Novel N-Phenyltriazinone Derivatives Containing Carbamate/Oxime Ester Fragments as Promising Protoporphyrinogen IX Oxidase Inhibitors

In order to continue the development of PPO-inhibiting herbicides, compound B16 was used as a lead compound to design and synthesize novel N-phenyltriazinone derivatives containing carbamate groups (G) and oxime ester moieties (H) by fragment deconstruction and recombination strategies. Bioassays revealed that compound H13 (K_i = 30.3 nM) exhibited outstanding NtPPO inhibitory activity and showed 100% control to 26 tested weed species at 150 g a.i./ha. It also demonstrated markedly superior crop safety to trifludimoxazin, with injury rates of only 30% on maize and wheat, and 20% on sorghum, whereas trifludimoxazin caused 80% injury to the three crops. Molecular simulation calculations revealed that compound H13 can stably bind to the NtPPO protein via forming three hydrophobic interactions with Leu356, Leu372, and Phe392 residues, and two hydrogen bonds with the Arg98 residue. The present work demonstrates that N-phenyltriazinone derivatives containing carbamate/oxime ester fragments can be used as promising PPO-targeting herbicides.