Sulfuric Acid → 2,3-Dihydro-1H-indole-7-carboxylic acid

Participants

Reaction Conditions

Reaction Steps

A mixture of 7-cyanoindoline (4.32 g) and 50% aqueous sulfuric acid (40 ml) was stirred at 110°-120° C. for 5.5 hours, cooled to 5° C. and adjusted to pH 7-8 with 24% aqueous sodium hydroxide. The mixture was washed with ethyl acetate and the aqueous layer was adjusted to pH 2.5-3.0 with 6N hydrochloric acid. The precipitates were collected by filtration to give indoline-7-carboxylic acid (3.25 g).

Provenance & Evidence