Tautomeric and non-tautomeric N-substituted 2-iminobenzimidazolines as new lead compounds for the design of anti-influenza drugs: An in vitro study.

A series of 1,3-disubstituted 2-iminobenzimidazolines as well as a number of their tautomeric analogs were synthesized. The synthesized compounds were tested for their cytotoxicity against MDCK cells and for inhibiting activity against influenza virus A/California/07/09 (H1N1)pdm09. Based on the results obtained, 50% cytotoxic concentration (CC50), 50% inhibiting concentration (IC50) and selectivity index (SI) were calculated for each compound. It was found that some of synthesized benzimidazole derivatives (7 of 22, 32%) possess strong virus-inhibiting activity against pandemic influenza virus (IC50's in low micromolar range) with quite moderate cytotoxicity (CC50 in the range of thousands micromoles). Due to their high selectivity (highest SI's=50-83) these compounds are of significant interest for further in vivo experiments as well as for further structural optimization and drug development.