MASS SPECTROMETRY IN STRUCTURAL AND STEREOCHEMICAL PROBLEMS .146. MASS SPECTROMETRIC FRAGMENTATIONS TYPICAL OF STEROLS WITH UNSATURATED SIDE CHAINS

The characteristic mass spectral features associated with the usual saturated side chain of sterols are drastically altered when double bonds are introduced into the side chain. One of the most diagnostic and mechanistically intriguing fragmentations of such unsaturated sterols involves the loss of the entire C-17 substituent together with the rearrangement of two hydrogen atoms. Attention is drawn to the utility of such mass spectral decompositions in structure elucidation of unknown sterols and the nature of the fragmentation processes has been clarified through the use of deuterium-labeled steroids. In that connection several syntheses of Δ22- and Δ24-steroidal olefins were developed. © 1968, American Chemical Society. All rights reserved.