Green synthesis of N-substituted-N-aryl carbonyl bifunctional thioureas under solvent-free conditions

A convenient method for the synthesis of bifunctional-N-substituted-N?-aryl carbonyl thioureas under solvent-free conditions has been developed. Ammonium thiocyanate and acid chlorides were mixed and stirred at room temperature without solvent, to give the corresponding isothiocyanates, which reacted smoothly with aryl diamines to produce the aryl dicarbonyl thioureas in good yields. Unusually large values of 5J = 12.2–15.1Hz are observed for 1-(2-fluorobenzoyl) - thiourea derivatives, which provide information about the Ar-C-N-H torsions in these compounds.