| Abstract: | Evidence for an acetylenic rearrangement, involving the ring-closure of ions containing the N-propargylaniline substructure to the corresponding quinoline ions, has been obtained in a study of the electron-impact induced fragmentation of 1,4-dihydro-4-oxo-2-phenyl-1-propargylquinazoline (I) and 1,2,3,4-tetrahydro-2-oxo-3-phenyl-1-propargylquinazoline (II). The N-propargylaniline moiety is formed from compounds I and II through the RDA process. N-Methyl-N-propargylaniline (III), which was examined as a model compound, was also found to undergo this rearrangement but N-methyl-N-propargyl-2,6-xylidine (IV), on the other hand, exhibits a quite different fragmentation pattern due to its blocking methyl groups, which prevent the rearrangement. Exact mass measurement and specific deuterium labelling were used to establish the fragmentation routes. |
