Design, synthesis and insecticidal activities of novel 1-substituted-5-(trifluoromethyl)-1H-pyrazole-4-carboxamide derivatives

Abstract

A series of novel 5-(trifluoromethyl)-1H-pyrazole-4-carboxamide derivatives (6a–6n, 7a, 7b, and 8a-8f) were synthesised by placing the amide bond at the 4-position of the pyrazole ring. These derivatives differed from the structure of chlorantraniliprole analogues with the amide bond at the 5-position of the pyrazole ring. Preliminary bioassay results revealed that a few title compounds exhibited good insecticidal activities against lepidopteran pests, such as Plutella xylostella, Mythimna separate, Heliothis armigera, and Ostrinia nubilalis. Some title compounds also elicited broad-spectrum insecticidal activities against dipterous insects including Culex pipiens pallens after altering the amide position. Similar to pyrazole-5-carboxamide analogues, compounds 6b and 6e showed 100% insecticidal activity against P. xylostella, C. pipiens pallens, and M. separate at concentrations of 200, 2, and 200μg/mL, respectively. This finding suggested that 5-(trifluoromethyl)-1H-pyrazole-4-carboxamide derivatives are potential alternative insecticides for management of agriculture pests.