[CH3:1][N:2]1[C:6]([N+:7]([O-:9])=[O:8])=[C:5]([CH:10]=[O:11])[CH:4]=[N:3]1.[OH-:12].[K+]>CO.[Ag-]=O>[CH3:1][N:2]1[C:6]([N+:7]([O-:9])=[O:8])=[C:5]([C:10]([OH:12])=[O:11])[CH:4]=[N:3]1A solution of 1-methyl-5-nitro-1H-pyrazole-4-carbaldehyde (0.42 g, 2.8 mmol) in methanol (5 mL) was treated with silver (I) oxide (1.29 g, 5.6 mmol) followed by 5N potassium hydroxide (1.5 mL) in 5 mL of methanol and then refluxed for 16 hours. The mixture was cooled to room temperature and quenched with concentrated HCl (8 mL) and ethyl acetate. The mixture was filtered through a layer of celite and concentrated to give crude 1-methyl-5-nitro-1H-pyrazole-4-carboxylic acid: 1H NMR (300 MHz, CDCl3) δ 8.05 (s, 1H), 4.22 (s, 3H).
Wird geladen…
