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: To study whether benzoylphenylureas analogues with a bipartite model could be designed and synthesized as novel insecticides with improved activities. Methods: Based on 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 the target compounds were confirmed by the ¹H NMR and high-resolution mass spectrum (HRMS). Results: The results of bioassays indicated that these target compounds possessed good larvicidal activities against a broad spectrum of insects such as oriental armyworm (Mythimna Separata Walker), diamondback moth (Plutella xylostella), and mosquito (Culex pipiens pallens). A compound containing N, N-diisopropyl (3g) exhibited the highest insecticidal activity against oriental armyworm (40% at 10 mg kg^-1), which was comparable with that of diflubenzuron. These compounds also had good larvicidal activities against diamondback moth and mosquito; most of these target compounds exhibited comparable larvicidal activities of diamondback moth with diflubenzuron and higher larvicidal activities of 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.