Synthesis of heparin fragments: a methyl alpha-pentaoside with high affinity for antithrombin III.

The synthesis is described of the methyl alpha-glycoside of the pentasaccharide which represents the sequence in heparin responsible for binding and activation of the anticoagulant protein Antithrombin III. It was obtained in a yield much better than that of the previously synthesised pentasaccharide and exhibited the same biological properties.