Pd/C-catalyzed reductive carbonylation of nitroaromatics for the synthesis of unsymmetrical ureas: one-step synthesis of neburon

A Pd/C catalyzed reductive carbonylation of nitroarenes for the synthesis of unsymmetrical ureas has been developed. Using inexpensive and stable nitroarenes as the substrates, a series of unsymmetrical ureas were produced in moderate to good yields. A range of functional groups including thioethers, halides and vinyl were compatible with this reaction. As a heterogeneous catalyst, Pd/C was recycled and reused four times without Losing activity. Notably, urea-based herbicide neburon was prepared in 64% yield under our standard conditions.