good correlation between the introduction of a Delta(24)-bond and a marked decrease in intensity of a band at 1365 cm(-1). NMR and IR spectra also allow an inference about the presence and location of nuclear double bonds in Ring B of cholesterol precursors.