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  • 1
    Electronic Resource
    Electronic Resource
    Effect of some crude and azadirachtin-enriched neem (Azadirachta indica) seed kernel extracts on larvae of Aedes aegypti (1984)
    Springer
    Entomologia experimentalis et applicata 35 (1984), S. 11-16 
    Details
    ISSN: 1570-7458
    Keywords: Azadirachta indica ; Aedes aegypti ; neem seed kernel extracts ; insect growth regulators ; growth-retarding effect ; natural insecticides
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung Zehn mit Wasser und verschiedenen organischen Lösungsmitteln hergestellte Niem-Samen-Extrakte wurden auf ihre Wirkung auf Larven der Gelbfiebermücke Aedes aegypti untersucht. Dauerhaltung der Viertlarven in behandeltem Wasser führte zu einer beträchtlichen wachstumshemmenden Wirkung, die hauptsächlich während der Imaginalentwicklung in Erscheinung trat. Der Wirkungsgrad der Extrakte steigerte sich im biotest mit abnehmender Polarität der bei der Extraktion verwendeten Lösungsmittel. Drei Extrakte (ANSKE, AZT-VR-K-E und MTB/H2O-K-NR-E) deren Wirkung auch auf Erstlarven untersucht wurde, verursachten erhebliche Entwicklungsverzögerungen wenn die Larven bis zum Erscheinen der Imagines behandeltem Wasser ausgesetzt waren. Die von den Extrakten verursachte Mortalität trat zu einem ähnlichen Zeitpunkt ein, wie er für einige synthetische Insektenwachstumshemmer berichtet wird.
    Notes: Abstract Bioassays against larvae of Aedes aegypti were conducted with neem seed kernel extracts obtained by extraction with water and organic solvents. Permanent exposure of fourth instar larvae to treated water resulted in a conspicuous growth-disrupting effect, mainly during imaginal development. The effectiveness of the extracts increased with decreasing polarity of the solvents used for extraction. Three neem seed kernel extracts caused an extreme prolongation of the larval period when first instar larvae were continuously exposed to treated water until adult emergence. The time necessary for lethal action of neem seed kernel extracts to set in was similar to that reported for some synthetic IGR's.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00343450
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  • 2
    Electronic Resource
    Electronic Resource
    Elektron-Donor-Acceptor-Verbindungen, XIX. Intramolekulare Chinhydrone der [3.3]Metacyclophan-Reihe: syn- und anti-6,9,15,18-Tetramethoxy[3.3]metacyclophane als Vorstufen (1980)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 233-240 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Electron Donor-Acceptor Compounds, XIX. Intramolecular Quinhydrones of the [3.3]Metacyclophane Series: syn- and anti-6,9,15,18-Tetramethoxy[3.3]metacyclophanes as PrecursorsIn the context of the synthesis of [3.3]metacyclophane quinhydrones (e. g, 1 and 2) the stereoisomeric 7,10,17,20-tetramethoxy-2,13-dithia[4.4]metacyclophanes (5/6) were synthesized via 8 - 12. From the disulfones, prepared by oxidation of 5/6, by vacuum gas-phase pyrolysis (570°C/10-4 Torr) two stereoisomeric 6,9,15,18-tetramethoxy[3.3]metacyclophanes were obtained the assignment of which to the syn-constitution 3 and the anti-constitution 4 has been made on the basis of 1H NMR spectra. As experiments on thermal isomerisation show the conformational stability of 3/4 as well as 5/6 is remarkably high. - As side-products of the cyclisation of 11 and 12, and of the sulfone pyrolysis, resp., the compounds 13 - 16 were isolated.
    Notes: Mit dem Ziel der Synthese von Chinhydronen der [3.3]Metacyclophan-Reihe (z. B. 1 und 2) wurden die stereoisomeren 7,10,17,20-Tetramethoxy-2,13-dithia[4.4]metacyclophane (5/6) über die Vorstufen 8 - 12 synthetisiert. Aus den durch Oxidation von 5/6 erhaltenen Disulfonen entstanden durch Gasphasen-Vakuum-Pyrolyse (570°C/10-4 Torr) zwei stereoisomere 6,9,15,18-Tetramethoxy[3.3]metacyclophane, deren Zuordnung zur syn-Konstitution 3 und anti-Konstitution 4 aufgrund der 1H-NMR-Spektren getroffen wurde. Wie Versuche zur thermischen Isomerisierung zeigen, ist die konformative Stabilität von 3/4 wie auch von 5/6 bemerkenswert groß. - Als Nebenprodukte der Cyclisierung von 11 und 12 bzw. der Sulfon-Pyrolyse wurden die Verbindungen 13 - 16 isoliert.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19801130124
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  • 3
    Electronic Resource
    Electronic Resource
    Elektron-Donor-Acceptor-Verbindungen, XX. Intramolekulare Chinhydrone der [3.3]Metacyclophan-Reihe: Synthese, Struktur, Stabilität und Charge-Transfer-Absorptionen von stereoisomeren [3.3]Metacyclophan-Chinhydronen (1980)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 241-254 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Electron Donor-Acceptor Compounds, XX. Intramolecular Quinhydrones of the [3.3]Metacyclophane Series: Synthesis, Stability, and Charge Transfer Absorptions of Stereoisomeric [3.3]Metacyclophane QuinhydronesOn the attempt to synthesize the syn- and anti-[3.3]metacyclophane quinhydrones 1 and 2 by demethylation of 3 and 4, resp., and subsequent oxidation the same [3.3](2,6)-p-benzoquinonophane (5) was obtained which on catalytic hydrogenation yielded syn-[3.3]metacyclophane quinhydrone 1. Partial demethylation, however, and following oxidation led from 3 to the dimethyl ether 7 of the syn-quinhydrone 1, and analogously from 4 to the dimethyl ether 8 of anti-[3.3]-metacyclophane quinhydrone 2. The structural assignment of the stereoisomers was confirmed by an X-ray structure analysis of 7. In addition to 7 and 8, the corresponding monomethyl ethers 10 and 12 were obtained. - The anti-[3.3]metacyclophanes 8 and 12 undergo a complete thermal rearrangement to the syn-isomers 7 and 11, resp., from which a stronger ground state stabilisation by charge transfer interaction is concluded for the donor-acceptor systems of the syn-series. - The quinhydrones 7, 8, 10, 11, and 12 show broad, intensive charge transfer absorptions in the range from 300 to 550 nm which for the pairs of stereoisomers 7/8 and 11/12, in spite of the very different donor-acceptor orientation, are surprisingly similar: the absorption intensity of the CT band, however, is considerably stronger for the anti-quinhydrones than for their syn-isomers.
    Notes: Bei Versuchen zur Darstellung der syn- und anti-[3.3]Metacyclophan-Chinhydrone 1 und 2 wurde durch Demethylierung von 3 bzw. 4 und anschließende Oxidation dasselbe [3.3](2,6)-p-Benzochinonophan (5) erhalten, das durch katalytische Hydrierung syn-[3.3]Metacyclophan-Chinhydron 1 ergab. Partielle Demethylierung und anschließende Oxidation führten jedoch ausgehend von 3 zum Dimethylether 7 des syn-Chinhydrons 1 und entsprechend aus 4 zum Dimethylether 8 des anti-[3.3]Metacyclophan-Chinhydrons 2. Die Strukturzuordnung der Stereoisomeren wurde durch Röntgen-Strukturanalyse von 7 bestätigt. Neben 7 und 8 wurden die entsprechenden Monomethylether 10 und 12 erhalten. - Die anti-Verbindungen 8 und 12 lagern sich thermisch quantitativ in die syn-Isomeren 7 bzw. 11 um, woraus auf eine stärkere Grundzustands-Stabilisierung durch Charge-Transfer-Wechselwirkung bei den Donor-Acceptor-Systemen der syn-Reihe geschlossen wird. - Die Chinhydrone 7, 8, 10, 11 und 12 zeigen breite, intensive Charge-Transfer-Absorptionen im Bereich von 300 - 550 nm, die bei den Stereoisomeren-Paaren 7/8 und 11/12 trotz der sehr unterschiedlichen Donor-Acceptor-Orientierung überraschend ähnlich sind; die Absorptionsintensität der CT-Bande ist jedoch bei den anti-Chinhydronen beträchtlich größer als bei den syn-Isomeren.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19801130125
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  • 4
    Electronic Resource
    Electronic Resource
    Kinetische Untersuchungen der Reaktionen von Methylradikalen mit Allen (1983)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 325 (1983), S. 680-684 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Kinetic Studies of the Reactions of Methyl Radicals with AlleneThe addition of methyl radicals to allene has been studied in the temperature range 573…595 K. The methyl radicals were produced by thermal decomposition of azomethane. It has been shown that the additions take place with a very high selectivity at the terminal carbon atoms in allene. The rate constant k2 of the addition can be expressed by the following Arrhenius equation: \documentclass{article}\pagestyle{empty}\begin{document}$$ {\rm k}_{{\rm 2 }} = 10^{7,76 \pm 0,2} {\rm e}^{{{ - \left({28,6 \pm 1,0} \right){\rm kJmol}} \mathord{\left/ {\vphantom {{ - \left({28,6 \pm 1,0} \right){\rm kJmol}} {{\rm RT}}}} \right. \kern-\nulldelimiterspace} {{\rm RT}}}} {\rm M}^{ - 1} {\rm s}^{ - 1} $$\end{document}
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19833250418
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  • 5
    Electronic Resource
    Electronic Resource
    Elektron-Donor-Acceptor-Verbindungen, XXXIII. Intramolekulare Chinhydrone der [3.3]Paracyclophan-Reihe (1983)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 116 (1983), S. 3813-3830 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Electron Donor-Acceptor Compounds, XXXIII. Intramolecular Quinhydrones of the [3.3]Paracyclophane SeriesAs key intermediates for the synthesis of the [3.3]paracyclophane quinhydrones 1 and 2, the 2,13-dithia[4.4]paracyclophanes 5/6 were prepared. The disulfones 7/8 derived therefrom, by vapour phase pyrolysis, yielded the diastereomeric tetramethoxy[3.3]paracyclophanes 9 and 10. From 9 1 was obtained by demethylation and subsequent oxidation, and correspondingly the pseudogeminal isomer 2 from 10. The dimethyl ethers 3 and 4, derived from 1 and 2, were prepared starting from 7/8. Both pairs of isomers (1/2 and 3/4) demonstrate the strong dependence of charge-transfer absorptions on donor-acceptor orientations (Fig. 1). - The assignment of compounds 1--4 to the pseudoortho and pseudogeminal series, resp., was confirmed by X-ray structure analysis. Molecular and crystal structures of 4, 9, and 10 are discussed.
    Notes: Zur Synthese der [3.3]Paracyclophan-Chinhydrone 1 und 2 wurden die 2,13-Dithia[4.4]paracyclophane 5/6 dargestellt, deren Disulfone 7/8 durch Gasphasen-Pyrolyse die diastereomeren Tetramethoxy[3.3]paracyclophane 9 und 10 ergaben. Aus 9 erhielt man durch Demethylierung und anschließende Oxidation 1, aus 10 entsprechend 2. Die von 1 und 2 abgeleiteten Dimethylether 3 und 4 wurden aus 7/8 dargestellt. Beide Isomerenpaare (1/2 und 3/4) demonstrieren die starke Abhängigkeit der Charge-Transfer-Absorption von der Donor-Acceptor-Orientierung (Abb. 1). - Die Zuordnung der Verbindungen 1-4 zur pseudoortho- bzw. pseudogeminalen Reihe wurde durch Röntgenstrukturanalysen geklärt. Molekül- und Kristallstrukturen von 4, 9 und 10 werden diskutiert.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19831161206
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  • 6
    Electronic Resource
    Electronic Resource
    PVC and other major plastics in the European economy (1983)
    Brookfield, Conn. : Wiley-Blackwell
    Journal of Vinyl and Additive Technology 5 (1983), S. 4-8 
    Details
    ISSN: 0193-7197
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Following a decade of strong development of plastics consumption, the European market and the production of European manufacturers have fallen back into stagnation since the oil crisis of 1973, followed by the second oil-price explosior. of 1979. The author presents the reasons of the economic recession prevaling in the European plastics industry for a number of years, notwithstanding the temporary upsurge of 1979, in a review of aspects relative to internal economic government policies in Europe, relative to external trade and relative to the Community's policies towards Third World countries. Prospects for the European plastics industry are considered as a function of economic and industrial government policies in Europe, of development in third countries, and of new approaches by the European industry. The various aspects considered are illustrated in particular by the case of PVC, a typical representative of the major plastics reviewed.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/vnl.730050104
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