Benzo [c][1, 2] thiazine nucleus is present in many synthetic pharmacologically active compounds. The derivatives of this heterocycle are shown to possess antiinflammatory, antiviral, CNS-depressive properties [1]. Much attention has been focused on approaches for the construction of the 1H-benzo [c][1, 2] thiazin-4-one system. The synthesis of this compound starting from sulfoacetic acid was reported [2a-b]. Also, new methods of ...