Effects of Stereoisomerisms on the Electron Ionization Mass Spectra and the IKE Spectra of Cinchona Alkaloids

Abstract

The mass spectra of two sets of stereoisomers possessing a quinuclidine base skeleton (quinine, quinidine, cinchonine and cinchonidine) were compared. All of the epimers have characteristically different electron ionization spectra. Similar differences were also found in the ion kinetic energy spectra. The main effects of stereoisomers on the abundance ratio clearly indicated the occurrence of some highly stereospecific or stereoselective decomposition processes. Conclusion concerning the mechanisms of these reactions, based on the normal and metastable ion spectra for the epimers, was also drawn.