Discovery of Pyrido[1,2‑a]pyrimidinone Mesoionic Compounds Incorporating a Dithioacetal Moiety as Novel Potential Insecticidal Agents

A series of novel mesoionic pyrido­[1,2-a]­pyrimidinone compounds incorporating a dithioacetal skeleton were designed and synthesized for use as insecticidal agents. The biological activity of the title compounds indicated good to excellent insecticidal activities against bean aphids (Aphis craccivora) and white-backed planthoppers (Sogatella furcifera). Compound 34 showed excellent insecticidal activity against bean aphids (A. craccivora) with an LC50 value of 2.80 μg/mL, exceeding the insecticidal activity of trifluoropyrimidine (LC50 = 4.20 μg/mL). Proteomics and molecular docking results indicated that compound 34 could act on nicotinic acetylcholine receptors. This study provides support for the application of mesoionic pyrido­[1,2-a]­pyrimidinone compounds containing dithioacetal as novel insecticidal agents.