Visible-light-promoted sulfenylation of 6-aminouracils under catalyst-free conditions†
Abstract
Visible-light-promoted reactions have proven to be a decent strategy for the synthesis of complex molecules. Here, we report a catalyst-free method for the sulfenylation of 6-aminouracils which uses visible light as a source of clean and eco-energy. Uracils are pyrimidine derivatives and many of them are biologically potent. When 6-aminouracil and its derivatives are reacted with different thiols under the irradiation of a compact fluorescent light (CFL, 20 W) in dimethyl sulfoxide solvent in an open reaction vessel at room temperature, sulfenylation takes place at the 5-position of 6-aminouracils and forms a new C–S bond. The products are obtained in 59–94% yields. This photochemical transformation without using any catalyst makes the method even more valuable. A wide range of 6-aminouracil substrates are well tolerated for the sulfenylation. The disulfide, a potential therapeutic, can also be synthesized under these conditions which is an added advantage of the method.