Chemoselective sulfoxidation by H2O2 or HNO3 using a phosphate impregnated titania catalyst

A variety of organosulfur compounds have been selectively oxidized to the corresponding sulfoxides by either H2O2 or HNO3 using a newly developed solid acid catalyst composed of 84.5% of TiO2 and 15.5% of [Ti4H11(PO4)9]·nH2O (n = 1-4). The chemoselective oxidation of sulfides in the presence of vulnerable groups such as -CN, -CC-, -CHO, or -OH, as well as sulfoxidation of substrates like benzothiazole, glycosyl sulfide, and dibenzothiophenes is some of the important attribute of the protocol. Nitric acid, under the present experimental conditions, brings about relatively better selectivity than hydrogen peroxide.

Graphical abstractVarious organic sulfides containing different oxidizable groups such as -OH, -CHO, and -CN have been chemoselectively oxidized to the corresponding sulfoxides separately by H2O2 or HNO3 using a solid catalyst composed of 84.5% of TiO2 and 15 .5% of [Ti4H11(PO4)9]. nH2O (n = 1-4).Download full-size image