Synthesis and Insecticidal Activities of Tetrahydroimidazo[1,2-a]pyridinones: Further Exploration on cis-Neonicotinoids

cis-Neonicotinoid, in which the nitro and cyano pharmacophore point to the same position relative to the heteroaromatic moiety, is a further extension of the neonicotinoid library. While seeking new cis-neonicotinoid candidates, a series of tetrahydroimidazo[1,2-a]pyridinone derivatives were synthesized by reactions of nitromethylene analogs with itaconic anhydride. All the compounds were confirmed by ¹H NMR, ¹³C NMR, and high-resolution mass spectroscopy. The target compounds had excellent insecticidal activities against cowpea aphids (Aphis craccivora) and brown planthopper (Nilaparvata lugens). Against armyworm, most of the compounds showed moderate activities. Interestingly, compound 12p was active against Tetranychus cinnabarinus. The synthesized compounds displayed good insecticidal activities against different insect species, which might provide useful guidance for further design of cis-neonicotinoid candidates.

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