Potassium Permanganate → HCID 22750023, compound

Participants

Reaction Steps

A solution of 15.8 gm (0.1 mols) of potassium permanganate in 300 ml of water was added dropwise over a period of 2.5 hours to a solution of 37.6 gm (0.125 mols) of ethyl 3-aminosulfinyl-5-chloro-1-methyl-indole-2-carboxylate in 2500 ml of acetone at 20° C. After stirring overnight at room temperature, the precipitate which had formed was filtered off and washed with warm water and acetone. The filtrate then was evaporated in vacuo at 25°-30° C. to a volume of about 350 ml. The crystallized product, ethyl 5-chloro-1-methyl-3-sulfamoyl-indole-2-carboxylate, was filtered off, washed with water and dried. Yield: 30.5 gm (77% of theory); M.p.: 207°-208° C. After acidification of the filtrate to pH 3, another product, 7-chloro-4-methyl-2H-isothiazolo[4,5-b]indole-3-(4H)-one-1,1-dioxide, was obtained, which was filtered off, washed with water and dried. Yield: 3.9 gm (12% of theory); M.p.: 288° C. (decomposition).

Provenance & Evidence