Application of the Atoms in Molecules Theory and Computational Chemistry in Mass Spectrometry Analysis of 1,4-Naphthoquinone Derivatives

Vessecchi, Ricardo; Lopes, José N. C.; Lopes, Norberto P.; Galembeck, Sérgio E.

doi:10.1021/jp203912d

Cited by 19 publications

(39 citation statements)

References 48 publications

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“…Proton affinity (PA) and gas‐phase basicity (GB) were calculated for all the compounds by computing the enthalpies and Gibbs energies of protonation . For the fragmentation mechanisms, the relative Gibbs energies at 298 K for each reaction step were computed by using the model described above or previously described models …”

Section: Methodssupporting

confidence: 86%

“…Experimental parameters for the protonation of natural products are scarce in the literature . Computational chemistry is an alternative tool to describe the reactivity of molecules that bear nitrogen and oxygen atoms and to suggest the most important protonation sites . The combination of experimental and computational studies to investigate alkaloid reactions has led to promising results .…”

Section: Resultsmentioning

confidence: 99%

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Gas‐phase dissociation study of erythrinian alkaloids by electrospray ionization mass spectrometry and computational methods

et al. 2017

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Alkaloids from plants of the genus Erythrina display important biological activities, including anxiolytic action. Characterization of these alkaloids by mass spectrometry (MS) has contributed to the construction of a spectral library, has improved understanding of their structures and has supported the proposal of fragmentation mechanisms in light of density functional calculations. In this study, we have used low-resolution and high-resolution MS analyses to investigate the fragmentation patterns of erythrinian alkaloids; we have employed the B3LYP/6-31+G(d,p) model to obtain their reactive sites. To suggest the fragmentation mechanism of these alkaloids, we have studied their protonation sites by density functional calculation, and we have obtained their molecular electrostatic potential map and their gas-phase basicity values. These analyses have indicated the most basic sites on the basis of the proton affinities of the nitrogen and oxygen atoms. The protonated molecules were generated by two major fragmentations, namely, neutral loss of CH OH followed by elimination of H O. High-resolution analysis confirmed elimination of NH by comparison with the losses of H and •CH . NH was eliminated from compounds that did not bear a substituent on ring C. The benzylic carbocation initiated the dissociation mechanism, and the first reaction involved charge transfer from a lone pair of electrons in the oxygen atoms. The second reaction consisted of ring contraction with loss of a CO molecule. The presence of hydroxy and epoxy groups could change the intensity or the occurrence of the fragmentation pathways. Given that erythrinian alkaloids are applied in therapeutics and are promising leads for the development of new drugs, the present results could aid identification of several analogues of these alkaloids in biological samples and advance pharmacokinetic studies of new plant derivatives based on MS and MS/MS analyses. Copyright © 2017 John Wiley & Sons, Ltd.

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Section: Methodssupporting

confidence: 86%

Section: Resultsmentioning

confidence: 99%

Gas‐phase dissociation study of erythrinian alkaloids by electrospray ionization mass spectrometry and computational methods

et al. 2017

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“…Electrospray ionization mass spectrometry (ESI‐MS) is an important tool for the analysis of synthetic, semi‐synthetic, and natural products . MS/MS studies with an ESI source have been conducted for characterization and structural elucidation, because the fragmentation pathways can furnish valuable information about the reactivity of new compounds, and the established mechanisms can aid the elucidation of other classes of compounds . In this context, computational quantum chemistry has been successfully employed in mass spectrometry fragmentation analysis …”

mentioning

confidence: 99%

Gas‐phase reactivity of protonated 2‐oxazoline derivatives: mass spectrometry and computational studies

Vessecchi

Tomaz

Santos

et al. 2012

Rapid Comm Mass Spectrometry

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“…In this work, we have used a combination of multiple‐stage mass spectrometry (MS n ) and computational quantum chemistry calculations to elucidate the gas‐phase fragmentation pathways of protonated cocaine …”

Section: Introductionmentioning

confidence: 99%

Gas‐phase fragmentation reactions of protonated cocaine: New details to an old story

Dias

Bento

Silva³

et al. 2018

J Mass Spectrom

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We have used a combination of multiple stage mass spectrometry (MSn) experiments, hydrogen/deuterium exchange experiments, and thermochemical data estimated by computational chemistry calculations at the B3LYP/6‐31+G(d,p) level of theory to revisit the gas‐phase fragmentation of protonated cocaine. The lone pair of nitrogen participates in major fragmentation routes of protonated cocaine, to generate cyclic iminium ions. The structure of product ion m/z 182, which has been previously proposed in the literature, was shown to be unstable; therefore, we have decided to revisit it. Here, we propose another ion structures for the product ion m/z 182 that is supported by thermochemical data. Compared with the formation of other product ions, the formation of the most intense product ions in the collision‐induced dissociation spectrum of protonated cocaine (m/z 182 and m/z 82) is the most energetically favorable. We propose the structure and formation of m/z 122 and m/z 91 for the first time. We suggest that m/z 91 originates from m/z 122 instead of m/z 119, as fully supported by MSn experiments. The results of this study could help to study and quantify cocaine metabolites.

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Application of the Atoms in Molecules Theory and Computational Chemistry in Mass Spectrometry Analysis of 1,4-Naphthoquinone Derivatives

Cited by 19 publications

References 48 publications

Gas‐phase dissociation study of erythrinian alkaloids by electrospray ionization mass spectrometry and computational methods

Gas‐phase dissociation study of erythrinian alkaloids by electrospray ionization mass spectrometry and computational methods

Gas‐phase reactivity of protonated 2‐oxazoline derivatives: mass spectrometry and computational studies

Gas‐phase fragmentation reactions of protonated cocaine: New details to an old story

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