Formation of 3-Amino-1,2,4-triazines by Thermolysis of Condensed N-Amino-α-Azidoimidazoles

1-Amino-2-azidobenzimidazole 7, 7-amino-8-azido- 9 and 9-amino-8-azido-theophillines 12, on heating in chlorobenzene solution, lose a molecule of nitrogen and finally give 3-amino-derivatives of benzo-1,2,4-triazine 3, 5,7-dimethylpyrimido[4,5-e]-1,2,4-triazine-6,8-dione 10 (isofervenulin) and 6,8-dimethylpyrimido[5,4-e]-1,2,4-triazine-5,7-dione 13 (fervenulin) in good yields; the reaction is thought to proceed through the recyclization of an intermediate C-nitrene of type 4.