2-Azidopyridine 1-oxides, thermolysis

The thermolysis of 2-azidopyridine iV-oxides leads to Ar-hydroxy-2-cyanopyrroles (185 — 186) (73JOC173) (see also Section 3.4.3.11). 

Thermolysis of 3-substituted 2-azidopyridine JV-oxides at 90°C was originally thought to give 2/Z-pyrrole iV-oxides (121a, 80-90%, Scheme 44).117 However, the product was recently to shown to be the isomeric oxazine 121b.117a... 

Azidopyridine 1-oxides undergo ring contraction on thermolysis to give the much sought after 2-cyano-A -hydroxypyrroles (93). This reaction, however, is not thought to involve a nitrene. 

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