Ammonium Chloride → tert-butyl (+/-)-4-(4-amino-1-methyl-1H-pyrazol-5-yl)-2-methylpiperazine-1-carboxylate

HRID 1915840Notes

Reaction equation

HRID 1915840 reaction equation
[CH3:1][CH:2]1[CH2:7][N:6]([C:8]2[N:12]([CH3:13])[N:11]=[CH:10][C:9]=2[N+:14]([O-])=O)[CH2:5][CH2:4][N:3]1[C:17]([O:19][C:20]([CH3:23])([CH3:22])[CH3:21])=[O:18].[NH4+].[Cl-]>CO.O.[Zn]>[NH2:14][C:9]1[CH:10]=[N:11][N:12]([CH3:13])[C:8]=1[N:6]1[CH2:5][CH2:4][N:3]([C:17]([O:19][C:20]([CH3:22])([CH3:21])[CH3:23])=[O:18])[CH:2]([CH3:1])[CH2:7]1

Participants

6

Reactant 2

HCID 25517Ammonium ChlorideHCID 86680058tert-butyl (+/-)-2-methyl-4-(1-methyl-4-nitro-1H-pyrazol-5-yl)piperazine-1-carboxylate

Product 1

HCID 86680057tert-butyl (+/-)-4-(4-amino-1-methyl-1H-pyrazol-5-yl)-2-methylpiperazine-1-carboxylateYield 142.9%

Reagents, catalysts & solvents 3

HCID 23994ZincCatalystHCID 887MethanolSolventHCID 962WaterSolvent

Procedure

To a solution of tert-butyl (±)-2-methyl-4-(1-methyl-4-nitro-1H-pyrazol-5-yl)piperazine-1-carboxylate (500 mg, 1.54 mmol) in MeOH (20 mL) and H2O (5 mL) was added zinc (845 mg, 13 mmol) and NH4Cl (1.4 g, 26 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 PE/EtOAc (10/1˜1/10) as eluting solvents to give tert-butyl (±)-4-(4-amino-1-methyl-1H-pyrazol-5-yl)-2-methylpiperazine-1-carboxylate (650 mg, ˜100%) as red solid. 1H NMR (500 MHz, CD3OD) δ (ppm): 7.22 (s, 1H), 4.35-4.33 (m, 1H), 4.12-4.11 (m, 1H), 3.94 (s, 3H), 3.43-3.46 (m, 1H), 3.25-3.30 (m, 2H), 3.01-3.00 (m, 1H), 2.89-2.87 (d, J=12 Hz, 1H), 1.49 (s, 9H), 1.34-1.36 (d, J=5.6 Hz, 3H); MS (ESI) m/z=296 (M+H+).

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 PE/EtOAc (10/1˜1/10)
  5. washas eluting solvents

Sources & evidence

ORD record
ord-1510ce00ae6e4f4ab2c51c4ef3e2fbe5
Source dataset
uspto-grants-2013_12
Patent number
US08614206B2

Reaction notes

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