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  • 1
    Electronic Resource
    Electronic Resource
    Specific features of the behavior of α- and β-glycosylfluoride tetraacetates during chemical ionization in isobutane and tetramethylsilane (1994)
    Springer
    Russian chemical bulletin 43 (1994), S. 578-582 
    Details
    ISSN: 1573-9171
    Keywords: mass-spectrometry ; chemical ionization ; tetramethylsilane ; glycosylfluorides ; anomeric effects ; fragmentation ; gas phase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Reactions of α- and β-glycosylfluoride tetraacetates with trimethylsilicenium ion in the gas phase during chemical ionization have been studied. The [M+SiMe3]+ ions formed from the glycosylfluorides are more stable than the corresponding [M+H]+ ions. The cleavage of the weakest glycosidic bond leading to the generation of glycosidic ions is not dominant for the trimethylsilylated ions, as it has been observed in the corresponding protolytic reactions. The ratio of the intensities of the [M+SiMe3]+ and [M−F]+ ions characterizes the probability of the initial localization of the trimethylsilyl ion at the glycosidic center; the equatorial orientation of fluorine at C(1) makes it possible for the electrophile to bond with this substituent. Generation of the glycosidic ions is rather weakly affected by increasing temperature, whereas [M-AcO]+ formation is significantly intensified.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00699827
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  • 2
    Electronic Resource
    Electronic Resource
    Peculiarities of interaction of H+, Me3C+, and Me3Si+ ions with multifunctional molecules in the gas phase (1995)
    Springer
    Russian chemical bulletin 44 (1995), S. 1698-1704 
    Details
    ISSN: 1573-9171
    Keywords: mass spectrometry, chemical ionization ; chelation, steric effects ; Ritter reaction ; nitriles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Peculiarities of interaction of H+, Me3C+, and Me3Si+ ions with functional groups of molecules in the gas phase have been studied. Proton tends to form chelates with virtually all of the functional groups studied, whereas Me3Si+ ions exhibit no capacity for chelation. Using isomeric xylenes as examples it was shown that Me3Si+ ions (unlike Me3C+ ions) experience virtually no steric hindrance when they react with nucleophilic centers. Effects of functional groups present in molecules of nitriles on the generation of [M+Me3C]+ adducts in the gas phase and the Ritter reaction in solution were estimated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01151294
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