Design, synthesis, nematicidal activity, and preliminary mechanism of thiazole derivatives through the scaffold hopping strategy

BACKGROUND Plant‐parasitic nematodes (PPNs) pose a serious threat to global agricultural productivity. Most of the currently available nematicides have limitations in terms of efficacy and environmental safety. Therefore, there is an urgent need to discover new, highly effective and environmentally friendly nematicides. RESULTS A series of thiazole derivatives were designed and synthesized through a scaffold‐hopping strategy. Some of these compounds exhibited excellent nematicidal activity. Compound A1 displayed remarkable toxicity against Bursaphelenchus xylophilus , Aphelenchoides besseyi , and Meloidogyne incognita with median lethal concentration ( LC 50 ) values of 4.3, 1.9, and 6.2 mg/L, respectively, outperforming the commercial nematicide tioxazafen. Mechanistic studies revealed that compound A1 effectively inhibited nematode egg hatching, induced excessive accumulation of reactive oxygen species ( ROS ), and caused vacuolization in nematode tissues. Pot experiments demonstrated that compound A1 not only reduced nematode invasion but also enhanced the root defense response of tomato plants. Moreover, compound A1 significantly inhibited succinate dehydrogenase ( SDH ) activity in M. incognita , suggesting that interference with mitochondrial energy metabolism may contribute to its nematicidal effect. CONCLUSION Thiazole‐based compound A1 can serve as an excellent lead compound from which new nematicides can be discovered through structural optimization in the future.