Mesoionic pyrido[1,2-a]pyrimidinones: A novel class of insecticides inhibiting nicotinic acetylcholine receptors

A novel class of mesoionic pyrido[1,2-a]pyrimidinones has been discovered with exceptional insecticidal activity controlling a number of insect species, particularly hemiptera and lepidoptera. Mode-of-action studies showed that they act on nicotinic acetylcholine receptors (nAChRs) primarily as inhibitors. Here we report the discovery, evolution, and preparation of this class of chemistry. Our efforts in structure–activity relationship elucidation and biological activity evaluation are also presented.