4-Bromo-N,N-bis(4-methoxyphenyl)aniline was synthesized as follows:
1. 4,4'-Dimethoxytriphenylamine (9.0 g, 29.5 mmol) was dissolved in 100 mL of dimethylformamide (DMF) in a 250 mL round bottom flask.
2. N-bromosuccinimide (NBS, 5.25 g, 29.5 mmol) was dissolved in 30 mL of DMF and slowly added dropwise to the above reaction mixture.
3. The reaction mixture was stirred at room temperature and the reaction process was monitored by thin layer chromatography (TLC) for 23 hours.
4. Upon completion of the reaction, the reaction was quenched with 600 mL of water followed by extraction with dichloromethane (4 x 150 mL).
5. The organic layers were combined, washed with saturated sodium thiosulfate solution (4 x 150 mL) and dried over anhydrous sodium sulfate.
6. Concentrate under pressure to remove the solvent and obtain the crude product.
7. The crude product was purified by rapid chromatography on silica gel with a 5:1 hexane/ethyl acetate solvent mixture as eluent to afford the pure 4-bromo-N,N-bis(4-methoxyphenyl)aniline (12.1 g, 100% yield).
8. The structure of the product was confirmed by 1H NMR (300 MHz, CDCl3): δ 7.28 (d, J = 9.0 Hz, 2H), 7.05 (d, J = 9.0 Hz, 4H), 6.90 (d, J = 9.0 Hz, 4H), 6.73 (d, J = 9.0 Hz, 2H), 3.77 (s, 6H).
