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

HRID 604300Notes

Reaction equation

HRID 604300 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 three 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 (m/z): 232 (M+1).

Workup

  1. temperaturereflux for 2 hr
  2. customEvaporate the mixture
  3. additionthen dilute with saturated sodium bicarbonate
  4. extractionextract three 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-067388ba85e74be4a2c5537d044bad48
Source dataset
uspto-grants-2011_03
Patent number
US07910588B2

Reaction notes

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