Synthesis of N-aminoacyl-β-glycopyranosylamines — derivatives of natural sialooligosaccharides

Abstract

A synthesis of aminospacered N-β-glycosides of tri-, penta-, hexaand nonasaccharides containing one or two α-D-Neu5Ac residue, namely, α-D-Neu5Ac-(2→6)-β-D-Galp-(1→4)-β-D-Glcp-NHCO(CH2)_nNH₂ (n = 1 (1d), 3 (1f), 5 (1i)), α-D-Neu5Ac-(2→3)-β-D-Galp-(1→4)β-D-Glcp-NHCO(CH₂)_nNH₂ (n = 1 (2d), 3 (2f), 5 (2i)), β-D-Galp-(1→3)-[α-D-Neu5Ac(2→6)]-β-D-GlcNAcp-(1→3)-β-D-Galp-(1→4)-β-D-Glcp-NHCOCH₂NH₂ (3d), α-D-Neu5Ac(2→3)-β-D-Galp-(1→3)-[α-D-Neu5Ac-(2→6)]-β-D-GlcNAcp-(1→3)-β-D-Galp-(1→4)-β-DGlcp-NHCOCH₂NH₂ (4d), α-D-Neu5Ac-(2→3)-β-D-Galp-(1→3)-[α-D-Neu5Ac-(2→6)]-β-D-GlcNAcp-(1→3)-{β-D-Galp-(1→4)-[α-L-Fucp-(1→3)]-β-D-GlcNAcp-(1→6)}-β-D-Galp(1→4)-β-D-Glcp-NHCOCH₂NH₂ (5d), has been developed. Mono- and disialooligosaccharides from human breast milk and urine treated with ammonium carbamate in aqueous methanol in the presence of NH₃ gave the corresponding β-glycopyranosylamines. Their N-acylation with N-hydroxysuccinimidyl esters of N-Z-glycine, N-Z-4-aminobutanoic (GABA) and N-Z-6-aminohexanoic acids (Z is the benzyloxycarbonyl) with subsequent hydrogenolysis of the Z group furnished N-aminoacyl-β-glycopyranosylamines of sialooligosaccharides 1d,f,i, 2d,f,i, 3d—5d in 30—50% yield.