Synthesis of 3,5-bis(acyl)-1,2,4-thiadiazoles via iodine mediated oxidative dimerization of α-oxothioamides

A novel and an efficient method for the synthesis of 3,5-bis(acyl)-1,2,4-thiadiazoles by the oxidative cyclization of α-oxothioamides with assistance of molecular iodine has been reported. The required substrates – α-oxothioamides have been synthesized by the reaction of α-oxodithioesters with ammonium chloride and sodium acetate. The probable mechanism for the formation of products has presented. A heterocyclization of two different α-oxothioamides furnished all four possible products. The protocol resulted in good to excellent yields under given conditions. Notably, reactions reported in this method can be used in scalable fashion.