Novel pyrazole fused heterocyclic ligands: Synthesis, characterization, DNA binding/cleavage activity and anti-BVDV activity

Abstract A series of novel pyrazole fused heterocyclic derivatives were synthesized via a two-step procedure or a one-pot two step method, and their catalytic DNA cleavage abilities and anti-BVDV activities were also evaluated. The results obtained indicated that compounds 3b – 3c could catalyze the cleavage of supercoiled DNA (pUC 19 plasmid DNA) to nicked DNA under physiological conditions with high yields via a hydrolytic mechanism. The studies on anti-viral activities against bovine viral diarrhea virus (BVDV) demonstrated that some of the pyrazole derivatives showed pronounced anti-BVDV activity with interesting EC 50 values and no significant cytotoxicity. Among them, compound 3l showed the highest antiviral activity (EC 50  = 0.12 μmol/L) and was 10 fold more than that of the positive control ribavirin (EC 50  = 1.3 μmol/L), which provided a potential candidate for the development of anti-BVDV agents.