Synthesis
General procedure for the synthesis of 2-bromo-4-chloroaniline from 4-chloroaniline: To a mixture of 4-chloroaniline (0.7 mmol) was added a dichloromethane (30 ml)-methanol (15 ml) solution of brominating agent (1) (0.72 g, 0.7 mmol). The reaction mixture was stirred at room temperature until decolorization of the orange solution occurred. The progress of the reaction was monitored by thin layer chromatography (TLC) (eluent: hexane/ethyl acetate, 7:3). After completion of the reaction, the solvent was evaporated and ether (10 ml) was added to the residue. The supernatant was decanted and the insoluble residue was washed with ether (3 x 10 ml). The combined organic extracts were dried over anhydrous magnesium sulfate and the solvent was evaporated under vacuum to give the crude product 2-bromo-4-chloroaniline. The crude product was further purified by silica gel fast column chromatography (hexane/ethyl acetate, 7:3).
References
[1] Synthetic Communications, 2009, vol. 39, # 2, p. 215 - 219
[2] Tetrahedron Letters, 2006, vol. 47, # 49, p. 8693 - 8697
[3] Canadian Journal of Chemistry, 2005, vol. 83, # 2, p. 146 - 149
[4] Synthetic Communications, 2010, vol. 40, # 5, p. 647 - 653
[5] Tetrahedron Letters, 2005, vol. 46, # 51, p. 8959 - 8963
