A-234 (nerve agent)

Last updated
A-234 (according to Mirzayanov)
A-234 Mirzayanov.svg
Names
IUPAC name
ethyl N-[(1E)-1-(diethylamino)ethylidene]-phosphoramidofluoridate
Other names
N-2-diethylaminomethylacetamido-ethoxyphosphonofluoridate
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
PubChem CID
  • InChI=1S/C8H18FN2O2P/c1-5-11(6-2)8(4)10-14(9,12)13-7-3/h5-7H2,1-4H3/b10-8+
    Key: SBPSVLLDDYOPDZ-CSKARUKUSA-N
  • CCOP(F)(=O)\N=C(/C)\N(CC)CC
Properties
C8H18FN2O2P
Molar mass 224.216 g·mol−1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

A-234 is an organophosphate nerve agent. It was developed in the Soviet Union under the FOLIANT program and is one of the group of compounds referred to as Novichok agents that were revealed by Vil Mirzayanov. [2] [3] [4] [5] In March 2018 the Russian ambassador to the UK, Alexander Yakovenko, claimed to have been informed by British authorities that A-234 had been identified as the agent used in the poisoning of Sergei and Yulia Skripal. [6] Vladimir Uglev, one of the inventors of the Novichok series of compounds, said he was "99 percent sure that it was A-234" in relation to the 2018 Amesbury poisonings, noting its unusually high persistence in the environment. [7] [8]

Contents

According to a classified report by the United States Army National Ground Intelligence Center, [9] the agent designated as A-232 and its ethyl analog A-234, developed under the FOLIANT program, were "as toxic as VX, as resistant to treatment as soman, and more difficult to detect and easier to manufacture than VX".

No certain data on toxicity exist but it is estimated that the median lethal concentration of A-234 is 7 mg/m3. This means that half of 70 kg men under slight physical activity –breathing 15 litres of air per minute –would die within two minutes of exposure. This equates to median lethal dose of 0.2 mg via respiration. [10]

Regulated chemical under the Chemical Weapons Convention

A-234 has recently (entry into force 7 June 2020) been added to Schedule 1 of the Annex on Chemicals of the Chemical Weapons Convention and it has been explicitly named as an example compound for schedule 1.A.14. [11] [12] For chemicals listed in Schedule 1, the most stringent declaration and verification measures are in place combined with far-reaching limits and bans on production and use. It is notable to say that Annex 1 does not explicitly relate this structure to the name A-234, instead adding this particular structure to the prohibited compounds section.

Alternative structure

A-234 (according to Hoenig)
A-234 Hoenig.svg
Names
IUPAC name
([(2-chloro-1-methylpropoxy)fluorohydroxyphosphinyl]oxy)carbonimidic chloride fluoride[ citation needed ]
Identifiers
3D model (JSmol)
  • InChI=1S/C5H8Cl2F2NO3P/c1-3(6)4(2)12-14(9,11)13-10-5(7)8/h3-4H,1-2H3/b10-5- Yes check.svgY
    Key: ROJDTMHBTCCYOZ-YHYXMXQVSA-N Yes check.svgY
  • F\C(\Cl)=N/OP(=O)(F)OC(C)C(C)Cl
Properties
C5H8Cl2F2NO3P
Molar mass 269.99 g·mol−1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

An alternative structure for A-234 and the related Novichok agents had previously been proposed by Western chemical weapons experts such as Steven Hoenig and D. Hank Ellison. [13] [14] [15] These structures were supported by Soviet literature of the time and were tested as acetylcholinesterase inhibitors, [16] [17] [18] however Mirzayanov explained that a number of weaker agents developed as part of the Foliant program were published in the open literature as organophosphate pesticides, in order to disguise the secret nerve agent program as legitimate pesticide research.

However, the presence of a carbonimidic chloride fluoride group and a dimethylchloroethyl group suggest that this molecule is a member of the C-series of organophosphate agents (C01), with additional mustard and (chlorofluoro-)phosgene oxime radicals, added to produce skin and lung toxicity as well as blistering effects. [19]

See also

Related Research Articles

Nerve agents, sometimes also called nerve gases, are a class of organic chemicals that disrupt the mechanisms by which nerves transfer messages to organs. The disruption is caused by the blocking of acetylcholinesterase (AChE), an enzyme that catalyzes the breakdown of acetylcholine, a neurotransmitter. Nerve agents are irreversible acetylcholinesterase inhibitors used as poison.

<span class="mw-page-title-main">Soman</span> Chemical compound (nerve agent)

Soman is an extremely toxic chemical substance. It is a nerve agent, interfering with normal functioning of the mammalian nervous system by inhibiting the enzyme cholinesterase. It is an inhibitor of both acetylcholinesterase and butyrylcholinesterase. As a chemical weapon, it is classified as a weapon of mass destruction by the United Nations according to UN Resolution 687. Its production is strictly controlled, and stockpiling is outlawed by the Chemical Weapons Convention of 1993 where it is classified as a Schedule 1 substance. Soman was the third of the so-called G-series nerve agents to be discovered along with GA (tabun), GB (sarin), and GF (cyclosarin).

<span class="mw-page-title-main">VX (nerve agent)</span> Chemical compound and chemical warfare nerve agent

VX is an extremely toxic synthetic chemical compound in the organophosphorus class, specifically, a thiophosphonate. In the class of nerve agents, it was developed for military use in chemical warfare after translation of earlier discoveries of organophosphate toxicity in pesticide research. In its pure form, VX is an oily, relatively non-volatile liquid that is amber-like in colour. Because of its low volatility, VX persists in environments where it is dispersed.

Cyclosarin or GF is an extremely toxic substance used as a chemical weapon. It is a member of the G-series family of nerve agents, a group of chemical weapons discovered and synthesized by a German team led by Dr. Gerhard Schrader. The major nerve gases are the G agents, sarin (GB), soman (GD), tabun (GA), and the V agents such as VX. The original agent, tabun, was discovered in Germany in 1936 in the process of work on organophosphorus insecticides. Next came sarin, soman and finally, cyclosarin, a product of commercial insecticide laboratories prior to World War II.

<span class="mw-page-title-main">VG (nerve agent)</span> Chemical compound

VG is a "V-series" nerve agent chemically similar to the better-known VX nerve agent. Tetram is the common Russian name for the substance. Amiton was the trade name for the substance when it was marketed as an insecticide by ICI in the mid-1950s.

Novichok is a family of nerve agents, some of which are binary chemical weapons. The agents were developed at the GosNIIOKhT state chemical research institute by the Soviet Union and Russia between 1971 and 1993. Some Novichok agents are solids at standard temperature and pressure, while others are liquids. Dispersal of solid form agents is thought possible if in ultrafine powder state.

<span class="mw-page-title-main">Organophosphate poisoning</span> Medical condition

Organophosphate poisoning is poisoning due to organophosphates (OPs). Organophosphates are used as insecticides, medications, and nerve agents. Symptoms include increased saliva and tear production, diarrhea, vomiting, small pupils, sweating, muscle tremors, and confusion. While onset of symptoms is often within minutes to hours, some symptoms can take weeks to appear. Symptoms can last for days to weeks.

<span class="mw-page-title-main">VR (nerve agent)</span> Chemical compound

VR is a "V-series" unitary nerve agent closely related to the better-known VX nerve agent. It became a prototype for the series of Novichok agents. According to chemical weapons expert Jonathan Tucker, the first binary formulation developed under the Soviet Foliant program was used to make Substance 33, differing from VX only in the alkyl substituents on its nitrogen and oxygen atoms. "This weapon was given the code name Novichok."

<span class="mw-page-title-main">Cholinesterase inhibitor</span> Chemicals which prevent breakdown of acetylcholine and butyrylcholine

Cholinesterase inhibitors (ChEIs), also known as anti-cholinesterase, are chemicals that prevent the breakdown of the neurotransmitter acetylcholine or butyrylcholine. This increases the amount of the acetylcholine or butyrylcholine in the synaptic cleft that can bind to muscarinic receptors, nicotinic receptors and others. This group of inhibitors is divided into two subgroups, acetylcholinesterase inhibitors (AChEIs) and butyrylcholinesterase inhibitors (BChEIs).

<span class="mw-page-title-main">EA-3148</span> Chemical compound

EA-3148 is a "V-series" nerve agent related to the better-known compounds VX and VR. It was studied by both the US and Soviet chemical weapons programmes during the Cold War, and is notable as the only V-series organophosphate nerve agent specifically identified in public domain sources as having a higher absolute potency as an acetylcholinesterase inhibitor than VX. However, both the US and Soviet investigations of the compound concluded that despite its high potency, the physicochemical properties of the substance made it unsuitable for weaponisation, and further research was not conducted.

Vil Sultanovich Mirzayanov is a Russian chemist of ethnic Tatar origin who now lives in the United States, best known for revealing secret chemical weapons experimentation in Russia.

<span class="mw-page-title-main">A-232</span> Chemical compound

A-232 is an organophosphate nerve agent. It was developed in the Soviet Union under the FOLIANT program and is one of the group of compounds referred to as Novichok agents that were revealed by Vil Mirzayanov. A-232 is reportedly slightly less potent as a nerve agent compared to some of the other compounds in the series such as A-230 and A-234, having similar potency to the older nerve agent VR. However it proved to be the most versatile agent as it was chemically stable and remained a volatile liquid over a wide temperature range, making it able to be used in standard chemical munitions without requiring special delivery mechanisms to be developed.

Chinese VX (CVX), also known as EA-6043, is an organophosphate nerve agent of the V-series. It is a structural isomer of both VX and Russian VX.

<span class="mw-page-title-main">A-230</span> Chemical compound

A-230 is an organophosphate nerve agent. It was developed in the Soviet Union under the FOLIANT program and is one of the group of compounds referred to as Novichok agents that were revealed by Vil Mirzayanov. A-230 is possibly the most potent nerve agent for which specific toxicity figures have been published, with a human lethal dose estimated to be less than 0.1 mg. However it was felt to be less suitable for weaponisation than other agents such as A-232 and A-234, due to issues with the liquid agent exhibiting low volatility and solidifying at low temperatures, as well as poor stability in the presence of water.

<span class="mw-page-title-main">A-242</span> Chemical compound

A-242 is an organophosphate nerve agent. It was developed in the Soviet Union under the FOLIANT program and is one of the group of compounds referred to as Novichok agents that were revealed by Vil Mirzayanov. Mirzayanov gives little specific information about A-242, stating that it is highly toxic but no figures are given to compare it to other related agents. It is reportedly a solid rather than a volatile liquid as with most nerve agents, and in order to weaponise it successfully, it had to be milled into a fine powder form that could be dispersed as a dust.

<span class="mw-page-title-main">GP (nerve agent)</span> Chemical compound

GP is an organophosphate nerve agent of the G-series, with a relatively slow rate of hydrolysis, and thus high stability and persistence in the environment.

<span class="mw-page-title-main">A-262</span> Chemical compound

A-262 is an organophosphate nerve agent. It was developed in the Soviet Union under the FOLIANT program and is one of the group of compounds referred to as Novichok agents that were revealed by Vil Mirzayanov. Mirzayanov gives little specific information about A-262, stating that it is highly toxic, but no figures are given to compare it to other related agents. It is reportedly a solid rather than a volatile liquid as with most nerve agents, and in order to weaponise it successfully, it had to be milled into a fine powder form that could be dispersed as a dust.

<span class="mw-page-title-main">GosNIIOKhT</span> Russian research institute

The State Research Institute of Organic Chemistry and Technology (GosNIIOKhT) is a Russian research institute engaged in the development of chemical technologies for use in the national economy and the production of relevant goods and products.

References

  1. Chai, Peter R.; Hayes, Bryan D.; Erickson, Timothy B.; Boyer, Edward W. (2018). "Novichok agents: A historical, current, and toxicological perspective". Toxicology Communications. 2 (1): 45–48. doi:10.1080/24734306.2018.1475151. PMC   6039123 . PMID   30003185.
  2. ↑ Mirzayanov, Vil S. (2008). State Secrets: An Insider's Chronicle of the Russian Chemical Weapons Program. Outskirts Press. ISBN   978-1-4327-2566-2.
  3. ↑ Vásárhelyi, Györgyi; Földi, László (2007). "History of Russia's chemical weapons" (PDF). AARMS. 6 (1): 135–146. Archived from the original (PDF) on 2018-03-14.
  4. ↑ Halámek, E.; Kobliha, Z. (2011). "Potenciální Bojové Chemické Látky". Chemické Listy. 105 (5): 323–333.
  5. ↑ Peplow, Mark (19 March 2018). "Nerve agent attack on spy used 'Novichok' poison". Chemical & Engineering News . 96 (12): 3. Retrieved 16 March 2018.
  6. ↑ "Russian spy: What are Novichok agents and what do they do?". BBC News . 19 March 2018.
  7. ↑ Carroll, Oliver (6 July 2018). "Novichok inventor on Amesbury poisoning: 'I completely understand panic of those living in Salisbury'" . The Independent . Archived from the original on 2018-07-05. Retrieved 26 May 2020.
  8. ↑ Harvey SP, McMahon LR, Berg FJ. Hydrolysis and enzymatic degradation of Novichok nerve agents. Heliyon. 2020 Jan 7;6(1):e03153. doi : 10.1016/j.heliyon.2019.e03153 PMID   32042950
  9. ↑ Gertz, Bill (4 February 1997). "Russia dodges chemical arms ban". The Washington Times . Retrieved 26 May 2020.
  10. ↑ Franca, Tanos C. C.; Kitagawa, Daniel A. S.; Cavalcante, Samir F. de A.; da Silva, Jorge A. V.; Nepovimova, Eugenie; Kuca, Kamil (January 2019). "Novichoks: The Dangerous Fourth Generation of Chemical Weapons". International Journal of Molecular Sciences . 20 (5): 1222. doi: 10.3390/ijms20051222 . PMC   6429166 . PMID   30862059.
  11. ↑ "S/1821/2019/Rev.1 Note by the Technical Secretariat GUIDANCE FOR STATES PARTIES ON ARTICLE VI DECLARATION OBLIGATIONS AND INSPECTIONS FOLLOWING ENTRY INTO FORCE OF CHANGES TO SCHEDULE 1 OF THE ANNEX ON CHEMICALS TO THE CHEMICAL WEAPONS CONVENTION" (PDF). 14 January 2020.
  12. ↑ "Schedule 1". OPCW. Retrieved 2020-07-26.
  13. ↑ Hoenig, Steven L. (2007), Compendium of Chemical Warfare Agents, Springer, ISBN   978-0-387-34626-7
  14. ↑ Ellison, D. Hank (2008), Handbook of Chemical and Biological Warfare Agents (Second ed.), CRC Press, ISBN   978-0-849-31434-6
  15. ↑ Jeong K, Choi J. Theoretical study on the toxicity of 'Novichok' agent candidates. R Soc Open Sci. 2019 Aug 7;6(8):190414. doi : 10.1098/rsos.190414 PMID   31598242
  16. ↑ Kruglyak, Yu. L.; Malekin, S. I.; Martynov, I. V. (1972). "Phosphorylated oximes. XII. Reactions of 2-halophospholanes with dichlorofluoronitrosomethane". Zhurnal Obshchei Khimii. 42 (4): 811–814.
  17. ↑ Raevskii, O. A.; Chapysheva, N. V.; Ivanov, A. N.; Sokolov, V. B.; Martynov, I. V. (1987). "Effect of Alkyl Substituents in Phosphorylated Oximes". Zhurnal Obshchei Khimii. 57 (12): 2720–2723.
  18. ↑ Raevskii, O. A.; Grigor'ev, V. Yu.; Solov'ev, V. P.; Ivanov, A. N.; Sokolov, V. B.; Martynov, I. V. (1987). "Electron-Donor Functions of Ethyl Methylchloroformimino Methylphosphonate". Zhurnal Obshchei Khimii. 57 (9): 2073–2078.
  19. ↑ Hank Ellison, D. (9 December 2022). Handbook of Chemical and Biological Warfare Agents, Volume 1: Military Chemical and Toxic Industrial Agents. CRC Press. ISBN   9781000484403.
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