Synthesis And Biological Activity Of Benzimidazole Hydrazone Derivatives

Benzimidazole and its derivatives had a wide range of biological activities,such as antibacterial,antiviral,anticancer,antioxidant,parasitic resistance,anti-inflammatory,etc.,used in pesticide,medicine and other fields successfully.For agricultural fungicide,dozens of benzimidazole fungicide were used in the market,such as carbendazim,thiabendazole and furidazol,etc.Their target was the β-tubulin with of pathogenic fungi.Then,for the vast and irrational use of pesticide in recent years,the resistance to drugs had been continuously deepened.Now,dozens of pesticide and medicine which containning benzimidazole were used in the market.The article was about synthesis and biological activity of benzimidazole hydrazone derivatives.The splicing of pharmacophore was used in chemical.The structure of hydrazone possessing wide bioactivities was introduced into ring two of benzimidazole.35 benzimidazole hydrazone derivatives(6a-6ai)were synthesized.Then,thiazole ring and hydrazone were introdunced into benzimidazole ring at the same time.9 benzimidazole thiazole-hydrazone derivatives(6aj-6ar)were also synthesized.Two types of compounds were characterized by H NMR,MS.The crystal structure was confirmed with X-ray single crystal diffraction using compound 6f as an example.The preliminary antifungal activities of all of the synthesized compounds were evaluated against four phytopathogens fungi(Rhizoctonia solani,Magnaporthe oryzae,Fusarium graminearum,Sclerotinia sclerotiorum)using the mycelium growth rate method in vitro.Benzimidazole hydrazone derivatives showed good inhibitory activity against R.Solani and M oryzae.The activity of compound 6f was the most prominent,the EC50 was 1.20,1.85μg/mL,separately.Compound 6f showed a certain effect on the germination of sclerotium and spore.At the concentration of 50 μg/mL,the control efficiency of compound 6f against sclerotium was 53.1%.At the concentration of 1μg/mL,compound 6f restrained the spore germination by 100%.The experiment was done to determine the inhibitory activity of compound 6f against R.Solani and M oryzae in vivo.At the concentration of 200μg/mL,the control efficiency of compound 6f against R.solani was 68.0%,close to the control efficiency of validamycin A(73.8%).At the concentration of 50μg/mL,the control efficiency of compound 6f against M oryzae was 37.6%.The research results showed that benzimidazole hydrazone derivatives with antifungal activity was a novel type of potential pesticide leading structures.