Selection of Functional Groups for Chemical Nerve Toxic Agents — Novichok

I was curious about what functional groups are utilized in war, so I wrote them into GlobalChem.

https://github.com/Sulstice/global-chem/blob/master/global_chem/global_chem/warfare/organophosphorous_nerve_agents.py

In the 1970’s the Soviet Union started researching chemical agents and constructed a facility in Novocheboksarsk. They shipped around 15,000 tons of chemical agents annually on a substance called “Substance-33” or rather with the acronym “VR” or the V-series of toxic agents.

The interesting chemical environment is the phosphorous that is sandwiched between the sulphur and the oxygen. The phosphorous core is the main component of any nerve toxic agent. With substance 33 as a backbone, in 1988 the soviets released A-230.

Slightly different and especially with the sp2 nitrogen that is also bonded to the phosphorous creates a very unique chemical space. A-232 was similar to A-230 but never got approval for use:

Later on the Soviet army wanted use the initial structures of these toxic agents for binary weapons, meaning it’s two chemical compounds mixed when fired. This was Dr. Mirzayanov’s account of what the formal chemical structures of this nerve agents looked like since this research was guarded by a lot of secrecy. Dr. Hoenig also speculated what these structures looked like, his version of the A-232 agent:

Which is pretty different so it’s hard to say exactly whether Mirzayanov or Hoenig’s versions are right but still the pattern of the drug is obvious.

The phosphorous core was played around with in a sea of different chemical space until they landed on the Novichok-5 tested in 1990. This is where things are pretty interesting in terms of the chemical environment surround the phosphorous:

The dioxaphospholane is a unique functional group especially with the fluorine attached. I found this ring system to be so simplistic yet powerful in an environment I wouldn’t have contrived myself which does show my lack of knowledge in designing warfare compounds. This ring system is an ample target forcefield parametirization which will drive the develpment of the CGenFF as a relevant forcefield especially for war.

Reference: Chemical Weapons Disarmament in Russia : Problems and Prospects