Abstract1,3-thiazolidin-4-ones, also known as thiazolidin-4-ones, are known to have a very wide range of biological activity. The corresponding S-oxides may show enhanced activity, and therefore viable synthetic routes to these S-oxides are required. S-oxidation of 3-cyclohexyl-2-phenyl-1,3-thiazolidin-4-ones with Oxone ® was investigated. For all compounds evaluated, selective oxidation to the sulfoxide was realized using 3 equivalents of Oxone ® at room temperature. Alternatively, the sulfone was prepared selectively at high temperature by increasing the equivalents of Oxone ® used; the extent of this selectivity was affected by the substituent of the aromatic ring. In those cases in which the reaction produced a mixture of the sulfoxide and sulfone, the ratio of the products was quantified by 1 H NMR.

S-oxidation of 2-aryl-3-phenyl-1,3-thiazolidin-4-ones with Oxone® was investigated. For all compounds evaluated, selective oxidation to the sulfoxide was realized using 3 equivalents of Oxone® at room temperature. Attempts to selectively prepare the sulfones of ortho-substituted 2-aryl-3-phenyl-1,3-thiazolidin-4-ones at high temperature by increasing the equivalents of Oxone® used were typically unsuccessful. These results contrast significantly with ortho-substituted 2-aryl-3-cyclohexyl-1,3-thiazolidin-4-ones evaluated previously. The extent of this selectivity was affected by the substituent and its position on the C2 aromatic ring. The ratio of the sulfoxide and sulfone products was quantified by isolating the products by liquid chromatography.Please find the scheme in PDF file.