ISSN:
0170-2041
Keywords:
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Description / Table of Contents:
Glycosyl Imidates, 161).- Synthesis of the Trisaccharide of the Repeating Unit of the Capsular Polysaccharide of Neisseria meningitidis (Serogroup L)D-Glucal was transformed into the O-benzyl-protected O-(2-azido-2-deoxy-α-D-glucopyranosyl)trichloroacetimidate 5 suitable as glucosyl donor. Compound 5 yielded with 3-O-unprotected 2-azido-2-deoxy-D-glucose derivative 12 as acceptor, also obtained from D-glucal, under Et2O- BF3 catalysis exclusively the β-(1 → 3) linked disaccharide 13. Compound 13 was transformed into the disaccharide donor α-trichloroacetimidate 15 which yielded with compound 12 as acceptor β-specifically the trisaccharide 16. Removal of the 1-O-silyl protective group, reduction of the azido groups, hydrogenolytic debenzylation, and peracetylation gave the per-O-acetylated trisaccharide β-D-GlcNAc-(1 → 3)-β-D-GlcNAc-(1 → 3)-β-D-GlcNAc from the repeating unit of the capsular polysaccharide of Neisseria meningitidis (Serogroup L).
Notes:
Aus D-Glucal wurde das O-benzylgeschützte O-(2-Azido-2-desoxy-α-D-glucopyranosyl)trichloracetimidat 5 als Glucosyldonor synthetisiert, das mit dem aus D-Glucal erhaltenen 3-O-ungeschützten 2-Azido-2-desoxy-D-glucose-Derivat 12 als Akzeptor unter Et2O- BF3-Katalyse ausschließlich das β-(1 → 3)-verknüpfte Disaccharid 13 lieferte. Überführung in das α-Trichloracetimidat 15 als Disaccharid-Donor führte dann mit dem Glycosylakzeptor 12 ebenfalls β-spezifisch zum Trisaccharid 16. Abspaltung der 1-O-Silylschutzgruppe, Reduktion der Azidgruppen, hydrogenolytische Debenzylierung und Peracetylierung lieferte das per-O-acetylierte Trisaccharid β-D-GlcNAc-(1 → 3)-β-D-GlcNAc-(1 → 3)-β-D-GlcNAc aus der „Repeating Unit“ des Kapselpolysaccharids von Neisseria meningitidis (Serogruppe L).
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/jlac.198519850803
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