Discovery of Triazone Derivatives Containing Acylhydrazone and Phenoxypyridine Motifs as Novel Insecticidal and Antiphytopathogenic Fungus Agents

A series of novel triazone derivatives containing acylhydrazone and phenoxypyridine motifs were designed, synthesized, and evaluated for their biological activities. The bioassay results indicated that most of the target compounds exhibited excellent insecticidal activities against bean aphids. In particular, compounds <b>3i</b> and <b>3e</b> showed excellent aphicidal activities comparable to pymetrozine, thus emerging as novel insecticidal lead compounds. Additionally, compounds <b>3c</b> (60%), <b>3e</b> (60%), and <b>3f</b> (60%) exhibited good larvicidal activities against C. pipiens pallens at 0.5 mg/kg. Further fungicidal activity tests revealed that most derivatives exhibited broad-spectrum fungicidal activities. A total of twelve compounds exhibited better fungicidal activities against cercospora arachidicola hori than carbendazim, and eight compounds exhibited better fungicidal activities against fusarium moniliforme than carbendazim. This work suggests that compound <b>3e</b> could serve as an insecticidal lead compound for further structural optimization.