Synthesis of some new fused and polyfused [1,2,4]triazolo[3,4-b][1,3,4]thiadiazepines

7-[1,3-Dithiolan-2-ylidene]-3-phenyl-5,6,7,8-tetrahydro[1,2,4]triazolo[3,4-b] [ 1,3,4]thiadiazepine-6,8-dione and 7-[5-oxo-1,3-dithiolan-2-ylidene]-3-phenyl-5,6,7,8-tetrahydro[1,2,4]triazolo-[3,4-b] [1,3,4]thiadiazepine-6,8-diones were obtained by treating 3-phenyl-5,6,7,8-tetrahydro[1,2,4] triazolo [3,4-b] [1,3,4] thiadiazepine-6,8 -diones with CS2, and chloroacetyl chloride, respectively. Treatment of the above compounds with mercaptoacetic acid gave 1,2-dibromoethane or corresponding spiro polyfused heterocycles. Some other triazolothiadiazepine derivatives including spiro polyfused compounds were also synthesized.