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 μm, SI > 5), which were all higher than that of the reference drug oseltamivir (EC(50) > 59.00 μm, SI > 1). However, no compound displays inhibitory activity against influenza B virus.