5-Pyrimidinylboronic acid

4595-59-9

109299-78-7

General procedure for the synthesis of 5-pyrimidinylboronic acid from 5-bromopyrimidine: BuLi (3.02 mL, 2M hexane solution, 7.55 mmol) was slowly added dropwise to a stirring anhydrous toluene (16 mL) and anhydrous THF (4 mL) in a mixed solution of 5-bromopyrimidine (1 g, 6.29 mmol) and triisopropyl borate (1.46 mL, 7.55 mmol), under nitrogen protection. mL) in a mixed solution at a reaction temperature of -70 °C. The reaction mixture was continuously stirred at -70 °C for 30 min and then removed from the cold bath. When the internal temperature rose to -20 °C, the reaction was quenched by dropwise addition of 2M HCl (10 mL). Phase separation was carried out after gradually warming the mixture to room temperature. The aqueous phase was adjusted to pH 5.5 with 2M KOH and extracted with THF (3 x 25 mL). The organic phases were combined, dried with MgSO4, filtered and concentrated under reduced pressure to give a colorless solid. The solid was slurried in acetonitrile (2 mL), collected by filtration and dried over a sintered mass to give the final target product 5-pyrimidinylboronic acid as a bright white solid (340 mg, 44% yield).8H (MeOD; 250 MHz) 8.98 (2H, s), 9.14 (1H, s).