Synthesis, NMR and Conformational Studies of Fucoidan Fragments, 8: Convergent Synthesis of Branched and Linear Oligosaccharides

Abstract

The brown seaweed polysaccharides fucoidans inhibit microbial adhesion, angiogenesis, P- and L-selectin-mediated inflammation, and blood coagulation. In this communication we report on the efficient highly stereoselective blockwise synthesis of linear and branched fucoidan chains related oligosaccharides α-L-Fucp-(1→3)-[α-L-Fucp-(1→3)] n -α-L-Fucp-OPr (n = 2, 4, 6), α-L-Fucp-( 1→)-[α-L-Fucp-(1→3)-oi-L-Fucp-(1→4)] n -α-L-Fucp-OPr (n = 1, 2), α-L-Fucp-(1→3)-α-L-Fucp-(1→3)-[α-L-Fucp-(1→2)]-α-L-Fucp-OPr and their derivatives bearing sulfonato groups at 02 or at 04 of fucose residues. [2+2], [2+4], and [4+4] Carbohydrate skeleton assembling strategies were applied for the synthesis oftetra-, hexa-, and octasaccharides, respectively. The target oligosaccharides are regarded as model compounds to assess the structure of fucoidan fragments responsible for their biological activity.