Synthesis and biological evaluation of sialic acid derivatives containing a long hydrophobic chain at the anomeric position and their C-5 linked polymers as potent influenza virus inhibitors.

Conversions of the C-5 acetamide group in sialic acid into two kinds of C=C double bond substituents were accomplished under Shotten-Baumann conditions. The polymerizable glycomonomers also contain a hydrophobic chain or hydroxyl group at the anomeric position. Radical polymerizations of the fully protected glycomonomers were carried out with acryl amide in the presence of ammonium persulfate (APS) and N,N,N',N'-tetramethylethylenediamine (TEMED), followed by deprotection to furnish water-soluble glycopolymers. The activities of the deprotected glycopolymers and glycomonomers against human influenza viruses (H1N1 and H3N2) and avian influenza virus (H5N3) were evaluated. Biological evaluations showed that the glycomonomers containing a long hydrophobic chain at the anomeric position had both hemagglutination and neuraminidase inhibitory activities.