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

695-6982-Acyl-4-(2'-methyl/phenyl/nicotinyl-thiazol-4'-yl) phenols 1 have been obtained from the condensation of 2, 4-diacylphenol and thioamides in one pot using phenyl trimethyl ammonium tribromide(PTr). The compounds 1 are then converted to their respective esters 2 by condensing with aroyl chlorides. The esters 2 are then subjected to B.V. transformation to yield l-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'-substi tutedphenyl)-1, 4-benzothiazines 4. The structures of the new products 4 have been confirmed by elemental and spectral methods. The results of the microbial screening of the compounds are also recorded