Insecticidal activity and mode of action of novel nicotinoids synthesized by new acylpyridinium salt chemistry and directed lithiation

• Published in: Pesticide biochemistry and physiology 2007-03, Vol.87 (3), p.211-219
• Main Authors: Stumpf, Christof F., Comins, Daniel L., Sparks, Thomas C., Donohue, Kevin V., Roe, R. Michael
• Format: Article
• Language: English
• Subjects: Acetamiprid; acetylcholine; adverse effects; agonists; Aphididae; Aphis gossypii; Beet armyworm; Biological and medical sciences; Biological control; chemical structure; Control; Corn earworm; Cotton aphid; derivatives; dosage; Frankliniella occidentalis; Fundamental and applied biological sciences. Psychology; Green peach aphid; Helicoverpa zea; House fly; insect pests; Insecticidal activity; insecticidal properties; larvae; mechanism of action; Mode of action; mortality; Musca domestica; Myzus persicae; Neonicotinoid; neonicotinoid insecticides; Nicotine; Nicotinoid; Phytopathology. Animal pests. Plant and forest protection; plant pests; Protozoa. Invertebrates; Prunus; pyridines; Spodoptera exigua; toxicity; Western flower thrips
• ISSN: 0048-3575; 1095-9939
• DOI: 10.1016/j.pestbp.2006.07.012

Novel acylpyridinium salt chemistry and directed lithiation methodology was developed to add for the first time substitutions directly to the phenylpyridine heterocyclic ring of nicotine. A variety of 3-(1-methylpyrrolidin-2-yl)-4-(alkyl, aromatic, heterocyclic and silanyl) and - N-alkyl pyridines were synthesized (compounds 1– 9). In vial tests with the green peach aphid, Myzus persicae, compounds 1– 4 were 1.1, 1.8, 2.3 and 1.9×, respectively, more active than nicotine and 64, 40, 31 and 38×, respectively, less active than acetamiprid. Against the western flower thrips, Frankliniella occidentalis, 1– 4 were 1.4, 2.1, 2.0 and 1.6×, respectively, more active than nicotine and 9, 6, 6 and 8×, respectively, less active than acetamiprid. For the cotton aphid, Aphis gossypii, the activity of 1– 9 was similar to nicotine. Compounds 7 and 9 when incorporated into artificial diet produced low mortality for larvae of the beet armyworm, Spodoptera exigua, but were not active against the corn earworm, Helicoverpa zea. When 1– 4 and 6– 9 were injected into larvae of the beet armyworm, a variety of symptoms similar to acetamiprid were observed which included tremors, uncoordinated movement, diuresis, paralysis and death. In addition, imidacloprid-binding to membranes from the house fly head, Musca domestica, was inhibited by compounds 1– 9, when using a concentration range of 1–100 μM. These studies demonstrate that our new chemistry enhances the insecticidal activity of nicotine with an apparent mode of action as an acetylcholine agonist.