The reaction was carried out at reflux for 4 hours at 120 °C with 4-bromophenylboronic acid (1 kg, 5 mol) and N-methyliminodiacetic acid (MIDA) (0.8 kg, 5.5 mol) in a solvent mixture of toluene (45 L) and dimethylsulfoxide (5 L) (9:1, v/v/v). After completion of the reaction, it was slowly cooled to room temperature and toluene was removed by rotary evaporation. The residue was diluted with water and extracted three times with ethyl acetate. The organic phases were combined and washed three times with saturated saline. The organic phase was dried over anhydrous magnesium sulfate, filtered and rotary evaporated to remove ethyl acetate. The crude product was recrystallized by petroleum ether, filtered to give a pale yellow solid and finally dried under vacuum overnight.
