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  • Chemistry  (16)
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  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 108 (1975), S. 1460-1467 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Mechanism of the „Criss-Cross“ Cycloaddition2-[3,3-Bis(trifluoromethyl)-1-pyrazolin-1-io]-1,1,1,3,3,3-hexafluoro-2-propanides (3) are the stable intermediates of the „criss-cross“ cycloaddition reaction of terminal olefins to hexafluoroacetone azine (1). The isolation of the 1:1 adducts makes the mixed „criss-cross“ cycloaddition reaction possible. The azomethine imine intermediate readily explains the reaction of olefins of the type R1CH=CHR2 with 1 to yield 3-pyrazolines (10).
    Notes: 2-[3,3-Bis(trifluormethyl)-1-pyrazolin-1-io]-1,1,1,3,3,3-hexafluor-2-propanide (3) sind die stabile 1:1-Zwischenstufe der „criss-cross“-Cycloaddition von terminalen Olefinen an Hexafluoracetonazin (1). Die Isolierung der 1:1-Addukte (3) macht die gemischte „criss-cross“-Cycloaddition möglich. Die Azomethinimin-Zwischenstufe erklärt auf einfache Weise die Reaktion von Olefinen des Typs R1CH=CHR2 mit 1 zu 3-Pyrazolinen (10).
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 2609-2619 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of 1,5-Diazabicyclo[3.3.0]octa-2,6-dienes by “Criss-Cross” CycloadditionHexafluoroacetone azine (1) reacts with alkynes (acetylene, phenylacetylene, methyl propiolate as well as ethoxyacetylene) according to the scheme of the “criss-cross” cycloaddition reaction yielding 1,5-diazabicyclo[3.3.0]octa-2,6-dienes. The regiochemistry of the cycloaddition steps will be discussed. In the case of the reaction of 1 with ethoxyacetylenes and ynamines it is possible to prove the intermediacy of an azomethine imine.
    Notes: Hexafluoracetonazin (1) reagiert mit Alkinen (Acetylen, Phenylacetylen, Propiolsäure-methylester sowie Ethoxyacetylen) nach dem Schema der „criss-cross“-Cycloaddition unter Bildung von 1,5-Diazabicyclo[3.3.0]octa-2,6-dienen. Die Regiochemie der einzelnen Cycloadditionsschritte wird diskutiert. Bei der Reaktion von 1 mit Ethoxyacetylenen und Inaminen kann der Nachweis einer Azomethinimin-Zwischenstufe erbracht werden.
    Additional Material: 1 Tab.
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 108 (1975), S. 1468-1474 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Reaction of Trifluoromethyl-substituted Azomethine Imines with Nucleophiles2-[5,5-Dimethyl-3,3-bis(trifluoromethyl)-1-pyrazolin-1-io]-1,1,1,3,3,3-hexafluoro-2-propanide (1a) adds to alcohols to yield 1-[1-alkoxy-2,2,2-trifluoro-1-(trifluoromethyl)ethyl]-5,5-dimethyl-3,3-bis-(trifluoromethyl)pyrazolidines 2. On the contrary the reaction with ethanethiol gives 5,5-dimethyl-3,3-bis(trifluoromethyl)-1-[2,2,2-trifluoro-1-(trifluoromethyl)ethyl]pyrazolidine (3) with reduction of the azomethine imine system. phosphites react with 1 to give [7,7,7-trifluoro-2,2,6-tris(trifluoromethyl)-1,5-diaza-5-heptenylidene]phosphoranes 4. The spectral data of the new compounds are discussed, a reaction mechanism for the iminophosphorane formation is proposed.
    Notes: 2-[5,5-Dimethyl-3,3-bis(trifluormethyl)-1-pyrazolin-1-io]-1,1,1,3,3,3-hexafluor-2-propanid (1a) addiert alkohole unter Bildung von 1-[1-Alkoxy-2,2,2-trifluor-1-(trifluormethyl)äthyl]-5,5-dimethyl-3,3-bis(trifluormethyl)pyrazolidinen 2, dagegen führt die Umsetzung mit Äthanthiol unter Reduktion des Azomethinimin-Systems zum 5,5-Dimethyl-3,3-bis(trifluormethyl)-1-[2,2,2-trifluor-1(tri-fluormethyl)äthyl]pyrazolidin (3). Phosphite liefern mit 1 [7,7,7-Trifluor-2,2,6-tris(trifluormethyl)-1,5-diaza-5-heptenyliden]phosphorane 4. Die spektroskopischen Daten der neuen Verbindungen werden diskutiert, für die Iminophosphoran-Bildung wird ein Reaktionsmechanismus vorgeschlagen.
    Additional Material: 3 Tab.
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 2620-2630 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 1,5-Diazabicyclo[3.3.0]octa-2,6-diene⇌4,5-Diazaocta-1,3,5,7-tetraene. A New Valence Isomeric Pair and its Part in Pyrazole Synthesis1,5-Diazabicyclo[3.3.0]octa-2,6-dienes of type 1 undergo a sequence of electrocyclic reactions on thermolysis and photolysis to yield 4,5-diazaocta-1,3,5,7-tetraenes 3. The influence of the substitution pattern upon the conditions necessary for initiation of the reaction and upon the valence isomeric equilibrium is studied. The reaction of aldazines with alkynes yields pyrazoles via the described valence isomerization process. The reaction mechanism will be discussed.
    Notes: 1,5-Diazabicyclo[3.3.0]octa-2,6-diene vom Typ 1 unterliegen sowohl bei der Thermolyse als auch bei der Photolyse einer Folge von elektrocyclischen Prozessen unter Bildung von 4,5-Diazaocta-1,3,5,7-tetraenen 3. Der Einfluß des Substitutionsmusters auf die Auslösebedingungen der Reaktion sowie auf die Lage des Valenzisomeren-Gleichgewichts wird untersucht. Die Umsetzung von Aldazinen mit Alkinen führt über den beschriebenen Valenzisomerisierungsprozeβ zu Pyrazolen. Der Mechanismus der Reaktion wird diskutiert.
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1979 (1979), S. 1205-1211 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Stereochemistry of 3,3′-(1,2-Diethylethylene)diphenols1-Chloro-1-(3-methoxyphenyl)propane 5 was converted by C-C coupling in to a mixture of dia-stereomeric 3,4-bis(3-methoxyphenyl)hexanes 6, which could be separated by crystallization into the meso- and rac-compounds 6a and 6b, respectively. After ether cleavage meso-3,3′-(1,2-di-ethylethylene)diphenol and rac-3,3′-(1,2-diethylethylene)diphenol (2a and 2b) were obtained; the latter was resolved via the diastereomeric (+)- and (-)-3,3′-(1,2-diethylethylene)diphenyl-3,4-bis[3-D-(+)-3-bromo-2-oxo-8-bonanylsulfonates] (7) into (+)-3,3′-(1,2-diethylethylene)diphenol and (-)-3,3′-(1,2-diethylethylene)diphenol [(+)-2b and (-)-2b]. The absolute configuration of the optical enantiomers could be established by means of oxidative degradation of (+)-2b.
    Notes: Aus 1-Chlor-1-(3-methoxyphenyl)propan (5) wurde durch C-C-Verknüpfung das Diastereomerenpaar 3,4-Bis(3-methoxyphenyl)hexan 6 erhalten. Durch Kristallisation konnten hieraus die meso- und die rac-Verbindungen 6a bzw. 6b isoliert warden. Die Spaltung der Ether führte zu meso-3,3′-(1,2-Diethylethylen)diphenol und rac-3,3′-(1,2-Diethylethylen)diphenol (2a bzw. 2b). Verbindung 2b wurde über die diastereomeren (+)- und (-)-3,3′-(1,2-Diethylethylen)diphenyl-3,4-bis[3-D-(+)-3-brom-2-oxo-8-bornanylsulfonate] (7) in (+)-3,3′-(1,2-Diethylethylen)diphenol und (-)-3,3′-(1,2-Diethylethylen)diphenol [(+)-2b bzw. (-)-2b] aufgetrennt. Die absolute Konfiguration der optischen Antipoden wurde durch oxidativen Abbau von (+)-2b ermittelt.
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  • 6
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions with Hexafluoroacetone Azine, XXI1).  -  [1,3-2,4] Cycloaddition of Electron-deficient Multiple Bond Systems to Hexafluoroacetone Azine  -  “Criss-cross” Cycloaddition Reactions with Acrylic Acid EstersHexafluoroacetone azine (1) and acrylic acid esters 2 react in a “criss-cross” cycloaddition process to give 1,5-diazabicyclo[3.3.0]octane dicarboxylates 3-5.
    Notes: Hexafluoracetonazin (1) reagiert mit Acrylsäureestern 2 (Molverhältnis 1:2) nach dem Schema der „Criss-cross“-Cydoaddition unter Bildung der 1,5-Diazabicyclo[3.3.0]octandicarbonsäureester 3-5.
    Additional Material: 2 Ill.
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  • 7
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Thermolysis of 1,5-Diazabicyclo[3.3.0]oct-2-enes, 4.  -  Generation and Cycloaddition Reactions of 1,5-Dipoles4,4,8,8-Tetrakis(trifluoromethyl)-1,5-diazabicyclo[3.3.0]oct-2-enes 1 are transformed into 1,5-dipoles 2 (conjugated azomethine imines) on heating. The latter in cycloaddition reactions participate as 4π systems exclusively. Cycloadduct 9 obtained from 2 and tetracyanoethylene spontaneously undergoes a [3 + 2] cycloreversion process with formation of the diene 10 and the azomethine imine 11 (dipole metathesis). 2 with acrylic acid esters gives a pair of stereoisomers 12/13, with acrylonitrile a pair of regioisomers 14/15.
    Notes: 4,4,8,8-Tetrakis(trifluormethyl)-1,5-diazabicyclo[3.3.0]oct-2-ene 1 liefern beim Erhitzen 1,5-Dipole 2 (konjugierte Azomethinimine). Diese reagieren in Cycloadditionsprozessen ausschließlich als 4π-Elektronensysteme. Das aus 2 und Tetracyanethylen entstehende Cycloaddukt 9 zerfällt spontan ([3 + 2]-Cycloreversion) unter Bildung des Diens 10 und des Azomethinimins 11 (Dipol-Metathese). Aus der Reaktion von 2 mit Acrylsäureestern resultieren Stereoisomeren-Paare 12/13, während mit Acrylnitril ein Regioisomeren-Paar 14/15 erhalten wird.
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  • 8
    ISSN: 0044-8249
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Tab.
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  • 9
    ISSN: 0044-8249
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Tab.
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  • 10
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für die chemische Industrie 89 (1977), S. 60-61 
    ISSN: 0044-8249
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Tab.
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