The reaction of 1 (ω haloalkyl) 3,5 dimethylisocyanurates with sodium salt of methyl thioglycolate afforded the corresponding 1 [ω (methoxycarbonylmethylthio)alkyl] 3,5 dime thylisocyanurates, the oxidation of which with the system 34% aqueous H 2 O 2 -0.2 M NaHCO 3 -Mn II leads to the corresponding sulfones. The oxidation of these compounds with 34% aq. H 2 O 2 in Ac 2 O gives alternative products, viz., sulfones, sulfoxides, or α acyloxy sul fides, depending on the temperature and number of methylene groups between the isocyanurate fragment and the sulfur atom.