Lithium Hydroxide → 1-cyclopentyl-5-methyl-1H-pyrazole-4-carboxylic acid

HRID 1098583Notes

Reaction equation

HRID 1098583 reaction equation
[CH:1]1([N:6]2[C:10]([CH3:11])=[C:9]([C:12]([O:14]CC)=[O:13])[CH:8]=[N:7]2)[CH2:5][CH2:4][CH2:3][CH2:2]1.[Li+].[OH-]>CCO.O>[CH:1]1([N:6]2[C:10]([CH3:11])=[C:9]([C:12]([OH:14])=[O:13])[CH:8]=[N:7]2)[CH2:2][CH2:3][CH2:4][CH2:5]1

Participants

5

Reactant 2

HCID 3939Lithium HydroxideHCID 63235031ethyl 1-cyclopentyl-5-methyl-1H-pyrazole-4-carboxylate

Product 1

HCID 612667041-cyclopentyl-5-methyl-1H-pyrazole-4-carboxylic acidYield 64%

Reagents, catalysts & solvents 2

HCID 702EthanolSolventHCID 962WaterSolvent

Procedure

A solution of ethyl 1-cyclopentyl-5-methyl-1H-pyrazole-4-carboxylate (15.5 g, 70 mmol) in EtOH (200 mL) was treated with a solution of LiOH (6 g, 250 mmol) in water (100 mL) and the resultant mixture was stirred at 60° C. overnight. The reaction was concentrated in vacuo and the residue was partitioned between EtOAc and water. The aqueous layer was acidified with aq HCl (2 M) to pH 3 and was extracted with EtOAc. The extract was concentrated under reduced pressure to give 1-cyclopentyl-5-methyl-1H-pyrazole-4-carboxylic acid (8.7 g, 64% yield). 1H NMR (300 MHz, DMSO-d6): δ 12.05 (br s, 1 H), 8.10 (s, 1 H), 4.60 (m, 1 H), 2.28 (s, 3 H, 2.04-1.97 (m, 2 H), 1.89-1.85 (m, 2H), 1.78-1.71 (m, 2 H), 1.62-1.59 (m, 2 H); MS (ESI) m/z: 194.99 [M+H]+.

Workup

  1. concentrationThe reaction was concentrated in vacuo
  2. customthe residue was partitioned between EtOAc and water
  3. extractionwas extracted with EtOAc
  4. concentrationThe extract was concentrated under reduced pressure

Sources & evidence

ORD record
ord-5161ffa84e334efd915fffe05c91c1d4
Source dataset
uspto-grants-2012_03
Patent number
US08143293B2

Reaction notes

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