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

Abstract

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‐CF3Ph 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.