Hexane → 2-Methylpyridine-5-boronic acid

Participants

Reaction Conditions

Reaction Steps

To a stirred solution of 5-bromo-2-methyl-pyridine (992 mg, 5.8 mmol) in diethyl ether (5 mL) was slowly added n-butyl lithium in hexane (1.4 M, 5 mL, 7 mmol) at −78° C. over a span of 10 minutes under nitrogen atmosphere. The reaction mixture was stirred at −78° C. for 90 minutes. At this time, tri-isopropyl borate (1.30 g, 6.9 mmol) was slowly added, and the resulting mixture was allowed to warm to room temperature and stirred for an additional 90 minutes. The reaction was quenched with 5% aqueous sodium hydroxide solution (6 mL) at 0° C. and was extracted with diethyl ether (25 mL×4). The pH of the aqueous solution was adjusted to about 7 by the slow addition of 2N hydrochloric acid. The aqueous layer was extracted with ethyl acetate (50 mL×3). The combined organic layers were dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure to give 2-methyl-5-pyridinylbronic acid, which was used without further purification.

Provenance & Evidence