OXIDATIVE DETOXIFICATION OF PHOSPHONOTHIOLATES

The chemical nerve agent O-ethyl S-[2-(diisopropylamino)ethyl] methylphosphonothiolate (VX) is an unusually selective oxidation substrate. Relative to the thiolo sulfur, the amino nitrogen was a more reactive oxidation site. The oxidation of VX and a phosphonothiolate derivative by a broad range of peroxygen compounds was examined in organic, polar organic, and aqueous solvents. Depending on the oxidant, VX was either unreactive or reactive via one of the following mechanisms: 1. In neutral solvents, the nitrogen was oxidized first to anN-oxide, which was stable in aqueous solvents but decomposed by a Cope reaction in organic solvents. 2. After the nitrogen had been oxidized or protonated in an acidic aqueous solvent, the sulfur in the TV-oxide or the protonated VX was further oxidized to a sulfoxide intermediate, which hydrolyzed immediately. Detoxification can be accomplished by the second mechanism. © 1990, American Chemical Society. All rights reserved.