Rearrangement reactions, oxazole synthesis 5-substituted oxazoles

Simple triazoles are thermally stable to ca. 300°C. However, triazole carboxamides, when heated to 150°C in sulfolane, rearrange with the elimination of nitrogen to give 2-substituted oxazoles. The reaction is general and it is useful for the synthesis of oxazoles with diverse 2-substitutents in excellent yields even for bulky substituents (Scheme 1). This reaction does not occur photochemically... 

---