Ultrasound-assisted improved synthesis of 5-(benzylthio)-1,3,4-thiadiazol-2-amine derivatives: an experimental and computational study

The main objects of this study are: (1) to propose alternative efficient methods for the synthesis of 5-amino-1,3,4-thiadiazole-2-thiol and 5-(benzylthio)-1,3,4-thiadiazol-2-amine derivatives, (2) to investigate the reactions and the chemical species which take place in the investigated reactions computationally via density functional theory (DFT) calculations, (3) to make a comparison between experimental and computationally obtained data, and (4) to make a comparison between the computational methods to find out the best computational technique to simulate the investigated molecules and reactions. The study consists of two parts. In the first part, synthesis of 5-amino-1,3,4-thiadiazole-2-thiol and 5-(benzylthio)-1,3,4-thiadiazol-2-amine derivatives have been carried out. For both syntheses, it has been proposed that the reactions can be carried out effectively with the use of ultrasound. To the best of our knowledge, this is the first use of ultrasound for both reactions. The results showed that ultrasound can increase the efficiency of the investigated reactions and can be a good alternative to conventional methods. In the second part of the study, some DFT calculations have been performed on the chemical species which take place in the investigated reactions. In computational studies, seven different basis sets have been used. In this second part, comparisons have been made (1) between experimental and computationally obtained data, and (2) between the computational techniques to reveal the best method for the investigated molecules.