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  • 1
    Electronic Resource
    Electronic Resource
    Cyclophanes, XXXIX. The Structure of the Dicyanoacetylene Adducts of [2.2]Paracyclophane (1995)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1995 (1995), S. 609-612 
    Details
    ISSN: 0947-3440
    Keywords: Cyclophanes ; Diels-Alder reactions ; Cyanoacetylenes ; [2+4] Cycloadditions ; Barrelenophanes ; Semibullvalenophanes ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The structures of the 1:1 and 1:2 addition products of dicyanoacetylene (2) to [2.2]paracyclophane (1) have been determined by X-ray structural analysis as 3 and 5, respectively. In contrast to literature reports, the latter possesses the „crossed“ double barrelene configuration. On irradiation 3 isomerizes to the semibullvalenophane 4 as was also shown by X-ray structural analysis.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199519950484
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  • 2
    Electronic Resource
    Electronic Resource
    Cyclophanes, XLIPart XL: Ref. [1]. Cyclophanes as Precursors for Saturated and Unsaturated Cage Hydrocarbons - the Catalytic Hydrogenation of [2.2]Paracyclophane (1997)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1997 (1997), S. 1499-1504 
    Details
    ISSN: 0947-3440
    Keywords: [2.2]Paracyclophane, hydrogenation of ; Olefins, strained ; Dichlorocyclopropanation ; Dichlorocyclopropanes ; Polycycles ; Cyclophanes ; Cage compounds ; Strained molecules ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The catalytic hydrogenation of [2.2]paracyclophane 1 has been reinvestigated with the following results: a) Best yields (95%) of the perhydrocyclophane 3 are obtained when 1 is hydrogenated over ruthenium on charcoal in ethanol at 200°C and 300 atm in the presence of lithium hydroxide; b) hydrogenation of 1 in ethyl acetate/acetic acid over platinum at room temperature and normal pressure leads to the monoene 7 and one diene, to which we assign structure 11 since dichlorocyclopropanation converts it to the bis-adduct 12, whose structure was determined by X-ray structural analysis; c) when the tetraene 13 (prepared from 1 by Birch reduction) is hydrogenated over palladium on charcoal in petroleum ether, the triene 14 is obtained in addition to the dienes 4 and 11. Again, dichlorocyclopropanation followed by X-ray structural analysis of the resulting tris-adduct 17 was employed for the structure determination of the hydrocarbon precursor. The strain energies of the anti-Bredt hydrocarbons 11 and 17 have been calculated by molecular mechanics calculations.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199719970728
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  • 3
    Electronic Resource
    Electronic Resource
    Neue Dienophile und Diene, III. Über die Addition von Cyanacetylen an [2.2]Paracyclophan (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 2015-2022 
    Details
    ISSN: 0009-2940
    Keywords: Dienophiles, triple-bond ; Cyclobutadiene ; Cyclophanes ; Diels-Alder adducts ; Nenitzescu systems ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: New Dienophiles and Dienes, III.  -  On the Addition of Cyanoacetylene to [2.2]ParacyclophaneHeating a benzene solution of [2.2]paracyclophane (2) in the presence of excess cyanoacetylene (1b) at 160°C in a sealed ampoule provides the novel 2:1-addition product 10, as well as the previously obtained cycloadducts 7-9. It is suggested that these Nenitzescu hydrocarbon systems are formed via the cyclobutadiene intermediates 17 and 18. This hypothesis is supported by the isolation of the side-products 1,2,4-and 1,2,3-tricyanobenzene (11 and 12). When a mixture of 7 and 8 is pyrolyzed at 220°C the novel dihydronaphthalene 24 is formed; the mechanism of this isomerization is discussed. The structures of 10 and 24 were confirmed by X-ray structure determination.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901231012
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  • 4
    Electronic Resource
    Electronic Resource
    Cyclophanes, XXXV. DNMR, molecular mechanics, and crystal structures of 2,11-dithia[3.3]orthometacyclophane and 2,11-dithia[3.3]orthoparacyclophane (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 2381-2386 
    Details
    ISSN: 0009-2940
    Keywords: Dithiacyclophanes ; DNMR ; Molecular mechanics ; Cyclophanes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The syntheses of 2,11-dithia[3,3]orthometacyclophane (5) and 2,11-dithia[3,3]orthoparacyclophane (6) by dithiol-dibromide coupling are described. Whereas the yield of 5 is not significantly affected by the substrate pairing, that of 6 is. Both compounds exhibit a temperature-dependent 1H-NMR spectrum. An energy barrier of 11.0 ± 0.2 kcal/mol (45.7 ± 0.8 kJ/mol) has been calculated for 5, but that of 6 was too low to be determined. Slightly contrasting results were obtained from two different molecular mechanics programs for the relative energies of the six limiting conformations of 5. Crystal structure determinations of 5 and 6 have been carried out, and the conformational behavior of 5 and 6 in solution and in the solid state is discussed.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901231221
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