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Spectroscopy
Volume 15 (2001), Issue 1, Pages 19-25
http://dx.doi.org/10.1155/2001/957870

Fragmentation studies of tetrahydropyridocarbazole derivatives by EI, ESI-MS/MS and FAB

Gilberto A. Romeiro,1 Vitor F. Ferreira,1 Marília dos S. Costa,1 Alexandre M. Joaquim,1 José Walkimarde M. Carneiro,1 and Bernd Kammerer2

1Instituto de Química - GQO/GQI/CEG, Universidade Federal Fluminense, Campus do Valonguinho S/N, Niteröi, CEP 24210-150, RJ, Brazil
2Institut für Organische Chemie, Universität Tübingen, Auf der Morgenstelle 18, D-72076 Tübingen, Germany

Copyright © 2001 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Four tetrahydropyridocarbazole derivatives were analysed by different mass spectrometry techniques: electrospray ionization, fast atom bombardment and by low and high resolution 70 eV electron ionization. Retro Diels Alder is the main fragmentation pathway, whereas other pathways leading to [M—1]+, [M—CH3]+ and double charge ions also occur to considerable extents. Semi-empirical calculation provided some evidence on the nature of tropylium ions [M—1]+. Calculation of ΔHf0 indicated that [M+—1] could be formed preferentially when a hydrogen atom is lost from the methyl substituent of the homoaromatic ring.