Synthesis and Preliminary Biologic Evaluation of 5‐Substituted‐2‐(4‐substituted phenyl)‐1,3‐Benzoxazoles as A Novel Class of Influenza Virus A Inhibitors

The diversity‐oriented chemistry synthesis together with the random screening approach has permitted the discovery and optimization of novel antiviral lead compounds. In this paper, a series of novel 5‐substituted‐2‐(4‐substituted phenyl)‐1,3‐benzoxazoles was synthesized and evaluated for their in vitro anti‐influenza A virus and anti‐influenza B virus activity. The activity was monitored by the MTS assay in the Madin–Darby canine kidney cells. Compound 7h showed excellent inhibitory activity and selective index against A/H3N2 (EC 50 = 37.03 μ m , SI > 5), which were all higher than that of the reference drug oseltamivir (EC 50 > 59.00 μ m , SI > 1). However, no compound displays inhibitory activity against influenza B virus.