A novel regioselective method for aminostilbene preparation-the role of sodium azide

The reaction between a derivative of 2,4-dinitrostilbene and sodium azide gave consistently 2-amino-4-nitrostilbenes as the sole products instead of the expected azidonitrostilbene. Based on this finding, we present a one-step preparative method for selective transformation of the ortho-NO2 group in (E)-2,4-dinitrostilbenes into an ortho-NH2 group to give (E)-2-amino-4-nitrostilbenes.