Hydrochloric Acid → 5-(2-hydroxy-phenyl)-1-methyl-1H-pyrazole-3-carboxylic acid

HRID 1093639Notes

Reaction equation

HRID 1093639 reaction equation
C([O:3][C:4]([C:6]1[CH:10]=[C:9]([C:11]2[CH:16]=[CH:15][CH:14]=[CH:13][C:12]=2[OH:17])[N:8]([CH3:18])[N:7]=1)=[O:5])C.CO.O[Li].O.Cl>C1COCC1.O>[OH:17][C:12]1[CH:13]=[CH:14][CH:15]=[CH:16][C:11]=1[C:9]1[N:8]([CH3:18])[N:7]=[C:6]([C:4]([OH:5])=[O:3])[CH:10]=1

Participants

7

Reactant 4

HCID 313Hydrochloric AcidHCID 887MethanolHCID 168937Lithium hydroxide, monohydrateHCID 1363801745-(2-hydroxy-phenyl)-1-methyl-1H-pyrazole-3-carboxylic acid ethyl ester

Product 1

HCID 1361706645-(2-hydroxy-phenyl)-1-methyl-1H-pyrazole-3-carboxylic acidYield 87%

Reagents, catalysts & solvents 2

HCID 962WaterSolvent2×HCID 8028TetrahydrofuranSolvent

Procedure

To a solution of 5-(2-benzyloxy-phenyl)-1H-pyrazole-3-carboxylic acid ethyl ester (0.25 g, 0.00078 mole) in DMF (5 mL) was added K2CO3 (0.225 g, 0.00163 mole) followed by methyl iodide (0.116 g, 0.00081 mole) and at the resulting mixture was stirred at ambient temperature for 1 hour. The mixture was then quenched with iced water and the resulting precipitate was isolated by filtration. The solid was recrystallized from ethyl acetate to afford 0.251 g (96%) of 5-(2-benzyloxy-phenyl)-1-methyl-1H-pyrazole-3-carboxylic acid ethyl ester. LCMS: 337.15 (M+1)+, 90.13%. To a stirred solution of 5-(2-benzyloxy-phenyl)-1-methyl-1H-pyrazole-3-carboxylic acid ethyl ester (0.251 g, 0.00075 mole) in methanol (40 mL) was added 10% Pd/C (0.05 g) and the resulting mixture was stirred under an atmosphere of hydrogen for 1 hour. The mixture was then filtered through celite and the celite was washed with methanol. The combined filtrate was concentrated under reduced pressure to afford 0.169 g (92%) of 5-(2-hydroxy-phenyl)-1-methyl-1H-pyrazole-3-carboxylic acid ethyl ester. LCMS: 247.1 (M+1)+, 99%. To a stirred solution of 5-(2-hydroxy-phenyl)-1-methyl-1H-pyrazole-3-carboxylic acid ethyl ester (0.169 g, 0.00069 mol) in a mixture of THF (10 mL), methanol (5 mL) and H2O (5 mL), was added LiOH.H2O (0.087 g, 0.00206 mol) at ambient temperature and the resulting mixture was stirred overnight. The reaction mixture was then diluted with cold water and acidified with 10% HCl. The product was extracted with ethyl acetate. The organic layer was dried over sodium sulfate and concentrated under reduced pressure to afford 0.13 g (87%) of 5-(2-hydroxy-phenyl)-1-methyl-1H-pyrazole-3-carboxylic acid. LCMS: 219.07 (M+1)+, 81.5%

Workup

  1. extractionThe product was extracted with ethyl acetate
  2. dry with materialThe organic layer was dried over sodium sulfate
  3. concentrationconcentrated under reduced pressure

Sources & evidence

ORD record
ord-c05c72e16a8c454b8e9f2ab32f2c5168
Source dataset
uspto-grants-2012_03
Patent number
US08129376B2

Reaction notes

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