3-Bromophenylhydrazine hydrochloride → Ethyl 1-(3-bromophenyl)-5-methyl-1h-pyrazole-3-carboxylate

HRID 733121Notes

Reaction equation

HRID 733121 reaction equation
Cl.[Br:2][C:3]1[CH:4]=[C:5]([NH:9][NH2:10])[CH:6]=[CH:7][CH:8]=1.[CH2:11]([O:13][C:14](=[O:21])[C:15](=O)[CH2:16][C:17](=O)[CH3:18])[CH3:12]>C(O)(=O)C>[Br:2][C:3]1[CH:4]=[C:5]([N:9]2[C:17]([CH3:18])=[CH:16][C:15]([C:14]([O:13][CH2:11][CH3:12])=[O:21])=[N:10]2)[CH:6]=[CH:7][CH:8]=1

Participants

4

Reactant 2

HCID 337573-Bromophenylhydrazine hydrochlorideHCID 69208Ethyl 2,4-dioxovalerate

Product 1

HCID 18549277Ethyl 1-(3-bromophenyl)-5-methyl-1h-pyrazole-3-carboxylateYield 85%

Reagents, catalysts & solvents 1

HCID 176Acetic AcidSolvent

Procedure

A solution of 3-bromophenylhydrazine hydrochloride (2 g, 8.9 mmol) and ethyl-2,4-dioxovalerate (1.69 g, 10.7 mmol) in acetic acid (44 ml) was refluxed for 16 hours. The reaction was cooled to room temperature and concentrated under reduced pressure. The residue was partitioned between ethyl acetate and water. The organic layer was washed with water, saturated bicarbonate and brine, and then dried over sodium sulfate, filtered and concentrated in vacuo. The crude product, thus obtained, was purified by silica-gel column chromatography (4.8:0.2 hexanes/ethyl acetate) to give the product (2.34 g, 84%) as a syrup.

Workup

  1. concentrationconcentrated under reduced pressure
  2. customThe residue was partitioned between ethyl acetate and water
  3. washThe organic layer was washed with water, saturated bicarbonate and brine
  4. dry with materialdried over sodium sulfate
  5. filtrationfiltered
  6. concentrationconcentrated in vacuo
  7. customThe crude product, thus obtained
  8. customwas purified by silica-gel column chromatography (4.8:0.2 hexanes/ethyl acetate)

Sources & evidence

ORD record
ord-4bd1734b898549f9ae0564afeda9c50e
Source dataset
uspto-grants-2009_09
Patent number
US07589116B2

Reaction notes

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