Novel syntheses of Idraparinux, the anticoagulant pentasaccharide with indirect selective factor Xa inhibitory activity

Idraparinux, the fully O-sulfated, O-methylated, heparin-related pentasaccharide possessing selective factor Xa inhibitory activity, was prepared by two novel synthetic pathways. Each route was based on a 2+3 block synthesis utilizing the same l-iduronic acid-containing trisaccharide acceptor, which was glycosylated with either a glucuronide disaccharide donor or its non-oxidized precursor. The latter route, involving the oxidation of the glucose unit into d-glucuronic acid at a pentasaccharide level proved to be much more efficient, providing the target pentasaccharide in a reasonable overall yield.