Ammonium Chloride → (+/-)-1-methyl-5-(3-(trifluoromethyl)piperazin-1-yl)-1H-pyrazol-4-amine

HRID 1915877Notes

Reaction equation

HRID 1915877 reaction equation
[CH3:1][N:2]1[C:6]([N:7]2[CH2:12][CH2:11][NH:10][CH:9]([C:13]([F:16])([F:15])[F:14])[CH2:8]2)=[C:5]([N+:17]([O-])=O)[CH:4]=[N:3]1.[NH4+].[Cl-]>CO.O.[Zn]>[CH3:1][N:2]1[C:6]([N:7]2[CH2:12][CH2:11][NH:10][CH:9]([C:13]([F:16])([F:15])[F:14])[CH2:8]2)=[C:5]([NH2:17])[CH:4]=[N:3]1

Participants

6

Reactant 2

HCID 25517Ammonium ChlorideHCID 86680080(+/-)-1-(1-methyl-4-nitro-1H-pyrazol-5-yl)-3-(trifluoromethyl)piperazine

Product 1

HCID 86680081(+/-)-1-methyl-5-(3-(trifluoromethyl)piperazin-1-yl)-1H-pyrazol-4-amineYield 90.9%

Reagents, catalysts & solvents 3

HCID 23994ZincCatalystHCID 887MethanolSolventHCID 962WaterSolvent

Procedure

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+).

Workup

  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

Sources & evidence

ORD record
ord-750540d4053541de8f72a3d27db47882
Source dataset
uspto-grants-2013_12
Patent number
US08614206B2

Reaction notes

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