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  • 1985-1989  (5)
  • 1975-1979  (6)
  • 1
    ISSN: 1520-6904
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 3879-3885 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Ring Contraction of 2,2-Dimethyl-2H-chromenes by Oxidation with Thallium(III) Nitrate. The Synthesis of CorylinExcept for the 5-acetoxy derivatives, which react very slowly, 2,2-dimethyl-2H-chromenes and 3,4-dihydro-2H-pyran are oxidized smoothly with TI(NO3)3. 2 H2O in methanol to give generally by ring contraction -3(dimethoxymethyl)-2,3-dihydrobenzofurans and -2(dimethoxymethyl)-tetrahydrofuran, respectively. Ring-contracted products were isolated as by-products in the synthesis of the pyranoisoflavone corylin (11).
    Notes: Mit Ausnahme der 5-Acetoxy-Derivate, die nur sehr langsam reagieren, unterliegen 2,2-Dimethyl-2H-chromene und 3,4-Dihydro-2H-pyran einer glatten Oxidation mit T1(NO3)3. 3H2O in Methanol, die im allgemeinen durch Ringverengung zu -3(Dimethoxymethyl)-2,3-dihydrobenzo-furanen bzw. -2(Dimethoxymethyl)tetrahydrofuran führt. Ringverengte Verbindungen wurden bei der Synthese des Pyranoisoflavons Corylin (11) als Nebenprodukte isoliert.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 109 (1976), S. 3811-3816 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Oxidative Rearrangement of Chalcones by Thallium(III) Nitrate, VI1 Synthesis of the Isoflavonoids Jamaicin and LeiocarpinInertness of the 2,2-dimethyl-2H-chromene system towards oxidation by Tl(NO3)3 makes possible the synthesis of the isoflavone jamaicin (1) and of the pterocarpan leiocarpin (4) from 6-acetyl-5-hydroxy-2,2-dimethyl-2H-chromene (9) by oxidative rearrangement of the corresponding chalcones (6,8).
    Notes: Die Unempfindlichkeit des 2,2-Dimethyl-2H-chromen-Systems gegen Oxidation mit TI(NO3)3 ermöglichte die von 6-Acetyl-5-hydroxy-2,2-dimethyl-2H-chromen (9) ausgehende Synthese des Isoflavons Jamaicin (1) und des Pterocarpans Leiocarpin (4) durch oxidative Umlagerung der entsprechenden Chalcone (6, 8).
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 480-483 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: A Novel Biomimetic Transformation of Chalcone Glycosides to Isoflavone GlycosidesAcetates of chalcone glucosides were oxidatively rearranged by thallium(III) nitrate in CH(OMe)3/, MeOH and the products cyclized with sodium methoxide to isoflavone glucosides. The pterocarpan medicarpin β-D-glucopyranoside (4) was prepared in an optically pure form.
    Notes: Acetate von Chalcon-glucosiden wurden mit Thallium(III)-nitrat in CH(OMe)3/MeOH oxidativ umgelagert und die Produkte mit Natriummethylat zu Isoflavon-glucosiden cyclisiert. Das Pterocarpan Medicarpin-β-D-glucopyranosid (4) wurde in optisch reiner Form hergestellt.
    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: Oxidative Rearrangement of Chalcones by Thallium(III) Nitrate, IV. The Synthesis of Dalpatin, Fujikinin, Glycitein and of Other Natural IsoflavonesThe synthesis of 7-hydroxy-2′,6-dimethoxy-4′,5′ -methylenedioxysoflavone-7-O-β-D-glucopyranoside (dalpatin, 1), 7-hydroxy-6-methoxy-3′,4′-methylenedioxyisoflavone (fujikinetin, 4), its 7-O-β-D-glucopyranoside (fujikinin, 6), 4′,7-dihydroxy-6-methoxyisoflavone (glucitein, 35), 6-hydroxy-2′,7-dimethoxy-4′,5′-methylenedioxy-(7) and 5,6,7-trimethoxy-3′,4′-methylenedioxyisoflavone (9), two constituents of Cordyla africana, further of 5,6,7,8-tetramethoxy-3′,4′-methylenedioxyiso-flavone (10) is described. 10 was not identical with an isoflavone from C. africana for which the same structure has been proposed.
    Notes: 7-Hydroxy-2′,6-dimethoxy-4′,5′-methylendioxyisoflavon-7-O-β-D-glucopyranosid (Dalpatin, 1), 7-Hydroxy-6-methoxy-3′,4′-methylendioxyisoflavon (Fujikinetin, 4), sein 7-O-β-D-glucopyranosid (Fujikinin, 6), 4′,7-Dihydroxy-6-methoxyisoflavon (Glycitein, 35) und zwei Inhaltsstoffe von Cordyla africana (6-Hydroxy-2′,7-dimethoxy-4′,5′-methylendioxy- (7) und 5,6,7-Trimethoxy-3′,4′-methylendioxyisoflavon (9)), weiterhin 5,6,7,8-Tetramethoxy-3′,4′-methylendioxyisoflavon (10) wurden hergestellt. 10 war mit einem Isoflavon aus C. africana, für das die gleiche Struktur vorgeschlagen worden war, nicht identisch.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1978 (1978), S. 107-117 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Acetals with Anionic Activation in Position 2: Sensitivity towards AlkaliAcetals 1-5 with a hydrogen atom in position 2, activated by a neighbouring carbonyl or cyano group, two ester groups, or one phenyl and one ester group, undergo alkali-catalysed alkoxy exchange and/or alcohol elimination (to vinyl ethers 6). In the presence of water they undergo hydrolysis.
    Notes: Die Acetale 1-5, die in 2-Stellung ein durch eine benachbarte Carbonyl- oder Nitrilgruppe, zwei Estergruppen oder eine Phenyl- und eine Estergruppe aktiviertes Wasserstoffatom enthalten, neigen zum alkalikatalysierten Alkoxyaustausch und/oder zur Alkoholabspaltung (zu den Vinylethern 6) sowie in Anwesenheit von Wasser zur Hydrolyse.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1989 (1989), S. 1141-1143 
    ISSN: 0170-2041
    Keywords: Liverwort ; Macrocyclic ether ; Marchantin I ; Riccardia multifida ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis of Marchantin I, a Macrocyclic Bis(bibenzyl Ether) from Riccardia multifidaThe unambigous synthesis of marchantin (1), a bis(bibenzyl ether) with a 18-membered ring, by Ullmann, Wittig, and modified Wurtz reaction is reported.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1985 (1985), S. 995-1003 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: An Attempted Synthesis of Multijuginol(3RS,3aSR,8aSR)-2,3,3a,8a-Tetrahydro-3-hydroxy-4,6-dimethoxy-4,6-dimethoxy-2,2-dimethylfuro[2,3-b]benzofuran (29), a partial structure of the title substance 2, was synthesized in 11 steps from phloroglucinol, but could not be transformed into rac-2. Some partly unexpected reactions of the intermediates, e.g. a pyridine-catalyzed transannular hydrogen migration (22 → 23), are described.
    Notes: (3RS, 3aSR,8aSR)-2,3,3a,8a-Tetrahydro-3-hydroxy-4,6-dimethoxy-2,2-dimethylfuro[2,3-b]benzofuran (29), eine Teilstruktur der Titelsubstanz 2, wurde aus Phloroglucin in 11 Schritten synthetisiert, konnte jedoch nicht in rac-2 übergeführt werden. Einige z. T. Unerwartete Reaktionen der Zwischenprodukte, u.a. eine durch Pyridin katalysierte transannulare Wasserstoffverschiebung (22 → 23), werden beschrieben.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1986 (1986), S. 2179-2181 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis of rac-5′-O-methylphaseollinisoflavanThe title substance 2 and its isomer 9 were synthesized from 4′,7-dihydroxy-2′-methoxy-isoflavone (4) in five steps.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1988 (1988), S. 555-558 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of the Natural Isoflav-3-enes Haginin A, B, and DThe synthesis of the title isoflav-3-enes haginin A (1), haginin B (2), and haginin D (4) as well as that of the isoflavan-4-one rac-lespedeol C (22) and of the pterocarpanes rac-nissolin (20) and rac-methylnissolin (21) by reduction of the corresponding isoflavones is described.
    Notes: Die Synthese der Isoflav-3-ene Haginin A (1), Haginin B (2) und Haginin D (4) sowie des Isoflavan-4-ons rac-Lespedeol C (22) und der Pterocarpane rac-Nissolin (20) und rac-Methylnissolin (21) durch Reduktion der entsprechenden Isoflavone wird beschrieben.
    Type of Medium: Electronic Resource
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