Synthesis of 2-aryl-2H,4H-imidazo[4,5-d][1,2,3]triazoles from triethyl N-(1-ethyl-2-methyl-4-nitro-1H-imidazol-5-yl) phosphorimidate by reaction with aryl isocyanates

The synthesis of a series of 2-aryl-2H, 4H-imidazo[4,5-d][ 1,2,3] triazoles is reported. These compounds are obtained in moderate to good yields by reaction of triethyl N-(1-ethyl-2-methyl-4-nitro-1H-imidazol-5-yl) phosphorimidate with aryl isocyanates. The X-ray crystal structures of triethyl (N-1-methyl-4-nitro-1H-imidazol-5-yl) phosphorimidate and a 2-(4-trifluoromethylphenyl) substituted 2H, 4H-imidazo[4,5-d][1,2,3] triazole are reported. Spectroscopic evidence is provided for a carbodiimide intermediate proposed in the reaction mechanism.