Discovery and Structure-Resistance Relationship Study of New Thieno[2,3-b] Pyridine HCV NS4B Inhibitors.

The non-structural protein 4B (NS4B) of hepatitis C virus (HCV) has emerged as a promising target for chronic hepatitis C treatment. The thieno[2,3-b]pyridine HCV inhibitor 2 has demonstrated properties as a NS4B inhibitor. Subsequent hybridization of 2 with our recently published imidazo[2,1-b]thiazole NS4B inhibitor 3 resulted in the discovery of several more potent compounds with sub-micromolar EC50 against HCV genotype 1b replicon. More importantly, the resistant profile study of the new synthesized HCV inhibitors illustrated that the bicyclic scaffold would mediate the resistance of H3R and Q26R mutations, while the piperazinone motif would mediate the resistance of H94R, F98C and V105M mutations, and the C3- amino group would disrupt the interaction between piperazinone motif and NS4B. This structure-resistance relationship detail could help us to develop new NS4B inhibitors with higher resistant barrier in the future.