Ethyl Bromide → 1-Ethyl-1H-pyrazole-4-boronic acid, pinacol ester

HRID 876808Notes

Reaction equation

HRID 876808 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][CH3:17].C([O-])([O-])=O.[K+].[K+]>CN(C=O)C.CCOC(C)=O>[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)[CH3:17]

Participants

6

Reactant 3

HCID 6332Ethyl BromideHCID 11430Potassium CarbonateHCID 27740104-(4,4,5,5-Tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole

Product 1

HCID 113790451-Ethyl-1H-pyrazole-4-boronic acid, pinacol esterYield 102.1%

Reagents, catalysts & solvents 2

HCID 6228DimethylformamideSolventHCID 8857Ethyl AcetateSolvent

Conditions

Temperature
60 °C

Procedure

To a solution of 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole (V-1) (3 g, 15 mmol) in DMF (6 mL) were added bromoethane (3.24 g, 30 mmol) and K2CO3 (4.26 g, 30 mmol). The reaction mixture was stirred at 60° C. overnight, then diluted with EtOAc, washed with water and then brine. The organic layer was separated, then dried over Na2SO4, and concentrated to afford the title compound (3.40 g). MS (m/z): 223 (M+1)+.

Workup

  1. washwashed with water
  2. customThe organic layer was separated
  3. dry with materialdried over Na2SO4
  4. concentrationconcentrated

Sources & evidence

ORD record
ord-c9c365ebf6ac49bd8a1eb44d2fd8032c
Source dataset
uspto-grants-2015_03
Patent number
US08987269B2

Reaction notes

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