Sulfuric Acid → 6H-thiazolo[5,4-e]indole-7,8-dione

Participants

Reaction Steps

To a 1-L 3-neck round bottom flask was placed a magnetic stir bar and 100 ml of concentrated sulfuric acid. The flask was fitted with a thermometer to monitor the temperature of the reaction. The sulfuric acid was heated to 100° C., and 10.0 g (45.2 mmol) of N-benzothiazol-6-yl-2-hydroxyimino-acetamide was added slowly. The solution was heated for ˜1 h, and the reaction mixture was poured into 750 g of ice and water. The residual reaction mixture in the reaction vessel was washed out with an additional 20 mL of cold water. The aqueous slurry was stirred for about 1 h and filtered. The solid was washed thoroughly with water, filtered, and air dried to yield 4.3 g (46%) of 6-H-1-thia-3,6-diaza-as-indacen-7,8-dione:

Provenance & Evidence