Design, Synthesis, and Evaluation of Nematicidal and Antifungal Activities of Novel Azoxy Compounds Incorporating an Ester Moiety.

is a parasitic nematode that causes serious ecological and economic harm to pine trees. Taking (LC = 0.889 μg·mL) as the lead compound, 26 azoxy compounds were designed and synthesized. Most of the azoxy compounds showed excellent nematicidal activity, especially , , and , with LC values of 0.424, 0.267, and 0.803 μg·mL, respectively, significantly better than avermectin (LC = 16.4 μg·mL) and emamectin benzoate (LC = 13.3 μg·mL). Scanning electron microscopy (SEM) showed that the nematodes treated with compounds and were severely shrivelled, and there were obvious local depressions and ruptures. Furthermore, the azoxy compounds that had good nematicidal activity against also showed good inhibition against , and compounds , , and showed good root knot inhibition activity. In addition, compound showed good fungicidal activity against and , with EC values of 2.00 and 1.80 μg·mL, respectively. SEM showed that the mycelium of and treated by compound was dry and varied in thickness, and the mycelium of even appeared fracture. A 3D-QASR model was established according to the bioactivity against , and it was advantageous to the promotion of activity when the 4-substituted group is more electronegative and smaller. In conclusion, the novel azoxy compounds, especially , , and , have great potential in the prevention and treatment of .