ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 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
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    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.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 2154-2174 
    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 Compounds of the 5,6-Diazalumibullvalene SeriesThe 9,10-diazasnoutane derivatives 3a und 16 can be rearranged to the 5,6-diazalumibullvalene derivatives 4a and 17 on treatment with acids.  -  The methyl-substituted diazasnoutane 16 is prepared by a new route. This compares favourably with an alternative procedure involving the bromination of methylcyclooctatetraene as a key step.  -  The thermal behaviour of the azo compounds 23 - 26  -  prepared from 4a  -  is investigated.  -  Some azoxy compounds of the 5,6-diazalumibullvalene series have been synthesized. The location of the oxygen atom can not be deduced from NMR spectroscopy and has been established by an X-ray analysis of 37.
    Notes: Die 9,10-Diazasnoutan-Derivate 3a und 16 lassen sich mit Säuren zu den 5,6-Diazalumibullvalen-Derivaten 4a und 17 umlagern.  -  Für die Darstellung des methyl-substituierten Diazasnoutan-Derivats 16 wird ein neuer Weg beschrieben, und es werden dessen Vorteile gegenüber einem alternativen Verfahren, das die Bromierung von Methylcyclooctatetraen beinhaltet, diskutiert.  -  Das thermische Verhalten der aus 4a zugänglichen Azoverbindungen 23 - 26 wird untersucht.  -  Die Position des Sauerstoffs in verschiedenen Azoxyverbindungen mit 5,6-Diazalumibullvalen-Gerüst läßt sich kernresonanzspektroskopisch nicht einwandfrei festlegen und wird über die Röntgenstrukturanalyse von 37 ermittelt.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für die chemische Industrie 82 (1970), S. 176-177 
    ISSN: 0044-8249
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    ISSN: 0044-8249
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 116 (1983), S. 2355-2365 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Attempts to Synthesize Derivatives of the 2,3-Diazabicyclo[2.2.2]octa-5,7-diene SystemThe 2,3-diazabicyclo[2.2.2]octa-5,7-diene derivatives 1a and b could neither be obtained by a photoaromatization reaction of 8 nor by an electrolytic oxidation of the dicarboxylic acids 13a, b. Cycloadditions to 21 lead to derivatives of the title system. At temperatures above -10°C these undergo a [4+2]-cycloreversion to produce the tetrahydrophthalazines 22. The thermal transformation of 21 to 22 is rationalized on the basis of a chain mechanism.
    Notes: Die 2,3-Diazabicyclo[2.2.2]octa-5,7-dien-Derivate 1a und b konnten weder über die Photoaromatisierung von 8 noch über die anodische Oxidation der Dicarbonsäure 13a, b erhalten werden. Cycloadditionen an 21 führten zu Derivaten des Titelsystems, die bereits oberhalb -10°C einer [4+2]-Cycloreversion unter Bildung der Tetrahydrophthalazine 22 unterliegen. Die thermische Umwandlung von 21 und 22 verläuft nach einem Kettenmechanismus.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 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.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 3935-3958 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Small Rings, 36: Attempts to Synthesize Tetramethyltetrahedrane from Alicyclic PrecursorsSynthesis as well as the thermal and photochemical behaviour of compounds with ring skeletons 1 and 3 are described. Whereas the former are accessible by standard procedures the approach to the bicyclobutane derivatives is based on the isomerization of diester 1b into valence isomer 3b which can be achieved in good yield by SiO2, or Al2O3. There are only minor differences in the cleavage of the pairs 1/3 provoked by heating or photochemical excitation. This is even true for irradiations in argon at 10 K. Under those conditions anhydrides la and 3a form the same charge transfer complex 28a between tetramethylcyclobutadiene and phthalic anhydride. A direct detection of tetramethyltetrahedrane using these means is not possible.
    Notes: Synthese sowie thermisches und photochemisches Verhalten von Verbindungen mit den Ringgerüsten 1 bzw. 3 werden beschrieben. Während erstere nach Standardverfahren zugänglich sind, fußt der präparative Zugang der Bicyclobutan-Derivate auf der mit SiO2 oder Al2O3 in guter Ausbeute erreichbaren Isomerisierung von Diester 1b zum Valenzisomeren 3b. Bei der durch Erhitzen oder Photoanregung bewirkten Spaltung unterscheiden sich die Paare 1/3 nur geringfügig. Dies gilt selbst für Bestrahlungen in Argon bei 10 K. Unter diesen Bedingungen liefern die Anhydride la und 3a den gleichen Charge-transfer-Komplex 28a zwischen Tetramethylcyclobutadien und Phthalsäureanhydrid. Ein direkter Nachweis von Tetramethyltetrahedran gelingt auf diese Weise nicht.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 115 (1982), S. 2214-2220 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Valence Isomerizations, 16. Preparation and Dynamic Properties of Cyclooctatetraene-1,4-dicarboxylic Acid DerivativesSynthesis and dynamic properties (ring inversion and bond shift) of dimethyl cyclooctatetraene-1,4-dicarboxylate (5) and its 2,3-dimethyl derivative 6 are described. Addition of optically active shift reagent causes a splitting of the NMR signals in the chiral d,l-pair as well in the achiral meso-bond shift isomer.
    Notes: Synthese und dynamische Eigenschaften (Ringinversion und Bindungsverschiebung) von Cyclooctatetraen-1,4-dicarbonsäure-dimethylester (5) und seinem 2,3-Dimethyl-Derivat 6 werden beschrieben. Zugabe von optisch aktivem Verschiebungsreagenz führt nicht nur beim chiralen d,l-Paar, sondern auch beim achiralen meso-Bindungsisomeren von 5 zu einer Aufspaltung der NMR-Signale.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 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.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...