C-13 NUCLEAR MAGNETIC-RESONANCE STUDIES OF C27 STEROL PRECURSORS OF CHOLESTEROL

The natural-abundance 13C nuclear magnetic resonance spectra of a number of C27 sterols at 25.2 MHz have been studied. Peak assignments for individual carbons of 5α-cholest-8-en-3β-ol, 5α-cholest-8(14)-en-3β-ol, 5α-cholest-7-en-3β-ol, cholest-4-en-3β-ol, 5α-cholesta-8, 14-dien-3β-ol, and 5α-cholesta-7, 14-dien-3β-ol have been made and were based upon single-frequency off-resonance decoupled spectra, considerations of the results of lanthanide-induced shift experiments, the use of empirical rules for chemical shifts, comparisons with the spectra of structurally related compounds, and, in one case, the use of a selectively deuterated analogue. The diagnostic use of 3J13 c-1H long-range coupling to distinguish the angular quaternary carbons (C-10 and C-13) of sterols has also been explored. © 1979, American Chemical Society. All rights reserved.