Hydrochloric Acid → (1,3-Dimethyl-1H-pyrazol-5-yl)acetic acid

HRID 1786196Notes

Reaction equation

HRID 1786196 reaction equation
CN([C:4](=[O:13])[CH2:5][C:6]1[N:7]([CH3:12])[N:8]=[C:9]([CH3:11])[CH:10]=1)N.Cl.[O:15]1CCOCC1>>[CH3:12][N:7]1[C:6]([CH2:5][C:4]([OH:13])=[O:15])=[CH:10][C:9]([CH3:11])=[N:8]1

Participants

4

Reactant 3

HCID 313Hydrochloric AcidHCID 312751,4-DioxaneHCID 68406791HCID 68406791, compound

Product 1

HCID 15321738(1,3-Dimethyl-1H-pyrazol-5-yl)acetic acid

Procedure

To a solution of (2,5-dimethyl-2H-pyrazol-3-yl)-acetic acid N-methyl-hydrazide (9.1 g, 41 mmol) in dioxane (50 mL) aqueous sodium hydroxide solution was added (5 N, 50 mL) and the and the resulting mixture was heated under reflux for 4 h. After addition of hydrochloric acid (5 N, 50 mL), all volatiles were evaporated. The residue was extracted with refluxing ethanol (150 mL) and the solvent was evaporated. Residual volatiles were azeotropically removed by coevaporation with toluene to afford (2,5-dimethyl-2H-pyrazol-3-yl)-acetic acid as a viscous oil. It was dissolved in ethanol (100 ml), p-toluene sulfonic acid (2.0 g, catalytic) was added and the resulting mixture was heated under reflux for 16 h. After evaporation of the solvent, the residue was extracted with ethyl acetate and water. The organic phase was dried over sodium sulfate, concentrated and chromatographed (SiO2, heptanes:ethyl acetate=100:0 to 40:60) to afford the title compound as a colorless oil (7.6 g, 100%). 1H-NMR (400 MHz, CDCl3): δ=1.22 (t, J=7 Hz, 3H), 2.22 (s, 3H), 3.61 (s, 2H), 3.75 (s, 2H), 4.18 (q, J=7 Hz, 2H), 5.95 (s, 1H).

Workup

  1. temperaturethe and the resulting mixture was heated
  2. temperatureunder reflux for 4 h
  3. customall volatiles were evaporated
  4. extractionThe residue was extracted with refluxing ethanol (150 mL)
  5. customthe solvent was evaporated
  6. customResidual volatiles were azeotropically removed by coevaporation with toluene

Sources & evidence

ORD record
ord-88dd805681fd48d29b7b3167014fdb42
Source dataset
uspto-grants-2009_03
Patent number
US07507729B2

Reaction notes

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