C([O:3][C:4]([C:6]1[N:7]([C:12]2[CH:17]=[CH:16][C:15]([O:18][CH3:19])=[CH:14][CH:13]=2)[N:8]=[C:9]([CH3:11])[CH:10]=1)=[O:5])C.[OH-].[Na+].Cl>C(O)C.O>[CH3:19][O:18][C:15]1[CH:14]=[CH:13][C:12]([N:7]2[C:6]([C:4]([OH:5])=[O:3])=[CH:10][C:9]([CH3:11])=[N:8]2)=[CH:17][CH:16]=1To a solution of 2-(4-methoxyphenyl)-5-methyl-2H-pyrazole-3-carboxylic acid ethyl ester (1.00 g, 3.84 mmol) in ethanol (20 mL) and water (20 mL) was added a sodium hydroxide solution (50% in water, 1 mL). The solution was stirred at 45° C. overnight. After the solution was allowed to cool to room temperature, 1 N HCl was added until the solution was acidic to pH paper. The solution was extracted with ethyl acetate (3×). The combined organic layers were dried (MgSO4) and concentrated to give 761 mg of the title compound, which was used in the next reaction without further purification. LC-MS (C12H12N2O3 calculated 232) m/z 233 (M+H).
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