3,3,5-Trimethylcyclohexyl 3-pyridyl methylphosphonate

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3,3,5-Trimethylcyclohexyl 3-pyridyl methylphosphonate.svg
Preferred IUPAC name
Pyridin-3-yl 3,3,5-trimethylcyclohexyl methylphosphonate
Other names
3D model (JSmol)
  • InChI=1S/C15H24NO3P/c1-12-8-14(10-15(2,3)9-12)19-20(4,17)18-13-6-5-7-16-11-13/h5-7,11-12,14H,8-10H2,1-4H3
  • CC2CC(OP(C)(=O)Oc1cccnc1)CC(C)(C)C2
Molar mass 297.335 g·mol−1
Occupational safety and health (OHS/OSH):
Main hazards
Extremely toxic
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

VP (3,3,5-Trimethylcyclohexyl 3-pyridyl methylphosphonate), also known as EA-1511, is an extremely toxic organophosphate nerve agent of the V-series.

Agent VP belongs to a class of organophosphates known as 3-pyridyl phosphonates. These agents are extremely potent acetylcholinesterase inhibitors.[2]


Methylphosphonic dichloride and triethylamine are dissolved in benzene. 3,3,5-Trimethylcyclohexanol is then slowly added while stirring and cooling. The reaction temperature is maintained at 10-15 °C. The mixture is then heated to 40 °C for 1 hour. A benzene solution of 3,3,5-trimethylcyclohexyl methylphosphonochloridate is formed.

Triethylamine is then added to reaction mixture and 3-pyridol is added slowly while stirring and cooling. The reaction temperature is maintained at 35 °C. The mixture is then stirred for 1 hour at room temperature. The mixture is washed with a sodium hydroxide solution and water. The solvent is then removed by distillation at reduced pressure to yield the final product. The resulting product can be converted to a quaternary salt by reacting with a haloalkane, such as methyl iodide, to produce a water-soluble agent.[2]

See also[edit]


  1. ^ Summary of major events and problems (PDF) (Report). U.S. Army Chemical Corps. October 1957 – via fas.org.
  2. ^ a b "3-Pyridyl phosphonates". Google Patents. 1956.