nes 3 and 10, obtained from 4-hydroxy-2-pyridones 1 and 8 after nitration and chlorination, gave with sodium azide 4-azido-3-nitropyridines 4 and 11, which cyclized on thermolysis to furoxans 6 and 12. Desoxygenation of the furoxan 6 with triphenylphosphane gave the furazan 7. Thermal decomposition conditions of the azide 4 and the desoxygenation reaction of 6 to 7 were studied by differ ential scanning