Synthesis of alkylene-tethered bis-imidacloprid derivatives as highly insecticidal and nerve-excitingagents with potent affinity to [~3H] imidacloprid-binding sites on nicotinic acetylcholine receptor

摘要

Bivalent molecules of bis-imidacloprid with 2-10 alkylene tethers as weel as tethers containing an ethenylene,ethynylene,phenylene and oxide joint wereprepared.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 clsoe to that of imidacloprid,and the potency was augmented up to about thirtyfive-fold follwoing pretreatment with metabolic inhibitors,while the binding affinity to [~3HH] imidacloprid-bidning sites on the nicotinic acetylcholine receptor was weaker than thatof 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.