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  • 1990-1994
  • 1970-1974  (2)
  • 1974  (2)
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  • 1990-1994
  • 1970-1974  (2)
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  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 107 (1974), S. 78-92 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Polar 1,4-Cycloadditions, XI. Diastereogenic Reactions for the Investigation of the Reaction Course of CycloadditionsThe cycloaddition of the chiral amidomethylium ion 2 to α-methylstyrenes 3 leads to diastereomeric oxazines 4. The investigation of this diastereogenic reaction under kinetic and thermodynamic product control and the persuit of the ring closure to 4 starting from the chiral γ-amidoalcohol 6 delivers informations, which are not to be reached by non-diastereogenic cycloadditions. Above all one gets results concerning the importance of the carbocation intermediate 5. This way a differentiation between a concerted and a two-step reaction course is possible.
    Notes: Die Cycloaddition des chiralen Amidomethylium-Ions 2 an α-Methylstyrole 3 führt zu diastereomeren Oxazinen 4. Die Untersuchung dieser diastereogenen Reaktionen unter kinetischer und thermodynamischer Produktsteuerung und die Verfolgung des Ringschlusses zu 4, ausgehend vom chiralen γ-Amidoalkohol 6, liefert vielseitigere und exaktere Informationen als sie durch nicht diastereogene Reaktionen erhalten werden können. Insbesondere sind Aussagen über die Bedeutung der Carbokation-Zwischenstufe 5 möglich. Damit ist eine Differenzierung zwischen konzertiertem und zweistufigem Reaktionsverlauf gegeben.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1974 (1974), S. 1856-1863 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Riburonic Acid Derivatives for Modification of the Ribose MoietyPermanganate oxidation of methyl-2,3-O-isopropylidene-β-D-ribofuranoside(2), which is readily available from D-ribose, provides a convenient method for the synthesis of methyl-2,3-O-isopropylidene-β-D-ribofuranosiduronic acid (5a), the methyl ester 5b of which is a key intermediate for directed chemical modification of the C-atoms 3, 4, and 5 of D-ribose. This is demonstrated by examples. The structures and conformations of the synthesized compounds are discussed.
    Notes: Die Permanganatoxidation von Methyl-2,3-O-isopropyliden-β-D-ribofuranosid (2), aus D-Ribose leicht zugänglich, stellt ein bequemes Verfahren zur Herstellung von Methyl-2,3-O-isopropyliden-β-D-ribofuranosiduronsäure (5a) dar. Ihr Methylester 5b ist eine Schlüsselsubstanz zur gezielten chemischen Veränderung der C-Atome 3, 4 und 5 der D-Ribose. Dies wird an einigen Beispielen gezeigt. Die Struktur und Konformation der hergestellten Verbindungen wird diskutiert.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
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