Design, synthesis and in vitro biological evaluation of isoxazol-4-carboxa piperidyl derivatives as new anti-influenza A agents targeting virus nucleoprotein

Influenza infection is a major cause of morbidity and mortality during seasonal epidemics and sporadic pandemics. It is important and urgent to develop new anti-influenza agents with a new mechanism of action. Nucleozin has been reported as a potent antagonist of nucleoprotein accumulation in the nucleus. In this study, a new series of isoxazol-4-carboxa piperidyl derivatives 1a–j were synthesized and their chemical structures were confirmed by (1)H, (13)C NMR and mass spectral data. Furthermore, all the synthesized compounds were evaluated for in vitro anti-influenza virus activity against influenza virus (A/PR/8/34 H1N1). Among all the compounds, 1a, 1b, 1c, 1f and 1g exhibited more potent activity than the standard drug, and compound 1b has showed most promising anti-influenza virus activity. These results are also consistent with the docking study results in terms of the design of compounds targeting influenza A via viral nucleoprotein.