Structure, Nuclear Magnetic Resonance Data, Biological Activity, and Synthesis of the Okaramine Family Compounds

The okaramine family of compounds, a class of alkaloids with broad-spectrum insecticidal activity, has been discovered from species of Penicillium and Aspergillus. These okaramines, characterized by their complex structures and diverse biological activities, have attracted widespread attention from biologists and chemists. To date, only a few okaramines have been synthesized, notably the highly active okaramines A and B, which feature a polycyclic skeleton, including an azocine ring and an unprecedented 2-dimethyl-3-methyl-azetidine ring. These compounds have not yet been synthesized artificially. Their potent insecticidal activity is due to their selective activation of glutamate-gated chloride channels in invertebrates without affecting human ligand-gated anion channels. They are promising candidates as lead insecticides and merit further research. This review provides an overview of the research progress in the structural characteristics, nuclear magnetic resonance data, biological activity, biosynthesis, and total synthesis of okaramines, offering a framework for the development of novel pesticides.