Selectivity in oxidation reactions of methylthio substituted pyrimidines and triazines

It was found during the oxidation of methylthio substituted pyrimidines and 1,3,5-triazines that pyrimidinesulphones were obtained in better yield tha n triazinesulphones because the oxidation is influenced by the structure an d substitution of heterocycles and it could not were selectively stopped at this level. Depending on the pH and solvent, the methylsulphonyl and the f ormed methylsulphonium groups can rapidly take part in nucleophilic substit ution reactions resulting in RO-triazine and -pyrimidine derivatives (R = H , CH3). These reactions may be utilised in such processes where the methylt hio substituted heterocycles are formed as by-products. After their oxidati on, the nucleophilic substitution leads to the desired clean products.