Nuclear Magnetic Resonance Spectroscopy. Carbon-13 Spectra of Steroids

Abstract

The natural abundance ^(13)C resonance spectra of a variety of sterols and steroidal hormones have been determined at 15.1 MHz. The chemical shifts of the carbons in these substances were found to span on the order of 200 ppm and for most steroids with the aid of complete proton decoupling it was possible to resolve all of the carbon resonances one from the other. It has also been possible by using specific single-frequency and off-resonance proton decoupling, hydroxyl acetylation effects on chemical shifts, deuteration, and substituent influences in analogous compounds to make self-consistent and unambiguous assignments of nearly all of the resonances encountered. The carbon resonances are in general far more informative than proton resonances for structural analysis of steroids.