Efficient synthesis and insecticidal activity of novel pyridin-3-yl-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazoles

A series of novel [1,2,4]triazolo[3,4-b][1,3,4]thiadiazoles bearing pyridine ring derivatives was synthesized from 2,6-dimethylpyridin-3,5-dicarboxylic acid diethyl ester. The structures of the compounds were characterized by use of IR, NMR, EI-MS, and elemental analysis. The structure of one compound was further confirmed by X-ray diffraction analysis. Biological assays showed that these compounds had potential insecticidal activity with especially strong regulation of the growth of 2nd instar Mythimna separata larvae. The effects on bioactivity of substituent groups on phenyl ring were also screened. .