Synthesis and acaricidal activity of curcumin isoxazole and pyrazole derivatives

In order to discover and develop the new natural products-based acaricidal agents,fifteen curcumin isoxazole and pyrazole derivatives were designed and synthesized,which based on the results of previous study.All structures of the title compounds were confirmed by IR,1H NMR and MS.The acaricidal assay results showed that curcumin isoxazole and pyrazole derivatives exhibited higher contact activity than the lead compound curcumin.Both of compounds 4 and 11 showed higher contact activity to Tetranychus cinnabarinus and Panonychus citri than the other derivatives.The 48 h LC50 values of 4 were 333.0 and 156.0 mg/L to T.cinnabarinus and P.citri,which exhibited about 6.35 and 4.56 fold higher acaricidal potency than curcumin,respectively.The 48 h LC50 values of 11 were 478.4 and 144.7 mg/L to T.cinnabarinus and P.citri,which exhibited about 4.42 and 4.92 fold higher acaricidal potency than curcumin,respectively.The 72 h LC50 values of 4 were 115.0 and 84.9 mg/L to T. cinnabarinus and P.citri,which exhibited about 5.02 and 1.43 fold higher acaricidal potency than curcumin,respectively.The 72 h LC50 values of 11 were 91.0 mg/L and 68.7 mg/L to T.cinnabarinus and P.citri,which exhibited about 6.35 and 1.77 fold higher acaricidal potency than curcumin,respectively.These two compounds are promising candidates as novel acaricidal agents.