Photolysis of 2-azidopyridine 1-oxides. A convenient synthesis of 1,2-oxazines
Abstract
Photolysis or thermolysis of 2-azidopyridine 1-oxides (1) in benzene leads to nitrogen-elimination and ring-opening followed by recyclisation to give 6-cyano- 1,2-oxazines (5) which then usually rearrange thermally to 2-cyano-1-hydroxypyrroles (2); the photolyses provide a ready, high-yield route to 1,2-oxazines.