943552-31-6

162607-17-2

4408-64-4

943552-31-6

The general procedure for the synthesis of 5-bromo-2-thiophene-2-boronic acid and N-methyliminodiacetic acid as raw materials for the synthesis of 5-bromo-2-thienylboronic acid methyliminodiacetic ester was as follows: (The synthetic route and products were provided by the team of Dr. Congze He from Fudan University) 5-bromothiophene-2-boronic acid (1.3 kg, 10 mol) and N-methyliminodiacetic acid (1.6 kg, 11 mol) were dissolved in a a solvent mixture of toluene and dimethyl sulfoxide (10:1, v/v) and the reaction was refluxed at 120°C for 4 hours. After completion of the reaction, it was slowly cooled to room temperature and the toluene was removed by distillation under reduced pressure. The residual solution was diluted by adding a large amount of water and a yellowish solid precipitate was precipitated. The resulting solid was dissolved in a solvent mixture of acetonitrile and dimethylformamide (5:1, v/v), and N-bromosuccinimide (1.8 kg, 10 mol) was slowly added under light protection and low temperature. The reaction mixture was stirred at room temperature overnight. At the end of the reaction, the acetonitrile was removed by distillation under reduced pressure and subsequently precipitated in water to give a yellowish solid product. Finally, the target compound 5-bromo-2-thienylboronic acid methyliminodiacetate was obtained by drying at high temperature.