Tris(2-chloroethyl)amine

Overview
Tris(2-chloroethyl)ethylamine is the organic compound with the formula N(CH2CH2Cl)3. Often abbreviated HN3, it is a powerful blister agent  and a so-called nitrogen mustard gas (it is not a gas) used for chemical warfare. HN-3 was the last of the nitrogen mustard agents developed. It was designed as a military agent and is the only one of the nitrogen mustards that is still used for military purposes. It is the principal representative of the nitrogen mustards because its vesicant properties are almost equal to those of HD.

Mode of action
Nitrogen mustards react via an initial cyclization to the corresponding iminium salt. The rate of this reaction is pH dependent because the protonated amine cannot cyclize.

Applications
HN-3 has found some applications in chemotherapy, e.g. for Hodgkin's disease, but it is mainly of interest for its military uses and is the only one of these agents that remains anywhere as a military agent. These agents are more immediately toxic than the sulfur mustards.

Safety
Like other chemical warfare agents, tris92-chloroethyl)amine is highly toxic.