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

HRID 1061776Notes

Reaction equation

Br[C:2]1[C:3]([F:15])=[C:4]([C:9]2[CH:10]=[N:11][CH:12]=[CH:13][CH:14]=2)[C:5]([F:8])=[CH:6][CH:7]=1.C([O-])(=O)C.[K+].[B:21]1(B2OCC(C)(C)CO2)[O:26]CC(C)(C)C[O:22]1>O1CCOCC1>[F:15][C:3]1[C:4]([C:9]2[CH:10]=[N:11][CH:12]=[CH:13][CH:14]=2)=[C:5]([F:8])[CH:6]=[CH:7][C:2]=1[B:21]([OH:26])[OH:22]

Participants

Conditions

Temperature: 90 °C

Procedure

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).

Workup

temperatureThe reaction was cooled
filtrationfiltered (
washwashing the filter cake with a small quantity of diethyl ether) and the filtrate
concentrationconcentrated in vacuo
customThe residue was partitioned between diethyl ether (100 mL) and 1 M sodium hydroxide (100 mL)
washThe aqueous was washed with more diethyl ether
temperaturecooled in an ice-water bath
filtrationThe resulting solid was collected by filtration
customdried under vacuum

Sources & evidence

ORD record: ord-edf0cb496af541afa39827811846e7f2
Source dataset: uspto-grants-2005_11
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US06960598B2

Reaction notes

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