26547-93-3Relevant academic research and scientific papers
Oxidation of thioethers and sulfoxides with hydrogen peroxide using TS-1 as catalyst
Hutchings,Lee,McMorn,Page,Robinson,Willock,Davies,Watson,McGuire,Lee,Bethell
, p. 1523 - 1529 (2007/10/03)
A combined experimental and molecular simulation study of the oxidation of thioethers with H2O2 was conducted using titanium-containing zeolites as catalysts. Regioselectivity was investigated for the oxidation of allyl methyl thioether using TS-1 as catalyst. Only products for the oxidation of sulfur, such as sulfoxide and sulfolane, were found. Shape-selective oxidation was studied with four isomeric butyl methyl thioethers. For n-, iso-, and sec-butyl methyl thioethers, the principal product for the TS-1 catalyzed reaction was the sulfone, but that for tert-butyl methyl thioether was from partial oxidation to sulfoxide. The origin of this effect was evaluated using molecular simulations. Thioether oxidation to sulfoxide readily occurred via a non-catalyzed solution reaction, while the oxidation of sulfoxide to sulfone was only observed in the catalyzed reactions. The non-catalyzed reaction can be suppressed by conducting the catalyzed reaction in the presence of a base, 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), that is too large to diffuse into the intracrystalline pore structure of TS-1. With DBU, the reaction rate with TS-1 as catalyst was much lower. The relative ratios of the sulfoxide and sulfone products can be elucidated through intramolecular steric hindrance and the shape selectivity of the zeolite. TS-1 has been used for the oxidation of alkenes, alcohols, allylic alcohols, phenols, and benzene.
Inhibition by carboxamides and sulfoxides of liver alcohol dehydrogenase and ethanol metabolism
Chadha,Leidal,Plapp
, p. 916 - 922 (2007/10/02)
Sulfoxides and amides were tested as inhibitors of liver alcohol dehydrogenase and ethanol metabolism in rats. With both series of compounds, increasing the hydrophobicity resulted in better inhibition, and introduction of polar groups reduced inhibition. Of the cyclic sulfoxides, tetramethylene sulfoxide was the best inhibitor as compared to the tri- and pentamethylene analogue and other compounds, and it may be a transition-state analogue. The most promising compounds, tetramethylene sulfoxide and isovaleramide, were essentially uncompetitive inhibitors of purified horse and rat liver alcohol dehydrogenases with respect to ethanol as substrate. These compounds also were uncompetitive inhibitors in vivo, which is advantageous since the inhibition is not overcome at higher concentrations of ethanol, as it is with competitive inhibitors, such as pyrazole. The uncompetitive inhibition constants for tetramethylene sulfoxide and isovaleramide for rat liver alcohol dehydrogenase were 200 and 20 μM, respectively, in vitro, whereas in vivo the values were 340 and 180 μmol/kg. The differences in the values may be due to metabolism or distribution of the compounds. Further studies will be required to determine if isovaleramide or tetramethylene sulfoxide is suitable for therapeutic purposes.
