Mass spectral studies on steroidal compounds—II: 7a-aza compounds in the cholestane series (ring Bε-lactams)

The mass spectra of four structurally related 7a-aza compounds in the cholestane series have been examined. These spectra are conspicuous by the presence of a fragment ion peak at m/e 222 (C₁₅H₂₈N). which can be of diagnostic value in characterisation of such ε-lactams. The fragmentation pathways are supported by accurate mass measurement of the salient fragment ions and in some cases by appropriate metastable peaks.