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

HRID 2183932Notes

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 1M 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 1M 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-55487be94dd14405850fedc9b86e69d3
Source dataset: uspto-grants-2005_05
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US06900215B2

Reaction notes

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