Mass Spectrometry of Bis-quinolizidine Alkaloids: Unexpected Dimerization in Electron Ionization Mass Spectrometry

Abstract

The electron-ionization mass spectra of dimers of bis-quinolizidine alkaloids: α-isosparteine, 2-methylsparteine, 17-hydroxylupanine, lupanine N-oxide and 2,17-dimethylsparteine are discussed and general fragmentation routes of their molecular cations are proposed. Dimers structures are also studied using PM5 methods. The recognition of the fragmentation pathways and relative abundances of the ions obtained will provide important information, useful for the identification of similar dimeric compounds.