Contiguous nitrogen atoms, compounds with

The diazotization of aromatic amines witii a nucleophilic substituent at the ortho position is a common mediod of synthesis of benzo-fosed heterocyclic compounds with two or more contiguous nitrogen atoms. Benzotriazoles (9), benzotriazinones (10), and benzothiadiazoles (11) are examples of heterocyclic ring systems that can be prepared in tiiis way. 

The first derivative of 1,2,3-triazine to be prepared, the triphenyl compound (2, R = Ph), was obtained in 1960 by thermolysis of 1,2,3-triphenylcyclopropenyl azide (1, R = Ph)." The physical and spectral (IR and UV) properties of 2 were consistent with the assigned structure, and the presence of three contiguous carbon atoms was demonstrated by hydrolysis experiments, which resulted in formation of 1,2,3-triphenyI-butane-l,3-dione. Photolysis of 2 gave a mixture of nitrogen, benzo-nitriie, and diphenylacetylene. 

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