2-Hydrazinopyridine → 5-methyl-1-pyridin-2-yl-1H-pyrazole-4-carboxylic acid ethyl ester

HRID 220477Notes

Reaction equation

HRID 220477 reaction equation
[CH2:1]([O:3][C:4](=[O:13])[C:5](=[CH:9]N(C)C)[C:6](=O)[CH3:7])[CH3:2].[N:14]1[CH:19]=[CH:18][CH:17]=[CH:16][C:15]=1[NH:20][NH2:21]>C(O)C>[CH2:1]([O:3][C:4]([C:5]1[CH:9]=[N:21][N:20]([C:15]2[CH:16]=[CH:17][CH:18]=[CH:19][N:14]=2)[C:6]=1[CH3:7])=[O:13])[CH3:2]

Participants

4

Reactant 2

HCID 786452-HydrazinopyridineHCID 3806790Ethyl 2-acetyl-3-(dimethylamino)acrylate

Product 1

HCID 222675745-methyl-1-pyridin-2-yl-1H-pyrazole-4-carboxylic acid ethyl esterYield 85%

Reagents, catalysts & solvents 1

HCID 702EthanolSolvent

Procedure

Dissolve 2-dimethylaminomethylene-3-oxo-butyric acid ethyl ester (0.662 g, 3.57 mmol) and pyridin-2-yl-hydrazine (0.410 g, 3.75 mmol) in ethanol (15 mL) and reflux for 2 hr. Evaporate the mixture then dilute with saturated sodium bicarbonate and extract 3 times with ethyl acetate. Dry the solution (sodium sulfate), filter and concentrate. Purify using silica gel chromatography, eluting with 50:50 ethyl acetate:hexane to give 5-methyl-1-pyridin-2-yl-1H-pyrazole-4-carboxylic acid ethyl ester as a white solid (0.700 g, 85%). MS (ES): m/z=232 [M+H]+.

Workup

  1. temperaturereflux for 2 hr
  2. customEvaporate the mixture
  3. additionthen dilute with saturated sodium bicarbonate
  4. extractionextract 3 times with ethyl acetate
  5. dry with materialDry the solution (sodium sulfate)
  6. filtrationfilter
  7. concentrationconcentrate
  8. customPurify
  9. washeluting with 50:50 ethyl acetate

Sources & evidence

ORD record
ord-951c108e61914c5bba8781af119e5ac2
Source dataset
uspto-grants-2012_06
Patent number
US08202873B2

Reaction notes

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