Novel inhibitors of influenza sialidase related to GG167 Synthesis of 4-amino and guanidino-4H-pyran-2-carboxylic acid-6-propylamides; selective inhibitors of influenza a virus sialidase

N-Propylcarboxamides 1a,b–3a,b have been synthesised from 2,3-didehydro-2,4-dideoxy-4-amino-N-acetylneuraminic acid 4. The tertiary amides 2a,b–3a,b are highly potent but selective inhibitors of influenza A sialidase. The exceptional inhibitory activity of the dipropylamides 3a and 3b against influenza A shows that the 6-dipropylcarboxamide substituent is preferable to the polar glycerol sidechain found in the related sialidase inhibitors GG167 and 4.