Synthesis
The general procedure for the synthesis of 4-bromo-2-chloroaniline from o-chloroaniline was as follows: 254 mg (2 mmol) of o-chloroaniline and 143 mg (1.2 mmol) of potassium bromide were dissolved in 10 mL of a solvent mixture of acetic acid (AcOH) and water (9:1, v/v), and the solution was subsequently transferred to a 50 mL three-neck flask. The reaction temperature was controlled by magnetic stirring at 25°C for 1 h in a thermostatic water bath with continuous stirring. Within the first 15 min of the start of the reaction, 1.8 g (1.8 mmol) of ZnAl-BrO3-LDHs was slowly added.After completion of the reaction, the reaction mixture was extracted with dichloromethane (2 × 10 mL) and the organic phases were combined. Two silica gels (200-300 mesh) were added to the combined organic phases, and the dichloromethane was subsequently removed by distillation under reduced pressure. Finally, purification was carried out using column chromatography (eluent was a solvent mixture of petroleum ether and ethyl acetate in a 10:1 ratio, v/v) to give 321 mg of gray solid product in 78% yield.
References
[1] Tetrahedron Letters, 2005, vol. 46, # 51, p. 8959 - 8963
[2] Russian Journal of Applied Chemistry, 2009, vol. 82, # 9, p. 1570 - 1576
[3] Chinese Chemical Letters, 2012, vol. 23, # 4, p. 387 - 390
[4] Monatshefte fur Chemie, 2013, vol. 144, # 2, p. 179 - 181
[5] Journal of the Iranian Chemical Society, 2012, vol. 9, # 3, p. 321 - 326
