Synthesis and antimicrobial activities of some new 4H-1,4-benzothiazines

Synthesis of substituted 4H-1,4-benzothiazines (4) by the condensation of 2-amino-5-bromo-3-methyl/2-amino-4-fluoro/2-amino-3-isopropylbenzenethiol with beta-diketones/beta-ketoesters in dimethylsulfoxide, which caused oxidative cyclization is being reported. Substituted 4H-1,4-benzothiazine sulfones (5) have been synthesized by oxidation of 4H-benzothiazines (4) on refluxing with 30% hydrogen peroxide in gl acetic acid. Synthesized compound have been characterized by IR, H-1 NMR, Mass spectra, elemental analysis and screened for antimicrobial activity.