series of asymmetric ureas were synthesized by a one-pot reaction of amines and carbonyl sulfide (COS) under catalyst-free conditions. The highly selective synthesis of asymmetric urea was successfully achieved by the use of weakly nucleophilic aromatic amines and highly nucleophilic secondary aliphatic amines. Moreover, a reaction mechanism was proposed based on the detailed NMR and FTIR study. This efficient
Trisubstituted ureas can be synthesized in a one-pot fashion from bench-stable α-chloroaldoxime O-methanesulfonates and secondary amines under mild reaction conditions.