Spontaneous conversion of 2-azido-3-nitropyridines to pyridofuroxans

Several pyridofuroxans were obtained by spontaneous N2 elimination from the corresponding 2-azido-3-nitropyridines. In this particular case, the presence of nitrogen in the pyridine ring must facilitate a cyclic extrusion mechanism. The pyridofuroxans prepared in this study did not present tautomerism as evidenced by NMR.