Design, Synthesis, and Insecticidal Evaluation of New Benzoylureas Containing Carbamate Groups Based on the Bipartite Model of Sulfonylurea Receptor Binding Site

Background: benzoylureas are the most commonly used chitin synthesis inhibitors. But, the exact target site of benzoylurea insecticides has not been identified. Objective: In order to study whether benzoylphenylureas analogues with a bipartite model could be designed and synthesized as novel insecticides with improved activities. Methods: On the basis of the bipartite model of the sulfonylurea receptor binding site and commercial diflubenzuron, a series of novel benzoylureas containing carbamate groups were designed and synthesized via the key intermediate 2,6-difluoro-N-((4-hydroxyphenyl)carbamoyl)benzamide (2). The structures of target compounds were confirmed by 1H NMR and high-resolution mass spectrum (HRMS). Results: The results of bioassays indicated that these target compounds possessed good larvacidal activities against a broad spectrum of insects such as oriental armyworm (Mythimna seperata Walker), diamondback moth (Plutella xylostella), and mosquito (Culex pipiens pallens). Compound containing N,N-diisopropyl (3g) exhibited the highest insecticidal activity against oriental armyworm (40% at 10 mg kg-1), which was comparable to that of diflubenzuron. These compounds also had good larvacidal activities against diamondback moth and mosquito; most of these target compounds exhibited a comparable larvacidal activities against diamondback moth to diflubenzuron and higher larvacidal activities against mosquito than diflubenzuron. Conclusion: The experimental data above preliminarily proved the rationality of our speculation and design ideology, and BPUs analogues with a bipartite model could improve the interaction with the target.