Synthesis of methyl O-alpha-L-rhamnopyranosyl-(1-->2)-alpha-D-galactopyranosides specifically deoxygenated at position 3, 4, or 6 of the galactose residue

Carbohydr Res. 1994 Jan 3:251:213-32. doi: 10.1016/0008-6215(94)84287-6.

Abstract

The title disaccharides were synthesized by condensation of 2,3,4-tri-O-benzoyl-alpha-L-rhamnopyranosyl bromide with suitably protected, deoxygenated derivatives of methyl alpha-D-galactopyranoside. Deoxygenation was achieved via activation of a protected methyl alpha-D-gluco- or galacto-pyranoside with N,N'-thiocarbonyldiimidazole followed by treatment with tributyltin hydride and azobisisobutyronitrile. At position 3, the deoxygenation was more successful when performed with the tri-O-benzoylated precursor, rather than the tri-O-benzylated one. The corresponding nucleophile was obtained by benzylidenation of the methyl 3-deoxy-alpha-D-xylo-hexopyranoside. The preparation of the glycosyl acceptor deoxygenated at position 4 could be pursued starting from derivatives having either the D-galacto or the D-gluco configuration. The pathway involving the former was found superior.

Publication types

  • Comparative Study

MeSH terms

  • Antibodies, Bacterial / immunology
  • Antigen-Antibody Reactions
  • Antigens, Bacterial / immunology
  • Carbohydrate Sequence
  • Disaccharides / chemical synthesis*
  • Epitopes / chemistry*
  • Fucose / analogs & derivatives*
  • Lipopolysaccharides / immunology
  • Molecular Sequence Data
  • Shigella dysenteriae / immunology

Substances

  • Antibodies, Bacterial
  • Antigens, Bacterial
  • Disaccharides
  • Epitopes
  • Lipopolysaccharides
  • methyl O-rhamnopyranosyl-(1-2)-3-deoxygalactopyranoside
  • methyl O-rhamnopyranosyl-(1-2)-4-deoxygalactopyranoside
  • methyl O-rhamnopyranosyl-(1-2)-6-deoxygalactopyranoside
  • Fucose