Design, Synthesis, Nematicidal Activity Evaluation, and Mode of Action Study of Novel Trifluorobutene Ester Derivatives as Potential Nematicides

Crop protection globally is under threat from infections caused by plant-parasitic nematodes (PPNs). PPNs can wreak havoc on agricultural production. However, only limited nematicides are currently available, and the growing resistance problem is a concern; therefore, novel nematicides are urgently needed. Thirty-three trifluorobutene ester derivatives were synthesized, and then their biological activity against Meloidogyne incognita was tested in this study. Among them, nine compounds exhibited excellent in vitro bioactivity against M. incognita; their LC_50/72h values reached 1.77-3.95 mg/L. In addition, the derivative of the active compound above containing a piperazine ring exhibited significant in vivo bioactivity against M. incognita with an inhibition rate of 77.3% at 1.25 mg/L in matrix. The structure-activity relationships (SARs) of all synthesized compounds were analyzed, and further comparative molecular field analysis (CoMFA) was calculated to discuss the SAR profile. The preliminary mechanisms of action study suggested that some compounds had a great inhibitory effect on the egg hatching, motility, feeding ability, and growth of Caenorhabditis elegans. Meanwhile, the effects of the active compounds on biochemical indices related to oxidative stress indicated that two compounds could significantly promote the oxidative stress of nematodes and induce toxicity through oxidative damage.