First synthesis of 3′-deoxy Lewisx pentasaccharide

The total synthesis of 3′-deoxy Lewisx pentasaccharide is reported. 4-O-Acetyl-2,6-di-O-benzoyl-3-deoxy-β-d-xylo-hexopyranosyl trichloroacetimidate was condensed with a diol of glucosamine to give a disaccharide, which was further fucosylated to a Lewisx trisaccharide analogue. Glycosylation of a lactoside diol with this trisaccharide provided a pentasaccharide, which after deprotection, afforded the target pentasaccharide.

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4-O-Acetyl-2,6-di-O-benzoyl-3-deoxy-β-d-xylo-hexopyranosyl trichloroacetimidateC24H22Cl3NO8[α]D = +20 (c 0.9, CHCl3)

Phenyl (4-O-acetyl-2,6-di-O-benzoyl-3-deoxy-β-d-xylo-hexopyranosyl)-(1 → 4)-6-O-benzyl-2-deoxy-2-phthalimido-1-thio-β-d-glucopyranosideC49H45NO13S[α]D = +17.4 (c 1.0, CHCl3)

Phenyl (4-O-acetyl-2,6-di-O-benzoyl-3-deoxy-β-d-xylo-hexopyranosyl)-(1 → 4)-[(2,3,4-tri-O-benzyl-α-l-fucopyranosyl-(1 → 3)]-6-O-benzyl-2-deoxy-2-phthalimido-1-thio-β-d-glucopyranosideC76H73NO17S[α]D = +3.3 (c 1.0, CHCl3)

2-(Trimethylsilyl)ethyl (4-O-acetyl-2,6-di-O-benzoyl-3-deoxy-β-d-xylo-hexopyranosyl)-(l → 4)-[(2,3,4-tri-O-benzyl-α-l-fucopyranosyl-(l → 3)]-6-O -benzyl-2-deoxy-2-phtalimido-β-d-glucopyranoside-(1 → 3)-(2,6-di-O-benzyl-β-d-galactopyranosyl)-(1 → 4)-2,3,6-tri-O-benzyl-β-d-glucopyranosideC122H131NO28Si[α]D = +6.2 (c 1.0, CHCl3)

2-(Trimethylsilyl)ethyl (3-deoxy-β-d-xylo-hexopyranosyl)-(1 → 4)-[(α-l-fucopyranosyl-(1 → 3)]-2-acetamido-2-deoxy-β-d-glucopyranoside-(1 → 3)-(β-d-galactopyranosyl)-(1 → 4)-2,-β-d-glucopyranosideC37H67NO24Si[α]D = −42.5 (c 0.4, CHCl3-MeOH1/1)