Acetic Acid → (1-phenyl-1H-pyrazol-5-yl)boronic acid

Participants

Reaction Steps

To a solution of 1-phenyl-1H-pyrazole (20.0 g) in tetrahydrofuran (700 mL) was added dropwise n-butyllithium (2.5M hexane solution, 58.3 mL) under a nitrogen atmosphere at −78° C., and the mixture was stirred at the same temperature for min. To the reaction mixture was added triisopropyl borate (52.2 g) at −78° C., and the mixture was stirred at the same temperature for 1 hr. The mixture was gradually warmed to room temperature, and stirred at room temperature for 20 hr. To the reaction mixture was added acetic acid (20 mL) to adjust to pH 5, and the mixture was concentrated to give the title compound (25.0 g).

Provenance & Evidence