Syntheses of Sialic Acid Derivatives

Abstract

Sialic acid as constituents of glycoproteins, glycolipids, and oligosaccharides plays an important role in many animal cells. N-Acetylneuraminic acid (NANA), the most important sialic acid was crystallized to fine needles (A) and prisms (B) from the different solvents used for recrystallization. The anomeric configuration of both crystals was confirmed as the β-configuration at C-2 position.
Syntheses of various kind of NANA derivatives are reported in this article. Methyl 2-chloro-4, 7, 8, 9-tetra-O-acetyl-N-acetyl-β-D-neuraminate (5) was prepared from methyl N-acetyl-β-D-neuraminate (4) in a good yield. From the chloride, mucin analogs, sialyllactose, monosaccharide and disaccharide nucleoside analogs were synthesized. Confirmation of the stereochemistry at C-2 position Of NANA of these products was reported by NMR and hydrolysis experiments.