Nuclear magnetic resonance and infrared spectra of Δ24- and C-24 saturated steroids

Abstract

The infrared (IR) and nuclear magnetic resonance (NMR) spectra of eight Δ24-steroids and nine C-24 saturated steroids were examined. NMR spectra allow unambiguous assignment of the biologically important Δ24-bond; introduction of a Δ24-bond causes the appearance of peaks at ∂ 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 6 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 Δ24-bond and a marked decrease in intensity of a band at 1365 cm-l. NMR and IR spectra also allow an inference about the presence and location of nuclear double bonds in Ring B of cholesterol precursors.

Keywords

• sterols
• steroids
• cholesterol
• biosynthesis
• infrared
• nuclear magnetic resonance