Synthesis of spacer-containing di- and tri-saccharides that represent parts of the capsular polysaccharide of Streptococcus pneumoniae type 6B

In the framework of studies towards oligosaccharide-conjugate-based vaccines against Streptococcus pneumoniae, the synthesis is reported of several spacer-containing oligosaccharides that represent parts of the capsular polysaccharide of S. pneumoniae serotype 6B, namely α-l-rhamnopyranosyl-(1→4)-5-O-(3-aminopropyl hydrogen phosphate)-d-ribitol, 3-aminopropyl d-ribitol-(5→hydrogen phosphate→2)-α-d-galactopyranoside, 3-aminopropyl α-l-rhamnopyranosyl-(1→4)-d-ribityl-(5→hydrogen phosphate→2)-α-d-galactopyranoside, and 3-aminopropyl d-ribityl-(5→hydrogen phosphate→2)-α-d-galactopyranosyl-(1→3)-α-d-glucopyranoside. Phosphorylations were carried out using the H-phosphonate method.