An effective synthesis of an arabinogalactan with a β-(1 → 6)-linked galactopyranose backbone and α-(1 → 2) arabinofuranose side chains Original Research Article

An octasaccharide, β-d-Galp-(1 → 6)-[α-l-Araf-(1 → 2)]-β-d-Galp-(1 → 6)-β-d-Galp-(1 → 6)-[α-l-Araf-(1 → 5)-α-l-Araf-(1 → 2)]-β-d-Galp-(1 → 6)-β-d-Galp-1 → OMP was synthesized. 4-Methoxyphenyl 2,3,4-tri-O-benzoyl-β-d-galactopyranoside (), 2,6-di-O-acetyl-3,4-di-O-benzoyl-α-d-galactopyranosyl trichloroacetimidate (), and 4-methoxyphenyl 2-O-acetyl-3,4-di-O-benzoyl-β-d-galactopyranoside (), 2,3,4,6-tetra-O-benzoyl-α-d-galactopyranosyl trichloroacetimidate (), and 2,3,5-tri-O-benzoyl-α-l-arabinofuranosyl trichloroacetimidate () were used as the synthons. A concise route was used to gain the tetrasaccharide donor by the use of , , , and . Meanwhile, treatment of with yielded β-(1 → 6)-linked disaccharide , and subsequent selective 6-O-deacetylation produced the disaccharide acceptor . Reaction of with gave , and subsequent selective 2-O-deacetylation afforded the hexasaccharide acceptor . Condensation of with α-l-(1 → 5)-linked arabinofuranose disaccharide , followed by deprotection, yielded the target octasaccharide.