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

Abstract

2-Acyl-4-(2'-methyl/phenyl/nicotinyl-thiazol-4'-yl) phenols <b>1</b> have been obtained from the condensation of 2, 4-diacylphenol and thioamides in one pot using phenyl trimethyl ammonium tribromide(PTr). The compounds <b>1</b> 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

<i>3</i>. These diones <b>3</b> 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 <b>4</b>. The structures of the new products <b>4</b> have been confirmed by elemental and spectral methods. The results of the microbial screening of the compounds are also recorded.