Synthesis and anti-hepatitis C virus activity of novel ethyl 1H-indole-3-carboxylates in vitro.

A series of ethyl 1H-indole-3-carboxylates 9a(1)(-)(6) and 9b(1)(-)(2) were prepared and evaluated in Huh-7.5 cells. Most of the compounds exhibited anti-hepatitis C virus (HCV) activities at low concentration. The selectivity indices of inhibition on entry and replication of compounds 9a(2) (>10; >16.7) and 9b(1) (>6.25; >16.7) were higher than those of the other evaluated compounds, including the lead compound Arbidol (ARB, 6; 15). Moreover, the selective index of inhibition on entry of compound 9a(3) (>6.25) was higher than that of ARB (6). Of these three initial hits, compound 9a(2) was the most potent.