Addition of Diazomethane to 3 and 4-Nitrophthalodinitriles

The reaction of two nitrophthalodinitriles with diazomethane is described. If the nitro group is at position 3, only one of the two nitrile functions reacts giving three isomeric N-methyl 1,2,3-triazoles. In contrast, if the nitro group is at position 4, both nitriles react, each producing a 2-N-methyl 1,2,3-triazole. The reactivity was accounted for in terms of electronic densities, which were determined for several nitrile compounds. Interestingly, for 4-nitrophthalodinitrile, original methylation of the aromatic ring at position 5 was also observed.