Thermal cyclization of 4‐azido‐3‐nitropyridines to furoxanes

Abstract

Abstract 4‐Chloro‐3‐nitro‐2‐pyridines 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 calorimetry (DSC).