Synthesis, herbicidal activity, enzyme activity, and molecular docking of novel aniline thiourea

A series of new acyl thiourea derivatives containing aniline moiety were designed and synthesized. The preliminary herbicidal activity tests showed that some compounds had good herbicidal activity against Digitaria adscendens, Amaranthus retroflexus, especially for compound 4j (N-((4-chloro-3-(trifluoromethyl)phenyl)carbamothioyl)-4-(methylsulfonyl)-2-nitrobenzamide) and 4 l (N-((2-bromo-5-fluorophenyl)carbamothioyl)-4-(methylsulfonyl)-2-nitrobenzamide). The results showed that compound 4j and 4l had an inhibition rate of 98% and 96% on the root growth of Brassica napus L. at the concentration of 100 mg L−1. Compounds 4j and 4 l had higher comparative activity on Echinochloa crusgalli than the commercial herbicide bensulfuron-methyl. The preliminary structure–activity relationship (SAR) was also summarized. We also tested the in vivo AHAS enzyme activity inhibition experiment of 17 compounds at 100 mg L−1, and the results showed that they all have inhibitory activity on the enzyme, with the highest inhibition rate reaching 43.66% (compound 4l). Based on the results of molecular docking to yeast acetohydroxyacid synthase (AHAS), the possible herbicidal activity mechanism of these compounds was evaluated.