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  • 1
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 64 (1981), S. 449-457 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The configurational isomers of astaxanthin (3,3′-dihydroxy-β,β-carotene-4,4′-dione) from the flesh of salmon (Salmo salar and Oncorhynchus) caught at different places in Europe and Canada were isolated and analyzed as (-)-camphanic acid diesters by means of HPLC. The biological variation in the composition of the configurational isomers in seven fish was surprisingly similar: 78 to 85% of (3S, 3′S)-astaxanthin, 12 to 17% (3R, 3′R)-astaxanthin and 2 to 6% meso-astaxanthin.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Astaxanthin (1; 3,3′-dihydroxy-β,β-carotene-4,4′-dione) isolated from lobster eggs (Homarus gammarus) was unexpectedly found to be a mixture of all three optical isomers as determined by HPLC. analysis of the corresponding diesters of (-)-camphanic acid. This is the first finding of meso-astaxanthin and a meso-carotenoid in general in nature.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: α-IsobufalinSystematic names are given at the titles of the Exper. Part. (1) and β-isoresibufogenin (3) have been synthesized from testosterone by a method which features a novel oxidative furan to pyrone transformation.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 1010-1019 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Transition Metal Carbyne Complexes, LII. (Tricarbonylchromium)-η6-phenyl as Substituent in Carbene- and Carbyne Complexes of the VI. SubgroupThe reaction of tricarbonyl(η6-phenyllithium)chromium with the metalhexacarbonyls of the VI. subgroup and subsequent alkylation by triethyloxonium tetrafluoroborate yields pentacarbonyl-{ethoxy[(tricarbonylchromium)-η6-phenyl]carbene} complexes of chromium, molybdenum, and tungsten (1 - 3). 1 and 3 react with boron trihalides BX3 (X = Cl, Br) by cleavage of the ethoxy group to form trans-tetracarbonylhalogeno[(tricarbonylchromium)-η6-phenylcarbyne]metal complexes 4 - 7. Properties, spectroscopic results, and the X-ray structure analysis of 6 are discussed.
    Notes: Die Umsetzung von Tricarbonyl(η6-phenyllithium)chrom mit den Metallhexacarbonylen der VI. Nebengruppe und anschließende Alkylierung mittels Triethyloxonium-tetrafluoroborat führt zu Pentacarbonyl{ethoxy[(tricarbonylchrom)-η6-phenyl]carben}-Verbindungen des Chroms, Molybdäns und Wolframs (1 - 3). 1 und 3 reagieren mit den Bortrihalogeniden BX3 (X = Cl, Br) unter Abspaltung der Ethoxygruppe zu den trans-Tetracarbonylhalogeno[(tricarbonylchrom)-η6-phenylcarbin]metall-Komplexen 4 - 7. Eigenschaften und spektroskopische Ergebnisse sowie die Röntgenstrukturanalyse von 6 werden diskutiert.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reaction of Metal and Metalloid Compounds with Polyfunctional Molecules, XXXIII. The Reaction of Propargylamines and N-Organyl-N-(trimethylsilyl)propargylamines with Boron-Halogen and Boron-Sulfur CompoundsThe N-organyl-N-(trimethylsilyl)propargylamines 1-5 are obtained from N-organylpropargylamines with chlorotrimethylsilane and triethylamine. The reaction of 1-5 with halogenoboranes, organylhalogenoboranes, or methylbis(methylthio)borane leads to the (organylpropargylamino)boranes 6-13. On the other hand, in the reaction of N-organylpropargylamines with halogenoboranes the C≡C triple bond inserts into the halogen-boron bond and yields the 1-azonia-2-borata-3-cyclopentene system 14-19 by intramolecular coordination. N-Organyl-N(trimethylsilyl)propargylamines react with bromodimethylborane in the molar ratio 1:2 under elimination of trimethylborane to give the 1-aza-2-bora-3-cyclopentene ring system 20-24. In the reaction of N-organyldipropargylamines with halogenoboranes both C≡C triple bonds insert into boronhalogen bonds to form the 1-azonia-5-boratabicyclo[3.3.0]octa-3,6-diene system 25-38. Tripropargylamine reacts with trichloro- and tribromoborane under three-fold insertion and intramolecular coordination to yield the 3,7,10-trihalogeno-1-azonia-5-boratatricyclo[3.3.3.01,5]undeca-3,6,10-trienes 39 and 40. For 39 the X-ray structure is reported.
    Notes: N-Organyl-N-(trimethylsily)propargylamine (1-5) werden aus N-Organylpropargylaminen mit Chlortrimethylsilan unter Zusatz von Triethylamin dargestellt. Die Reaktion von 1-5 mit Halogenboranen, Organylhalogenboranen bzw. Methylbis(methylthio)boran führt zu den entsprechenden (Organylpropargylamino)-boranen 6-13. Bei der Umsetzung der nicht silylierten N-Organylpropargylamine mit Halogenboranen erfolgt dagegen Einschiebung der C≡C-Dreifachbindung in die Halogen-Bor-Bindung und intramolekulare Koordination zum 1-Azonia-2-borata-3-cyclopenten-System 14-19. N-Organyl-N-(trimethylsily)propargylamine reagieren mit Bromdimethylboran im Molverhältnis 1:2 unter Abspaltung von Trimethylboran zum 1-Aza-2-bora-3-cyclopenten-Ring 20-24. Bei der Umsetzung von N-Organyldipropargylaminen mit Halogenboranen erfolgt Einschiebung der beiden C≡C-Dreifachbindungen in zwei Bor-Halogenbindungen wobei das 1-Azonia-5-boratabicyclo[3.3.0]octa-3,6-dien-Ringsystem 25-38 entsteht. Tripropargylamin reagiert mit Trichlor- bzw. Tribromboran unter dreifacher Einschiebung und intramolekularer Koordination zum 3,7,10-Trihalogen-1-azonia-5-boratatricyclo[3.3.3.01,5]undeca-3,6,10-trien-System 39 und 40. Für 39 wird die Röntgenstruktur mitgeteilt.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Hog thyrocalcitonin has been isolated in the form of an homogeneous peptide. After digestion with trypsin three fragments have been separated by paper electrophoresis. the amino acid composition of intact thyrocalcitonin and of the three tryptic fragments is given in a table.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
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