反应详情

A solution of N-bromosuccinimide (4.94 g, 27.7 mmol) in DMF (20 mL) was added dropwise to a stirred solution of ethyl 1H-indole-2-carboxylate (5.0 g, 26.4 mmol) in DMF (15 mL) at 0˜5° C. After the addition was completed, the reaction was warmed to room temperature and stirring was continued for an additional 1.5 h. The reaction mixture was poured over ice water and the resulting precipitate was collected and dried to give 3-bromo-1H-indolecarboxylic acid ethyl ester (6.68 g, 81%) as a white solid: 1H NMR (DMSO-d6) δ 1.37 (t, J=7.2 Hz, 3H), 4.38 (q, J=7.2 Hz, 2H), 7.18-7.22 (m, 1H), 7.34-7.38 (m, 1H), 7.50 (dd, J=8.3, 0.8 Hz, 1H), 7.55 (dd, J=8.3, 0.8 Hz, 1H), 12.22 (br s, 1H); MS (ESI) m/z 268 (MH+); 266 ([M−H]−).

1. additionAfter the addition
2. customthe resulting precipitate was collected
3. customdried