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  • 1
    ISSN: 0947-3440
    Keywords: Phenazin-5(10H)-yl radicals ; Radical pairs ; π-π-Interactions ; Pimerization ; Dimer absorption ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The unit cell of 10-ethylphenazin-5(10H)yl · H2O consists of eight phenazin-5(10H)-yls that are arranged in four independent radical pairs A-D. All pairs show close interplanar distances (3.28-3.36 Å). Furthermore, A, B, and D are characterized by short intermolecular contacts between atoms with significant spin populations. This is not valid for the pair C with the closest interplanar distance of 3.28 Å. Magnetic susceptibility measurements as a function of temperature indicate complete spin pairing (“pimerization”) between 20 and 100 K. Therefore, the radical pair C provides evidence that unspecific close interplanar contacts together with a reasonable overlap of the π systems are sufficient to lead to pimerization.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Preparation of Radioactive Organic Compounds, I. L-3-[14C]-Methoxy-ω-[1-hydroxy-1-phenylisopropylamino]-propiophenone Hydrochloride. [14C]-Labeled Oxyfedrin · HClFor the synthesis of the title compound 4 with 14C-activity located only in the methoxy group, on ethanolic solution of sodium alcoholate 1 is treated with [14C]-CH3I and then the methylation completed with inactive CH3I. By a Mannich synthesis with formaldehyde 2 is condensed with 3. The resulting 4 has been purified.
    Notes: Zur Darstellung der Titelverbindung 4 mit 14C-Aktivität ausschließlich in der Methoxy-Gruppe wird 1 in äthanolischer Natriumalkoholat-Lösung mit [14C]-CH3J und anschließend mit inaktivem CH3J methyliert, das gebildete 2 mit Formaldehyd und 3 durch Mannich-Synthese zu 4 umgesetzt und gereinigt.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 0947-3440
    Keywords: Phenazin-5(10H)-yl ; ESR spectroscopy ; Radical pairs ; π Interactions ; Dimer absorption ; Magnetic susceptibility ; Nitrogen heterocycles ; Radicals ; Magnetic properties ; Solid-state chemistry ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Introduction of tert-butyl groups into the phenazine frame-work was accomplished by treatment of 5-acetyl-5,10-dihydrophenazine (2a) with tert-butyl chloride in the presence of AlCl3. Starting from the 2,8- or 3,7-di-tert-butyl-substituted derivatives 2c and 2b, a series of phenazin-5(10H)-yl radicals (1c-i) was synthesized and characterized by ESR and EN-DOR spectroscopy. With the exception of 1c, all phenazin-5(10H)-yls were obtained in crystalline form, and for 1d-f the long-wavelength absorption band at λ ≈ 870 nm indicates intermolecular π-π interactions in the solid state. For 1d, 1e and 1h the crystal structure could be determined. The unit cell of 1d consists of eight phenazin-5(10H)-yls. Surprisingly, four of them are arranged in radical pairs, whereas the other four lie independently in the lattice. In agreement with this structure, the magnetic susceptibility results correspond to a content of 50% monoradical and an almost complete spinpairing in the radical pairs up to T = 220 K. In 1e, the four phenazin-5(10H)-yls in the unit cell are arranged in two independent radical pairs, A and B, which are characterized by close interplanar distances and short intermolecular contacts between atoms with significant spin populations. Accordingly, the susceptibility data indicate strong spin-pairing at low temperature. Due to extensive steric shielding of the phenazin-5(10H)-yl framework, the crystal structure of 1h gives no evidence of any π-π interactions between adjacent radicals. As expected, the magnetic susceptibility of 1h corresponds to that of an ordinary monoradical.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 654 (1962), S. 64-81 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Die CH-Acidität von 1.1.3.3-Tetraphenyl-propen und von 1.1.5.5-Tetraphenyl-pentadien nimmt um viele Zehnerpotenzen zu, wenn mindestens 2 der Phenylreste zu einem Biphenylenrest eingeebnet werden. Derartige Kohlenwasserstoffe geben in geeigneten Lösungsmitteln bereits mit 0.1 n wäßrigen Laugen tieffarbige Salze, die bei Ausschluß von Luft beständig sind. Die durch Entladung der roten bzw. blauen Anionen mit K3Fe(CN)6 resultierenden paramagnetischen Radikale sind gelb und fallen durch ihre geringe Reaktionsgeschwindigkeit mit O2 auf. Im Falle des 1.1.5.5-Bis-biphenylen-pentadiens-(1.4) liefert das mesomere Anion mit Methyljodid zwei verschiedene Methylderivate.  -  Es wird eine qualitative theoretische Deutung für den Einfluß der Biphenylenbindungen auf die Säuredissoziationskonstanten vorgeschlagen.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 706 (1967), S. 107-111 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Die Kupplung von Benzoldiazoniumchlorid mit Trimethylacetaldehyd-phenylhydrazon in Pyridin/DMF ergibt den Bisazokörper 1, der erst durch starke Basen in das Formazan 2 umgelagert wird. Durch Belichten läßt sich 2 nicht in eine offene, gelbe Form überführen. Von 1 und 2 werden dieselben Metallkomplexe erhalten.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 706 (1967), S. 104-106 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Durch Umsetzung von Malonsäure mit 3 Molen Aryldiazoniumchlorid in Dimethylformamid/Pyridin werden N.N′.C-Triaryl-formazane vom Typ 1 erhalten.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Preparation of Radioactive Organic Compounds, II. L-3-Methoxy[3H]-ωM-[1-hydroxy-1-phenyl-isopropylamino]-propiophenone Hydrochloride2)3H-Methyliodide (1) is used for the methylation of m-methoxy[3H]-acetophenone (2). The resulting radiochemically pure m-methoxy[3H]-acetophenone (3) with formaldehyde and 1-norephedrine (4) gives the title compound 5. Following the course of this Mannich reaction by thinlayer chromatography and radiometric measurements, it is shown that 3 cannot be transformed completely into 5.
    Notes: Methyljodid-[3H] (1) wird im Überschuß zur Methylierung von m-Hydroxy-acetophenon (2) eingesetzt. Das erhaltene, radiochemisch reine m-Methoxy-[3H]-acetophenon (3) gibt mit Formaldehyd und 1-Norephedrin (4) die Titelverbindung 5.
    Type of Medium: Electronic Resource
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