Streptococcus pneumoniae type XIV polysaccharide: synthesis of a repeating branched tetrasaccharide with dioxa-type spacer-arms |
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Authors: | Paul-Henri Amvam-Zollo and Pierre Sinaÿ |
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Institution: | Laboratoire de Biochimie Structurale, U.A. 499, U.E.R. de Sciences Fondamentales et Appliquées, B.P. 6759, F-45067 Orléans France |
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Abstract: | β-Glycosides of 2-acetamido-2-deoxy-
-glucopyranose were synthesized, using either 7-methoxycarbonyl-3,6-dioxa-1-heptanol or 8-azido-3,6-dioxa-1-octanol. Selective β-lactosylation of 7-methoxycarbonyl-3,6-dioxaheptyl 2-acetamido-3-O-benzyl-2-deoxy-β-
-glucopyranoside with hepta-O-acetyl-lactosyl-trichloroacetimidate, followed by β-galactosylation of the secondary hydroxyl group with O-(2,3,4,6-tetra-O-acetyl- -
-galactopyranosyl)trichloroacetimidate, catalytic hydrogenolysis, and O-deacetylation, gave 7-methoxycarbonyl-3,6-dioxaheptyl 2-acetamido-2-deoxy-4-O-β-
-galactopyranosyl-6-O-(4-O-β-
-galactopyranosyl-β-
-glucopyranosyl)β-
-glucopyranoside. Selective β-lactosylation of 8-azido-3,6-dioxaocytl 2-acetamido-3-O-benzyl-2-deoxy-β-
-glucopyranoside with hepta-O-acetyl-lactosyl bromide in the presence of silver triflate, followed by condensation with 2,3,4,6-tetra-O-acetyl- -
-galactopyranosyl bromide in the presence of silver triflate, catalytic hdyrogenolysis, and O-deacetylation, gave 8-azido-3,6-dioxaoctyl 2-acetamido-2-deoxy-4-O-β-
-galactopyranosyl-6-O-(4-O-β-
-galactopyranosyl-β-
-glucopyranosyl)-β-
glucopyranoside. |
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Keywords: | |
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