Benzilylcholine mustard (N-2-chloroethyl-N-methyl 2-aminoethyl benzilate) is a modified version of acetylcholine, so named because after cyclization in solution it forms an aziridinium derivative that is structurally similar to benzilylcholine.

It is well known for being an irreversible antagonist of the muscarinic acetylcholine receptor.

[1] It has been used in pharmacological experiments investigating the relationship between receptor occupancy and response.

It was also one of the tools in characterization of the muscarinic acetylcholine receptor.

[3] Groups that can be alkylated in this way include thiols, alcohols, imines and carboxylic acids.