Potassium Carbonate → 1-(3-(Benzyloxy)propyl)-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole

HRID 2279714Notes

Reaction equation

[CH3:1][C:2]1([CH3:14])[C:6]([CH3:8])([CH3:7])[O:5][B:4]([C:9]2[CH:10]=[N:11][NH:12][CH:13]=2)[O:3]1.C(=O)([O-])[O-].[K+].[K+].Br[CH2:22][CH2:23][CH2:24][O:25][CH2:26][C:27]1[CH:32]=[CH:31][CH:30]=[CH:29][CH:28]=1>CN(C=O)C>[CH2:26]([O:25][CH2:24][CH2:23][CH2:22][N:12]1[CH:13]=[C:9]([B:4]2[O:5][C:6]([CH3:7])([CH3:8])[C:2]([CH3:14])([CH3:1])[O:3]2)[CH:10]=[N:11]1)[C:27]1[CH:32]=[CH:31][CH:30]=[CH:29][CH:28]=1

Participants

Conditions

Temperature: 80 °C

Procedure

A mixture of 4-(4,4,5,5-tetramethyl[1,3,2]dioxaborolan-2-yl)-1H-pyrazole (5.0 g, 26 mmol), potassium carbonate (4.27 g, 30.9 mmol) and 1-bromo-3-benzyloxypropane (6.20 g, 27.0 mmol) in DMF (20 mL) was stirred at 80° C. overnight, quenched with water (20 mL) and extracted with EtOAc (100 mL). The organic layer was washed with water (2×30 mL), brine (30 mL), dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The residue was purified by silica gel chromatography (ISCO system: EtOAc/Heptane=30-70%) to afford 7.67 g of the title compound as a light-yellow oil (87%). 1H NMR (CDCl3, 400 MHz): δ=7.80 (s, 1H), 7.66 (s, 1H), 7.30-7.36 (m, 5H), 4.48 (s, 2H), 4.28 (t, J=6.8 Hz, 2H), 3.43 (t, J=5.8 Hz, 2H), 2.17 (m, 2H), 1.33 (s, 12H). MS (ES+): m/z=343.36 [MH+]. HPLC: tR=4.20 min (ZQ3: polar—5 min).

Workup

customquenched with water (20 mL)
extractionextracted with EtOAc (100 mL)
washThe organic layer was washed with water (2×30 mL), brine (30 mL)
dry with materialdried over anhydrous sodium sulfate
filtrationfiltered
concentrationconcentrated under reduced pressure
customThe residue was purified by silica gel chromatography (ISCO system: EtOAc/Heptane=30-70%)

Sources & evidence

ORD record: ord-99852fc7d6ec4ff494f1272814af51db
Source dataset: uspto-grants-2015_09
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US09133224B2

Reaction notes

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