Discovery of novel 2H-pyrrol-2-one herbicides through multicomponent synthesis and photosystem II evaluation

The genus Senna includes several aggressive weed species that pose significant challenges to agricultural productivity across tropical and subtropical regions worldwide. In this study, twelve 1,5-diaryl-3-(arylamino)-1,5-dihydro-2 H -pyrrol-2-one derivatives ( 8a–l ) were efficiently synthesized via a one-pot multicomponent reaction involving substituted anilines, aromatic aldehydes, and ethyl pyruvate. The synthesized compounds were evaluated for their herbicidal potential through germination bioassays, chlorophyll a fluorescence, and molecular docking studies targeting the photosystem II (PSII) reaction center. The bioassay results revealed that compound 8b significantly inhibited both radicle and hypocotyl growth in S. alata seedlings, while compound 8 h displayed potent activity against S . obtusifolia , and 8k selectively suppressed hypocotyl elongation in S. occidentalis . Chlorophyll a fluorescence assays demonstrated that 8b-c , 8i , and 8k disrupted electron transport within PSII, with compound 8i exhibiting effects comparable to the commercial herbicide Velpar K. Molecular docking supported these findings, showing strong binding affinities of compounds 8c and 8i to the D1 protein of PSII, primarily mediated by hydrogen bonding interactions with key amino acid residues. These results highlight 2 H -pyrrol-2-one derivatives as promising candidates for developing selective herbicides targeting invasive Senna species.