Design, Synthesis, and Insecticidal Activity of Novel Pyrido[1,2-?]pyrimidinone Mesoionic Compounds Containing an IndoleMoiety as Potential Acetylcholine Receptor Insecticides

In this study, a series of novel mesoionic pyrido[1,2-a]pyrimidinone compounds containing a natural skeleton indolewere designed and synthesized, and the insecticidal activities of the target compounds were tested. The results showed that the targetcompounds had good to excellent insecticidal activities against white-backed planthoppers (Sogatella furcifera) and bean aphids(Aphis craccivora). Among them, compound7showed outstanding insecticidal activities against bothS. furciferaandA. craccivora,with LC50values of 0.86 and 0.85 mu g/mL, respectively. The insecticidal activity against bean aphids (A. craccivora) was superior tothat of triflumezopyrim (LC50= 3.67 mu g/mL). Proteomics and quantitative real-time polymerase chain reaction (qRT-PCR) resultsrevealed that compound7may interact with alpha 1 and alpha 7 nAChR subunits ofS. furcifera. The results of enzyme activities indicated thatcompound7was an inhibitor of AChE inS. furcifera. This study provides new ideas for the discovery of new mesoionic pyrido[1,2-a]pyrimidinone insecticides.