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  • mass spectra  (2)
  • Best. von Organ. Säuren  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 8 (1982), S. 95-114 
    ISSN: 1573-1561
    Keywords: Sex pheromone ; Tenthredinidae ; Pikonema alaskensis ; hydrocarbons ; dienes ; synergists ; experimental design ; ozonolysis ; mass spectra ; methoxymercuration ; Hymenoptera
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The primary sex pheromone of the yellowheaded spruce sawfly,Pikonema alaskensis (Rohwer) (Hymenoptera: Tenthredinidae), was found to include a series of straight-chain hydrocarbon dienes, all with the double bonds in the 9 and 19 positions and all with the (Z, Z) configuration. The major components, of 29, 31, 33, 35, and 37 carbon atoms, were synthesized. In the field and the greenhouse, the synthetic dienes were far above control levels in activity but, at least during the first hours of bioassay, were somewhat less active than the female-derived materials on a weight basis. In the field, a mixture of all five synthetic dienes, in the proportions found in the females, was more attractive than any single one, on a mole basis. In addition, (Z, Z)-9,19 dienes of 28, 30, 32, 34, 36, 38, and 39 carbons have been detected in females in minor amounts. The first five were bioassayed, and each was found to be similar in activity to the 35-carbon component when compared on a weight basis. The synthetic dienes, while active by themselves, were strongly synergized by two, more polar, Florisil fractions derived from females. Experimental design considerations are discussed.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 10 (1984), S. 291-300 
    ISSN: 1573-1561
    Keywords: Sex pheromone ; Hymenoptera ; Ichneumonidae ; Syndipnus rubiginosus ; ethyl (Z)-9-hexadecenoate ; parasitoid ; Pikonema alaskensis ; mass spectra ; ozonolysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract A female-produced sex pheromone ofSyndipnus rubiginosus Walley (Hymenoptera: Ichneumonidae), a parasitoid of the yellowheaded spruce sawfly,Pikonema alaskensis (Rohwer) (Hymenoptera: Tenthredinidae), was isolated and identified from hexane extracts of 250 virgin females. Column chromatography (Florisil), gas chromatography, mass spectrometry, high performance liquid chromatography, and ozonolysis indicated the structure was ethyl (Z)-9-hexadecenoate. The optimum male response is at 300–1000 ng (3–10FE). No cross-attraction betweenS. rubiginosus and the sympatric sawfly parasitoidS. gaspesianus (Provancher) could be demonstrated.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Fresenius' Zeitschrift für analytische Chemie 264 (1973), S. 381-385 
    ISSN: 1618-2650
    Keywords: Acidität ; Steigerung durch Erdalkalisalze in organ. Lösungsmitteln ; Best. von Organ. Säuren ; Volumetrie ; Salzeffekt in organ. Lösungsmitteln
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Summary The acid strength of short-chain carboxylic acids in acetonitrile and acrylonitrile can, by addition of anhydrous alkaline earth perchlorates, be enhanced sufficiently to permit titration of the acid with a tertiary amine in the presence of acid anhydride. This salt effect has been studied by means of potentiometric and automatic thermometric titrations and two distinct mechanisms are thought to be involved: a metathetical reaction at low salt concentrations and a proton desolvation effect at high salt concentrations. High-resolution infra-red spectroscopy has been used to assess the extent of sol vent-cation interaction in acetonitrile. Several equations are used to describe the probable interactions taking place in such salt enhancement phenomena.
    Notes: Zusammenfassung Der Säuregrad von kurzkettigen Carbonsäuren in Acetonitril und Acrylnitril kann durch Hinzufügen von wasserfreien Perchloraten der Erdalkalien genügend gesteigert werden, um bei Vorhandensein von Säureanhydrid eine Titration der. Säure mit einem tertiären Amin zu ermöglichen. Dieser Salzeffekt wurde mit Hilfe von potentiometrischen und automatischen thermometrischen Titrationen untersucht, und es wird angenommen, daß dabei zwei verschiedene Vorgänge eine Rolle spielen: eine Austauschreaktion bei schwachen und ein Desolvatationseffekt bei hohen Salzkonzentrationen. Zur Beurteilung des Ausmaßes der Wechselwirkung zwischen Lösung und Kation in Acetonitril wurde die Infrarot-Spektroskopie mit hoher Auflösung benutzt. Die wahrscheinlich stattfindenden Reaktionsvorgänge werden anhand verschiedener Gleichungen beschrieben.
    Type of Medium: Electronic Resource
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