ISOMERIZATION OF THIOAMIDOMETHYLPYRIDINE YLIDES AND ISOQUINOLINE YLIDES UNDER ELECTRON-IMPACT

The electron impact and collision-induced dissociation spectra of 2-(2 -carbethoxy-1-imino-1-methylthio)-ethylene isoquinoline ylide(1), 2-(2 -cyano-1-phenylamino-1-methylthio)-ethylene pyridine ylide (2), 2-(2-c arboethoxy-1-amino-1-thio)-ethylene pyridine ylide (3), 2-(2-carboetho xy-1-amino-1-thio)-ethylene isoquinoline ylide (4) and 2-(1-N-phenylam ide-1-cyano)-ethylene pyridine ylide (5) were studied, The molecular i ons of compounds 1-4 were shown to undergo cyclization to the correspo nding heterocyclic compounds, analogous to the reaction of compound 1 in solution, Proposed fragmentation schemes are presented based on tan dem mass spectrometry and high resolution mass spectrometry data.