Photoreactions of Thiobarbiturates. Intermolecular Cycloaddition with Alkenes and Ring Contraction Reaction of Trithiobarbiturate

Abstract

Upon irradiation of mono-, di-, and trithiobarbiturates in the presence of alkenes, [2+2]cycloaddition occurred regioselectively to give thietanes and their desulfurized products. In the case of trithiobarbiturate, a noevl type of ring contraction product, dithiohydantoin, was also obtained.