Lithium Hydroxide → 1-[(4-methoxyphenyl)methyl]-1H-pyrazole-4-carboxylic acid

HRID 1910842Notes

Reaction equation

[Li+].[OH-].[CH3:3][O:4][C:5]1[CH:21]=[CH:20][C:8]([CH2:9][N:10]2[CH:14]=[C:13]([C:15]([O:17]CC)=[O:16])[CH:12]=[N:11]2)=[CH:7][CH:6]=1>O.C1COCC1.CO>[CH3:3][O:4][C:5]1[CH:6]=[CH:7][C:8]([CH2:9][N:10]2[CH:14]=[C:13]([C:15]([OH:17])=[O:16])[CH:12]=[N:11]2)=[CH:20][CH:21]=1

Participants

Conditions

Temperature: 60 °C

Procedure

According to Scheme 1 Step 2: A solution of LiOH (358 mmol, 15.3 g) in water (2 M) was added at room temperature to a solution of ethyl 1-(4-methoxybenzyl)-1H-pyrazole-4-carboxylate (143 mmol, 37.2 g) in THF/MeOH (1:1, 400 mL) and the reaction mixture was heated at 60° C. overnight. After evaporation of THF and MeOH, a solid was filtered, water (150 mL) was added and the aqueous phase was extracted with Et2O. The aqueous phase was then acidified with a solution of HCl 1 M until pH=1-2 and extracted with DCM. The organic phase was washed with brine, was dried over MgSO4, was filtered and was concentrated under reduced pressure to yield 1-(4-methoxybenzyl)-1H-pyrazole-4-carboxylic acid (138 mmol, 32.1 g, 97%) as a pale yellow solid. The crude product was used without further purification.

Workup

customAfter evaporation of THF and MeOH
filtrationa solid was filtered
additionwater (150 mL) was added
extractionthe aqueous phase was extracted with Et2O
extractionextracted with DCM
washThe organic phase was washed with brine
dry with materialwas dried over MgSO4
filtrationwas filtered
concentrationwas concentrated under reduced pressure

Sources & evidence

ORD record: ord-019be3864b8246f8974047e5a5362bbe
Source dataset: uspto-grants-2013_12
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08604033B2

Reaction notes

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