A New Convenient Method for the Synthesis of Symmetrical and Unsymmetrical<i>N</i>,<i>N</i>′-Disubstituted Ureas

Abstract

A new method is described for the preparation of symmetrically and unsymmetrically disubstituted ureas by aminolysis of bis(4-nitrophenyl) carbonate. The second substitution is slower than the first one, and it is possible to isolate monosubstituted intermediates when equimolar amounts of substrates are used, The reaction of the intermediates with different amines gives unsymmetrical derivatives of urea.