New Synthetic Method and Insecticidal Activities of Novel Imidazopyridine Mesoionic Derivatives Containing an Ester Group.

To develop novel insecticides with high efficiency, a new mode of action, and safety to nontarget organisms and the environment, a series of imidazopyridine mesoionic compounds containing an ester group have been designed and synthesized via a new synthetic method discovered by our group. The bioactivity results showed that most of the target compounds exhibited significant insecticidal activities against Aphis craccivora , and some of them showed moderate insecticidal activities against Sogatella furcifera . Among them, compounds C2 , C4 - C11 , and D3 showed excellent insecticidal activities against A. craccivora (LC 50 values were lower than 4.5 μg/mL), which were superior to those of pymetrozine (LC 50 = 6.19 μg/mL) and triflumezopyrim (LC 50 = 4.68 μg/mL). Remarkably, the insecticidal activity of compound C9 was 5.9-fold greater than that of triflumezopyrim with an LC 50 value of 0.8 μg/mL. Proteomics and molecular docking results indicated that compound C9 may affect the nervous system of A. craccivora and act on nicotinic acetylcholine receptors like triflumezopyrim.