Design,Synthesis And Activity Study Of Novel Benzoylurea Compounds

As a class of chitin synthesis inhibitors,benzoylurea compounds achieve the effect of sterilization and insecticidal by inhibiting the cell wall of fungi and the synthesis of chitin in insects.It is widely used in agricultural production because of its unique mechanism of action,high environmental safety,high selectivity to non-target organisms,low toxicity and high efficiency.But resistance have occurred during long-term use,and the efficacy decreased significantly.Therefore,the development of new benzoylurea compounds is of great significance.In order to find new benzoylurea chitin synthesis inhibitors with higher activity,the first series of N-2,6-difluorobenzoyl-N’-1-phenyl-4-cyano-1H-pyrazolylureas（C1～C19）and the second series of N-2,6-difluorobenzoyl-N’-1H-quinazolinylureas（E1～E3）were designed and synthesized by using the principle of active substructure splicing and bioisosterism.A total of 22 new benzoylurea compounds with nitrogen-containing heterocyclic structure were obtained.The structure of the target products was confirmed by¹H NMR and ¹³C NMR.The fungicidal activity of the target compounds was determined by mycelium growth rate method.The preliminary results showed that at the concentration of 50μg/m L,the inhibition rates of the first series of compounds C12,C13 and C16 against botrytis cinerea were 65.72%,71.09%and 65.06%,respectively.The inhibition rates of compounds C9 and C18 against phytophthora infestans were 56.43%and 52.08%,respectively,showing good fungicidal activity.The insecticidal activity of the target compounds was determined by leaf dipping method.The preliminary results showed that some compounds have good insecticidal activity against plutella xylostella and pieris rapae at the concentration of 30 mg/L.The mortality of compounds C7,C8,C9,C11,C17 and C18 against plutella xylostella were96.67%,100%,100%,100%,93.33%and 100%,respectively,which were equivalent to the positive control diflubenzuron（lethal rate=100%）.The compounds C18,C19 and E3showed good insecticidal activity against plutella xylostella and pieris rapae at the concentration of 30 mg/L,with the mortality of 80.00%,73.33%and 76.67%,respectively.The target compounds synthesized exhibited certain fungicidal and insecticidal activities,and some of the compounds showed remarkable activities,which is of further research significance.The results provided experimental data and theoretical basis for the development of benzoylurea compounds.