Potassium Acetate → 2,4-Difluoro-3-(pyridin-3-yl)benzeneboronic acid

Participants

Reaction Conditions

Reaction Steps

A mixture of 3-(3-bromo-2,6-difluorophenyl)pyridine (2.97 g, 11 mmol), potassium acetate (2.16 g, 22 mmol) and bis(neopentyl glycolato)diboron (2.86 g, 12.7 mmol) in 1,4-dioxane (30 mL) was heated at 90° C. for 16 h. The reaction was cooled, filtered (washing the filter cake with a small quantity of diethyl ether) and the filtrate concentrated in vacuo. The residue was partitioned between diethyl ether (100 mL) and 1 M sodium hydroxide (100 mL) and the organics discarded. The aqueous was washed with more diethyl ether and then cooled in an ice-water bath. The pH was adjusted to approximately 6 with 36% hydrochloric acid, and allowed to stand for 1 h. The resulting solid was collected by filtration and dried under vacuum to afford 2,4-difluoro-3-(pyridin-3-yl)benzeneboronic acid (2.2 g, 85%) as a grey solid: m/z (ES+) 236 (M++H).

Provenance & Evidence