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  • Organic Chemistry  (2)
  • carboxyacetylquercinic acid derivatives  (1)
  • 1
    Digitale Medien
    Digitale Medien
    Amsterdam : Elsevier
    Phytochemistry 29 (1990), S. 923-928 
    ISSN: 0031-9422
    Schlagwort(e): Ganoderma sp. ; Polyporaceae ; anti-tumour promoter. ; carboxyacetylquercinic acid derivatives ; homolanostanoids
    Quelle: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Thema: Biologie , Chemie und Pharmazie
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The structure and absolute configuration of a new acetylenic alkaloid gephyrotoxin isolated from skin extracts of the Colombian frog Dendrobates histrionicus, has been determined by Röntgen-ray crystallography. Gephyrotoxin, previously referred to as HTX-D, is a novel tricyclic alkaloid, [1 S, 3aS, 5aS, 6S(Z), 9a R, 10 R]dodeca-hydro-6-(2-penten-4-yl)pyrrolo[1,2-a]quinoline-1-ethanol. Dihydrogephyrotoxin, a minor skin constituent, contains a 6-(2,4-pentadienyl)substituent. Two further spiropiperidine alkaloids related in structure to histrionicotoxin, (6 R[6α[2S*(Z)],[7β(Z), 8α]]7-(1-buten-3-ynyl)-2-(2-penten-4-ynyl)-1-azaspiro [5.5]undecan-8-ol), have been isolated from Dendrobates histrionicus: allodihydrohistrionicotoxin which differs from histrionicotoxin in having a 2-(4-pentynyl)-substituent, while allotetrahydrohistrio-nicotoxin, a minor constituent, has 2-(4-pentynyl)- and 7-(1,3-butadienyl)-substituents. Three alkaloids related in structure to pumiliotoxin C, ([2 S, 4a S, 5R, 8a R]5-methyl-2-n-propyl-cis-decahydroquinoline), have been isolated from Dendrobates histrionicus. These alkaloids, with molecular weights of 195, 223, and 269, have, respectively, a 2-butylsubstituent, 2-propyl and 5-propyl-substituents, and 2-(3,4-pentadienyl) and 5-(2-penten-4-ynyl)-substituents. The last compound was hydrogenated to a dodecahydro-derivative identical in molecular weight, but not in other properties, with authentic dodecahydro-8-deoxy-histrionicotoxin, which was prepared from histrionicotoxin. Gephyrotoxin, in contrast to histrionicotoxin and pumiliotoxin C, is a muscarinic antagonist.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Four analogs of the acetylenic alkaloid, histrionicotoxin (C19H25NO) and the allenic alkaloid, isodihydrohistrionicotoxin have been isolated from extracts of skins of the arrow poison frog, Dendrobates histrionicus and characterized as neodihydrohistrionicotoxin, tetrahydrohistrionicotoxin, isotetrahydrohistrionicotoxin and octahydrohistrionicotoxin. These spiropiperidine (8-hydroxy-1-azaspiro[5.5]undecane) alkaloids differ only in the degree of unsaturation in the five carbon atoms (position 2) and four carbon atoms (position 7) side chains. A fifth compound, HTX-D, corresponds in empirical formula to a tetrahydrohistrionicotoxin with a 7-(cis-1-butenyl-3-ynyl) side chain, but the major mass spectral fragmentation with loss of C2H5O is not characteristic of the histrionicotoxins. Reduction of histrionicotoxin with hydrogen and Lindlar catalyst affords an isomeric dihydrohistrionicotoxin with the terminal acetylene of the five carbon atoms side chain reduced, tetrahydrohistrionicotoxin and hexahydrohistrionicotoxins, while reduction with hydrogen and palladium on charcoal affords dodecahydrohistrionicotoxin which is readily methylated to the tertiary amine by methyl iodide.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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