371-42-6Relevant articles and documents
Development of selective colorimetric probes for hydrogen sulfide based on nucleophilic aromatic substitution
Montoya, Leticia A.,Pearce, Taylor F.,Hansen, Ryan J.,Zakharov, Lev N.,Pluth, Michael D.
, p. 6550 - 6557 (2013/07/26)
Hydrogen sulfide is an important biological signaling molecule and an important environmental target for detection. A major challenge in developing H2S detection methods is separating the often similar reactivity of thiols and other nucleophiles from H2S. To address this need, the nucleophilic aromatic substitution (SNAr) reaction of H2S with electron-poor aromatic electrophiles was developed as a strategy to separate H2S and thiol reactivity. Treatment of aqueous solutions of nitrobenzofurazan (7-nitro-1,2,3-benzoxadiazole, NBD) thioethers with H 2S resulted in thiol extrusion and formation of nitrobenzofurazan thiol (λmax = 534 nm). This reactivity allows for unwanted thioether products to be converted to the desired nitrobenzofurazan thiol upon reaction with H2S. The scope of the reaction was investigated using a Hammett linear free energy relationship study, and the determined ρ = +0.34 is consistent with the proposed SN2Ar reaction mechanism. The efficacy of the developed probes was demonstrated in buffer and in serum with associated submicromolar detection limits as low as 190 nM (buffer) and 380 nM (serum). Furthermore, the sigmoidal response of nitrobenzofurazan electrophiles with H2S can be fit to accurately quantify H2S. The developed detection strategy offers a manifold for H2S detection that we foresee being applied in various future applications.
Solvent-free synthesis of thiophenol using uncatalyzed transfer hydrogenation
Zhou, Shaodong,Qian, Chao,Chen, Xinzhi
experimental part, p. 2432 - 2439 (2012/06/18)
Clean and sustainable transfer hydrogenation for aryl sulfonamides and sulfonyl chlorides is described. The protocol is chemoselective and uses neither catalyst nor solvent.
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.
