It was investigated as a chemical warfare agent starting in 1940.

It does not go through the blood-brain barrier due to the charge on quaternary nitrogen.

A phenyl carbamate ester is bonded in the meta position to the nitrogen on a diethylmethyl amine.

First, m-diethylaminophenol is reacted with methyl isocyanate to produce a methylcarbamate.

The resulting methylcarbamate is then reacted with methyl iodide to produce T-1123.