反应详情

5-Isopropyl-4-nitro-1H-pyrazol-3-carboxylic acid amide (3 g, 15.1 mmol) and 10% palladium on carbon (500 mg) in ethanol (30 ml) were stirred under hydrogen (50 psi) at room temperature for 18 hours. The reaction mixture was filtered and the solid was washed with methanol (50 ml), dichloromethane (50 ml), ethanol (50 ml) and ethyl acetate (50 ml). The filtrate was concentrated under reduced pressure and the residue was purified by flash column chromatography on silica gel eluting with dichloromethane methanol (9:1, by volume) to give 4-amino-5-isopropyl-1H-pyrazol-3-carboxylic acid amide (2.6 g) as an off-white solid. 1H NMR (400 MHz, DMSO-D6): δ=12.20-12.30 (1H, brs), 7.02-7.14 (1H, brs), 6.85-6.95 (1H, brs), 4.30-4.46 (2H, brs), 2.90-3.00 (1H, m), 1.15-1.21 (6H, d) ppm. LRMS (electrospray): m/z [M−H]+ 167, [2M−H]+ 335. Anal. Found C, 49.86; H, 7.21; N, 33.07. C7H12N4O requires C, 49.99; H, 7.19; N, 33.31%.

1. filtrationThe reaction mixture was filtered
2. washthe solid was washed with methanol (50 ml), dichloromethane (50 ml), ethanol (50 ml) and ethyl acetate (50 ml)
3. concentrationThe filtrate was concentrated under reduced pressure
4. customthe residue was purified by flash column chromatography on silica gel eluting with dichloromethane methanol (9:1, by volume)