Hydrochloric Acid → 3-iodo-1H-indole-5-carboxylic acid

Participants

Reaction Steps

To a solution of 1H-indole-5-carboxylic acid (2.08 g, 12.89 mmol, Acros) in DMF (20 mL) was added I2 (3.27 g, 12.89 mmol) and KOH (1.807 g, 32.2 mmol). The reaction was stirred at RT for 1 h then the mixture was poured into ice and H2O (120 mL) containing sodium bisulfite (1.341 g, 12.89 mmol). The mixture was treated with 5 M HCl to pH=4. The resulting yellow solid was collected by filtration, washed with water and dried to give crude 3-iodo-1H-indole-5-carboxylic acid (7.13 g) as a yellow amorphous solid. MS (ESI, pos. ion) m/z: 288.0 (M+1). 1H NMR (400 MHz, MeOH) δ ppm 8.09-8.14 (1H, m), 7.88 (1H, dd, J=8.6, 1.6 Hz), 7.48 (1H, s), 7.45 (1H, d, J=8.6 Hz).

Provenance & Evidence