Synthesis and bioactivity of novel pyridazin-3(2H)-one derivatives containing 5-phenyl-2-furan (I)

A series of novel pyridazin-3(2H)-one derivative with 5-phenyl-2-furan were designed and synthesized. All the title compounds were characterized by IR, 1H NMR and elemental analysis. Bioassay indicated that the title compounds had low insecticidal effects on Plutella xylostella, Mythimna separate and Culex pipiens pallens, but most compounds exhibited good fungicidal activities against Botrytis cinerea, Fusarium oxysporum and Corynespora cassiicola. In particular, compounds 3 k showed considerable activity (86.29%±1.51%) against B. cinerea at 50 mg/L, which was equal to the fungicide procymidone. The preliminary structure-activity relationship showed that the difference of R group affected the fungicidal activity.