Hydrochloric Acid → HCID 21318141, compound

Participants

Reaction Steps

A suspension of 1.50 g. (5.4 mmol) of 2-cyano-3-phenylindole-5-carboxylic acid methyl ester in 50 ml. of 6 N hydrochloric acid was heated under reflux, enough ethanol (~ 100 ml.) was added to effect solution, and heating was continued for 11 days. The reaction was concentrated to a small volume under vacuum, diluted with water and made basic with sodium hydroxide. Filtration gave 840 mg. of recovered 2-cyano-3-phenylindole-5-carboxylic acid methyl ester. The basic solution was acidified, the amorphous precipitate was collected by filtration and recrystallized four times from methanol with charcoal to give 111 mg. (19%) of 2-cyano-3-phenylindole-2-carboxylic acid as colorless crystals, m.p. 302°-304°.

Provenance & Evidence