Synthesis and Acaricidal Activity of Pyrazole-5-carboxamide Derivatives

Abstract

Seventy-four pyrazole derivatives were synthesized and their acaricidal activity was determined. In general, N-benzylpyrazole-5-carboxamides having methyl group at the 1-position of the pyrazole ring, halogen atom, methyl group or methoxy group at the 4-position of the pyrazole ring, and bulky alkyl group at the 4-position of the benzene ring were highly acaricidal. Among them, N-(4-tert-butylbenzyl)-4-chloro-3-ethyl-1-methylpyrazole-5-carboxamide (35, code No. MK-239, tebufenpyrad) was the most active acaricide. MK-239 was highly active against various mite species including Tetranychus spp. and Panonychus spp. Acaricidal activity of MK-239 and its related compounds is discussed in this paper.