[CH3:1][N:2]1[C:6]([C:7]2[CH:8]=[N:9][CH:10]=[CH:11][CH:12]=2)=[C:5](/[CH:13]=[CH:14]/[C:15]([O:17]CC)=[O:16])[CH:4]=[N:3]1.[OH-].[Na+].C(O)(=O)CC(CC(O)=O)(C(O)=O)O>CO>[CH3:1][N:2]1[C:6]([C:7]2[CH:8]=[N:9][CH:10]=[CH:11][CH:12]=2)=[C:5](/[CH:13]=[CH:14]/[C:15]([OH:17])=[O:16])[CH:4]=[N:3]1To a mixture of ethyl (2E)-3-[1-methyl-5-(3-pyridinyl)-1H-pyrazol-4-yl]acrylate (700 mg) and methanol (5 ml) was added a 2N aqueous sodium hydroxide solution (2.7 ml) and the mixture was stirred at 40° C. for 14 hrs. A saturated aqueous citric acid solution was poured into the reaction mixture to adjust pH to 5, and the mixture was extracted with ethyl acetate. The organic layer was washed with water, dried over anhydrous magnesium sulfate, and concentrated. The residue was recrystallized from ethyl acetate-isopropyl ether to give (2E)-3-[1-methyl-5-(3-pyridinyl)-1H-pyrazol-4-yl]acrylic acid (296 mg, 47%) as pale-yellow prism crystals. melting point: 236-237° C.
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