Thiol Peroxidase Activity of Diorganyl Tellurides

A number of diorganyl tellurides, including diaryl tellurides, diheteroaryl tellurides, and alkyl aryl and dialkyl tellurides, were found to catalyze the reaction of hydrogen peroxide with thiols. The thiol peroxidase activity of the compounds war assessed by using a 1 H NMR method previously developed in our laboratories. In this assay, thiols (N-acetylcysteine, tert-butyl mercaptan, and 1-octyl mercaptan) were oxidized in the presence of hydrogen peroxide and catalyst (0.3 mol %) and the time required to reduce the thiol concentration with (0%, t 50 , determined. In a series of 4,4'-disubstituted (R=H, Me, OH, OMe, NH 2 , NMe 2 , NHPh, CF 3 ) diphenyl tellurides 5, the catalytic activity increased when mesomerically electron-donating substituents were present