反应详情

To a stirred solution of 5-(4-benzyloxy-phenyl)-1H-pyrazole-3-carboxylic acid ethyl ester (5.8 g, 0.018 mole) in a mixture of methanol (50 mL) and THF (180 mL) was added 10% Pd/C (2 g) and the resulting mixture was stirred under an atmosphere of hydrogen for 5 hours. The reaction mixture was then filtered through celite, and the celite was washed with methanol. The filtrate was collected and concentrated under reduced pressure afford 4.05 g (97%) of 5-(4-Benzyloxy-phenyl)-1H-pyrazole-3-carboxylic acid ethyl ester. LCMS: 233.08 (M+1)+, 97%. To a stirred solution of 5-(4-hydroxy-phenyl)-1H-pyrazole-3-carboxylic acid ethyl ester (4 g, 0.01724 mol) in a mixture of 1,4-dioxane (88 mL) and H2O (88 mL) was added NaOH (1.57 g, 0.03793 mol) and the resulting mixture was stirred at ambient temperature overnight. The reaction mixture was then acidified with concentrated HCl solution. The mixture was concentrated and the resulting precipitate was isolated by filtration and dried to afford 3.1 g (76%) of 5-(4-hydroxy-phenyl)-1H-pyrazole-3-carboxylic acid. LCMS: 205.05 (M+1)+, 91.6%.

1. concentrationThe mixture was concentrated
2. customthe resulting precipitate was isolated by filtration
3. customdried