Epichlorohydrin → 3-(3,4-dichloro-phenyl)-1-oxiranylmethyl-1H-pyrazole

HRID 271745Notes

Reaction equation

HRID 271745 reaction equation
[Cl:1][C:2]1[CH:3]=[C:4]([C:9]2[CH:13]=[CH:12][NH:11][N:10]=2)[CH:5]=[CH:6][C:7]=1[Cl:8].C(=O)([O-])[O-].[Cs+].[Cs+].[CH2:20]([CH:22]1[O:24][CH2:23]1)Cl>CN(C=O)C>[Cl:1][C:2]1[CH:3]=[C:4]([C:9]2[CH:13]=[CH:12][N:11]([CH2:20][CH:22]3[CH2:23][O:24]3)[N:10]=2)[CH:5]=[CH:6][C:7]=1[Cl:8]

Participants

5

Reactant 3

HCID 7835EpichlorohydrinHCID 10796Cesium carbonateHCID 178477946HCID 178477946, compound

Product 1

HCID 179754053-(3,4-dichloro-phenyl)-1-oxiranylmethyl-1H-pyrazoleYield 82%

Reagents, catalysts & solvents 1

HCID 6228DimethylformamideSolvent

Procedure

A stirred solution of 3-(3,4-dichlorophenyl)pyrazole (300 mg, 1.4 mmol) in DMF (5 mL) was treated with cesium carbonate (550 mg, 1.69 mmol) and epichlorohydrin (1.1 mL, 14.0 mmol) at room temperature for 18 h. The crude reaction mixture was then partitioned between EtOAc (50 mL) and water (35 mL). The aqueous phase was further extracted (2×50 mL) and the combined organic layers were washed with brine, dried (Na2SO4), filtered and concentrated under reduced pressure to yield crude product. Purification by column chromatography (silica, 25% EtOAc/hexanes) afforded 308 mg (82%) of the title compound. 1NMR (400 MHz, CDCl3): 7.83 (d, J=2 Hz, 1H), 7.54 (dd, J=2, 8 Hz, 1H), 7.44 (d, J=2 Hz, 1H), 7.38 (d, J=8 Hz, 1H), 6.48 (d, J=2 Hz, 1H), 4.45 (dd, J=3, 9.7 Hz, 1H), 4.12 (dd, J=6, 15 Hz, 1H), 3.31 (m, 1H), 2.81 (dd, J=4.0, 4.6 Hz, 1H), 2.47 (dd, J=2.6, 4.7 Hz, 1H).

Workup

  1. customThe crude reaction mixture
  2. customwas then partitioned between EtOAc (50 mL) and water (35 mL)
  3. extractionThe aqueous phase was further extracted (2×50 mL)
  4. washthe combined organic layers were washed with brine
  5. dry with materialdried (Na2SO4)
  6. filtrationfiltered
  7. concentrationconcentrated under reduced pressure
  8. customto yield crude product
  9. customPurification by column chromatography (silica, 25% EtOAc/hexanes)

Sources & evidence

ORD record
ord-4c5fc79c89bc436cb4fbca327016ff5a
Source dataset
uspto-grants-2008_11
Patent number
US07452890B2

Reaction notes

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