Synthetic studies on glycosphingolipids from protostomia phyla: synthesis of glycosphingolipids and related carbohydrate moieties from the parasite Schistosoma mansoni.

Stereocontrolled syntheses of three neutral glycosphingolipids and six oligosaccharide derivatives found from the parasite Schistosoma mansoni have been accomplished. A pentasaccharide glycosphingolipid β-d-Galp-(1→4)-[α-l-Fucp-(1→3)]-β-d-GlcpNAc-(1→3)-β-d-GalpNAc-(1→4)-β-d-Glcp-(1↔1)-Cer (1), two hexasaccharide glycosphingolipids α-l-Fucp-(1→3)-β-d-Galp-(1→4)-[α-l-Fucp-(1→3)]-β-d-GlcpNAc-(1→3)-β-d-GalpNAc-(1→4)-β-d-Glcp-(1↔1)-Cer (2) and β-d-Galp-(1→4)-[α-l-Fucp-(1→3)]-β-d-GlcpNAc-(1→3)-β-d-GlcpNAc-(1→3)-β-d-GalpNAc-(1→4)-β-d-Glcp-(1↔1)-Cer (3), together with their non-reducing end tri- and tetrasaccharides, β-d-Galp-(1→4)-[α-l-Fucp-(1→3)]-β-d-GlcpNAcOR (4) and α-l-Fucp-(1→3)-β-d-Galp-(1→4)-[α-l-Fucp-(1→3)]-β-d-GlcpNAcOR (5), were synthesized by block synthesis. Moreover, non-reducing end oligosaccharides of schistosomal glycosphingolipids, β-d-GalpNAc-(1→4)-[α-l-Fucp-(1→3)]-β-d-GlcpNAcOR (6), α-l-Fucp-(1→3)-β-d-GalpNAc-(1→4)-[α-l-Fucp-(1→3)]-β-d-GlcpNAcOR (7), α-l-Fucp-(1→3)-β-d-GalpNAc-(1→4)-[α-l-Fucp-(1→2)-α-l-Fucp-(1→3)]-β-d-GlcpNAcOR (8) and α-l-Fucp-(1→3)-β-d-GalpNAc-(1→4)-[α-l-Fucp-(1→2)-α-l-Fucp-(1→2)-α-l-Fucp-(1→3)]-β-d-GlcpNAcOR (9) [R=2-(trimethylsilyl)ethyl], were synthesized as probes to explore their diagnostic potential to detect schistosomiasis from patients’ sera.