Methyl iodide → 4-Bromo-1-methyl-1H-indole-2,3-dione

Participants

Reaction Steps

To a stirred solution of 4-bromoisatin (90.4 g, 400 mmol) in N,N-dimethylformamide (400 mL) was added cesium carbonate (196.0 g, 600 mol) at ambient temperature. The reaction mixture was stirred for 30 min, iodomethane (37.4 mL, 600 mmol) was added and the mixture was stirred at ambient temperature for 18 h. The solid was removed by filtration, the filtrate was concentrated in vacuo, and the residue was triturated in water and washed with diethyl ether to afford 4-bromo-1-methyl-1H-indole-2,3-dione (82.0 g, 85%): 1H NMR (300 MHz, DMSO-d6) δ 7.95-7.89 (m, 1H), 7.68-7.64 (m, 1H), 7.53-7.49 (m, 1H), 3.50 (s, 3H).

Provenance & Evidence