Synthesis of Alkylene-Tethered Bis-Imidacloprid Derivatives as Highly Insecticidal and Nerve-Exciting Agents with Potent Affinity to [3H]Imidacloprid-Binding Sites on Nicotinic Acetylcholine Receptor

Abstract

Bivalent molecules of bis-imidacloprid with 2–10 alkylene tethers as well as tethers containing an ethenylene, ethynylene, phenylene and oxide joint were prepared. These dimeric chloronicotinyl molecules were highly insecticidal against American cockroaches on injection at 2–30 nanomolar doses. The minimum lethal dose of the most potent hexamethylene derivative was close to that of imidacloprid, and the potency was augmented up to about thirty-five-fold following pretreatment with metabolic inhibitors, while the binding affinity to [3H]imidacloprid-binding sites on the nicotinic acetylcholine receptor was weaker than that of imidacloprid by a factor of 160. The hexamethylene derivative elicited impulses in cockroach central nerves with an initial excitation and subsequent block at a potency comparable to imidacloprid. © 2002, Pesticide Science Society of Japan. All rights reserved.