Design and one-pot synthesis of 2-thiazolylhydrazone derivatives as influenza neuraminidase inhibitors.

Two series of novel 2-thiazolylhydrazone derivatives were designed and synthesized via one-pot reaction of benzaldehyde derivatives, [Formula: see text]-haloketones and thiosemicarbazide. The structures of compounds 1 and 2 were characterized by [Formula: see text] NMR and [Formula: see text] NMR, and compound 1g was further confirmed by X-ray crystallography. All of the target compounds were evaluated for their NA inhibitory activity against influenza viral neuraminidase (H1N1) in vitro, and the results showed that many compounds exhibited moderate to strong inhibitory activities against influenza viral neuraminidase (H1N1). Among them, compounds 1p, 1q and 2c showed the most potent inhibitory activities with [Formula: see text] values ranging from 10.50 to [Formula: see text]. Our structure-activity relationship analysis indicated that 2-thiazolylhydrazone is an effective scaffold for NA inhibitors and that introducing an ethoxycarbonyl group to the 5-position of thiazole ring could enhance inhibitory potency. Molecular docking was performed on the most active compounds 1p and 2c to provide more insight into their mechanism of interaction.