Cesium carbonate → 1-(2-Methoxyethyl)-1H-pyrazole-4-boronic acid, pinacol ester

HRID 2168159Notes

Reaction equation

HRID 2168159 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.Br[CH2:16][CH2:17][O:18][CH3:19].C(=O)([O-])[O-].[Cs+].[Cs+]>CN(C=O)C>[CH3:19][O:18][CH2:17][CH2:16][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

Participants

5

Reactant 3

HCID 10796Cesium carbonateHCID 809722-Bromoethyl methyl etherHCID 27740104-(4,4,5,5-Tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole

Product 1

HCID 112304911-(2-Methoxyethyl)-1H-pyrazole-4-boronic acid, pinacol ester

Reagents, catalysts & solvents 1

HCID 6228DimethylformamideSolvent

Conditions

Temperature
80 °C

Procedure

4-(4,4,5,5-Tetramethyl-[1,3,2]dioxaborolan-2-yl)-1H-pyrazole (19.4 g, 0.10 mol), 1-bromo-2-methoxy-ethane (14.18 ml, 0.15 mol), and caesium carbonate (32.58 g, 0.1 mol) are dissolved in DMF (200 ml). The suspension is stirred for 16 h at 80° C., filtered and the solvent is removed in vacuum. The residue is treated with tert-butyl methyl ether (200 ml), filtered over Celite and then the solvent is removed in vacuum; yield: 25.4 g 1-(2-methoxy-ethyl)-4-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-1H-pyrazole; HPLC/MS: 1.82 min, [M+H]=253.

Workup

  1. filtrationfiltered
  2. customthe solvent is removed in vacuum
  3. additionThe residue is treated with tert-butyl methyl ether (200 ml)
  4. filtrationfiltered over Celite
  5. customthe solvent is removed in vacuum
  6. custom1.82 min, [M+H]=253

Sources & evidence

ORD record
ord-a493acbd5d04466895264caec91eda90
Source dataset
uspto-grants-2015_06
Patent number
US09045493B2

Reaction notes

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