AlphaFold-Assisted Design and Synthesis of V-Type Amidazoles as Chitin Synthase Inhibitors against <i>Plutella xylostella</i>

Chitin synthase serves as a promising target for developing eco-friendly insecticides. Nevertheless, the lack of structural insights into insect chitin synthase has impeded the rational design of specific inhibitors. Herein, we utilized AlphaFold to predict the structure of <i>Px</i>Chs1. A series of V-type amidazoles mimicking the catalytic sites of <i>Px</i>Chs1 were synthesized. Notably, compounds <b>6k</b> and <b>6l</b> exhibited significant insecticidal efficacy against <i>Plutella xylostella</i>, with LC₅₀ values of 0.789 and 0.951 μg/mL, respectively, and induced profound molting disruptions in the larvae. Moreover, the expression of genes involved in chitin metabolism was significantly downregulated. V-type amidazoles with potent insecticidal activity showed favorable docking interactions with <i>Px</i>Chs1. Notably, compounds <b>6k</b> and <b>6l</b> exhibited minimal toxicity toward Chinese honeybees and <i>Danio rerio</i>. This study provides a valuable approach for developing innovative <i>Px</i>Chs1 inhibitors despite a limited structural understanding of the protein.