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

HRID 1799017Notes

Reaction equation

HRID 1799017 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.CN(C)[C:17](=O)[CH3:18].C(=O)([O-])[O-].[K+].[K+].C(I)C>C(OCC)C.O>[CH2:17]([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)[CH3:18]

Participants

7

Reactant 4

HCID 6340IodoethaneHCID 11430Potassium CarbonateHCID 31374DimethylacetamideHCID 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 38%

Reagents, catalysts & solvents 2

HCID 962WaterSolventHCID 3283Diethyl EtherSolvent

Conditions

Temperature
60 °C

Procedure

4,4,5,5-Tetramethyl-2-(1H-pyrazol-4-yl)-1,3,2-dioxaborolane (5.0 g), N,N-dimethylacetamide (50 ml), potassium carbonate (5.3 g) and ethyl iodide (2.1 ml) were mixed, and the mixture was stirred at 60° C. overnight. The reaction mixture was cooled to room temperature, water (100 ml) and ethyl ether (100 ml) were added, and the mixture was partitioned in a separatory funnel. The aqueous layer was further extracted with ethyl ether (100 ml), and the organic layers were combined. The organic layer was washed 3 times with water (100 ml) and once with saturated brine (100 ml), dried over anhydrous sodium sulfate, and filtered. The filtrate was concentrated under reduced pressure, hexane (50 ml) was added to the obtained residue and the mixture was partitioned in a separatory funnel. The organic layer was washed 3 times with water (40 ml) and once with saturated brine (40 ml), dried over anhydrous sodium sulfate, and filtered. The filtrate was concentrated under reduced pressure to give the title compound (2.1691 g, 38%).

Workup

  1. temperatureThe reaction mixture was cooled to room temperature
  2. customthe mixture was partitioned in a separatory funnel
  3. extractionThe aqueous layer was further extracted with ethyl ether (100 ml)
  4. washThe organic layer was washed 3 times with water (100 ml)
  5. dry with materialonce with saturated brine (100 ml), dried over anhydrous sodium sulfate
  6. filtrationfiltered
  7. concentrationThe filtrate was concentrated under reduced pressure, hexane (50 ml)
  8. additionwas added to the obtained residue
  9. customthe mixture was partitioned in a separatory funnel
  10. washThe organic layer was washed 3 times with water (40 ml)
  11. dry with materialonce with saturated brine (40 ml), dried over anhydrous sodium sulfate
  12. filtrationfiltered
  13. concentrationThe filtrate was concentrated under reduced pressure

Sources & evidence

ORD record
ord-ee5e9e2fcd4f4da6b352d711f7613ef0
Source dataset
uspto-grants-2013_01
Patent number
US08343994B2

Reaction notes

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