Mass spectrometry and theoretical calculations about the loss of Methyl radical from methoxilated coumarins

E.BORKOWSKI; F,CECATTI; F.SUVIRE; D.RUIZ; C.ARDANAZ; G.ROMANELLI; ENRIZ R D

JOURNAL OF MOLECULAR STRUCTURE

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2015 vol. 1093 p. 49 - 58

0022-2860

In this study we have performed CID mass spectrometry measurements and theoreticalcalculations in a selected series of coumarins. Our theoretical and experimental resultsindicate that there is room for reasonable doubts about the fragmentation way previouslyproposed by Shapiro and Djerassi (1965). A complementary explanation about thefragmentation way of the methyl loss from methoxy coumarins has been reported in thiswork. Our results demonstrated that different theoretical models are very useful to explainthe fragmentation occurred in MS, supporting the usual rules of fragmentation. Althoughthe QTAIM analysis gives a good correlation in order to explain the formation of p-quinoidresonance forms; however, the best correlation has been obtained using the NBOapproximation as well as from the Wiberg indexes.