Mass spectral studies on steroidal compounds—I: Steroidal 6-one ethylene acetals

The mass spectra of several steroidal 6-one ethylene acetals have been examined. The spectra of I and II are conspicuous by an intense [M — 55] peak. This differentiates them from other acetals reported in the present study. The acetals III, IV, V, VI, VII and VIII show the expected behaviour related to the acetal IX. The fragmentation pathways suggested are supported by accurate mass measurement of the salient fragment ions and in some cases also by appropriate metastable peaks.