Synthesis of biologically important new 1,4-benzothiazines bearing thiazole substitted aroyl moiety

摘要

2-Acyl-4-(2'-methyl/phenylicotinyl-thiazol-4'-yl) phenols 1 have been obtained from the condensation of 2,4-diacylphenol and thioamides inone pot using phenyl trimethyl ammonium tribromide (PTT). The compounds 1 are then converted to their respective esters 2 by condensing with aroyl chlorides. The esters 2 are then subjected to V.V.transformation to yield 1-phenyl-3-[2'-hydroxy-5'-(2"-substitutedthiazol-4'-yl)]phenylpropane-1,3-diones 3. These diones 3 and 2-aminobenzenethiol when allowed to react in DMSO afford the cyclocondensed products 2-[2'-hydroxy-5'-(2"-substitutedthiazol-4"-yl)benzoyl]-3-(4'-substitutedphenyl)-1,4-benzothiazines 4. The structures of the new products 4 have been confirmed by elemental and spectral methods. The results of the microbialscreening of the compounds are also recorded.