Differentiation between 3,4-and 4,15-Epoxyeudesmanolides by Electrospray Ionization Tandem Mass Spectrometry

Autor(es)

Dias, Herbert Junior ; Stefani, Ricardo ; Tomaz, Jose Carlos ; Vessecchi, Ricardo ; Miller Crotti, Antonio Eduardo

• Tipo de documento: Artigo Científico
• Fonte: JOURNAL OF ANALYTICAL METHODS IN CHEMISTRY; v. 2017, p. 9-pg., 2017-01-01.

Resumo

We investigated the fragmentation of the eudesmanolide-type sesquiterpene lactones 1 alpha-(4-hydroxymethacryloyloxy)-3 alpha,4 alpha-epoxy-8 alpha-hydroxyeudesm-11(13)-6 alpha,12-olide (1) and 1 alpha-(2,3-epoxyangeloyloxy)-4 alpha,15-epoxy-8 alpha-hydroxyeudesm-11(13)-6 alpha,12-olide (2) by electrospray ionization tandem mass spectrometry (ESI-MS/MS). The elimination of the different ester substituent at C(1) directly from protonated 1 and 2 (A) led to the formation of two regioisomer product ions B (A - RCO2H). Further fragmentation of B resulted from consecutive eliminations of H2O and CO molecules. However, we identified four product ions that allowed for the differentiation between 3,4- and 4,15-epoxyeudesmanolides. The formation of these diagnostic ions was associated with the C(3)-O bond of compound 1, which propitiates the participation of the lone pair of the oxygen epoxide in the formation of B through a Grob-Wharton-type fragmentation, then resulting in an alternative fragmentation pathway. These data can be useful for the fast differentiation between epoxyeudesmanolide regioisomers directly from Dimerostemma extracts by liquid chromatographytandem mass spectrometry (LC-MS/MS), as an alternative to NMR, or even for quantitation studies of these compounds using multiple reaction monitoring (MRM) scan. (AU)

• Processo FAPESP: 13/20094-0 - Avaliação da atividade antiparasitária e inseticida de compostos benzofurânicos e estudo de suas reações de fragmentação em fase gasosa empregando espectrometria de massas sequencial
• Beneficiário: Antônio Eduardo Miller Crotti
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 14/23604-1 - Química computacional: uma ferramenta para estudos envolvendo espectrometria de massas, reatividade e mecanismos de reação/fragmentação de compostos orgânicos
• Beneficiário: Ricardo Vessecchi Lourenço
• Modalidade de apoio: Auxílio à Pesquisa - Regular