The general procedure for the synthesis of 2-amino-5-bromobenzonitrile from 2-aminobenzonitrile was as follows: 2-aminobenzonitrile (11.8 g, 0.1 mol) was dissolved in acetic acid (120 ml) and ammonium bromide (10.3 g, 0.105 mol) and hydrogen peroxide (10.2 ml, 35% aqueous solution, 0.105 mol) were added sequentially. The reaction mixture was stirred at room temperature for about 1 hour, followed by continued stirring for 24 hours until LCMS analysis confirmed the completion of the reaction. Upon completion of the reaction, the acetic acid was removed by concentration and the residue was stirred with 30% aqueous sodium hydroxide solution to alkaline. The resulting solid was collected by filtration, washed with water and dried. The dried solid was dissolved in an excess of dichloromethane, the solution was concentrated until a precipitate began to appear and left to crystallize completely. The crystals were collected by filtration and washed with a small amount of dichloromethane to afford the target compound 2-amino-5-bromobenzonitrile as an off-white crystalline solid (19.2 g, 97% yield).1HNMR data: δ 7.61 (1H, d, J=2.5 Hz), 7.43 (1H, dd, J=9,2.5 Hz), 6.75 (1H, d, J=9 Hz), 6.28 ( 2H, br s); LC-MS retention time: 2.24 min.
