Design, synthesis, herbicidal activity, and the molecular docking study of novel diphenyl ether derivatives as protoporphyrinogen IX oxidase inhibitors

Protoporphyrinogen oxidase (PPO, EC 1.3.3.4) is an important herbicide target. In this study, a series of novel diphenyl ethers derivatives with 2-pyrrolidone structure were developed as PPO inhibitors. Thereinto, compound H7 (IC50 = 0.0262 mg/L) has better PPO enzyme inhibitory activity than commercial herbicide oxyfluorfen (IC50 = 0.0426 mg/L). Greenhouse herbicidal activity experiments exhibited that even under the condition of 37.5 g ai/ha, H7 still had excellent broad-spectrum herbicidal activity. Moreover, rice, peanut, and cotton had strong tolerance to H7 at 300 g ai/ha. Field trial showed that H7 had comparable herbicidal activity to oxyfluorfen. These experimental results indicated that H7 could be developed as a novel PPO Inhibitor candidate for weed control in the field.