Article ID Journal Published Year Pages File Type
1349049 Tetrahedron: Asymmetry 2010 5 Pages PDF
Abstract

A convergent chemical synthesis of a pentasaccharide found in the O-specific polysaccharide of Escherichia coli O4:K3, O4:K6, and O4:K12 has been achieved in excellent yield. A [3+2] block synthetic strategy has been adopted to couple a disaccharide donor 11 with a trisaccharide acceptor 10 for the construction of the pentasaccharide derivative 12 which on deprotection furnished target pentasaccharide 1 as its 4-methoxyphenyl glycoside. Disaccharide thioglycoside donor 11 and trisaccharide acceptor 10 were prepared from suitably protected monosaccharide intermediates. Yields were excellent in all steps.

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4-Methoxyphenyl (3,4-di-O-acetyl-2-azido-2-deoxy-α-l-fucopyranosyl)-(1→3)-4,6-O-benzylidene-2-deoxy-2-N-phthalimido-β-d-glucopyranosideC38H38N4O13[α]D25=-16.8 (c 1.0, CHCl3)Source of chirality: d-glucosamine, l-fucose

4-Methoxyphenyl (4-O-acetyl-2-azido-2-deoxy-α-l-fucopyranosyl)-(1→3)-4,6-O-benzylidene-2-deoxy-2-N-phthalimido-β-d-glucopyranosideC36H36N4O12[α]D25=+19.4 (c 1.0, CHCl3)Source of chirality: d-glucosamine, l-fucose

4-Methoxyphenyl (6-O-acetyl-2,3,4-tri-O-benzyl-α-d-glucopyranosyl)-(1→3)-(4-O-acetyl-2-azido-2-deoxy-α-l-fucopyranosyl)-(1→3)-4,6-O-benzylidene-2-deoxy-2-N-phthalimido-β-d-glucopyranosideC65H66N4O18[α]D25=+15.2 (c 1.0, CHCl3)Source of chirality: d-glucosamine, l-fucose, d-glucose

4-Methoxyphenyl (2,3,4-tri-O-benzyl-α-d-glucopyranosyl)-(1→3)-(4-O-acetyl-2-azido-2-deoxy-α-l-fucopyranosyl)-(1→3)-4,6-O-benzylidene-2-deoxy-2-N-phthalimido-β-d-glucopyranosideC63H64N4O17[α]D25=-1.6 (c 1.0, CHCl3)Source of chirality: d-glucosamine, l-fucose, d-glucose

Phenyl (2,3,4,6-tetra-O-benzyl-α-d-glucopyranosyl)-(1→3)-2-O-acetyl-4-O-benzyl-1-thio-α-l-rhamnopyranosideC55H58O10S[α]D25=+3.2 (c 1.0, CHCl3)Source of chirality: l-rhamnose, d-glucose

4-Methoxyphenyl (2,3,4,6-tetra-O-benzyl-α-d-glucopyranosyl)-(1→3)-(2-O-acetyl-4-O-benzyl-α-l-rhamnopyranosyl)-(1→6)-(2,3,4-tri-O-benzyl-α-d-glucopyranosyl)-(1→3)-(4-O-acetyl-2-azido-2-deoxy-α-l-fucopyranosyl)-(1→3)-4,6-O-benzylidene-2-deoxy-2-N-phthalimido-β-d-glucopyranosideC112H116N4O27[α]D25=+10.8 (c 1.0, CHCl3)Source of chirality: d-glucose, l-rhamnose, l-fucose, d-glucosamine

4-Methoxyphenyl (α-d-glucopyranosyl)-(1→3)-(α-l-rhamnopyranosyl)-(1→6)-(α-d-glucopyranosyl)-(1→3)-(2-acetamido-2-deoxy-α-l-fucopyranosyl)-(1→3)-2-acetamido-2-deoxy-β-d-glucopyranosideC41H64N2O25[α]D25=+9.2 (c 1.0, CH3OH)Source of chirality: d-glucose, l-rhamnose, l-fucose, d-glucosamine

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