Synthesis, structure, and isomerism of N-2,4-dinitrophenylbenzotriazoles

Both isomers of N-(2′,4′-dinitrophenyl)benzotriazole, the 1(3)- and the 2-substituted, have been characterized and their reciprocal isomerism was studied. Cross-experiments in the presence of 5(6)-nitro-1H-benzotriazole proved that the isomerization of 2-(2′,4′-dinitrophenyl)-2H-benzotriazole into the 1-isomer occurs by an intermolecular mechanism. The reported reaction of 5(6)-nitro-1H-benzotriazole with 1-chloro-2,4-dinitrobenzene has been reexamined discovering that there is an error in the proportions of N-substituted isomers. A possible explanation for the observed isomerizations was proposed. Identification of all compounds by multinuclear magnetic resonance, including solid-state studies, has been achieved.