Water → 1-(4-Carboxy-3-chlorophenyl)-1H-pyrazole-3-carboxylic acid
Reaction equation
[Cl:1][C:2]1[CH:10]=[C:9]([N:11]2[CH:15]=[CH:14][C:13]([CH3:16])=[N:12]2)[CH:8]=[CH:7][C:3]=1[C:4]([OH:6])=[O:5].[OH-:17].[K+].[Mn]([O-])(=O)(=O)=O.[K+].[OH2:25]>>[C:4]([C:3]1[CH:7]=[CH:8][C:9]([N:11]2[CH:15]=[CH:14][C:13]([C:16]([OH:25])=[O:17])=[N:12]2)=[CH:10][C:2]=1[Cl:1])([OH:6])=[O:5]Participants
Procedure
A vigorously stirred solution of 2-chloro-4-(3-methyl-1 H-pyrazol-1-yl)benzoic acid (7.08 g, 30.0 mmol) and 1 N potassium hydroxide (30 mL, 30.0 mmol) in water (200 mL) was heated to between 60–65° C. and treated gradually over ninety minutes with several aliquots of solid potassium permanganate (Total: 49.78 g, 315 mmol, 5.25 equivalents). The mixture was heated for an additional 2.5 hours (4 hours total). After cooling to room temperature, the mixture was filtered and evaporated to a residue. The residue was dissolved in 2 N hydrochloric acid and extracted with ethyl acetate (3×). The combined organic phase was washed with water, dried over anhydrous sodium sulfate, filtered, and the solvent removed in vacuo to yield, after crystallization from a mixture of ethyl acetate-diethyl ether-hexane, the title compound (1.27 g, 4.8 mmol, 16%) as a homogeneous solid, m.p. 260–263° C.;
Workup
- temperatureThe mixture was heated for an additional 2.5 hours (4 hours total)
- filtrationthe mixture was filtered
- customevaporated to a residue
- dissolutionThe residue was dissolved in 2 N hydrochloric acid
- extractionextracted with ethyl acetate (3×)
- washThe combined organic phase was washed with water
- dry with materialdried over anhydrous sodium sulfate
- filtrationfiltered
- customthe solvent removed in vacuo
- customto yield
- customafter crystallization
- additionfrom a mixture of ethyl acetate-diethyl ether-hexane
Sources & evidence
- ORD record
- ord-aeea68427383430c858e8417ccf3e86b
- Source dataset
- uspto-grants-2006_11
- Patent number
- US07138393B2
Reaction notes
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