4-Bromophenylhydrazine hydrochloride → HCID 57437901, compound

HRID 1799401Notes

Reaction equation

HRID 1799401 reaction equation
[CH2:1]([O:3][C:4](=[O:15])[C:5]([C:10]([CH:12]1[CH2:14][CH2:13]1)=O)=[CH:6][N:7](C)C)[CH3:2].Cl.[Br:17][C:18]1[CH:23]=[CH:22][C:21]([NH:24]N)=[CH:20][CH:19]=1.CCN(C(C)C)C(C)C>C(O)C>[Br:17][C:18]1[CH:23]=[CH:22][C:21]([N:24]2[C:10]([CH:12]3[CH2:14][CH2:13]3)=[C:5]([C:4]([O:3][CH2:1][CH3:2])=[O:15])[CH:6]=[N:7]2)=[CH:20][CH:19]=1

Participants

5

Reactant 3

HCID 121574-Bromophenylhydrazine hydrochlorideHCID 81531DiisopropylethylamineHCID 66877036HCID 66877036, compound2×

Product 1

HCID 57437901HCID 57437901, compound

Reagents, catalysts & solvents 1

HCID 702EthanolSolvent

Procedure

Ethyl-2-(cyclopropanecarbonyl)-3-dimethylamino-prop-2-enoate (Intermediate #32) (316 mg, 1.5 mmol) was dissolved in ethanol (5 mL). 4-bromophenylhydrazine hydrochloride (335 mg, 1.5 mmol) and DIPEA (264 μL, 1.5 mmol) were added and the mixture was heated to reflux for 2 h. The reaction mixture was cooled to ambient and evaporated under reduced pressure. The residue was dissolved in DCM (10 mL) washed with water and poured through a phase separating tube. The product was recovered from the filtrate by flash column chromatography (SiO2, elution gradient 0-25% EtOAc in isohexane). Pure fractions were combined and evaporated to give ethyl 1-(4-bromophenyl)-5-cyclopropyl-pyrazole-4-carboxylate as an oil that crystallised on standing. (343 mg, 87%)

Workup

  1. temperaturethe mixture was heated
  2. temperatureto reflux for 2 h
  3. temperatureThe reaction mixture was cooled to ambient and
  4. customevaporated under reduced pressure
  5. dissolutionThe residue was dissolved in DCM (10 mL)
  6. washwashed with water
  7. additionpoured through a phase
  8. customseparating tube
  9. customThe product was recovered from the filtrate by flash column chromatography (SiO2, elution gradient 0-25% EtOAc in isohexane)
  10. customevaporated

Sources & evidence

ORD record
ord-af255feddcab418aa7f38665bfa0ef42
Source dataset
uspto-grants-2013_01
Patent number
US08344016B2

Reaction notes

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