Water → 5-bromo-6-chloro-1H-indole-3-carbaldehyde

Participants

Reaction Steps

A round-bottom flask was charged with DMF (54 mL). Phosphorus oxychloride (6.21 mL, 66.8 mmol) was added dropwise over 5 minutes, and the reaction mixture was stirred at room temperature for an additional 5 minutes. A solution of 5-bromo-6-chloro-1H-indole (7700 mg, 33.41 mmol) in DMF (7 mL) was added dropwise to the reaction mixture, which caused a precipitate to form. The reaction mixture was then heated to 95° C. for 25 minutes. The reaction mixture was treated with 1N aqueous sodium hydroxide (170 mL) and water (170 mL). The reaction mixture was stirred at 95° C. for 11 minutes. The reaction mixture was cooled to 0° C., and the solids were collected by filtration. The solids were washed with water (50 mL) and diethyl ether (50 mL) and dried in vacuo for 16 hours at 65° C. to afford the title compound (7.77 g, 90%) as a tan solid. MS (AP+) 257.9 (M+H)+. 1H NMR (400 MHz, DMSO-d6) δ 9.93 (s, 1H), 8.40 (s, 1H), 8.38 (s, 1H), 7.80 (s, 1H).

Provenance & Evidence