Abstract The protection of the 7-NH group in 8-bromo-3-methyl-3, 7-dihydro-1 H-pyrine-2, 6- dione during the synthesis of 7-ubsubstituted 1-alkyl-8-bromo-3-methyl-3, 7-dihydro-1 H- pyrine-2, 6-diones with a thienyl group was applied that was introduced by the reaction with 2-chloromethylthiirane. The thietanyl protection was removed by treating with sodium alcoholate after the oxidation with hydrogen peroxide to thietane 1, 1-dioxide group.
