24,25-epoxysterols. Differentiation of 24R and 24S epimers by 13C nuclear magnetic resonance spectroscopy.

The 24R and 24S epimers of the acetates of 24,25-epoxycholesterol and 24,25-epoxylanosterol have been prepared and purified by preparative normal phase high performance liquid chromatography. Neither pair of epimers could be differentiated by 1H NMR. However, the 13C NMR spectra of the epimeric pairs were sufficiently different to permit samples of individual epimers to be assigned as 24R or 24S.