Design, Synthesis, and Insecticidal Activity of Novel Triazone Derivatives Containing Sulfonamide or Sulfonimide Moieties

On the basis of sulfonamide moieties widely used in drugs and the mode of action of pymetrozine and the structures of some transient receptor potential channel antagonists and to improve the insecticidal activities of triazone insecticides, a series of triazone derivatives containing sulfonamide or sulfonimide moieties were designed, synthesized, and characterized. The bioassay results showed that most of these derivatives containing sulfonamide moieties exhibited excellent insecticidal activities against Aphis craccivora. Especially, (substituted)phenylsulfonylamino triazones I-9 (LC₅₀ = 2.9869 mg/kg), I-10 (LC₅₀ = 3.4957 mg/kg), I-11 (LC₅₀ = 2.3154 mg/kg), I-12 (LC₅₀ = 4.1614 mg/kg), I-13 (LC₅₀ = 2.1690 mg/kg), and I-14 (LC₅₀ = 3.0077 mg/kg) exhibited much higher aphicidal activity than pymetrozine (LC₅₀ = 6.0635 mg/kg). All monosulfonyl-substituted 4-amino-triazinones had better activities than the corresponding disulfonyl-substituted compounds. In addition, some derivatives also exhibited insecticidal activities against Culex pipiens pallens. Among Helicoverpa armigera, Mythimna separata, and Ostrinia nubilalis, compounds I-18 and I-21 exhibited good larvicidal activities (LC₅₀ values were 0.6929 and 0.2592 mg/kg, respectively) against C. pipiens pallens.

Synthesis process optimization and field trials of insecticide candidate NKY-312

NKY-312 is a highly active insecticide candidate with a simple structure. In order to carry out field trials and toxicity tests, its scale preparation is urgently needed, but the final step of the original synthetic route is a low-yielding sulfonylation reaction that generates a high proportion of a bissulfonylated by-product, its foliar contact activities against bean aphid (80% at 100 mg/kg) is significantly lower than that of NKY-312 (100% at 5 mg/kg), and uses pyridine as the solvent. In this work, we developed a highly selective (4-dimethylaminopyridine)-catalyzed monosulfonylation reaction that avoids the use of pyridine as a solvent and shows a much higher yield (98% yield with 98% HPLC purity) than the original reaction (68%). Then, we carried out the field trials and toxicity tests. In field experiments, the activities of NKY-312 against rice planthopper and wheat aphid were equal to pymetrozine and imidacloprid respectively.