Discovery of Pyrimidinedione Derivatives as Potential Herbicides: Design, Synthesis, and Evaluation of Herbicidal Activity

Weeds significantly impact crop yields, and pyrimidinedione herbicides remain essential for weed control. Protoporphyrinogen IX oxidase (PPO, EC 1.3.3.4), a key enzyme whose inhibition disrupts chloroplast formation in plants, serves as a critical target for developing eco-friendly herbicides. To discover novel, potent, and environmentally benign herbicidal agents, we designed and synthesized a series of sulfonamide-containing pyrimidinedione derivatives via scaffold hopping. Postemergence tests revealed that most compounds exhibited strong herbicidal activity against broadleaf weeds. Notably, compound 6q achieved 100% efficacy against Zinnia elegans (ZE) and Abutilon theophrasti (AT) at 9.375 g a.i./ha, comparable to saflufenacil. Electrostatic potential (ESP) analysis indicated a correlation between the charge distribution and herbicidal activity. Molecular docking demonstrated that 6q forms a hydrogen bond with Arg98 and π-π stacking with Phe392. This study provides the theoretical basis for the discovery of pyrimidinedione derivatives as potential herbicides.