Structural design and insecticidal activity of 1,3,4-oxadiazole-ring containing pyridylpyrazole-4-carboxamides

The insecticidal activity of 1,3,4-oxadiazole-ring containing pyridylpyrazole-4-carboxamides against diamondback ( Plutella xylostella ) and noctuid ( Spodoptera frugiperda ) moths were evaluated. Only substitutions on the 1,3,4-oxadiazole moiety dictated bioreactivity, with 8q2 m -CF 3 Ph being the most effective against Plutella xylostella, showing 80%–93% mortality at a concentration of 0.5–500 μg ml −1 while the others remained inactive or less active (highest mortality being 63%). The larvicidal activity against Spodoptera frugiperda was inferior compared with that of Plutella xylostella , with the highest mortality being 33%. A crystal of 8q5 was obtained and analyzed, revealing the effects of intramolecular H-bonds and intermolecular π  π interactions.