21402-26-6

108-42-9

21402-26-6

General method: A solution was prepared by dissolving m-chloroaniline (2a or 2b) in DMF as starting material. Subsequently, another solution was prepared by dissolving NBS (92 mmol, 1.0 eq.) in 100 ml DMF. The DMF solution of m-chloroaniline was added dropwise to the DMF solution of NBS at room temperature. After the dropwise addition, the reaction mixture was stirred continuously for 3 hours at room temperature. After completion of the reaction, the reaction mixture was diluted with 500 ml of ethyl acetate and washed with 2 x 150 ml of brine. The organic phase was separated, dried with anhydrous Na2SO4, filtered and concentrated to give 4-bromo-3-chloroaniline (3a or 3b) as a brown solid in 90-92% yield. In another experiment, m-chloroaniline (2a or 2b, 0.8 mmol) was dissolved in a solvent of choice (1 ml) and a solution of NBS (0.8 mmol) in the same solvent (1 ml) was added in batches at room temperature. The reaction progression was monitored by LC-MS/MS and a final mixture containing traces of the dibrominated product was obtained.