Syntheses of methyl glycosides of 6-deoxyheptoses
作者:
Gerald O. Aspinall,
Armando G. McDonald,
Ramesh K. Sood,
期刊:
Canadian Journal of Chemistry
(NRC Available online 1994)
卷期:
Volume 72,
issue 1
页码: 247-251
ISSN:0008-4042
年代: 1994
DOI:10.1139/v94-037
出版商: NRC Research Press
数据来源: NRC
摘要:
Methyl α-D-glycopyranosides of 6-deoxy-D-altro-heptose, 6-deoxy-D-manno-heptose, and 6-deoxy-D-talo-heptose have been prepared. Displacements of methyl 2,3,4-tri-O-benzylhexopyranoside 6-trifluoromethanesulfonates with potassium cyanide, followed by reduction of the resulting heptopyranosidurononitriles with diisobutylaluminum hydride, hydrolysis of the imine, further reduction with sodium borohydride, and catalyticO-debenzylation, give the corresponding methyl 6-deoxyheptopyranosides. Configurational change at C-4 of methyl 6-deoxy-7-O-tert-butyldiphenylsilyl-α-D-manno-heptopyranoside to give thetaloisomer was effected by oxidation followed by stereoselective reduction.1H nuclear magnetic resonance data of the glycosides, and gas chromatography of acetylated glycosides of (R)- and (S)-2-butanol serve to establish ring and enantiomeric configurations of the parent sugars when these are encountered as constituents of lipopolysaccharides or extracellular carbohydrate polymers, as inCampylobacterspecies.
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