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  • 1975-1979  (4)
  • 1
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 12 (1977), S. 706-709 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Competitive fragementations of doubly charged ions formed by charge stripping have been observed for some hydrocarbon ions. The reproducibility of the abundance ratios indicates that they may be used to characterize the structural identity or non-identity of non-decomposing monocharged positive ions.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 12 (1977), S. 209-212 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Some sidechain rearrangements of N-propylbromotrizoles are studied by mass analysed ion kinetic enery and collision induced dissociation techniques. Loss of an allyl radical is shown to produce a protonated bromotriazole ion by double hydrogen transfer to the heterocyclie ring. Ethylene elimination gives rise to isomers of the methyl bromotriazole molecular ions. Finally, it is shown that no ring expansion occurs in the production of the [M-C2H5]+ ions.
    Notes: Quelques réactions de réarrangement faisant intervenir la chaîne latérale de N-propylbromotriazoles sont étudiées par les techniques ‘MIKE’ et ‘CID.’ La perte d'un radical allyle produit une structure bromotriazole protontée par double transfert d'hydroghe vers le noyau hétérocyclique. L'élimination d'ithylbéne donne naissance à des structures isoméres des ions moléculaires des méthylbromotriazoles. Enfin, les résultats montrent qu'il n'y a pas de réaction d'extension cyclique au niveau des ions [M—C2H5]+ de ces composés.
    Additional Material: 7 Tab.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 12 (1977), S. 205-208 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: C-bromo-1,2,4-trizole is generated in three different tautomeric forms by ethylene elimination from the N-ethyl compounds and these toutomes are shown to retain their structure prior to further fragmentation. The analysis of mass analysed ion kinetic energy and collision incuded dissociation spectra confrrms that ethylene loss proceeds by a tw-step mechanism with a five- (or four-) centred hydrogen transfer. The results show also that the 3- and 5-bromotriazole structures only are responsible for the mass spectrum of the parent heterocycle. Similar data are dicussed for the loss of propene from N-propylbromotriazoles.
    Notes: Le C-bromotriazole est généré en ses trois formes tautoméres par élimination d'éthylène à partir de composes N-éthylés et ces ions tautomères conservent leur structure avant toute fragmentation ultérieure. L'analyse de spectres ‘MIKE’ et ‘CID’ montre que la perte d'éthylbne se déroule suivant un mécanisme non concerté avec un transfert d'hydrogéne à quatre ou cinq centres. Les résultats montrent également que les 3-et 5-bromotriazoles contribuent au spectre de masse de l'hétérocycle parent. La perte de propéne de N-propylbromotriazoles est également discutée.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 12 (1977), S. 631-635 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The collision induced dissociation spectra of ions generated by ionization or fragmentation of various samples reveal at least five non-decomposing structures. In contrast, the kinetic energy release measurements for the loss of carbon monoxide from the metastable ions are in agreement with the occurrence of a common reactive species. Isomerization into an ‘α,β-unsaturated aldehyde-like’ structure prior to fragmentation is proposed to accommodate these collision induced dissociation and mass analysed ion kinetic energy data. Some resuts suggest also that carbon monoxide loss from the phenol molecular ion may not occur via the cyclohexadienone tautomer.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
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