Synthesis and Antifungal Activity of Halogen-Substituted 2,1-Benzothiazine-2,2-dioxide Derivatives

Abstract

A convenient synthesis of a series of new halogen-substituted 2,1-benzothiazine-2,2-dioxide derivatives has been described. The starting compound un/substituted methyl anthranilate is converted into 2,1-benzothiazine-2,2-dioxide heterocyclic ring system via sulfonamide formation, N-alkylation, cyclization and subsequent dihalogenation. The target halogen-substituted molecules are expected to serve as prodrugs. Structural elucidation was achieved by FT-IR, NMR, MS and single crystal X-ray diffraction analyses. Crystal structure data for compound 5f has been reported here. The 3,3-dichloro- and dibromo-derivatives (5b and 5c) have shown promising antifungal activities against Acremonium chrysogenum, Aspergillus niger and Penicillium notatum.