Cesium carbonate → 1-[2-(oxan-2-yloxy)ethyl]-4-(tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole

HRID 2385611Notes

Reaction equation

HRID 2385611 reaction equation
[NH:1]1[CH:5]=[C:4]([B:6]2[O:14][C:11]([CH3:13])([CH3:12])[C:8]([CH3:10])([CH3:9])[O:7]2)[CH:3]=[N:2]1.C(=O)([O-])[O-].[Cs+].[Cs+].Br[CH2:22][CH2:23][O:24][CH:25]1[CH2:30][CH2:29][CH2:28][CH2:27][O:26]1>CN(C=O)C>[O:26]1[CH2:27][CH2:28][CH2:29][CH2:30][CH:25]1[O:24][CH2:23][CH2:22][N:2]1[CH:3]=[C:4]([B:6]2[O:7][C:8]([CH3:9])([CH3:10])[C:11]([CH3:13])([CH3:12])[O:14]2)[CH:5]=[N:1]1

Participants

5

Reactant 3

HCID 10796Cesium carbonateHCID 866212-(2-Bromoethoxy)tetrahydro-2H-pyranHCID 27740104-(4,4,5,5-Tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole

Product 1

HCID 593418191-[2-(oxan-2-yloxy)ethyl]-4-(tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazoleYield 65%

Reagents, catalysts & solvents 1

HCID 6228DimethylformamideSolvent

Procedure

To a solution of 4-pyrazole boronic acid pinacol ester (2.0 g, 10.3 mmol) in anhydrous DMF (20 mL) was added cesium carbonate (4.03 g, 12.4 mmol) and the mixture stirred at RT for 10 minutes. 2-(2-Bromoethoxy)tetrahydro-2H-pyran (1.87 mL, 12.4 mmol) was added in two portions and the mixture was heated to 70° C. After heating for 18 hours the mixture was allowed to cool to RT and partitioned between water (100 mL) and EtOAc (100 mL). The aqueous layer was washed with EtOAc (3×20 mL) and the combined organic layers washed with water (3×100 mL) followed by brine, dried (Na2SO4) and concentrated in vacuo. The resultant residue was purified by flash chromatography (SiO2, gradient 0-100% EtOAc in cyclohexane) to afford the title compound (2.15 g, 65%). LCMS: RT=3.97 min, [M+Na]+=345

Workup

  1. temperaturethe mixture was heated to 70° C
  2. temperatureAfter heating for 18 hours the mixture
  3. temperatureto cool to RT
  4. custompartitioned between water (100 mL) and EtOAc (100 mL)
  5. washThe aqueous layer was washed with EtOAc (3×20 mL)
  6. washthe combined organic layers washed with water (3×100 mL)
  7. dry with materialdried (Na2SO4)
  8. concentrationconcentrated in vacuo
  9. customThe resultant residue was purified by flash chromatography (SiO2, gradient 0-100% EtOAc in cyclohexane)

Sources & evidence

ORD record
ord-230e9f913ba746c7a6fc148f272c59fb
Source dataset
uspto-grants-2012_09
Patent number
US08263633B2

Reaction notes

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