Nicotine analogues: Phenyl azetidines and azetidinones as potential insecticidal agents

Nicotine shows insecticidal properties, acting as an agonist at the insect nicotinic acetylcholine receptor. Our work involves the investigation of the insecticidal properties of compounds based on the structure of nicotine. The important structural components of nicotine include the aromatic pyridine ring and the aliphatic pyrolidine ring. Our interest is in changing both of these ring types (to benzene and azetidine, respectively) and measuring the insecticidal properties of the intermediates and end products. Because the pyridine ring is deactivated compared to benzene, we have deactivated the benzene ring by adding a chloro group. The chloro group has been added in the ortho, meta, and para position. Suitably substituted vinyl chloro benzene has been used as a starting compound to ultimately generate the azetidine. Synthesis of these compounds involves a (2+2) addition of chloro sulfonyl isocyanate to vinyl benzene to give the azetidinone in two steps followed by a reduction to yield the azetidine ring.

A biological assay for each of the intermediate compounds was performed using the third instar larval stage of Musca domestica. This stage was chosen because it is physiologically similar to the adult and easier to handle, and also because the strongest activity of nicotine is observed on soft-bodied insects. Synthesis and bioassay results will be presented.