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  • 1
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Aromatic Phosphines with Second Order Substituents, XVI1).  -  Phenylogous PO-activated Olefination: Synthesis of 4′-Donator Substituted 4-(Diphenylphosphinyl)stilbenesBeing a  -  M substituent, the 4-diphenylphosphinyl group acidifies the methyl group of toluene to a similar degree as a 4-cyano group. The carbanion formed by deprotonation reacts with N-benzylidene anilines to yield 4-(diphenylphosphinyl)stilbenes. In these, UV-spectroscopically the phosphorus on the one hand behaves like a  -  M substituent, on the other hand it acts as a barrier to through-conjugation.
    Notes: Als  -  M-Substituent acidifiziert eine 4-Diphenylphosphinyl-Gruppe die Methylgruppe des Toluols ähnlich stark wie eine 4-Cyangruppe. Das durch Deprotonierung entstehende Carbanion reagiert mit N-Benzylidenanilinen zu 4-(Diphenylphosphinyl)stilbenen. In ihnen erweist sich der Phosphor UV-spektroskopisch einerseits als Konjugationssperre, andererseits als mesomer wirksamer Substituent.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1976 (1976), S. 2126-2135 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Aromatic Phosphines with Second Order Substituents, XV. - Nucleophilic Aromatic Substitution Activated by PhosphorusIn hexamethylphosphoric triamide (HMPT) the halogen (particularly fluorine) of p-halogeno-phenylphosphines or (preferably) their oxides and sulfides can be replaced by R2N-, RNH-,HO-, NC-, and O2N-groups. The substitution hardly occurs in the meta-isomers thus demonstrating the mesomeric nature of the electron-withdrawing effect of phosphorus.
    Notes: In Hexamethylphosphorsäuretriamid (HMPT) läßt sich Halogen, vor allem Fluor, von p-Halogenphenylphosphinen oder (besser) ihren Oxiden und Sulfiden durch R2N-, RNH-,HO-, NC- und O2N-Gruppen ersetzen. Die Reaktion versagt weitgehend bei den meta-Isomeren und erweist so die mesomere Natur des Akzeptoreffektes des Phosphors.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
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