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  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 102 (1969), S. 3304-3309 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Die aus Cyclooctatetraen und Azodicarbonsäure-diäthylester über mehrere Stufen zugängliche Hydrazoverbindung 3 liefert bei der Dehydrierung an Stelle der Azoverbindung 4 Bicyclo[4.2.0]octatrien-(2.4.7) (5). Die leicht erfolgende Stickstoffeliminierung aus 4 wird mit einem elektrocyclischen Mechanismus im Sinne einer Retro-Diels-Alder-Reaktion erklärt.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 3046-3051 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Thermolysis of 4,5-Diazatwist-4-ene to 9-NortwistbrendaneTwistane derivatives 5a, b are formed via the dihydrointermediates 4a, b by hydrogenation of diazabasketanes 3a, b. Starting with 5a, b 4,5-diazatwist-4-ene (1) is obtained. Thermolysis of 1 leads to the formation of 9-nortwistbrendane 2.
    Notes: Die Diazabasketane 3a, b werden über die Dihydrozwischenstufen 4a, b zu den Twistanderivaten 5a, b hydriert. Ausgehend von 5a, b erhält man das 4,5-Diazatwist-4-en (1), dessen Thermolyse 9-Nortwistbrendan 2 liefert.
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 98 (1965), S. 2322-2326 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Durch Photoaddition an Butin-(2) werden die Anhydride IV und XII und daraus die Ester der bicyclischen Dicarbonsäuren (V und XIII) dargestellt. Aus IV werden der Äther VIII sowie Tetramethyl-bicyclo[4.2.0]octen X gewonnen. Alle Verbindungen sind thermisch sehr beständig.
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 100 (1967), S. 3916-3923 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Das aus Tetramethyl-Dewar-phthalsäureester (1) leicht herstellbare ditertiäre Glykol 2) gibt bei der UV-Bestrahlung u. a. das säureempfindliche Prismanderivat 9. Erhitzen von 9 in Pyridin führt zu einem isomeren, von 2 verschiedenen Glykol 10, das bei der Belichtung 9 zurückbildet. Zahlreiche Wege führen von 2, 9 und 10 zu aromatischen Verbindungen.
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 102 (1969), S. 275-288 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Durch säurekatalysierte Isomerisierung von methylierten Methylencyclobutenen mit ungesättigten Seitenketten gelangt man zu den in der Überschrift genannten Bicyclen. Im Gegensatz zu den niederen Homologen läßt sich der 4-8-Ring-Kohlenwasserstoff leicht zu einem Monocyclus pyrolysieren, weil bei ihm die energetisch günstigere Konrotation möglich ist.
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  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 109 (1976), S. 1887-1897 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Reactions of Octamethylbicyclo[4.2.0]octa-2,4,7-trieneThe synthesis of the title compound 2 from octamethylcyclooctatetraene (1) is described. The kinetic data for the rearrangement of 2 to 1 are given. 2 cycloadds to several dienophiles already at 0°C to yield 12, 13, the formation of which from 1 requires substantially higher temperatures. - Two cycloadducts of octamethylsemibullvalene (3) previously were attributed structures corresponding to 12-13; they have now been shown to be 16 and 17. - The facile elimination of nitrogen from azo compound 19 is interpreted as a concerted cycloreversion.
    Notes: Die Titelsubstanz 2, deren Synthese ausgehend von Octamethylcyclooctatetraen (1) beschrieben wird, lagert sich oberhalb von 0°C in 1 um. Die kinetischen Parameter dieser Reaktion wurden bestimmt. 2 liefert mit verschiedenen Dienophilen bereits bei 0°C die Addukte 12, 13, zu deren Bildung aus 1 wesentlich höhere Temperaturen notwending sind. - Früher beschriebenen Cycloaddukten von Octamethylsemibullvalen (3), für welche eine obigen Addukten entsprechende Struktur angenommen wurde, kommt in Wirklichkeit die Konstitution 16 bzw. 17 zu. - Die leichte Stickstoffeliminierung der Azoverbindung 19 wird als einstufige Cycloreversion erklärt.
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  • 7
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 2307-2313 
    ISSN: 0009-2940
    Keywords: Cycloadditions ; Cyclobutenes ; Cyclopropanes ; Tetracyclooctanes ; Photoreactions ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Photoreaction of 3,6-Dihydrophthalic Anhydride with AlkynesThe title compound 1 and various alkynes undergo photocycloadditions to give cyclobutenes 3 and/or tetracyclooctane derivatives 4. The proportion varies from 100% cyclobutene (3d) to 100% tetracyclooctane (4e, 1) according to the substituents on the alkyne and the temperature.
    Additional Material: 1 Tab.
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  • 8
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 115 (1982), S. 748-753 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Absolute Configuration of Optically Active 4,5-Diazatwist-4-eneThe adduct 5 of diphenyl azodicarboxylate and 7,8-dibromobicyclo[4.2.0]octa-2,4-diene is transformed via 6 and 7 to the twistane derivative 8a, which is partially resolved on cellulose triacetate. Hydrogenation of (-)-4,5-Diazatwist-4-ene ((-)-1), obtained from (-)-8a, yields 2e, isolated as the hydrochloride (+)-2d. Since (+)-2d correlates with (+)-(2S, 5S)-bicyclo[2.2.2]octane-2,5-dicarboxylic acid ((+)-2a), M-helicity is attributed to (-)-1.
    Notes: Das Addukt 5 aus Azodicarbonsäure-diphenylester und 7,8-Dibrombicyclo[4.2.0]octa-2,4-dien liefert über 6 und 7 das Twistanderivat 8a, das sich an Triacetylcellulose partiell in die Enantiomeren trennen läßt. Hydrierung des aus (-)-8a zugänglichen (-)-4,5-Diazatwist-4-ens ((-)-1) ergibt 2e, das als Hydrochlorid (+)-2d isoliert wird. Da (+)-2d mit der (+)-(2S, 5S)-Bicyclo[2.2.2]octan-2,5-dicarbonsäure ((+)-2a) korreliert ist, wird (-)-1 die M-Helizität zugeordnet.
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  • 9
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 116 (1983), S. 2366-2370 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: New Kind of Formation of an Azo Compound with a Secopentaprismane C-SkeletonDecarboxylating hydrolysis of 5a, which is generated by the reaction of 4 with tetrazine 2, followed by oxidation yields the hexacyclic azo compound 7a. Thermal denitrogenation of 7a leads to azo compound 14, while irridiation of both 7a and 14a yields the hexacyclic compound 15, which could not be transformed into the pentaprismane 16.
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  • 10
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 125 (1992), S. 1927-1937 
    ISSN: 0009-2940
    Keywords: Azo compounds, polycyclic ; Denitrogenation ; Pyrrolidines ; Semibullvalenes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Stereochemical Course of the Denitrogenation of Optically Active 9,10-Dihydro-5,6-diazalumibullvalene to Optically Active 3,4-DihydrosemibullvaleneThermal decomposition of optical active diazalumibullvalene derivative (+)-6 gives optical active dihydrosemibullvalene (+)-5. The absolute configurations of optical active 6 and 5 were determined by correlation to tricyclooctanone 9 and 2-cyclopentene-1-acetic acid (21), respectively. From these results it is concluded that thermal denitrogenation of 6 occurs by concerted six-electron cycloreversion competing most likely to a multi-step N2 elimination via the symmetrical diradical intermediates 8 and 7.
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