Antiviral activity of benzimidazole derivatives. III. Novel anti-CVB-5, anti-RSV and anti-Sb-1 agents

Abstract A library of eighty-six assorted benzimidazole derivatives was screened for antiviral activity against a panel of ten RNA and DNA viruses. Fifty-two of them displayed different levels of activity against one or more viruses, among which CVB-5, RSV, BVDV and Sb-1 were the most frequently affected. In particular, fourteen compounds exhibited an EC 50 in the range 9–17 μM (SI from 6 to >11) versus CVB-5, and seven compounds showed an EC 50 in the range 5–15 μM (SI from 6.7 to ⩾20) against RSV, thus resulting comparable to or more potent than the respective reference drugs (NM108 and ribavirin). Most of these compounds derive from 2-benzylbenzimidazole, but also other molecular scaffolds [as 1-phenylbenzimidazole ( 2 ), 2-trifluoromethylbenzimidazole ( 69 ), dihydropyrido[3′,2′:4,5]imidazo[1,2- a ][1,4]benzodiazepin-5-one ( 3 ), dibenzo[ c , e ]benzimidazo[1,2- a ]azepine ( 22 ), and 2-(tetrahydropyran-2-yl)benzimidazole ( 81 , 82 and 86 )] are related to interesting levels of activity against these or other viruses (BVDV, Sb-1). Thus, these scaffolds (some of which, so far unexplored), represent valid starting points to develop more efficient agents against pathologies caused by CVB-5, RSV, BVDV and Sb-1 viruses.