Green and efficient synthesis of thioureas, ureas, primary O-thiocarbamates, and carbamates in deep eutectic solvent/catalyst systems using thiourea and urea

An efficient and general catalysis process was developed for the direct preparation of various primary O-thiocarbamates/carbamates as well as monosubstituted thioureas/ureas by using thiourea/urea as biocompatible thiocarbonyl (carbonyl) sources. This procedure used choline chloride/tin(ii) chloride [ChCl][SnCl2](2) with a dual role as a green catalyst and reaction medium to afford the desired products in moderate to excellent yields. Moreover, the DES can be easily recovered and reused for seven cycles with no significant loss in its activity. Besides, the method shows very good performance for synthesizing the desired products on a large scale.

Automated summary

An efficient catalysis process using deep eutectic solvents as catalyst and reaction medium was developed for the direct preparation of various primary O-thiocarbamates/carbamates and monosubstituted thioureas/ureas. The procedure showed moderate to excellent yields and the deep eutectic solvent could be easily recovered and reused for multiple cycles without significant loss in activity. Additionally, the method demonstrated good performance for synthesizing the desired products on a large scale.