Facile Synthesis of Derivatives of 1,1,3‐Trioxo‐2H,4H‐pyrrolo[1,2‐b][1,2,4,6]thiatriazine: A New Heterocyclic System.

Ring closure and Claisen rearrangement of pyrrole carboxylic acid (III) promoted by diphenylphosphoryl azide leads to the new heterocyclic system (IV) which are further functionalized.