1: benzo-2,1,3-thiadiazole With potassium permanganate in acetic acid; benzene T=80°C; 24 h; 2: [1,2,5]thiadiazole-3,4-dicarboxylic acid T=180°C; thermal decarboxylation in vacuum;

potassium permanganate in water; acetone 18 h;

chloroform; ozone Zersetzen des entstandenen Ozonids mit H2O;