Dimethylformamide → 1H-Pyrazole-4-carboxaldehyde, 3-ethyl-1-phenyl-

HRID 220467Notes

Reaction equation

HRID 220467 reaction equation
P(Cl)(Cl)(Cl)=O.[CH3:6]/[C:7](=[N:10]\[NH:11][C:12]1[CH:17]=[CH:16][CH:15]=[CH:14][CH:13]=1)/[CH2:8][CH3:9].[C:18](=[O:21])([O-])[O-].[K+].[K+].[CH3:24]N(C)C=O>>[CH2:8]([C:7]1[C:6]([CH:18]=[O:21])=[CH:24][N:11]([C:12]2[CH:17]=[CH:16][CH:15]=[CH:14][CH:13]=2)[N:10]=1)[CH3:9]

Participants

5

Reactant 4

HCID 6228Dimethylformamide2×HCID 11430Potassium CarbonateHCID 24813Phosphorus oxychlorideHCID 9576180Phenylhydrazone-2-butanone

Product 1

HCID 121403841H-Pyrazole-4-carboxaldehyde, 3-ethyl-1-phenyl-Yield 15%

Procedure

To an ice cold solution of N,N-dimethylformamide (4.59 mL, 59.36 mmol) and phosphoryl chloride (5.52 mL, 59.36 mmol) add a solution of N-[1-methyl-prop-(E)-ylidene]-N′-phenyl-hydrazine (3.21 g, 19.79 mmol) in N,N-dimethylformamide (2 mL) dropwise. Warm to room temperature, then heat to 75° C. for 5 hr. Cool to room temperature and pour into an ice-cold solution of saturated potassium carbonate. Extract with DCM (3×20 mL), pass through an IST Phase Separator Frit® and concentrate. Purify (silica gel chromatography, eluting with 0:100 to 20:80 ethyl acetate:isohexane), to give the title compound as a brown solid (600 mg, 15%). MS (ES): m/z=201 [M+H]+.

Workup

  1. temperatureheat to 75° C. for 5 hr
  2. temperatureCool to room temperature
  3. extractionExtract with DCM (3×20 mL)
  4. concentrationconcentrate
  5. customPurify
  6. wash(silica gel chromatography, eluting with 0:100 to 20:80 ethyl acetate:isohexane)

Sources & evidence

ORD record
ord-8e885ade14fd45249a1109befa2a1b23
Source dataset
uspto-grants-2012_06
Patent number
US08202873B2

Reaction notes

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