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  • 1980-1984  (12)
  • Inorganic Chemistry  (12)
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  • 1
    Electronic Resource
    Electronic Resource
    Polare und unpolare Cycloadditionen von 1,3-Butadien und Cyclopentadien an Anthracene (1980)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 1458-1471 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Polar and Non-polar Cycloadditions of 1,3-Butadiene and Cyclopentadiene to AnthracenesThe photoadditions of anthracene (1a) and 9-anthracenecarbonitrile (1b) with 1,3-butadiene (2) lead to very different ratios of [4 + 2]- and [4 + 4]-adducts. This and, in contrast to the behavior of 1a, the complete suppression of photo-Diels-Alder additions between 1b,c,d and cyclopenta-diene (9) at 0°C are readily rationalized as an effect of hybridization in terms of the well established and successful diradical mechanism. At higher temperatures the [4 + 4]-adducts 11 undergo suprafacial 1,3-shifts into Diels-Alder adducts 12 and [4 + 4]-cycloreversions into 1 and 9. At such temperatures, added 1,3-dienes (or 1 and 9 generated in situ) combine with 11 to give well defined polycyclic adducts. Spectroscopic and quenching data are discussed.
    Notes: Die Photoadditionen von Anthracen (1a) und 9-Anthracencarbonitril (1b) mit 1,3-Butadien (2) führen zu deutlich verschiedenen Verhältnissen an [4 + 2]- und [4 + 4]-Addukten. Dies und die  -  im Gegensatz zu 1a  -  völlige Unterdrückung der Photo-Diels-Alder-Addition zwischen 1b,c,d und Cyclopentadien (9) bei 0°C ist als Hybridisierungseffekt beim vielfach bewährten Diradikalmechanismus zu verstehen. Bei höheren Temperaturen gehen die [4 + 4]-Addukte 11 durch suprafaciale 1,3-Verschiebung in Diels-Alder-Addukte 12, durch [4 + 4]-Cycloreversion in 1 und 9, oder mit zugesetzten 1,3-Dienen (bzw. in situ gebildetem 1 und 9) in wohldefinierte poly-cyclische Addukte über. Spektroskopische und Löschdaten werden diskutiert.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19801130425
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  • 2
    Electronic Resource
    Electronic Resource
    Photoadditionen von Dibenz[a,c]- und Dibenz[a,h]anthracen an Cyclopentadien (1980)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 1626-1631 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Photoadditions of Dibenz[a,c]- and Dibenz[a,h]anthracene to CyclopentadieneThe electronically excited carcinogens and mutagens 1 and 5 react with cyclopentadiene (2) at 0°C to give the stereochemically well defined [4 + 2]- (3) and [4 + 4]- (4) or [4 + 2]- (6) and [2 + 4]-adducts (7), resp. The products are characterized by UV, fluorescence, and 1H NMR spectra which reveal transannular interactions. 4 gives the cage compound 10 on photolysis.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19801130442
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  • 3
    Electronic Resource
    Electronic Resource
    Chemilumineszenz von Diradikalen aus Lepidopterin, Dibenzylidentriasteran und Diphenylbicyclooctadien (1980)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 3932-3936 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Chemiluminescence of Diradicals from Lepidopterene, Dibenzylidenetriasterane, and DiphenylbicyclooctadieneThe hydrocarbons lepidopterene (1), sym-dibenzylidene-dimethyltriasterane (5), and 2,6-diphenylbicyclo[3.3.0]octa-2,6-diene (8) are sources of intense emission of red light upon UV-excitation under specified experimental conditions (solutions, glassy media, crystals). These unusual observations are interpreted in terms of initial diradical formation and their subsequent decay to intramolecular exciplexes and triplet excimers, resp., which undergo the radiative decay.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19801131227
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  • 4
    Electronic Resource
    Electronic Resource
    Thermische [2, 1, 3]-Eliminierung von Methanthiol aus einem 1,5-Benzothiazepin-Derivat (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1643-1646 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Thermal [2,1,3]-Elimination on Methanethiol from a 1,5-Benzothiazepine DerivativeUpon heating to 200°C, the 1,5-benzothiazepine derivative 1 eliminates methanethiol to form the benzothiazole derivative 2, but not the 1,5-benzothiazepine 5. The structure of 2, is established by independent synthesis from 3, photolysis to give 4, spectroscopic data. The reaction of 1, to give 2 and methanethiol is termed a [2,1,3]-elimination.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19841170433
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  • 5
    Electronic Resource
    Electronic Resource
    Dien-katalysierte Photo-Dimerisierung über Excimere (Exciplexe) oder Dienaddition an Anthracen und 9-Phenylanthracen? (1980)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 3669-3674 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Diene-Catalyzed Photodimerization via Excimers (Exciplexes) or Diene Addition to Anthracene and 9-PhenylanthraceneThe [4 + 4]-photodimerization of anthracene (1) is not enhanced by 2,4-hexadiene (3) but impeded due to formation of [4 + 2]- (4) and [4 + 4]-adducts (5, 6). 6 and 1 combine to give the bisadduct 7 at room temperature. The selective photolysis of 9-phenylanthracene (8) leads to the anti-[4 + 4]-dimer (9). This can be compared with the [4 + 4]-photodimerization of 9-methylanthracene which affords the anti- and the thermolabile syn-product. 1,3-Dienes such as 1,3-pentadiene (10) or 1,3-cyclohexadiene (13) are not necessary for the formation of 9 but undergo cycloadditions with 8 to yield [4 + 2]- (11, 12, 14), [4 + 4]- (15), and [2 + 2]-adducts (16, 17). The structures of the products are established primarily by high field 1H-NMR spectroscopy.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19801131126
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  • 6
    Electronic Resource
    Electronic Resource
    1,2-Photoadditionen von Stilbenen und Diarylacetylenen an bicyclische 1,4-Cyclohexadiene: Propellane und 1,2-Substitutionsaddukte (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 2217-2237 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 1,2-Photoadditions of Stilbenes and Diarylacetylenes to Bicyclic 1,4-Cyclohexadienes: Propellanes and Substitutive 1,2-AdductsThe photoreactions of stilbene, 4,4′-dichloro-, 4,4′-dicyano-, 4,4′-dimethoxystilbene, diphenylacetylene, and bis(4-cyanophenyl)acetylene with 2,3,4,7-tetrahydroindene and 1,4,5,8-tetrahydronaphthalene have been investigated. Despite severe steric hindrance and because of electrostatic support the propellanes 3, 12, 23, 26 are formed as the major [2 +2]-cycloadducts. The products of dehydrogenation 41, 44, 45 and hydrogenation 29 are obtained from them. Further major products of the photolyses are the substitutive 1,2-adducts 4, 5, 14, 15, 24, 27, whereas the ene-adducts 25, 28 occur only in trace amounts. The mechanistic grounds are discussed in terms of diradicals with consideration of exciplex emissions and with the aid of comparative reactions involving 1,4-cyclohexadiene and methyl cinnamate. The photolyses of several propellanes with varying degrees of hydrogenation are described (decomposition, dehydrocyclization, intramolecular cycloaddition, and 1,5-shift). The structures of the products have been determined spectroscopically (IR, UV, fluorescence, 1H-NMR, 13C-NMR) and in part by chemical degradation and independent synthesis.
    Notes: Die Photoreaktionen von Stilben, 4,4′-Dichlor-, 4,4′-Dicyan-, 4,4′-Dimethoxystilben, Diphenyl-acetylen und Bis(4-cyanphenyl)acetylen mit 2,3,4,7-Tetrahydroinden und 1,4,4,8-Tetrahydronaphthalin werden untersucht. Durch [2 + 2]-Cycloaddition enstehen trotz sterischer Hinderung elektrostatisch gefördert überwiegend die Propellane 3, 12, 23, 26, aus denen Dehydrierungsprodukte (41, 44, 45) und das Hydrierungsprodukt 29 gewonnen werden. Weitere Hauptprodukte bei den Photolysen sind 1,2-Substitutionsaddukte (4, 5, 14, 15, 24, 27), während En-Addukte (25, 28) nur spurenweise auftreten. Die mechanistischen Gründe werden anhand von Exciplex-Emissionsspektren und unter Zuhilfenahme von Vergleichsreaktionen mit 1,4-Cyclohexadien sowie Zimtsäure-methylester auf der Grundlage von Diradikalen diskutiert. Die Photolysen mehrerer Propellane unterschiedlichen Hydrierungsgrads werden beschrieben (Zerfall, Dehydrocyclisierung, intramolekulare Cycloaddition und 1,5-Verschiebung). Die Konstitutionen der Produkte werden spektroskopisch (IR, UV, Fluoreszenz, 1H-NMR, 13C-NMR) und zum Teil durch chemischen Abbau und unabhängige Synthesen aufgeklärt.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811140619
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  • 7
    Electronic Resource
    Electronic Resource
    Dispirocyclobutane und Propellane aus 1,2-Bisenollactonen (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 1983-1990 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Dispirocyclobutanes and Propellanes from 1,2-BisenollactonesElectronically excited biphthalidylidene (1) and isocoumarino-isocoumarin (5) are trapped by electron-Poor stilbenes and by 1,3-dienes to give the dispirocyclobutanes 3, 8, 9, 11, 12 and the heterocyclic [4.4.2]propellanes 6 and 14 resp. The unusual tetraspirocyclobutane 4 is formed upon photodimerization of 1 as a by-product. The structures of the products have been established primarily by high-field, 1H-NMR spectroscopy and in part by chemical transformations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811140539
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  • 8
    Electronic Resource
    Electronic Resource
    Fragmentierende Ringverengungen des 1:2-Addukts aus Pyridin und Acetylendicarbonsäure-dimethylester (1982)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 115 (1982), S. 2467-2477 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Fragmentative Ring Contractions of the 1:2-Adduct of Pyridine and Dimethyl Acetylene-dicarboxylateThe structure 1a is secured for the 1:2-adduct of pyridine and dimethyl acetylenedicarboxylate. Its UV/VIS and 1H NMR spectra are temperature-dependent. Dichromate oxidation of 1a produces not only the indolizine 3, but also the quinolizinone 4. The indolizines 8, 3, 9, and 10 are formed in the ratio 10:5:5:1 upon thermolysis of 1a at 220°C, whereas 4 is stable under these conditions. The complex ring contractions with fragmentations and in part rearrangements are classified and interpreted mechanistically (high energy valence tautomers; cyclopropane-, ylide-, zwitterion/diradical-intermediates). The gaseous and liquid further products of the thermolysis are compatible with the intermediacy of carbene and radical fragments. Analytical and spectroscopic data (UV, fluorescence, IR, 1H, 13C NMR, MS) as well as independent syntheses (3, 10) and the synthesis of the reference compound 12 secure the constitutions of the compounds.
    Notes: Für das 1:2-Addukt aus Pyridin und Acetylendicarbonsäure-dimethylester wird die Konstitution 1a gesichert. Die UV/VIS- und 1H-NMR-Spektren sind temperaturabhängig. Die Dichromat-Oxidation von 1a liefert nicht nur das Indolizin 3, sondern auch das Chinolizinon 4. Die Thermolyse von 1a bei 220°C ergibt die Indolizine 8, 3, 9 und 10 im Verhältnis 10:5:5:1, während 4 unter diesen Bedingungen stabil ist. Die komplizierten Ringverengungen mit Fragmentierungen und teilweise Umlagerungen werden klassifiziert und mechanistisch gedeutet (energiereiche Valenztautomere; Dreiring-, Ylid-, Zwitterion/Diradikal-Intermediate). Die gasförmigen und flüssigen weiteren Produkte der Thermolyse stehen im Einklang mit dem Auftreten von Carben- und Radikal-Fragmenten, die aus den formulierten Intermediaten entstehen sollten. Zur Konstitutionssicherung dienen analytische und spektroskopische (UV, Fluoreszenz, IR, 1H-, 13C-NMR, MS) Daten sowie unabhängige Synthesen (3, 10) und die Synthese der Referenzverbindung 12.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19821150709
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  • 9
    Electronic Resource
    Electronic Resource
    1,4-Addition von Kalium-cycloheptatrienid an (9-Phenyl-)Anthracen (1982)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 115 (1982), S. 3208-3211 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1,4-Addition of Potassium Cycloheptatrienide to (9-Phenyl-)AnthraceneIn liquid ammonia the cycloheptatriene anion adds to anthracene (3) and 9-phenylanthracene (9) to give the anions 4 and 10, resp., which are quenched at -35°C to give the substitutive 1,4-adducts 5 and 11 + 12, resp. Upon heating up to 20°C the intermediate anion 4 cyclizes to the Diels-Alder product 6, which is quenched to give the asymmetric and symmetric [4 + 2]-adducts 7 and 8. The structures of the products have been established primarily by high-field 1H-NMR spectroscopy.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19821150924
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  • 10
    Electronic Resource
    Electronic Resource
    Cyclovinyloge Additionen von 1,3-Diphenylbenzo[c]furan an 1,3,5-Cycloheptatrien (1983)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 116 (1983), S. 618-629 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cyclovinylogous Additions of 1,3-Diphenylbenzo[c]furan to 1,3,5-Cycloheptatriene1,3-Diphenylbenzo[c]furan (1) reacts thermally with 3,4-dimethylenecyclobutene (2) and 1,3,5-cycloheptatriene (5) to give exo- and endo-Diels-Alder adducts. The reaction of 1 with potassium cycloheptatrienide leads to substitutive adducts (13, 14) at low temperature, but to [4 + 2]-ring closure (15) at higher temperatures, via the anionic intermediate 12. The photoaddition of 1 to 5 gives the exo- and endo-[4 + 2]-, endo-[4 + 6]-, exo-[4 + 4]- und cis-1,4(1,3)-substitutive adducts 7, 6, 16, 17 und 14, in divergence to recent literature data. The structures of the products are elucidated by 1H NMR spectra and in part by chemical transformations, their formation can be interpreted in terms of the approved diradical mechanism. The endo-/exo-isomerization of 16 into 19 proceeds solvolytically. The products 7 and 16 are formed out of 17 by suprafacial thermal 1,3-alkyl shifts. Further exo- und endo-[4 + 2]- as well as [4 + 4]-additions of 1 are achieved with dimethyl maleate (23, 24) and anthracene (26), resp.
    Notes: 1,3-Diphenylbenzo[c]furan (1) reagiert thermisch mit 3,4-Dimethylencyclobuten (2) und 1,3,5-Cycloheptatrien (5) zu exo- und endo-Diels-Alder-Addukten. Die Reaktion von 1 mit Kaliumcycloheptatrienid führt über das Anionzwischenprodukt 12 bei tiefer Temperatur zu Substitutionsaddukten (13, 14), bei höherer Temperatur dagegen zum [4 + 2]-Ringschluß (15). Die Photoaddition von 1 an 5 führt abweichend von Literaturangaben zu den exo- und endo-[4 + 2]-, endo-[4 + 6]-, exo-[4 + 4]- und cis-1,4(1,3)-Substitutions-Addukten 7, 6, 16, 17 und 14, deren Konstitution 1H-NMR-spektroskopisch sowie z. T. durch chemische Umwandlungen belegt wird und deren Bildung auf der Grundlage des bewährten Diradikalmechanismus gedeutet werden kann. Die endo-/exo-Isomerisierung von 16 zu 19 gelingt solvolytisch. Durch suprafaciale thermische 1,3-Alkylverschiebungen entstehen aus 17 die Produkte 7 und 16. Weitere exo- und endo-[4 + 2]- sowie [4 + 4]-Additionen von 1 werden mit Maleinsäure-dimethylester (23, 24) und Anthracen (26) erreicht.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19831160221
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