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  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1979 (1979), S. 210-218 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reaction of Epoxides will Isocyanates, III-Study of 2-Oxazolidinones by Mass SpectrometryThe decomposition of 2-oxazolidinones in the mass spectrometer is initiated essentially by two steps: 1) Elimination of carbon dioxide by α-decomposition; 2) a-cleavage by liberation of carbon monoxide and of the corresponding aldehyde.-The 5-aryl-3-phenyl-2-oxazolidinones (e. g. 1) undergo both reactions at roughly equal rates. 5-Alkyl- or 5-alkylidene-3-phenyl-2-oxazolidi-nones (e. g.4, 5) preferentially eliminate carbon dioxide. The main degradation reaction of 4-aryl-3-phenyl-2-oxazolidinones (e. g. 2) is α-cleavage.
    Notes: Der Zerfall von 2-Oxazolidinonen im Massenspektrometer wird im wesentlichen durch zwei Primärschritte eingeleitet: 1) Abspaltung von Kohlendioxid durch p-Zerfall; 2) a-Spaltung unter Freisetzung von Kohlenmonoxid und dem entsprechenden Aldehyd.-Bei 5-Aryl-3-phenyl-2-oxazolidinonen (z. B. 1) vollziehen sich beide Reaktionen in gleichem Maße; 5-Alkyl- oder 5-Alkyliden-3-phenyl-2-oxazolidinone (z. B. 4, 5) spalten vorzugsweise Kohlendioxid ab. 4-Aryl-3-phenyl-2-oxazolidinone (z. B. 2) zeigen als Hauptreaktion die α-Spaltung.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1979 (1979), S. 200-209 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reaction of Epoxide with Isocyanates, II1b)-Preparation and Characterization of 2-OxazolidinonesIsocyanates react with epoxides to yield 2-oxazolidinones. The reaction of isocyanates with un-symmetrically substituted epoxides 1 was studied in order to investigate differences in the direction of ring opening of the epoxides as a function of the type of catalyst (nucleophilic or electrophilic). With the exception of styrene oxides, where 4- and 5-substituted 2-oxazolidinones 4 and8 are formed, all other epoxides examined lead to 5-substituted 2-oxazolidinones, independent of the catalyst, e.g. 2a-c.
    Notes: Isocyanate reagieren mit Epoxiden zu 2-Oxazolidinonen. Um auf die Öffnungsrichtung des Epoxidringes in Abhängigkeit vom Katalysator (nucleophil oder elektrophil) schließen zu können, wurden Umsetzungen von Isocyanaten mit unsymmetrisch substituierten Epoxiden 1untersucht; dabei konnte festgestellt werden, daß nur aus Styroloxid auch in 4-Stellung substituierte2-Oxazolidinone 4 und 8 gebildet werden. Alle anderen untersuchten Epoxide führen unabhängig vom Katalysator ausschließlich zu 5-substituierten 2-Oxazolidinonen, z. B. 2a-c.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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