Synthesis of 2-Amino-5-Substituted-1,3,4-Thiadiazoles (ATDA) and Their Derivatives Using Conventional and Microwave Techniques*

A variety of 2-Amino-5-substituted -1,3,4-thiadiazoles (ATDA) were prepared by the reaction of thiosemicarbazide with different substituted carboxylic acids and phosphorous oxychloride as catalyst using conventional methods in comparison with the advantages of microwave techniques.
The 5-(substituted-1,3,4-thiadiazol-2-yl) carbamates derivatives were prepared by refluxing these (ATDA) with ethyl chloroformates using pyridine as a base to neutralize the acid produced which gave higher yield than sodium carbonate. The structures of the products were supported by IR spectroscopy.