AM1 and electron impact mass spectrometry study of the fragmentation of 4-acyl isochroman-1,3-diones

Abdoulaye, Djandé; Sessouma, Bintou; Kini, Félix B.; Kabore, L.; Karifa, Bayo; Guissou, Pierre I.; Saba, Adama

doi:10.4314/bcse.v26i2.15

Cited by 1 publication

(1 citation statement)

References 10 publications

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“…55,56 Proton migration has not only been observed for amides; dibenzyl ether, 57 the pharmaceutical compound maraviroc, 22 dialkylphosphoric acid esters 58 and thiourea/urea compounds 59 have all been reported to exhibit proton migration in their mass spectra. Crucially, it has been reported that fragmentation occurs at the atoms bearing the positive charge 60 and that this may involve migration of the proton to the 'dissociative site' 57 which triggers charged directed fragmentation. Therefore, it is proposed that it is proton migration to a dissociative site in dofetilide, O12 (cation A-6), which initiates the fragmentation to generate product ion m/z 255.…”

Section: Proton Migration/tunnellingmentioning

confidence: 99%

Understanding collision-induced dissociation of dofetilide: a case study in the application of density functional theory as an aid to mass spectral interpretation

Wright

Alex²,

Harvey³

et al. 2013

Analyst

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Fragmentation of molecules under collision-induced dissociation (CID) conditions is not well-understood. This may make interpretation of MSMS spectra difficult and limit the effectiveness of software tools intended to aid mass spectral interpretation. Density Functional Theory (DFT) has been successfully applied to explain the thermodynamics of fragmentation in the gas phase by the modelling the effect that protonation has on the bond lengths (and hence bond strengths). In this study, dofetilide and four methylated analogues were used to investigate further the potential for using DFT to understand and predict the CID fragmentation routes. The products ions present in the CID spectra of all five compounds were consistent with charge-directed fragmentation, with protonation adjacent to the cleavage site being required to initiate fragmentation. Protonation at the dissociative site may have occurred either directly or via proton migration. A correlation was observed between protonation-induced bond lengthening and the bonds which were observed to break in the CID spectra. This correlation was quantitative in that the bonds calculated to elongate to the greatest extent gave rise to the most abundant of the major product ions. Thus such quantum calculations may offer the potential for contributing to a predictive tool for aiding the accuracy and speed mass spectral interpretation by generating numerical data in the form of bond length increases to act as descriptors flagging potential bond cleavages.

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