反应详情

To a solution of (±)-1-(1-methyl-4-nitro-1H-pyrazol-5-yl)-3-(trifluoromethyl)piperazine (420 mg, 1.5 mmol) in MeOH (20 mL) and H2O (5 mL) was added zinc (590 mg, 4 mmol) and NH4Cl (805 mg, 10 mmol). The reaction mixture was stirred at ambient temperature for 2 hours and filtered through Celite. The filtrate was concentrated under reduced pressure to give a residue. The residue was purified by silica gel chromatography using PE/EtOAc (10/1˜1/10) as eluting solvents to afford (±)-1-methyl-5-(3-(trifluoromethyl)piperazin-1-yl)-1H-pyrazol-4-amine (340 mg, 90%) as red solid. 1H NMR (500 MHz, DMSO-d6) δ (ppm): 6.84 (s, 1H), 3.38-3.52 (m, 5H), 3.13-3.17 (m, 2H), 2.94-3.00 (m, 2H), 2.50-2.78 (s, 3H), 1.98 (m, 1H); MS (ESI) m/z: 250 (M+1+).

1. filtrationfiltered through Celite
2. concentrationThe filtrate was concentrated under reduced pressure
3. customto give a residue
4. customThe residue was purified by silica gel chromatography
5. washas eluting solvents