ABSTRACT
Recently we have described an efcient and simple method for the synthesis of (α2-6) sialooligosaccharides by the classical Koenigs-Knorr reaction, in which the simplest sialyl donor (i.e., the glycosyl chloride of the peracetylated methyl ester of sialic acid) is used for glycosylation of galacto-4,6-diols (mono-and disaccharides). The reaction is high yielding, regio-and stereoselective, and takes place at room temperature in the presence of Ag2CO3 or Ag2CO3/AgOTf as promoters. The approach is applicable to various forms of sialic acid, namely, Neu5Ac, Neu5Gc, 9-deoxy-9-N-Ac-Neu5Ac, and (α2-8) oligosaccharides of Neu5Ac.1,2 Here we apply the cited method for the synthesis of the spacer-armed 6′-sialyl-N-acetyllactosamine 5-α, α-Neu5Ac-(2 → 6)-β-d-Gal-(1 → 4)-β-d-GlcNAc-O(CH2)3NH2.
