Hydrochloric Acid → 5-Fluoro-2-methoxypyridine-3-boronic acid

Participants

Reaction Conditions

Reaction Steps

n-Butyllithium (1.6 M solution in hexanes, 20 mL, 32 mmol) was slowly added (0.4 mL/min) to a solution of 3-bromo-5-fluoro-2-methoxypyridine (6.0 g, 29.12 mmol) and triisopropylborate (8.4 mL, 36.62 mmol) in dry tetrahydrofuran (70 mL) at −100° C. under argon atmosphere. The reaction mixture was stirred at −100° C. for 2 hours and afterwards the temperature was allowed to warm up slowly overnight to ambient temperature before being cooled down to 0° C. Aqueous hydrochloric acid (1N solution, 120 mL) was slowly added and the mixture was stirred at 0° C. for 1 hour. A solution of sodium hydroxide (32% in water) was then added until pH was around 6 and the resulting mixture was extracted with diethyl ether (×3). The combined organic layers were dried over magnesium sulphate and the solvent removed under reduced pressure to yield the title compound (3.28 g, 66%) as a white solid.

Provenance & Evidence