General procedure for the synthesis of 3,6-dibromo-9-(4-bromophenyl)-9H-carbazole from 9-(4-bromophenyl)carbazole:
1. 9-(4-bromophenyl)-9H-carbazole (0.1 g, 0.31 mmol, 1 eq.) was dissolved in DMF to prepare a solution.
2. A DMF solution (3.5 mL) of N-bromosuccinimide (0.12 g, 0.69 mmol, 2.2 eq.) was slowly added dropwise to the above solution under stirring.
3. The reaction mixture was stirred continuously for 3 hours at room temperature.
4. Upon completion of the reaction, water was added to the mixture and a white precipitate was precipitated.
5. The precipitate was purified by hexane recrystallization to give a white solid product (0.082 g, 55% yield).
Product characterization data:
1H NMR (CDCl3, 400 MHz) δ 7.20 (d, 2H, J = 8.5 Hz), 7.37 (d, 2H, J = 8.6 Hz), 7.50 (dd, 2H, J = 1.9, 8.7 Hz), 7.73 (d, 2H, J = 8.5 Hz).
13C NMR (100 MHz, CDCl3) δ 139.8, 136.0, 133.5, 129.7, 128.7, 124.2, 123.5, 121.9, 113.5, 111.4.
HRMS (TOF MS ES+): calculated value C18H10Br3N [M]+ 478.8338, measured value 478.8349.
