Hydrochloric Acid → N-methyl-2,3-dihydro-1H-indole-5-sulfonamide

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Reaction Steps

To a stirred solution of 23.42 g (0.0975 mol) of 5-methylsulfamoyl-N-formylindoline in 500 ml of methanol was added 40 ml of concentrated hydrochloric acid. The solution was heated to reflux for one hour. Thin layer chromatography in chloroform showed the reaction was complete. The solution was allowed to cool, and then the methanol was removed under reduced pressure. The aqueous slurry remaining was dissolved ice water and neutralized by the addition of sodium hydroxide solution. The precipitate was extracted with methylene chloride, washed with water and saturated aqueous sodium chloride solution. The solution was dried over sodium sulfate and then concentrated under reduced pressure. The residue was allowed to air dry to give 17.02 g (0.08 mol) (82% by weight yield) of 5-methylsulfamoylindoline.

Provenance & Evidence