Heterocyclic Interconversion of Oxazolones into Triazolines and Triazoles

Significance

Oxazolones are unique in that these substrates contain multiple reactive sites capable of yielding a range of different products (e.g. oxazoles, imidazolines) by manipulating the reaction conditions. The present reaction to
1,2,4-triazolines was anticipated based on previous precedent. True to this prediction, treatment of oxazolones with azodicarboxylates (DEAD, ­DIAD, PTAD) led to the desired triazolines in excellent yields. Four of these triazolines were further converted into the corresponding triazoles in good yields by refluxing with base. The reaction tolerates bulkier azodicarboxylates, and the substrate scope is otherwise limited by the availability of substituted oxazolones.