Sodium Hydroxide → 5-ethyl-1-methyl-1H-pyrazole-3-carboxylic acid

HRID 1452104Notes

Reaction equation

HRID 1452104 reaction equation
[CH2:1]([C:3]1[N:7]([CH3:8])[N:6]=[C:5]([C:9]([O:11]CC)=[O:10])[CH:4]=1)[CH3:2].[OH-].[Na+]>C(O)C.O>[CH2:1]([C:3]1[N:7]([CH3:8])[N:6]=[C:5]([C:9]([OH:11])=[O:10])[CH:4]=1)[CH3:2]

Participants

5

Reactant 2

HCID 14798Sodium HydroxideHCID 22145397Ethyl 5-ethyl-1-methyl-1H-pyrazole-3-carboxylate

Product 1

HCID 199675945-ethyl-1-methyl-1H-pyrazole-3-carboxylic acidYield 47%

Reagents, catalysts & solvents 2

HCID 702EthanolSolventHCID 962WaterSolvent

Procedure

Ethyl 5-ethyl-1-methylpyrazole-3-carboxylate (6.86 g) in ethanol (70 ml) was treated with sodium hydroxide (1.58g) in water (30 ml) and heated under reflux for 6 h. The solution was concentrated and the aqueous phase washed with ethyl acetate before adding dichloromethane (50 ml). The solution was acidified with 5M hydrochloric acid, and the mixture exhaustively extracted with dichloromethane. The remaining undissolved solid was filtered off suspended in water and the pH adjusted to 6 with saturated sodium hydrogen carbonate. The solution was again extracted with dichloromethane. The combined organic layers were dried over anhydrous magnesium sulphate and concentrated to give the title compound as a white solid, (2.72g, 47%); (Found: M+, 154.0742. C7H10N2O2 requires M, 154.0742); nmax (CH2Cl2) 3689 and 1760 cm-1 ; dH (CDCl3) 1.30 (3H, t, J7.4 Hz), 2.64 (2H, q, J7.4 Hz), 3.88 (3H, s) and 6.65 (1H, s).

Workup

  1. temperatureheated
  2. temperatureunder reflux for 6 h
  3. concentrationThe solution was concentrated
  4. washthe aqueous phase washed with ethyl acetate
  5. additionbefore adding dichloromethane (50 ml)
  6. extractionthe mixture exhaustively extracted with dichloromethane
  7. filtrationThe remaining undissolved solid was filtered off
  8. extractionThe solution was again extracted with dichloromethane
  9. dry with materialThe combined organic layers were dried over anhydrous magnesium sulphate
  10. concentrationconcentrated

Sources & evidence

ORD record
ord-7cc63069e0ce4353ad26c2b45e90da4f
Source dataset
uspto-grants-1997_02
Patent number
US05606051

Reaction notes

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