17231-94-6Relevant articles and documents
Fedorov et al.
, (1975)
A study of the kinetics of La3+-promoted methanolysis of S-aryl methylphosphonothioates: Possible methodology for decontamination of EA 2192, the toxic byproduct of VX hydrolysis
Dhar, Basab B.,Edwards, David R.,Brown, R. Stan
, p. 3071 - 3077 (2011/05/09)
The kinetics of the La3+-catalyzed methanolysis of a series of S-aryl methylphosphonothioates (4a-e, phenyl substituents = 3,5-dichloro, 4-chloro, 4-fluoro, 4-H, 4-methoxy) were studied at 25 °C with ss pH control. The reaction involves saturation binding of the anionic substrates to dimeric La3+/methoxide catalysts formulated as La2 3+(-OCH3)x, where x = 2-5 depending on the solution ss pH. Cleavage of the La3+-bound methylphosphonothioates is fast, ranging from 5 × 10-3 s -1 to 5.5 × 10-5 s-1 for substrates 4a-e at a ss pH of 8.4 and 1.6 × 10-1 s-1 to 4 × 10-3s-1 at a ss pH of 11.7. The rate accelerations for the methanolysis of substrates 4a-e, relative to their background methoxide-promoted reactions, average 7 × 1010 and 1.5 × 109, respectively, at sspH's of 8.4 and 11.7. The catalytic system is predicted to cleave EA 2192 (S-2(N,N-di-iso-propylaminoethyl) methylphosphonothioate), a toxic byproduct of the hydrolysis of VX, with a t1/2 between 4 and 8 min at a ss pH of 8.4, and 27 min at a ss pH of 11.7.
Solvent deuterium kinetic isotope effects for the methanolyses of neutral C=O, P=O and P=S esters catalyzed by a triazacyclododecane : Zn 2+-methoxide complex
Maxwell, Chris,Neverov, Alexei A.,Brown, R. Stan
, p. 4329 - 4336 (2007/10/03)
The methanolyses of several organophosphate/phosphonate/phosphorothioate esters (O, O-diethyl O-(4-nitrophenyl) phosphate, paraoxon, 3; O, O-diethyl S-(3,5-dichlorophenyl) phosphorothioate, 4; O-ethyl O-(2-nitro-4-chlorophenyl) methylphosphonate, 5; O, O-dimethyl O-(3-methyl-4-nitrophenyl) phosphorothioate, fenitrothion, 6; O-ethyl S-(3,5-dichlorophenyl) methylphosphonothioate 7) and a carboxylate ester (p-nitrophenyl acetate, 2) catalyzed by methoxide and the Zn2+(-OCH3) complex of 1,5,9- triazacyclododecane (1 : Zn2+(-OCH3)) were studied in methanol and d1-methanol at 25°C. In the case of the methoxide reactions inverse skie's were observed for the series with values ranging from 2 to 1.1, except for 7 where the kD/kH = 0.90 ± 0.02. The inverse kD/kH values are consistent with a direct nucleophilic methoxide attack involving desolvation of the nucleophile with varying extents of resolvation of the TS. With the 1 : Zn 2+(-OCH3) complex all the skie values are kD/kH = 1.0 ± 0.1 except for 7 where the value is 0.79 ± 0.06. Arguments are presented that the fractionation factors associated with complex 1 : Zn2+(-OCH3) are indistinguishable from unity. The skie's for all the complex-catalyzed methanolyses are interpreted as being consistent with an intramolecular nucleophilic attack of the Zn2+-coordinated methoxide within a pre-equilibrium metal : substrate complex. The Royal Society of Chemistry 2005.
