Abstract
Symmetrically N,N′-disubstituted ureas/thioureas were synthesized by heating amines or phenyl hydrazine and urea/thiourea on a preheated hot plate at 80–85°C under solvent-free conditions in the presence of a catalytic amount of ZnCl2 as a catalyst. The protocol has the advantages of not using toxic phosgene and other hazardous substrates or organic solvents. Increased reaction rate, good yield, and a simple workup procedure are involved.
Notes
a All the products were characterized by spectral analysis and compared with authentic samples.
b Isolated yields.
c Melting points of compounds are consistent with reported values.
a All the products were characterized by spectral analysis and compared with authentic samples.
b Isolated yields.
c Melting points of compounds are consistent with reported values.