Sequential Regioselective Diorganochalcogenations of Imidazo[1,2-a]pyrimidines Using I2/H3PO4 in Dimethylsulfoxide.

The dichalcogenation of imidazoheterocycles led to the first functionalization of imidazo[1,2-a]pyrimidine cores on the C6-position. The methodology, involving iodine/dimethylsulfoxide oxidation of diaryldichalcogenides, started with C3-chalcogenation, followed by C6 selanylation, activated in acidic medium. This novel sequential dichalcogenation strategy proceeded efficiently with excellent regioselectivity and yields.