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  • 1
    Electronic Resource
    Electronic Resource
    Resolution of Pheromonal Epoxydienes by Chiral HPLC, Stereochemistry of Separated Enantiomers, and Their Field Evaluation (1997)
    Springer
    Journal of chemical ecology 23 (1997), S. 1403-1417 
    Details
    ISSN: 1573-1561
    Keywords: Chiral HPLC ; sex pheromone ; Lepidoptera ; Geometridae ; epoxydiene ; stereochemistry ; Mosher's method
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Resolution of insect pheromonal cis-epoxydiene racemates derived from (Z,Z,Z)-3,6,9-trienes with a C18–C23 chain was examined utilizing chiral HPLC columns, and the result showed that a Chiralpak AS column was suitable to separate enantiomers of the 3,4-epoxides, and a Chiralpak AD column was indispensable for the resolution of the racemic 6,7- and 9,10-epoxides. The absolute configuration of the enantiomers of the 3,4- and 9,10-epoxides separated by HPLC was studied after methanolysis of their epoxy rings. Examination of the 1H NMR data from esters of the methoxyalcohols produced by a modified Mosher's method with (S)- and (R)-α-methoxy-α-(trifluoromethyl)phenylacetic acid indicated that the dextrorotatory parent epoxides with a shorter R t were 3S,4R and 9S,10R isomers and the levorotatory enantiomers having a longer R t possessed 3R,4S and 9R,10S configuration. Field tests with both enantiomers of (Z,Z)-6,9-cis-3,4-epoxynonadecadiene separated by HPLC with the chiral column revealed new specific attraction of geometrid forest defoliators, Pachyerannis obliquaria, to the 3R,4S isomer and Zethenia albonotaria nesiotis to the 3S,4R isomer.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/B:JOEC.0000006472.12370.c6
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  • 2
    Electronic Resource
    Electronic Resource
    Sex attractants of geometrid and noctuid moths: Chemical characterization and field test of monoepoxides of 6,9-dienes and related compounds (1995)
    Springer
    Journal of chemical ecology 21 (1995), S. 299-311 
    Details
    ISSN: 1573-1561
    Keywords: Sex pheromone ; lepidopterous attractant ; field test ; monoepoxymonoene ; monoepoxydiene ; mass spectrum ; Geometridae ; Noctuidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract (Z,Z)-6,9-Dienes with straight C18–C23 chains were synthesized from linoleic acid, and a C17 chain was synthesized by hydrogenation of the corresponding 6,9-diyne prepared from propargyl alcohol. Oxidation of the homoconjugated dienes withm-chloroperoxybenzoic acid yielded a 1:1 mixture of two monoepoxides that could be separated by repeated medium-pressure liquid chromatography with a Lobar column. The chemical structure of each positional isomer was confirmed by analyses of the ozonolysis products, and the isomers showed characteristic13C signals in their NMR spectra and fragment ions in their EI mass spectra. In addition to the (Z,Z,Z)-3,6,9-trienes with straight C18–C23 chains and their monoepoxides, field tests using single source lures incorporating one of the above seven dienes and 14 monoepoxymonoenes were carried out in a forest in Tokyo from 1992 to 1994. Consequently, attraction of six geometrid species and five noctuid species was observed for the first time.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02036719
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  • 3
    Electronic Resource
    Electronic Resource
    13C NMR assignments of brassinosteroids by two-dimensional techniques (1993)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 31 (1993), S. 94-99 
    Details
    ISSN: 0749-1581
    Keywords: Brassinosteroids ; 13C NMR ; 2D NMR ; Brassinolide ; Steroids ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1H NMR spectra of eight naturally occurring brassinosteroids, plant hormones with a steroid skeleton, and five synthetic analogues were analysed by COSY and long-range COSY measurements. Based on the 1H resonances, the 13C signals were assigned by a combination of C—H COSY and long-range C—H COSY spectra detecting 13C nuclei, or by HMQC and HMBC spectra detecting 1H nuclei. Although the steroids showed complex 1H signals around 1-2 ppm, the resonances for the two angular methyl groups and the other methyl groups in the side-chain could be assigned unambiguously and used as a reference point for the other assignments. Strong correlation peaks between the methyl protons and carbons connected with the protons through two or three bonds were observed in the long-range C—H COSY or the HMBC spectra. These spectra provide valuable information for assigning the 13C NMR resonances of this class of compounds.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrc.1260310119
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