Electron ionization-induced fragmentation of N-alkyl- o-nitroanilines: observation of new types of ortho-effects

Danikiewicz, Witold

doi:10.1255/ejms.206

Cited by 12 publications

(5 citation statements)

References 12 publications

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“…In MS 3 , the odd-electron ion F363 + O is further fragmented by OH • loss (m/z 362.078, C 20 H 13 FN 3 OS + ), suggesting N-oxidation. [22,23] This is consistent with the comparably high RRT. [18] The strong preference for the CH 3 • loss over OH • loss from the N-oxide suggests that the OH • loss is significantly easier from the oddelectron ion than from the even-electron ion.…”

Section: Structure Elucidation Of Sb203580 Conversion Productssupporting

confidence: 86%

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Tandem mass spectrometry study of p38α kinase inhibitors and related substances

et al. 2013

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The p38 mitogen-activated protein kinase α (p38α) is an important drug target widely investigated for therapy of chronic inflammatory diseases. Its inhibitors are rather lipophilic and as such not very favourable lead compounds in drug discovery. Therefore, we explored various approaches to access new chemical space, create diversity, and generate lead libraries with improved solubility and reduced lipophilicity, based on known p38α inhibitors, e.g., BIRB796 and TAK-715. Compound modification strategies include incubation with human liver microsomes and bacterial cytochrome P450 mutants from Bacillus megaterium and treatment by electrochemical oxidation, H2O2, and intense light irradiation. The MS/MS fragmentation pathways of p38α inhibitors and their conversion products have been studied in an ion-trap-time-of-flight MS(n) instrument. Interpretation of accurate mass MS(n) data for four sets of related compounds revealed unexpected and peculiar fragmentation pathways that are discussed in detail. Emphasis is put on the usefulness of HRMS(n)-based structure elucidation in a screening setting and on peculiarities of the fragmentation with regard to the analytes and the MS instrument. In one example, an intramolecular rearrangement reaction accompanied by the loss of a bulky group is observed. For BIRB796, the double-charge precursor ion is used in MS(2), providing a wider range of fragment ions in our instrument. For TAK-715, a number of related compounds could be produced in a large-scale incubation with a Bacillus megaterium mutant, thus enabling comparison of the structure elucidation by (1)H NMR and MS(n). A surprisingly large number of homolytic cleavages are observed. Competition between two fragmentation pathways involving either the loss of CH3(•) or OH(•) radicals was observed for SB203580 and its conversion products.

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Section: Structure Elucidation Of Sb203580 Conversion Productssupporting

confidence: 86%

“…The major fragment ( F363 + O ) excludes both CH 3 ‐hydroxylation and S ‐oxidation. In MS 3 , the odd‐electron ion F363 + O is further fragmented by OH • loss ( m / z 362.078, C 20 H 13 FN 3 OS + ), suggesting N ‐oxidation . This is consistent with the comparably high RRT .…”

Section: Resultssupporting

confidence: 70%

Tandem mass spectrometry study of p38α kinase inhibitors and related substances

et al. 2013

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“…12 In N-alkyl-o-nitroanilines also the source of the hydrogen atom in the OH Á fragment can be either the a-carbon atom of the N-alkyl substituent or the nitrogen atom. 17 The 70 eV mass spectrum of the N-labelled derivative 9d 1 (Fig. 1(b)) indicates that deuterium elimination is slightly preferred (60%) in the hydroxyl radical loss.…”

Section: (Iii) Loss Of Oh ámentioning

confidence: 94%

Studies in organic mass spectrometry. Part 24† Electron ionization mass spectra of some aryl(2-nitrobenzo[b]thiophen-3-yl)amines

Avellone¹,

Ceraulo̊²,

Lamartina³

et al. 1999

Rapid Commun. Mass Spectrom.

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“…In Moreover, it indicates that the molecular ion of 4 has the structure of 4-(nitrobenzylamino)pent-3-en-2-one, analogous to that deduced for 5 and 6 ( Figure 1; tautomer a), because the loss of water was observed for molecular ions of compounds containing a single -NH-CH 2 -bond ortho to the nitro group. 31,32 The amino hydrogen was eliminated during the formation of the [157]…”

Section: Compoundmentioning

confidence: 99%

Investigation of 4-(Nitrophenylamino)Pent-3-En-2-Ones and 4-(Nitrobenzylamino)Pent-3-en-2-Ones by Electron Ionization Mass Spectrometry. Observation of Characteristic Ortho Effects

Frański

Gierczyk

Fiedorow

et al. 2003

Eur J Mass Spectrom (Chichester)

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The compounds 4-(phenylamino)pent-3-en-2-ones (1-3) and 4-(benzylamino)pent-3-en-2-ones (4-6) substituted with a nitro group on the aromatic ring were studied by electron ionisation mass spectrometry (EIMS). It was deduced that the compounds 1-3 are converted into the tautomeric 4-(arylimino)pentan-2-one during the EI process. Mass spectrometric decompositions of ortho-substituted derivatives (1 and 4) were found to be different from those observed for meta- and para-isomers. The fragmentation pathways are discussed on the basis of data from linked B/E and B(2)/E scans, mass-analysed ion kinetic energy (MIKE) spectra, accurate mass measurements and isotope labelling.

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Electron ionization-induced fragmentation of N-alkyl- o-nitroanilines: observation of new types of ortho-effects

Cited by 12 publications

References 12 publications

Tandem mass spectrometry study of p38α kinase inhibitors and related substances

Tandem mass spectrometry study of p38α kinase inhibitors and related substances

Studies in organic mass spectrometry. Part 24† Electron ionization mass spectra of some aryl(2-nitrobenzo[b]thiophen-3-yl)amines

Investigation of 4-(Nitrophenylamino)Pent-3-En-2-Ones and 4-(Nitrobenzylamino)Pent-3-en-2-Ones by Electron Ionization Mass Spectrometry. Observation of Characteristic Ortho Effects

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