Negative ion electrospray ionization mass spectrometry and computational studies on substituted 7-hydroxycoumarins.
Twenty-two substituted 7-hydroxycoumarins were studied by negative ion electrospray ionization collision- induced dissociation (CID) mass spectrometry. Fragmentation pathways were also investigated by computation method using the B3LYP density functional theory. In general, the most important fragmentations of the 7- hydroxycoumarin [M - H](-) ions were the elimination of CO(2) and CO which agreed with the calculated energies of the proposed fragmentation reactions. In most cases, methyl group elimination was also favorable. Methyl group elimination occurred in three different ways, the most interesting being hydrogen rearrangement from a neighboring alkyl group to a ring carbon, which led to a benzyl radical formation. In some cases, CH(2)CO elimination was observed as well. Isomeric compounds gave rise to different CID spectra.
Timonen
Juri
J
Department of Chemistry, University of Joensuu, PO Box 111, 80101 Joensuu, Finland.
Aulaskari
Paula
P
Hirva
Pipsa
P
Vaomoptalo
Pirjo
P
D003198:Computer Simulation; D007536:Isomerism; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods; D014468:Umbelliferones / Q000032:analysis*
D014468:Umbelliferones; C031477:7-hydroxycoumarin