Synthesis, structure–activity relationship and in vitro biological evaluation of N-arylethyl isoquinoline derivatives as Coxsackievirus B3 inhibitors

Currently, there is no approved antiviral drug for the infection caused by enteroviruses. A series of novel N-arylethyl isoquinoline derivatives defined with substituents on the ring A and C were designed, synthesized and evaluated in vitro for their activities against Coxsackievirus B3 (CVB3). The primary structure–activity relationship revealed that substituents on the ring A were not beneficial for the activity. Among these analogs synthesized, compound 7f bearing a methylenedioxy at the R 4 and R 5 positions afforded an anti-CVB3 activity and a reasonable selectivity index (SI = 26.8); furthermore, 7f exhibited a moderate activity against enterovirus 71 (EV71) with SI value of 9.0. Thus it has been selected as an anti-enteroviral lead compound for further investigation.