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Names | |
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IUPAC name ethyl N-[(1E)-1-(diethylamino)ethylidene]-phosphoramidofluoridate | |
Other names N-2-diethylaminomethylacetamido-ethoxyphosphonofluoridate | |
Identifiers | |
3D model (JSmol) | |
ChEBI | |
ChemSpider | |
PubChem CID | |
CompTox Dashboard (EPA) | |
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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]
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]
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.
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Names | |
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IUPAC name ([(2-chloro-1-methylpropoxy)fluorohydroxyphosphinyl]oxy)carbonimidic chloride fluoride [13] | |
Identifiers | |
3D model (JSmol) | |
CompTox Dashboard (EPA) | |
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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. [14] [15] [16] These structures were supported by Soviet literature of the time and were tested as acetylcholinesterase inhibitors, [17] [18] [19] 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. [20]
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.
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).
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 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.
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.
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.
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."
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).
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.
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.
EA-2192 is an extremely toxic degradation product of the VX nerve agent. It is a white solid that is very soluble and stable in water.
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.
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.
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.
EA-1356 is an organophosphate nerve agent of the G-series. It is highly resistant to enzymatic degradation in the body. The nerve agent was tested at Edgewood Arsenal in Maryland among many other chemicals tested on humans. A novel enzyme was patented by the US Army in 2018 to break down EA-1356. It is a schedule 1 substance by the Chemical Weapons Convention standards. It is under the category of munitions of ML7.b.1.a.
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.
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.