Zn catalyzed a simple and convenient method for thiourea synthesis

A straightforward and convenient synthesis of symmetrical and unsymmetrical thiourea derivatives by the reaction of primary amines and carbon disulfide in the presence of a Zn catalyst is presented. Under modest reaction conditions, a range of biologically relevant thiourea derivatives can be produced in good to outstanding yields without a lengthy work-up. A variety of primary aliphatic and aromatic amines with various substituted functional groups were transformed into thiourea derivatives. Zn-mediated symmetric thiourea creation occurs at room temperature for aliphatic amines, whereas for aromatic amines it occurs at 60°C. However, unsymmetrical thiourea for aliphatic amines occurs at 0°C. Benefits of this method include environment-friendly reaction conditions, sustainability, and enumerating tolerance of functional groups such as hydroxyl and halides. Experimental observations were rationalized by DFT calculations based on transition structures and zwitterionic intermediate stabilities.