VR (nerve agent)

The development of VR started in 1957, after the Soviet Union obtained information about detection of high level of toxicity in phos{{shy}}phoryl{{shy}}thio{{shy}}cholines{{cite book|last=Major General Antonov|first=Nikolai S.|title=Khimicheskoe Oruzhiye na Rubezhe Dvukh Stoletii|script-title=ru:Химическое оружие на рубеже двух столетий |trans-title=Chemical Weapons at the Turn of the Century|language=ru|url=http://documents.theblackvault.com/documents/weapons/2009-03137-F.pdf|page=22|location=Moscow|publisher=Progress|year=1994|isbn=5-01-004462-5|lccn=96160418}} (the same year Lars-Erik Tammelin published his first articles on fluoro{{shy}}phos{{shy}}phoryl{{shy}}cholines and phos{{shy}}phoryl{{shy}}thio{{shy}}cholines in Acta Chemica Scandinavica) by a team from the Soviet Union's Scientific Research Institute No. 42 (NII-42). Sergei Zotovich Ivin, Leonid Soborovsky, and Iya Danilovna Shilakova jointly developed this analogue of VX. They completed their work in 1963 and were later awarded the Lenin Prize for their achievement.Tucker, J. B.; War of Nerves; Anchor Books; New York; 2006; pp 181-182. A binary weapon comprising two less toxic precursors which mixed during flight to form Substance 33 was later developed by a team led by Nikolai Kuznetsov.Vil S. Mirzayanov. State Secrets. An Insider's Chronicle of the Russian Chemical Weapons Program. (2009) pp166-168. {{ISBN|978-1-4327-2566-2}}

In 1972 the Soviets opened Cheboksary Khimprom, a manufacturing plant for VR in Novocheboksarsk.Tucker, J. B.; War of Nerves; Anchor Books; New York; 2006; pp 230–231. All facilities in USSR produced 15,557 tons of VR according to their declaration to the Organisation for the Prohibition of Chemical Weapons (OPCW),{{Cite web|url=http://www.cbwinfo.com/Chemical/Nerve/VR.shtml|title=Factsheets on Chemical and Biological Warfare Agents}} although most if not all of this has now been destroyed under disarmament treaties.{{Cite web|url=http://www.fas.org/nuke/guide/russia/cbw/cw.htm|title=Chemical Weapons – Russian / Soviet Nuclear Forces}}

VR has similar lethal dose levels to VX {{nowrap|(10{{hsp}}–{{hsp}}}}50 mg), as well as being similar in appearance.{{Cite web|url=https://www.acs.org/content/acs/en/molecule-of-the-week/archive/v/vr.html|title=VR|website=American Chemical Society}} However, due to usage of diethyl{{shy}}amino radicals instead of diiso{{shy}}propyl{{shy}}amino it is more prone to decomposition. The former are worse at sterically protecting the nitrogen atom from attacking either phosphorus or the α-carbon atom adjacent to sulfur than the latter. According to UK Defence Science and Technology Laboratory Detection Department scientists Robin M. Black and John M. Harrison, chemical stability was an important factor why of all the similarly toxic phos{{shy}}phoryl{{shy}}thio{{shy}}cholines, ethyl N-2-diiso{{shy}}propyl{{shy}}amino{{shy}}ethyl methyl{{shy}}phos{{shy}}phono{{shy}}thiolate in particular (now known as VX), was weaponized in the West.Black R.M., Harrison J.M. The chemistry of organo{{shy}}phosphorus chemical warfare agents. Chapter 10 of The chemistry of organo{{shy}}phosphorus compounds. Volume 4, Ter- and quinque-valent phosphorus acids and their derivatives. (1996) {{Cite book|doi=10.1002/9780470682531.pat0070|isbn=978-0-471-95706-5|chapter=The Chemistry of Organophosphorus Chemical Warfare Agents|title=PATai's Chemistry of Functional Groups|year=2009|last1=Black|first1=R. M.|last2=Harrison|first2=J. M.}}

According to Russian CW developer Vil Mirzayanov, in the late 1980s a group of GosNIIOKhT chemists led by Georgiy Drozd prepared a scientific report that Substance 33 had much lower shelf life than VX. The report, writes Mirzayanov, caused 'panic' in the institute top management and the military representative office, and later was met with administrative resistance. This finding was independently verified by another chemist Igor Revelskiy but his report wasn't approved either.{{Cite book | url=https://books.google.com/books?id=ldpNPgAACAAJ |title = State Secrets: An Insider's Chronicle of the Russian Chemical Weapons Program|isbn = 978-1-4327-1923-4|last1 = Mirzayanov|first1 = Vil S.|date = December 2008| publisher=Outskirts Press, Incorporated }}

Following the poisoning of Sergei and Yulia Skripal, former head of the GosNIIOKhT security department Nikolay Volodin said in an interview to Novaya Gazeta that Substance 33 was decomposing too quickly in combat conditions, and implied that this fact may have influenced the decision to continue research on the Novichok program.{{Cite web|url=https://www.novayagazeta.ru/articles/2018/03/23/75908-demonstrativnoe-ubiystvo-mozhno-bylo-organizovat-prosche|title="Новичок" — это слишком для одного Скрипаля"|date=March 23, 2018|website=Новая газета - Novayagazeta.ru}}

Both agents have similar symptoms and method of action to other nerve agents that act on cholin{{shy}}esterase, and treatment remains the same. However, the window for effectively treating second generation V series seizures is shorter, as they rapidly denature the acetyl{{shy}}cholin{{shy}}esterase protein in a similar manner to soman, making treatment with the standard nerve gas antidote pralidoxime ineffective unless it is given very soon after exposure.{{citation needed|date=March 2018}} Pre-treatment with pyrido{{shy}}stigmine prior to exposure, and treatment with other drugs such as atropine and diazepam after exposure, will reduce symptoms of nerve agent toxicity but may not be sufficient to prevent death if a large dose of nerve agent has been absorbed. In addition to the standard seizures, some of the second generation V series agents are known to cause comas.

• A-234 (nerve agent)
• Novichok agent

{{Chemical warfare}}

{{Neurotoxins}}

{{Acetylcholine metabolism and transport modulators}}

Category:Acetylcholinesterase inhibitors

Category:V-series nerve agents

Category:Phosphonothioates

Category:Chemical weapons

Category:Cold War weapons of the Soviet Union

Category:Soviet inventions

Category:Science and technology in the Soviet Union

Category:Diethylamino compounds

Category:Soviet chemical weapons program

Category:Isobutyl esters