GS (nerve agent)

GS
Names
	IUPAC name 2-[fluoro(methyl)phosphoryl]oxycyclopentane
	Other names Cyclopentyl methylphosphonofluoridate
Identifiers
CAS Number	7284-82-4;
3D model (JSmol)	Interactive image;
ChemSpider	493016;
PubChem CID	567108;
	InChI InChI=1S/C6H12FO2P/c1-10(7,8)9-6-4-2-3-5-6/h6H,2-5H2,1H3 Key: JVMPZDDDTZJTKS-UHFFFAOYSA-N;
	SMILES P(C)(=O)(OC1CCCC1)F;
Properties
Chemical formula	C6H12FO2P
Molar mass	166.132 g·mol−1
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

GS (IUPAC name: Cyclopentyl methylphosphonofluoridate), also known as G-agent S candidate No. 3 or EA-1246 (Edgewood Arsenal cryptonym), is an organophosphate nerve agent, part of a series of nerve agents "G-series".^[1] It is a potent acetylcholinesterase inhibitor with properties similar to other nerve agents. GS is structurally a derivative of the nerve agent sarin, being closely structurally related to GP. The carbon-carbon bond angle makes it less persistent than sarin. It is a derivative of its acyclic equivalent, 3-pentanyl methylphosphonofluoridate.^[2]

GS rapidly ages the acetylcholinesterase, exhibiting a rate approximately half that of soman.^[3]^[4] GS was the third candidate in a series of 6 other organophosphonates, in which the vast majority are cycloalkyl/alkyl methylphosphonofluoridates, with the exception of GS-7, a derivative of the pesticide monitor.^[3]

References

^ Samuel, John B.; Penski, Elwin C.; Callahan, John J.. Physical Properties of Standard Agents, Candidate Agents, and Related Compounds at Several Temperatures - Special publication Aug 1970-Sep 1982. ARMY ARMAMENT RESEARCH AND DEVELOPMENT COMMAND ABERDEEN PROVING GROUND MD CHEMICAL SYSTEMS LAB. 1983 May 01
^ "Investigation of chemical warfare installations in the Munsterlager area, including Raubkammer - Digital Collections - National Library of Medicine". collections.nlm.nih.gov. Retrieved 2026-02-16.
^ ^a ^b Mager, Peter P. (1984). Multidimensional pharmacochemistry: design of safer drugs. Medicinal chemistry. Orlando: Academic Press. ISBN 978-0-12-465020-6.
^ De Jong, L. P. A.; Wolring, G. Z. (1978-01-01). "Reactivation and aging of cyclopentyl methylphosphonylated acetylcholinesterase in the presence of some 1-alkyl-2-hydroxyiminomethyl-pyridinium salts". Biochemical Pharmacology. 27 (24): 2911–2917. doi:10.1016/0006-2952(78)90208-3. ISSN 0006-2952. PMID 736984.

[1] Samuel, John B.; Penski, Elwin C.; Callahan, John J.. Physical Properties of Standard Agents, Candidate Agents, and Related Compounds at Several Temperatures - Special publication Aug 1970-Sep 1982. ARMY ARMAMENT RESEARCH AND DEVELOPMENT COMMAND ABERDEEN PROVING GROUND MD CHEMICAL SYSTEMS LAB. 1983 May 01

[2] "Investigation of chemical warfare installations in the Munsterlager area, including Raubkammer - Digital Collections - National Library of Medicine". collections.nlm.nih.gov. Retrieved 2026-02-16.

[:0-3] Mager, Peter P. (1984). Multidimensional pharmacochemistry: design of safer drugs. Medicinal chemistry. Orlando: Academic Press. ISBN 978-0-12-465020-6.

[4] De Jong, L. P. A.; Wolring, G. Z. (1978-01-01). "Reactivation and aging of cyclopentyl methylphosphonylated acetylcholinesterase in the presence of some 1-alkyl-2-hydroxyiminomethyl-pyridinium salts". Biochemical Pharmacology. 27 (24): 2911–2917. doi:10.1016/0006-2952(78)90208-3. ISSN 0006-2952. PMID 736984.

[1]

[2]

[3]

[4]