[C:1]([N:5]1[C:9]([CH3:10])=[C:8]([C:11]([O:13]C)=[O:12])[CH:7]=[N:6]1)([CH3:4])([CH3:3])[CH3:2].[OH-].[Na+]>CO>[C:1]([N:5]1[C:9]([CH3:10])=[C:8]([C:11]([OH:13])=[O:12])[CH:7]=[N:6]1)([CH3:4])([CH3:2])[CH3:3]A solution of methyl 1-tert-butyl-5-methyl-1H-pyrazole-4-carboxylate in MeOH (20 mL) was treated with 2 M aqueous NaOH solution (7.95 mL, 15.9 mmol) for 48 h at room temperature. The solvent was removed under reduced pressure and the resulting residue was dissolved in H2O (20 mL). The resulting solution was then acidified to pH-2 using 2 M HCl. The resulting precipitate was isolated by filtration, washed once with H2O (20 mL), and the solid was dried under high vacuum to yield 1-tert-Butyl-5-methyl-1H-pyrazole-4-carboxylic acid. 1H-NMR (400 MHz, d6-DMSO) δ: 12.16 (br. s., 1H), 7.67 (s, 1H), 2.69 (s, 3H), 1.59 (s, 9H).
Wird geladen…