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  • 1
    Electronic Resource
    Electronic Resource
    Structural Variations of N-Acetylneuraminic Acid, 10. Synthesis of 2,7-, 2,8-, and 2,9-Dideoxy- and 2,4,7-Trideoxy-2,3-didehydro-N-acetylneuraminic Acids and Their Behavior Towards Sialidase from Vibrio cholerae (1989)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1989 (1989), S. 159-165 
    Details
    ISSN: 0170-2041
    Keywords: N-Acetylneuraminic acid ; Sialidase ; Vibrio cholerae ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Strukturelle Abwandlungen an N-Acetylneuraminsäure, 101). - Synthese von 2,7-, 2,8- und 2,9-Didesoxy- und 2,4,7-Tridesoxy-2,3-didehydro-N-acetylneuraminsäure und ihr Verhalten gegenüber Sialidase aus Vibrio choleraeDie peracetylierten Methylester-Derivate von 7-Desoxy-Neu5Ac (2c), 8-Desoxy-Neu5Ac (3a), 9-Desoxy-Neu5Ac (4a) und 4,7-Didesoxy-Neu5Ac (5a) wurden mit Trifluormethansulfonsäuretrimethylsilylester in die entsprechenden 2-Desoxy-2,3-didehydro-Derivate 2b-5b umgewandelt, wobei auch in wechselnder Menge die 4,5-Oxazolino-Abkömmlinge 6b-8b gebildet wurden. Hydrolyse von 2b-5b führte zu den freien Säuren 7-Desoxy-Neu5Ac2en (2c), 8-Desoxy-Neu5Ac2en (3c), 9-Desoxy-Neu5Ac2en (4c) und 4,7-Didesoxy-Neu5Ac2en (5c). Diese hemmen die Hydrolyse von 4-Methylumbelliferyl-α-Neu5Ac durch Sialidase aus Vibrio cholerae in einem signifikant unterschiedlichen Ausmaß. Der Vergleich ihrer ermittelten α-Seitenprofile mit demjenigen von Neu5Ac2en ermöglicht ein Verständnis für den sehr unterschiedlichen Einfluß auf die Enzymreaktion.
    Notes: The peracetylated methyl ester derivatives of 7-deoxy-Neu5Ac (2a), 8-deoxy-Neu5Ac (3a, 9-deoxy-Neu5Ac (4a), and 4,7-dideoxy-Neu5Ac (5a) were transformed by trimethylsilyl trifluoromethanesulfonate into the corresponding 2-deoxy-2,3-didehydro derivatives 2b-5b. As additional products, the 4,5-oxazolino derivatives 6b-8b were formed. Hydrolysis of 2b-5b yielded the free acids 7-deoxy-Neu5Ac2en (2c), 8-deoxy-Neu5Ac2en (3c), 9-deoxy-Neu5Ac2en (4c), and 4,7-dideoxy-Neu5Ac2en (5c). They showed significantly different inhibitory influences on the hydrolysis of 4-methylumbelliferyl-α-Neu5Ac by sialidase from Vibrio cholerae. The comparison of their evaluated α-side profiles with that of Neu5Ac2en (1c) enables a suitable explanation of their different inhibitory potencies.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198919890131
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  • 2
    Electronic Resource
    Electronic Resource
    Structural Variations on N-acetylneuraminic acid, 20. Synthesis of some 2,3-didehydro-2-deoxysialic Acids structurally varied at C-4 and their behavior towards Sialidase from Vibrio cholerae (1991)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1991 (1991), S. 129-134 
    Details
    ISSN: 0170-2041
    Keywords: N-Acetylneuraminic acid ; Sialidase ; Vibrio cholerae ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The peracetylated methyl ester 1 of N-acetylneuraminic acid was transformed into the oxazoline derivative 2, which was hydrogenated with Pd/C/H2 to give the 4-deoxy-Neu5Ac2en derivative 3. Acid cleavage of the oxazoline 2 by trifluoroacetic acid (THF) gave the 4-epi-Neu5Ac2en derivative 4a, which was saponified to the known 4-epi-Neu5Ac2en 4b. Treatment of 4a with triphenylphosphane/diethylazodicarboxylate (DEAD)/HN3 in toluene gave the 4-azido-4-deoxy-Neu5Ac2en derivative 5a as well as the 4-epi-azido-4-deoxy-Neu5Ac2en derivative 6a. Both epimers could be saponified yielding the free dehydrosialic acid derivatives 5b and 6b. Furthermore, 4-formamido-4-deoxy-Neu5Ac2en 7b was prepared via the derivative 7a, which was formed from 5a by reaction with triphenylphosphane/formyl acetate. In addition, the free dehydrosialic acid derivatives 5b and 6b were transformed into the stable P—N ylides 8 and 10, but only 8 could be hydrolyzed to the triethylammonium salt of 4-amino-4-deoxy-Neu5Ac2en 9a, which was converted into the zwitter ionic compound 9b. Finally 4-acetamido-4-deoxy-Neu5Ac2en 11e was prepared from 4-acetamido-4-deoxy-N-acetylneuraminic acid 10 via the derivatives 11a and 11b by well-known methods. The compounds 4b, 5b, 6b, 7b, 9b, and 11c were investigated as inhibitors of Vibrio cholerae sialidase, and their Ki values were determined.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199119910124
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    Paper (German National Licenses)
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