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  • 1
    Electronic Resource
    Electronic Resource
    Cyclodehydrogenation of 2′-hydroxychalcones with hypervalent iodine reagent: A new synthesis of flavonesDedicated to Prof. Dr. Sándor Makleit on the occasion of his 65th birthday. (1995)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1995 (1995), S. 1711-1715 
    Details
    ISSN: 0947-3440
    Keywords: Cyclodehydrogenation ; 2′-Hydroxychalcones ; Flavones ; Iodosobenzene diacetate ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new synthesis of chrysin (1) and luteolin (4) was accomplished by the cyclodehydrogenation of the appropriately substituted 2′-hydroxychalcones 21 and 22 in the presence of iodosobenzene diacetate/potassium hydroxide in methanol. The scope and limitation of this transformation is discussed.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.1995199509240
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  • 2
    Electronic Resource
    Electronic Resource
    Flavonoide, XXXIV Nucleophile Substitution an 3-(Alkyl- und 3-(Arylsulfonyloxy)flavanone; eine neue Methode zur Herstellung von 3-Aminoflavenonen (1979)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1979 (1979), S. 162-173 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Flavonoids, XXXIV.-Nucleophilic Substitution in 3-(Alkyl- and 3-(Arylsulfonyloxy)-favanones; a New Method for Synthesis of 3-AminoflavenonesTeilweise vorgetragen auf dem 5. Ungarischen Bioflavonoid-Symposium, Matrafüred, 1977; vgl.: T. Patonay, M. Rdkosi, Gy. Litkel, T. Mester und R. Bognár in Flavonoids and Bioflavonoids, Current Research Trends, Proceedings of the 5th Hungarian Bioflavonoid Symposium, M átrafured, 25-27 May 1977 (L. Farkas, M. Gábor und F. Kallay), S. 227, Akadémiai Kiado, Budapest und Elsevier, Amsterdam 1977.3-Hydroxyflavanones 1-4 and 3-hydroxyflavenone (14) react with alkane- and arenesulfonyl chlorides giving the corresponding 3-sulfonates 5-8, 10-13 and 15-20, respectively. 3-(Tosyl-oxy)flavanone (9)cannot be obtained. On reaction with azide ions, the 3-(methysulfonyloxy)fla-vanones 5-8 give the 3-azidoflavanones 25-28 with azide ions, which transform into the 3-aminoflavenones 21-24 in a base-induced, secondary reaction. The corresponding reaction is accompanied by a (3-elimination leading to flavenones 29-32. The ratio of products 21-24 29-32 is determined by the R1-substituent of ring B of the starting compounds 5-8. 3-Azidoflavanone (25) can be isolated on quenching of the reaction; compound 25 gives 3-aminoflavanone (36) and 3-(triphenylphosphoranediylamino)flavenone (39) on catalytic hydrogenation and treatment with triphenylphosphine, respectively.
    Notes: Die Umsetzungen der 3-Hydroxyflavanone 1-4 und des 3-Hydroxyflavenons (14) mit Alkan- und Arensulfonsäruechloriden liefern die entsprechenden 3-Sulfonate 5-8, 10-13 bzw. 15-20 Das 3-(Tosyloxy)flavanon (9) läßt sich nicht auf diese Weise herstellen. Die 3-(Methylsulfonyloxy)flavanone 5-8 bilden mit Azidionen 3-Azidoflavanone 25-28, die sich in einer baseninduzierten Sekundärreaktion zu 3-Aminoflavenonen 21-24 umsetzen. Daneben entstehen die ent sprechenden Flavenone 29-32. Das Produktverhältnis 21-24 29-32 wird durch den Substituenten R1 am Ring B der Ausgangsverbindungen 5-8bestimmt. Durch frühzeitigen Abbruch der Reaktion läßt sich das 3-Azidoflavanon (25) isolieren, das durch katalytische Hydrierung in das 3-Aminoflavanon (36) und mit Triphenylphosphin in das 3-(Triphenylphosphorandiylamino)-flavenon (39) übergeführt wird.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.197919790204
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  • 3
    Electronic Resource
    Electronic Resource
    Flavonoide, XXXV Herstellung von α-Azido-2′ -oxychalkonen und ihre Umwandlung in 3-Aminoflavenone (1979)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1979 (1979), S. 174-180 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Flavonoids, XXXV1.-Synthesis of α-Azido-2′-oxychalcones and Their Transformation into 3-AminoflavenonesTeilweise vorgetragen auf dem 5. Ungarischen Bioflavonoid-Symposium. Mátrafüred, 1977; vgl.: T. Patonay, M. Rákosi, Gy. Litkei, T. Mester und R. Bogná in Flavonoids and Bioflavonoids, Current Research Trends, Proceedings of the 5th Hungarian Bioflavonoid Symposium, Mátrafüred, 25-27 May 1977 (L. Farkas, M. Gábor und F. Kállay), S. 227, Akadémia Kiadó, Budapest und Elsevier, Amsterdam 1977.The regioselective reaction of the benzylacetophenone dibromides 5a-d with sodium azide in dimethylformamide affords a 9:1 mixture of α-azido-2′-oxychalcones 4a-dand isoxazoles 7a, b, d. On treatment with bases 4a and4d are transformed into 3-aminoflavenone (11), whereas 4b gives the same product with acid. 4a-c give 2′-oxy-a-(triphenylphosphoranediylamino)chalcones 14a-c with triphenylphosphine, whereas 4d yields 2,3-trans-3-(triphenylphophoranediylamino)-flavanone (15) under the same conditions.
    Notes: In einer regioselektiven Reaktion werden aus den Benzylacetophenondibromiden 5a-d mil Natriumazid in Dimethylformamid die α-Azido-2′-oxychalkone 4a-d und Isooxazole 7a, b und dim Verhältnis 9:1 hergestellt. Aus 4a und d erhält man mit Basen und aus 4b mit Sauren 3-Aminoflavenon (11). Mit Triphenylphosphin bilden 4a-c die 2′-Oxy-a-(triphenylphosphorandiylamino)chalkone 14a-c, während 4d 2,3-trans 25-3-(Triphenylphosphorandiylamino)flavanon (15) liefert.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.197919790205
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  • 4
    Electronic Resource
    Electronic Resource
    Liquid chromatography/thermospray mass spectrometry of monosaccharides and their derivatives (1992)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 27 (1992), S. 1271-1275 
    Details
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Thermospray (TSP) mass spectrometry has proved to be a useful technique for analysing various highly polar compounds. The use of a quadrupole mass spectrometer equipped with a thermospray/plasmaspray interface in the analysis of more than 30 monosaccharides and sugar derivatives is described. A 1:1 mixture of methanol or acetonitrile and 0.1 M aqueous ammonium acetate as eluent at 1 cm3 min-1 affords the best results. The correct setting of the capillary tip temperature and repeller voltage was fundamental for the ionization of carbohydrates. The/optimum values of these parameters were 240-250°C and 220-240 V, respectively. The thermospray mass spectra of most carbohydrates exhibit strong [M + NH4]+ ions which provide molecular mass information. The underivatized and derivatized monosaccharides could be grouped according to the presence or absence and the relative abundances of [M + NH4 - H2O]+, [M + H]+ and [M + NH4]+ ions.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/oms.1210271120
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