Potassium Hydroxide → 2-Carbamoyl-1H-indole-5-carboxylic acid

Participants

Reaction Steps

To a suspension of methyl 2-carbamoyl-1H-indole-5-carboxylate (300 mg, 1.38 mmol) in tetrahydrofuran (4.5 mL) and ethylene glycol (4.5 mL) was added potassium hydroxide (3.16 g, 56.4 mmol). The mixture was heated to reflux and stirred for 2 hours. The reaction was cooled to room temperature and diluted with water. The tetrahydrofuran was removed under reduced pressure. The solids were filtered off and the filtrate was acidified to pH 4 with concentrated hydrochloric acid. The resulting precipitate was collected by filtration and dried under vacuum to give 2-carbamoyl-1H-indole-5-carboxylic acid (230 mg, 82%). 1H NMR (400 MHz, DMSO-d6, δ): 12.53 (br. s., 1 H), 11.88 (br. s., 1 H), 8.28 (s, 1 H), 8.04 (br. s., 1 H), 7.77 (d, J=8.6 Hz, 1 H), 7.46 (m, J=8.6 Hz, 2 H), 7.25 (s, 1 H).

Provenance & Evidence