Insecticidal activity of N,N‐diethyl‐, N,N‐dipropyl‐, N,n‐di‐isopropyl‐, and n,n‐di‐isobutylalkanamides against mosquito larvae

Abstract

N,N‐Diethyl‐, N,N‐dipropyl‐, N,N‐di‐isopropyl, and N,N‐di‐isobutylalkanamides in which the acyl moiety ranged from C8 to C21 were synthesised, and their larvicidal activity was determined against the first‐instar larvae of the southern house mosquito Culex quinquefasciatus Say. The four homologous series of amides generally showed an increase in their larvicidal activity as the carbon number in the acyl moiety of the amides increased, until the activity reached a maximum. Subsequently, an increment of carbon number resulted in declining activity in the higher homologues, until the activity disappeared. N,N‐Diethyltetradecanamide, N,N‐dipropylundecanamide, N,N‐di‐isopropylundecanamide, and N,N‐di‐isobutlynonanamide or ‐dodecanamide were the most active compounds in their respective homologous series of amides; however, they were less active than their analogous N,N‐dimethylalkanamides previously studied.