Cyclocondensation of hydrazine with α-oxodithioesters: a new method for the synthesis of 2,5-bis(acyl)-1,3,4-thiadiazoles

In this article, we report the synthesis of 2,5-bis(acyl)-1,3,4-thiadiazoles by the annulation of hydrazine sulfate with α-oxodithioesters in ethanol in the presence of anhydrous sodium acetate at 70 °C for 4–5 h. A good number of examples demonstrated the generality of the reaction in which diverse substrates with aryl and heteroaryl groups were compatible. The only exceptions were α-oxodithioesters with nitro group gave ethyl nitrobenzoates instead of anticipated 1,3,4-thiadiazoles. Good yield, fair substrate scope and use of ethanol as green solvent are the attractive features of this method.