Synthesis and Larvicidal Properties of Some Cyclopropylcarboxamides Related tocis-Permethrin

Abstract

Twenty-seven carboxamide derivatives of (±)-cis-3-(2,2-dichloroethenyl)-2,2-dimethylcyclopropanecarboxylic acid (permethrin acid) have been synthesized and evaluated in the laboratory against mosquito larvae (Aedes aegypti). These cis-cyclopropylcarboxamides, with N-(substituted)phenyl, N-(substituted)phenylmethyl, N-(substituted)phenylethyl, N-phenylpropyl, and N-phenylbutyl groups, were synthesized from the acid chloride of permethrin acid and various arylamines in methylene chloride. The samples were characterized by 13C NMR spectroscopy and mass spectrometry. Secondary amides with electron-donating (e.g., methoxy) and electron-withdrawing (e.g., trifluoromethyl) substituents on the phenyl ring as well as nine tertiary amides were investigated. 3-(2,2-Dichloroethenyl)-2,2-dimethyl-N-(3-phenoxyphenyl)methylcyclopropanecarboxamide was the most active experimental compound and was 25 times less potent than (±)-cis-permethrin. Cyclopropylcarboxamides of the N-(substituted)phenyl, N-(substituted)phenylethyl, and N-phenylpropyl types were essentially inactive in the larvicidal tests. Keywords: Pyrethroid amides; synthesis; purification; spectroscopy; mosquitoes; larvicidal activity