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  • Organic Chemistry  (3)
  • Wiley-Blackwell  (3)
  • International Union of Crystallography (IUCr)
  • Periodicals Archive Online (PAO)
  • Springer
  • 1985-1989  (3)
Collection
Publisher
  • Wiley-Blackwell  (3)
  • International Union of Crystallography (IUCr)
  • Periodicals Archive Online (PAO)
  • Springer
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Year
  • 1
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Glycosylierungen von Pyrazino[2,3-c]-1,2,6-thiadiazin-2,2-dioxiden zu Schwefeldioxid-Analogen von Pteridin-NucleosidenDie Pyrazino[2,3-c]-1,2,6-thiadiazin-2,2-dioxide 1, 2 und 3 werden als Trimethylsilyl-Derivate mit 1-O-Acetylribose-Derivaten glycosyliert. 1 liefert ein Gemisch der N-1- und N-8-Monoriboside sowie das N-1,4-N-Diribosid, wobei die Produktverteilung von den Reaktionsbedingungen abhängt. Mit den 6,7-disubstituierten Pyrazino[2,3-c]-1,2,6-thiadiazinen 2 und 3 werden lediglich die N-1-Monoriboside gebildet. Die Strukturen der neu synthetisierten Verbindungen werden auf der Basis der UV-, 1H-NMR- und 2D-NMR-Spektren diskutiert und gesichert.
    Notes: Pyrazino[2,3-c]-1,2,6-thiadiazine 2,2-dioxides 1, 2, and 3 have been glycosylated as their trimethylsilyl derivatives with 1-O-acetyl derivatives of ribose. 1 leads to mixtures of N-1 and N-8 monoribosides and N-1,4-N diribosides, the relative proportions depending on the reaction conditions used. However, in the case of 6,7-disubstituted pyrazinothiadiazines 2 and 3 only the N-1 monoribosides have been obtained. The structures of the newly synthesized compounds are discussed on the basis of UV, 1H NMR and 2D homonuclear NMR data.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1985 (1985), S. 589-598 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Photolyse von Enolacetaten und α-Bromderivaten von o-(Acyloxy)acetophenonenUV-Bestrahlung der Enolacetate 3a - g in Benzol liefert o-(Acetoxy)acetophenone 2 und 2-Methyl-chromone 4 als Hauptprodukte. Unter den gleichen experimentellen Bedingungen bleiben die Dimethylderivate 3h und 3i unverändert. Das α-Bromketon 5a liefert in Abhängigkeit von den Bestrahlungsbedingungen Mischungen aus o-(Acetoxy)acetophenon (2a), dem Diketon 6 und/oder α-Acetoxy-o-hydroxyacetophenon (7). Die Ähnlichkeiten und Unterschiede zwischen beiden Reihen von Experimenten sowie mechanistische Überlegungen werden diskutiert.
    Notes: UV irradiation of enol acetates 3a - g in benzene gives mainly o-(acetoxy)acetophenones 2 and 2-methylchromones 4. Under the same conditions, the dimethyl derivatives 3h and 3i remain unaffected. The α-bromo ketone 5a gives rise to mixtures of o-(acetoxy)acetophenone (2a), the diketone 6, and/or α-acetoxy-o-hydroxyacetophenone (7), depending on the irradiation conditions. The similarities and differences between the two series of experiments, as well as their possible mechanistic implications, are discussed.
    Additional Material: 2 Tab.
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  • 3
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Untersuchung der Rotationsisomerie und Synthese von Pyrazino[2,3-c][1,2,6]thiadiazin-2,2-dioxid-GlucosidenGlucosidierungen des 4-Amino-8H-pyrazino[2,3-c][1,2,6]thiadiazin-2,2-dioxids und seiner 6,7-Dimethyl- und 6,7-Diphenyl-Derivate mit Hilfe der „Silyl-Methode“ Werden beschrieben. Die Reaktion führt bevorzugt zu N-1-Substitution. Die entsprechenden Tetra-O-acetylglucopyranosyl-Derivate 5, 6 und 7 sowie die freien Nucleoside 8, 9 und 10 wurden isoliert und durch UV-, 1H- und 2D-NMR-Spektroskopie charakterisiert. Die freien Nucleoside liegen bei Raumtemperatur als rotationsgehinderte „syn/anti“-Isomere vor. Die freien Energien der Aktivierung wurden berechnet.
    Notes: Glucosidations of 4-amino-8H-pyrazino[2,3-c][1,2,6]thiadiazine 2,2-dioxide and its 6,7-dimethyl- and 6,7-diphenyl derivatives via the “silylation method” are described. The reaction favors N-1 substitution and the tetra-O-acetylglucopyranosyl derivatives 5, 6, and 7 as well as the free nucleosides 8, 9, and 10 have been isolated and characterized by UV, 1H, and 2D-NMR spectroscopy. The latter compound exist at room temperature, as rotationally restricted “syn-anti” isomers, and the free energies of activation have been calculated.
    Additional Material: 3 Tab.
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