The reaction of 2-chloro-5-methoxynitrobenzene (I) with aniline (II) in basic medium gives the diphenylamine (III), which is reduced at the NO2 group with H2 over Pd/C in methanol yielding the o-phenylenediamine (IV). Finally, this compoud is cyclized with formamidine (V) in refluxing 2-methoxyethanol.