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Fragmentation of plumeran indole alkaloids from Aspidosperma spruceanum by electrospray ionization tandem mass spectrometry
Author(s) -
Aguiar Gabriela P.,
Wakabayashi Kamila A. L.,
Luz Guilherme F.,
Oliveira Vilma B.,
Mathias Leda,
Vieira Ivo J. C.,
BrazFilho Raimundo,
Crotti Antonio E. M.
Publication year - 2010
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.4389
Subject(s) - chemistry , tandem mass spectrometry , fragmentation (computing) , electrospray ionization , mass spectrometry , protonation , indole test , moiety , electron ionization , medicinal chemistry , stereochemistry , ion , organic chemistry , ionization , chromatography , computer science , operating system
The fragmentation of six plumeran indole alkaloids (PIAs) previously isolated from Aspidosperma spruceanum has been investigated by electrospray ionization tandem mass spectrometry (ESI‐MS/MS) in the positive ion mode. The fragmentation pathways have been established on the basis of MS/MS experiments using fragment ions generated in‐source and deuterium‐labeled alkaloids as precursor ions and on the basis of accurate mass measurements. Our results demonstrated that the fragmentation routes observed for the protonated PIAs are essentially derived from a pericyclic reaction and from the opening of rings D and E, followed by 1,4‐hydrogen rearrangements. Product ions resulting from radical eliminations were also observed, contrary to the ‘even‐electron rule’. Our data reveals that some product ions from protonated PIAs provide crucial information for the characterization of the acyl substituent at N‐1, the methoxyl and hydroxyl groups at the aromatic moiety, and give evidence of an ether bridge between C‐18 and C‐21. The data reported here were used for the dereplication of these compounds in a stem bark methanolic extract of Aspidosperma spruceanum . Copyright © 2010 John Wiley & Sons, Ltd.