3-H-1,2,3-BENZODITHIAZOLE-2-OXIDES AS SYNTHONS FOR THE SYNTHESIS OF 5-MEMBERED AND 6-MEMBERED HETEROCYCLES CONTAINING SULFUR AND NITROGEN

The reaction of 6-substituted-1,2,3-benzodithiazole-2-oxides (2) with aromatic aldehydes, carboxylic acids and acid chlorides in the presenc e of an organic base such as triethylamine and N,N-dimethylaniline lea d to the formation of 6-substituted-2-arylbenzothiazoles (3). The reac tion of 2 with phenacyl bromides and ethyl chloroacetate under similar conditions give 3-aryl-7-substituted-1,4-benzothiazines (4) and 7-sub stituted-3-oxo-3,4-dihydro-1,4-benzothiazines (5), respectively. This provides a new method for the synthesis of benzothiazoles and 1,4-benz othiazines without involving the preparation of intermediate 2-aminobe nzenethiols.