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  • 1
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 6 (1972), S. 1321-1331 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The mass spectra of benzisothiazole, three benzoselenazoles and three benzisoselenazoles have been determined and compared with those of the corresponding benzothiazoles. The elimination of CS known to occur from these latter substances is confirmed in the case of benzisothiazole, but a different mechanism is proposed.The fragmentation of the selenium analogues led to ions of the same type as the benzothiazoles and benzisothiazole, through extrusion of molecules of the type CN - R, but loss of the heteroatom was not accompanied by loss of carbon. Furthermore, the isoselenazole structure seems to be more sensitive to electronolysis than its isomer.All six selenium heterocyclics investigated gave rise to two ions (130 and 132) resulting from a recombination of various fragments, suggesting that this is a characteristic feature of the electron-impact fragmentation of compounds of this type.
    Notes: Les spectres de masse du benzisothiazole, de trois benzosélénzoles et de trois benzisoséléazoles not été mesurés et comparés à ceux des benzothiazoles correspondants. La perte de CS mise en évidence chez ces derniers est confirmée dans le cas du benzisothiazole, mais un mécanisme différent est proposé.La fragmentation des analogues séléniés conduit à des ions du même type que dans le cas des benzothiazoles et du benzisothiazole par perte de molécules du type CN - R, cependant, la perte de l'hétéroatome ne s'accompagne pas de perte de carbone. En outre, il semble que la structure isosélénazole soit plus sensible à l'electronolyse que son isomére.Les six hétérocycles séléniés étudiés ont tous donné naissance à deux ions (130 et 132) provenant d'une recombinaison de divers fragments. Ce phénomène laisse à penser qu'il s'agit là d'un élément caractéristique dans la fragmentation électronique de tels composés.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1980), S. 138-139 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: [C2H3O]+ ions with the initial structures [CH3CO]+, and [CH2CHO]+ cannot be distinguished on the basis of their collisional activation spectra, demonstrating that these isomers interconvert at energies below their threshold for decomposition. Self-protonation of ketene leads to the [CH3CO]+ ion, while the [C2H3O]+ ion generated from glycerol most probably has the structure of an oxygen protonated ketene [CH2=C=OH]+.
    Additional Material: 1 Tab.
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  • 3
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 16 (1981), S. 514-514 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
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  • 4
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 7 (1980), S. 314-316 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Collisional activation of field desorbed di- and tripeptides leads to abundant fragments which contain sequence information.
    Additional Material: 1 Ill.
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  • 5
    ISSN: 0935-6304
    Keywords: Gas chromatography, GC ; Fused silica and glass capillary columns ; Selective complexation ; Isomer separation ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The use of glass and fused silica open tubular columns for selective separation of structural, configurational, and optical isomers (enantiomers) of underivatized aliphatic alcohols and ketones by complexation gas chromatography on optically active metal chelates is described. The method represents a powerful analytical tool for the precise determination of diastereomeric (d.e.) and enantiomeric (e.e.) excesses in asymmetric syntheses and in natural product characterization. The direct screening of the enantiomeric composition and absolute configuration of terpinene-4-ol, the aggregation phermone of Polygraphus poligraphus (L), is described.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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