52-66-4Relevant articles and documents
Reactions of Thiols and Disulfides with Phosphite Radicals. A Chain Mechanism and RS*/PO32-* Equilibrium
Schaefer, K.,Asmus, K.-D.
, p. 852 - 855 (1981)
Thiyl and phosphite radicals exist in equilibrium, PO32-* + RSH = RS* + HPO32-, with equilibrium constants of 800 where RSH is ethyl mercaptan and 1500 where RSH is penicillamine.Rate constants for the respective forward reactions are 3.0E8 M-1s-1 for both compounds, and for the back reeactions, 2.0E5 and 3.8E5 M-1s-1.In solutions containing both phosphite and disulfide an SH2 reaction, PO32-* + RSSR ---> RSPO32- + RS*, yields phosphate thioester and thiyl radicals.At higher phosphite concentrations, a chain reaction mechanism is established, based on re-formation of PO32-* radicals in the reverse reaction of the above equilibrium.G values of up to about 30 are observed for thiol formation and disulfide destruction in these systems.One of the factors controlling the extent of the chain mechanism seems to be the thiyl/phosphite radical equilibrium.
Quinoxalinyl macrocyclic hepatitis C serine protease inhibitors
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Page/Page column 56, (2008/06/13)
The present invention relates to compounds of Formula I or II, or a pharmaceutically acceptable salt, ester, or prodrug, thereof: which inhibit serine protease activity, particularly the activity of hepatitis C virus (HCV) NS3-NS4A protease. Consequently, the compounds of the present invention interfere with the life cycle of the hepatitis C virus and are also useful as antiviral agents. The present invention further relates to pharmaceutical compositions comprising the aforementioned compounds for administration to a subject suffering from HCV infection. The invention also relates to methods of treating an HCV infection in a subject by administering a pharmaceutical composition comprising the compounds of the present invention.
Reactivity of sulfur nucleophiles towards S-nitrosothiols
Munro, Andrew P.,Williams, D. Lyn H.
, p. 1794 - 1797 (2007/10/03)
Rate constants have been measured for the reactions of a range of S-nitrosothiols with the following sulfur-centred nucleophiles: sulfite ion, thiourea, thiocyanate ion, thiosulfate ion, thiomethoxide ion and sulfide ion. Many of the reactions were very fast and were followed in a stopped-flow spectrophotometer. For the sulfite reaction the reactive species over the pH range 4-8 was shown to be exclusively SO32-. For two RSNO species the reactivity sequence was established as: SO32- > MeS- > S2O32- ? SC(NH2)2 SCN-. The reaction with sulfide ion was also rapid and generated a fairly stable yellow species (λmax 410 nm), which was probably the nitrosodisulfide ion ONSS-, but the absorbance-time data were too complex for a simple kinetic analysis. This reaction could have some potential as an analytical procedure for the determination of RSNO species. The kinetic results are discussed in terms of the factors affecting nucleophilicity and are compared with the corresponding reactions of other nitrosating species.
Reduction Potential of the .CO2- Radical Anion in Aqueous Solution
Surdhar, Parminder S.,Mezyk, Stephen P.,Armstrong, David A.
, p. 3360 - 3363 (2007/10/02)
The reduction potential for the .CO2- radical anion has been determined by equilibration of formate with sulfhydryl radicals of β-mercaptoethanol, penicillamine, and lipoamide in aqueous solutions at pH 3-6.The reaction .CO2- + e- + H+ = HCO2- yields the value E09 = 1.49 V with an uncertainty of +/-0.06 V.On the basis of this value and the known free energies of CO2(aq) and HCO2-(aq), E019 for CO2 + e- = .CO2- was found to be -1.85 V.