Synthesis of the pentasaccharide related to the repeating unit of the antigen from Shigella dysenteriae type 4 in the form of its methyl ester 2-(trimethylsilyl)ethyl glycoside Original Research Article

Starting from d-mannose, d-glucose and l-fucose, the pentasaccharide derivative methyl 2,3,4-tri-O-benzyl-α-l-fucopyranosyl-(1→3)-2-O-acetyl-4,6-O-benzylidene-α-d-mannopyranosyl-(1→3)-2-O-acetyl-6-O-benzyl-4-O-(2,3,4-tri-O-benzyl-α-l-fucopyranosyl)-α-d-mannopyranosyl-(1→4)-[2-(trimethylsilyl)ethyl 2,3-di-O-benzyl-β-d-glucopyranosid]uronate was synthesized. This compound with two α-mannopyranosyl units was transformed, via Walden inversion and subsequent deprotection, into the α-d-glucosamine-type target compound, namely methyl α-l-fucopyranosyl-(1→3)-2-acetamido-2-deoxy-α-d-glucopyranosyl-(1→3)-2-acetamido-2-deoxy-4-O-(α-l-fucopyranosyl)-α-d-glucopyranosyl-(1→4)-[2-(trimethylsilyl)ethyl β-d-glucopyranosid]uronate which is related to the repeating unit of the O-antigen from Shigella dysenteriae type 4.