The sulfoxidation of thiodiglycolic acid with iron(III)-salen chloride, which acts as an oxidizing agent without any terminal oxidant, in 50% aqueous acetonitrile medium has been studied. A substantial red shift in the λ<sub>max</sub>value of FeIII-salen was observed in aqueous medium. The spectrophotometric kinetic study indicates that [Fe<sup>III</sup>(salen)]+ is the active oxidizing species and the reaction follows Michaelis-Menten kinetics with respect to the substrate. The rate of the reaction is highly sensitive to the medium. A reaction mechanism involving electron transfer from sulfur atom of thiodiglycolic acid to the central iron atom of [Fe<sup>III</sup>(salen)]<sup>+</sup> is proposed. The presence of nitrogenous bases like pyridine, imidazole and 1-methylimidazole shows a retarding effect on the reaction rate. This can be explained on the basis of binding of these ligands to the coordination sphere of [Fe<sup>III</sup>(salen)]<sup>+</sup> prior to the reaction with the substrate. The observed order of reactivity, pyridine > 1-methylimidazole > imidazole, is in accordance with the inverse of <em>π</em>-donating ability of nitrogen bases.
Multiple fixed drug eruption due to carbocysteine: Presence of circulating interferon-γ-producing CD8+ T cells reactive with its night metabolite thiodiglycolic acid
