A simple direct phosgeneless route to N-heteroaryl unsymmetrical ureas

29 Nov 2011

Scientists from Italy have developed a simple and green approach to the synthesis of N-heteroaryl unsymmetrical ureas avoiding the use of phosgene.

N-heteroaryl unsymmetrical ureas are widely used as synthetic intermediates and usually possess biological activityor interesting pharmacological properties. However, traditional methods used to synthesis these compounds usually involve phosgene or phosgene-derivatives, a toxic and harmful reagent on which government policies are placing larger constraints on its usage for environmental protection.

In this work, Eugenio Quaranta and co-workers have developed a route to N-heteroaryl unsymmetrical ureas via the reaction of N-phenoxycarbonyl derivatives of pyrrole, indole and carbazole with amines. The reaction can be catalyzed by DBU under mild conditions providing the desired target molecules in good yields, avoiding traditional multistep procedures and without using phosgene or its derivatives.