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  • 1
    Electronic Resource
    Electronic Resource
    Partial Purification and Characterization of Raucaffricine β-D-Glucosidase from Plant Cell-Suspension Cultures of Rauwolfia serpentina BENTH (1986)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 69 (1986), S. 538-547 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A novel highly substrate-specific Rauwolfia enzyme, raucaffricine β-D-glucosidase, was isolated from cell-suspension cultures of R. serpentina. The enzyme has been purified ca. 1350-fold, its major characteristics such as Mr = 66600 ± 5%, pH optimum 5.1, temperature optimum 38°, and inhibition of its activity by glucose and fructose were investigated. Its limited distribution in different cell cultures and differentiated plants indicates that the enzyme is present in significant amounts exclusively in cultured Rauwolfia cells.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19860690303
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  • 2
    Electronic Resource
    Electronic Resource
    Synthesis of Chiral 12-Phenyl(2H)dodecanoic Acids: Useful metabolic probes for the biosynthesis of 1-alkenes from fatty acids (1989)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 72 (1989), S. 917-928 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis of chiral 12-phenyi(2H)dodecanoic acids as metabolic probes for the evaluation of the stereo-chemical course of the biosynthesis of 1-alkerses from fatty acids in plants and insects is described. The diastereoisomeric (2R, 3R)- or (2S, 3S)-12-phenyl(2,3-2H2)dodecanoic acids 11 are obtained in high chemical and optical yield (〉97% e.e.) from the readily available (E)-12-phenyl(2,3-2H2)dodec-2-enoic acid (10) or (E)-12-phenyldodec-2-enoic acid (10a) by microbial reduction with wet packed cells of Clostridium tyrobutyricum in either 2H2O or H2O buffer. (2R)- and (2S)-12-phenyl(2-2H)dodecanoic acids 9 (〉97% e.e.) are accessible from the allylic alcohol 6 via Sharpless epoxidation with (+)-L- or (-)-D-diethyl tartrate, Synthetic routes to the (E)- and (Z)-11-phenyl(1-2H) undec-1-enes 16 and 16a as reference compounds are also included.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19890720507
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  • 3
    Electronic Resource
    Electronic Resource
    Stereochemical Studies on Homoterpene Biosynthesis in Higher Plants; Mechanistic, Phylogenetic, and Ecological Aspects (1991)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 74 (1991), S. 1773-1789 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In higher plants, the two homotcrpenes 4,8-dimethylnona-l,3,7-triene (1) and 4,8,12-trimethyltrideca-1,3,7,11-teiracnc (2) originate from nerolidol (3) or geranyllinalool (4) by anoxidative cleavage of their C-skele-lons. The reaction proceeds with exclusive loss of H8-C(5) of 3 and formal production of a C4 fragment. The site specificity of the enzyme(s) is identical for all of the hitherto examined plant families (Agavaceae, Asclepiadaceae, Asteraceae, Leguminosae, Magnoliaceae, and Saxifragaceae). The enzyme tolerates a wide range of structural modifications at the polar head of 3. Instead of 3, also gcranylacclone 12 and the secondary alcohol 13 can be cleaved to the homoterpene 1 and as yet unidentified carbonyl fragments. The C=C bonds within the aliphatic chain of 3 seem to be essential for the oxidative bond cleavage as well as for recognition and embedding of the substrate into the active center of the enzyme(s). The feed-induced biosynthesis of 1 and 2 in leaves of the Lima bean Phaseolus lunatm infested with the spider mite Tetranychus urticae probably requires a preceding release of nerolidol (3) or geranyllinalool (4) from phylogenic glycosides prior to the fragmentation reaction. The microbial reduction of the trienoic acids 6 and 6ais the key stop for the synthesis of deuterium labelled nerolidol (3RS,5R)-and (3RS,5S)-9.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19910740820
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  • 4
    Electronic Resource
    Electronic Resource
    Hofmann-Abbau Tritium-markierter quartärer Ammoniumjodide mit PhenyllithiumHerrn Prof. Dr. G. Wittig zum 65. Geburtstag (1962)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 654 (1962), S. 111-118 
    Details
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Durch Hofmann-Abbau von Trimethyl-äthyl[2-T]-ammoniumjodid und Trimethyl-n-propyl[2-T]-ammoniumjodid mit Phenyllithium wurde eine α´.β-Eliminierung nach Wittig1) bewiesen. Dabei treten äußerst kleine Isotopeneffekte auf. Frühere Ergebnisse2), nach denen der Hofmann-Abbau des Trimethyl-äthyl-ammoniumhydroxyds bei 40° i. Vak. nach dem β-Eliminierungs-Mechanismus verläuft, werden bestätigt, hingegen sind die Angaben2), wonach bei Temperaturen über 100° die α'.β-Eliminierung eine Rolle spielt und eine Tritium-markierte Methylgruppe einen “Ausgleichseffekt” zeigt, aus experimentellen Gründen zu revidieren.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.19626540112
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  • 5
    Electronic Resource
    Electronic Resource
    Darstellung neuer Azo-alkene und Derivate, insbesondere Additionsprodukte CH-acider VerbindungenHerrn Prof. Dr. Hans Beyer zum 65. Geburtstag gewidmet. (1971)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 745 (1971), S. 193-203 
    Details
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of New Azo-alkenes and Derivatives, Especially Addition Products with CH-activated CompoundsBesides other so far unknown benzeneazo-ene compounds, benzeneazoethylene (1a) and 2-benzeneazopropylene (1b) have been prepared from chloroacetaldehyde, chloroacetone or acetone according to Ortoleva-King, via the pyridinio-phenylhydrazone halides. The benzeneazo-ene system 1 adds sodium hydrogen sulfite, acetic acid and compounds with activated C-H bonds, such as diethyl malonate, to the phenylhydrazones 2c-2k. The addition of acetoacetic ester to 1 is followed by water elimination under formation of the hexahydrocinnolin derivative 5. 2-Pyridiniocyclohexanone semicarbazone chlorides 6 eliminate pyridine also. N-phenylcarbamidazo-cyclohexene 7b exists in solution, adds 2.4-dinitrothiophenol forming 8, and rearranges to the ene-semicarbazone 9b.
    Notes: Neben anderen bisher unbekannten Benzolazo-en-Verbindungen werden Benzolazoäthylen (1a) und 2-Benzolazo-propylen (1b) aus Chloracetaldehyd bzw. Chloraceton oder Aceton nach Ortoleva-King über die Pyridinio-phenylhydrazon-halogenide dargestellt. Das Benzolazo-en-System 1 addiert Natriumhydrogensulfit, Essigsäure sowie CH-acide Verbindungen, wie Malonsäurediäthylester und andere Malonsäure-Derivate, zu den Phenylhydrazonen 2c-2k. Bei der Addition von Acetessigester an 1 hingegen erfolgt Wasser-Abspaltung zum Hexahydrocinnolin-Derivat 5. 2-Pyridinio-cyclohexanonsemicarbazonchloride 6 eliminieren ebenfalls Pyridin. In Lösung kann 1-[N-Phenyl-carbamoylazo]-cyclohexen (7b) in Form des Additionsproduktes 8 nachgewiesen werden. 7b lagert sich in das En-semicarbazon 9b um.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.19717450123
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