Design, Synthesis, Acaricidal Activities, and Structure-Activity Relationship Studies of Novel Oxazolines Containing...

With the ultimate goal of addressing pest-related constraints on global agricultural production, we used combination principles to design and synthesize 2,4-diphenyl-1,3-oxazolines containing a sulfonate moiety at the para-position of the 4-phenyl group. The target compounds, which have strong affinity for lipids and can be expected to traverse cell membranes, were characterized by ¹H and ¹³C NMR spectroscopy and high-resolution mass spectrometry. Their activities against the larvae and eggs of carmine spider mites (Tetranychus cinnabarinus) were determined by a leaf-dipping method and compared with the activity of the commercial acaricide etoxazole. Most of the test compounds displayed good ovicidal and larvicidal activities. In particular, a tert-butylphenyl-substituent compound possessed better larvicidal activity (LC₅₀ = 0.022 ± 0.009 mg/L) and ovicidal activity (0.044 ± 0.020 mg/L) than etoxazole (0.091 ± 0.051 and 0.095 ± 0.059 mg/L, respectively). Given its outstanding bioactivities, this compound deserves further attention as a pesticide candidate.