反应详情

5-cyclopentyl-4-nitro-1H-pyrazol-3-carboxylic acid amide (4.48 g, 20 mmol) and 10% palladium on carbon (800 mg) in ethanol (50 ml) were stirred under hydrogen (50 psi) at room temperature for 18 hours. The reaction mixture was filtered through arbocel and the solid was washed with ethanol (50 ml), methanol (50 ml), dichloromethane (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-cyclopentyl-1H-pyrazol-3-carboxylic acid amide (4.0 g) as an off-white solid which was a mixture of rotamers. 1H NMR (400 MHz, DMSO-D6): δ=12.20-12.31 (0.75H, brs), 11.78-11.87 (0.25H, brs), 7.02-7.18 (1.5H, brs), 6.80-6.93 (0.5H, brs), 4.22-4.56 (2H, 2×brs), 2.92-3.02 (1.96 (2H, m), 1.48-1.78 (6H, 2×m) ppm. LRMS (electrospray): m/z [M−H]+ 193. Anal. Found C, 56.12; H, 7.39; N, 27.55. C9H14N4O. 0.2 mol acetone requires C, 56.01; H, 7.44; N, 27.22%.

1. filtrationThe reaction mixture was filtered through arbocel
2. washthe solid was washed with ethanol (50 ml), methanol (50 ml), dichloromethane (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)