Classical chemical nerve agents are organophosphate based compounds such as Sarin, Soman, Tabun, VX and others. These compounds inhibit acetylcholinesterases in the synapses of nerve junctions. Instead of inactivating acetylcholinesterases, compounds, quaternary amines, can block nerve transmission by binding primarily to the acetylcholine receptor sites. The U.S. Patent Office has published 23 unique patents or invention registrations on the synthesis of compounds that can bind to muscarinic and nicotinic acetylcholine receptors. It is likely that some of these compounds could serve as either polarizing or nonpolarizing nerve agents that bind to the acetylcholine receptor and block binding of acetylcholine. This paper has systematically reviewed a series of bisquaternary amines that could be potentially deadly nerve agents. Analogous tertiary amines, based on the structure of the parent bisquaternary amines, have been proposed as compounds that might be more soluble in membranes making them more bioavailable and toxic. Finally, methods have been discussed that could identify this class of compounds using a bioassay for binding to the acetylcholine receptor. A tool in the identification of these compounds, the Hofmann elimination reaction, has been proposed as a novel method for helping to establish that quaternary or tertiary amines are functional groups of the nerve agent.

Keywords: Quaternary ammonium salts; nerve agents; chemical warfare; acetylcholine receptor