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  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 3896-3905 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Disila[4.1.1]propellanes: Synthesis and StructureThe reaction of tricyclo[4.1.0.02,7]hept-1-yllithium with dichlorosilanes or tetrachlorosilane afforded silyl-Substituted tricyclo[4.1.0.02,7]heptane derivatives 2, 4 which, after metalation of the bicyclo[1.1.0]butane bridgehead positions, could be cyclized with dichlorosilanes to give disila[4.1.1]propellanes 5, 6. The structure of 5a has been determined by X-ray analysis.
    Notes: Durch Umsetzung von Tricyclo[4.1.0.02,7]hept-1-yllithium (1b) mit Dichlorsilanen oder mit Siliciumtetrachlorid wurden silylsubstituierte Tricylco[4.1.0.02,7]heptan-Derivate 2, 4 erhalten, die nach erneuter Metallierung der Bicyclo[1.1.0]butan-Brückenkopfpositionen mit Dichlorsilanen zu Disila[4.1.1]propellanen 5, 6 cyclisiert werden konnten. Die Struktur von 5a wurde durch Röntgenanalyse ermittelt.
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 116 (1983), S. 2205-2218 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Diels-Alder Adducts of 1,7-DehydroquadricylaneThe reaction of bulky lithium amides and 1-chloroquadricyclane in the presence of anthracene, 9-methoxyanthracene, 2,5-dimethylfuran, furan, and 1,2,3-trimethylisoindole afforded the corresponding Diels-Alder adducts of 1,7-dehydroquadricyclane 4a, 4b, 8a, 10 and 17 in satisfactory to good yields. The structure of 4a has been established by x-ray analysis. Attempts to isomerize the quadricyclane parts of the adducts to the corresponding norbornadiene units led only to polymeric material. Thiophenol selectively cleaved the central propellane bond of 4a to give the thioether 28a. Dimethyl acetylenedicarboxylate and diethyl azodicarboxylate reacted with the quadricyclane system of 17 leading to the bridgehead olefins 24 and 25.
    Notes: Nach Einwirkung von sperrigen Lithiumamiden auf 1-Chlorquadricyclan in Gegenwart von Anthracen, 9-Methoxyanthracen, 2,5-Dimethylfuran, Furan oder 1,2,3-Trimethylisoindol isolierte man die entsprechenden Diels-Alder-Addukte des 1,7-Dehydroquadricyclans 4a, 4b, 8a, 10 und 17 in befriedigenden bis guten Ausbeuten. Die Konstitution von 4a wurde durch Röntgenstrukturanalyse gesichert. Versuche zur Isomerisierung des Quadricyclan-Teils der Addukte zu der entsprechenden Norbornadien-Einheit lieferten nur polymeres Material. Thiophenol addierte sich selektiv an die zentrale Propellan-Bindung von 4a zum Thioether 28a. Acetylendicarbonsäuredimethylester und Azodicarbonsäure-diethylester reagierten am Quadricyclan-System von 17 unter Bildung der Brückenkopfolefine 24 und 25.
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 116 (1983), S. 2285-2310 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Thermal Isomerization of Tricyclo[4.1.0.02,7]hept-1(7)-ene: Formation and Trapping Reactions of 1,2,3-CycloheptatrieneThe reaction of (7-bromotricyclo[4.1.0.02,7]hept-1-yl)trimethylsilane (1d) with potassium fluoride or cesium fluoride in dimethyl sulfoxide led to the formation of tricyclo[4.1.0.02,7]hept-1(7)-ene (2) which, above 80°C, rearranged almost completely to 1,2,3-cycloheptatriene (6). 6, as a short-lived reactive intermediate, afforded cycloaddition products with numerous 1,3-dienes and with some 1,3-dipoles. The primary adduct of 6 with N, α-diphenylnitrone isomerized at room temperature to the bridgehead olefin 41, the structure of which has been established by an x-ray analysis. When 6 was generated via 2 from 1-chlorotricyclo[4.1.0.02,7]heptane (1f) and potassium tert-butoxide in tetrahydrofuran above 30°C, the cyclocumulene 6 even in the presence of anthracene yielded the vinyl ether 8.
    Notes: Die Reaktion von (7-Bromtricyclo[4.1.0.02,7]hept-1-yl)trimethylsilan (1d) mit Kaliumfluorid oder Caesiumfluorid in Dimethylsulfoxid führt zur Bildung von Tricyclo[4.1.0.12,7]hept-1(7)-en (2), das sich oberhalb von 80°C praktisch vollständig in das 1,2,3-Cycloheptatrien (6) umlagert. Als kurzlebige, reaktive Zwischenstufe ergibt 6 mit zahlreichen 1,3-Dienen und mit einigen 1,3-Dipolen Cycloadditionsprodukte. Das Primäraddukt von 6 an N, α-Diphenylnitron isomerisiert bei Raumtemperatur zum Brückenkopfolefin 41, dessen Konstitution durch Röntgenstrukturanalyse gesichert wurde. Erzeugt man 6 über 2 aus 1-Chlortricyclo[4.1.0.02,7]heptan (1f) und Kalium-tert-butylat in Tetrahydrofuran oberhalb von 30°C, so entsteht aus dem Cyclocumulen 6 auch in Gegenwart von Anthracen hauptsächlich der Enolether 8.
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  • 4
    ISSN: 0044-8249
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für die chemische Industrie 103 (1991), S. 1044-1046 
    ISSN: 0044-8249
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
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  • 6
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Cyclopentannulation of 4-tert-butyldimethylsilyloxy-2-cyclopenten-1-one from a β-metallated dioxolane-type orthoester affords 4-tert-butyldimethylsilyloxy-8,8-ethylenedioxy-6-phenylsuiphonyl-2-oxobicyclo [3·3·0] octanes as a mixture of two diastereoisomers. Their stereochemical structures were established by NMR and x-ray analysis. The minor product possesses a cis ring fusion, the sulphonyl and the tert-butyldimethylsilyloxy groups being endo and exo, respectively. The major isomer also has a cis ring fusion but an exo position for both dimethylsilyloxy and sulphonyl groups. Both cyclopentannulation products result from an anti addition with respect to the 4-tert-butyldimethylsilyloxy group on the enone.
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  • 7
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 4 (1991), S. 721-725 
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The x-ray structure of methyl 5-nitro-2-methylbenzoate was determined [M,r = 195.17, monoclinic, P,21/c, a, = 7.265(1), b, = 7.749(1), c, = 16.526(3) Å, α; = 91.50(2)., V, = 930.0(3) Å3, Z, = 4, D,x = 1.39 g cm-3, Cu Kα, Λ = 1.5418 Å, μ = 9.56 cm-1, F,(000) = 408, T, = 291 K, R, = 0.081 for 1295 observed reflections]. In contrast to the planar molecule of the corresponding acid, studied previously, the carboxylate group in the ester molecule is twisted through an angle 25° from the ring plane. This torsion angle was estimated to be 65° in benzene solution; the estimation was based on the dipole moment and that of methyl 2-methylbenzoate. For the corresponding ethyl esters a value of 79° was found in a similar way. Although these results are expressed in terms of one non-planar conformation, the alternative explanation of an equilibrium of two planar forms is not excluded in solution. The only safe conclusion is that the energy differences are small and the conformation is sensitive both to the conditions and to small changes in structure; a large part of the observed effects of an ortho,-methyl group are due to reasons other than to the hindered resonance.
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  • 8
    ISSN: 1434-193X
    Keywords: Cyclopropanes ; Rearrangements ; Cyanohydrins ; Schiff bases ; Small ring systems ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: -The direct cyclization of 2-amino-4-chloro-3,3-dimethylbutanenitrile with potassium tert-butoxide in THF afforded 1-amino-2,2-dimethylcyclopropane-1-carbonitrile and a dimerization product. Various new cis- and trans-1-(tert-butylamino)-2-benzyl-2-methylcyclopropane-carbonitriles and© the corresponding cyclopropanecarboxamides have been synthesized, with focus on the isolation of the pure stereoisomeric cyclopropanecarboxamides. The relative configuration of the stereoisomers was established by X-ray crystallographic analysis of one of the model compounds. A new route to the latter functionalized cyclopropanes was developed by reaction of 1-methoxycyclopropylamines with potassium cyanide. Some remarkable rearrangements of 1-aminocyclopropane-1-carbonitriles into azetidine and oxazine derivatives via Favorskii-derived intermediates are reported. Various aspects of the chemistry of geminally functionalized cyclopropanes are discussed.
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  • 9
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Kristallstruktur von (Z)-1-Phenyl- und von (Z)-1-Dimethylamino-2-phthalimido-diazen-1-oxidDurch Röntgen-Strukturanalyse wurden die Konstitution und die (Z)-Konfiguration der im Titel genannten Produkte (3a und 3b) aus der Addition von Phthalimido-nitren (1) an Nitrosobenzol (2a) bzw. an Dimethylnitrosamin (2b) im Einklang mit früheren, spektroskopischen Strukturzuordnungen bestätigt. In beiden Molekeln (3a und 3b) ist die Phthalimidogruppe nicht mit der Diazenoxidfunktion konjugiert, dagegen besteht offensichtliche Konjugation der zentralen NNO-Funktion mit der Phenylgruppe in 3a bzw. mit der Dimethylaminogruppe in 3b. Die Ebene der NNO-Gruppe ist in beiden Molekeln nur wenig gegenüber derjenigen der Substituenten an N(1) verdrillt (5° bei 3a bzw. 7° bei 3b). Die Bindungslänge zwischen N(1) und dem Dimethylamino-Stickstoffatom in 3b entspricht mit 1,347 Å nahezu einer N,N-Anderthalb-Bindung, und beide zuletzt genannten N-Atome sind coplanar mit ihren jeweiligen drei Liganden. Die Bindungslänge zwischen N(1) und dem benachbarten C-Atom in 3a von 1,459 Å entspricht derjenigen einer Einfachbindung zwischen sp2-hybridisierten N- bzw. C-Atomen, analog den Bindungslängen zwischen N(1) und dem benachbarten C-Atom in 1,2-Diaryl-diazen-1-oxiden (5; R, R′ = Aryl).
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  • 10
    ISSN: 0044-8249
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
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