Potassium Carbonate → 4-(2,6-Dinitro-phenyl)-piperazine-1-carboxylic acid tert-butyl ester

HRID 746966Notes

Reaction equation

HRID 746966 reaction equation
Cl[C:2]1[C:7]([N+:8]([O-:10])=[O:9])=[CH:6][CH:5]=[CH:4][C:3]=1[N+:11]([O-:13])=[O:12].[C:14]([O:18][C:19]([N:21]1[CH2:26][CH2:25][NH:24][CH2:23][CH2:22]1)=[O:20])([CH3:17])([CH3:16])[CH3:15].C([O-])([O-])=O.[K+].[K+]>C(#N)C>[C:14]([O:18][C:19]([N:21]1[CH2:26][CH2:25][N:24]([C:2]2[C:7]([N+:8]([O-:10])=[O:9])=[CH:6][CH:5]=[CH:4][C:3]=2[N+:11]([O-:13])=[O:12])[CH2:23][CH2:22]1)=[O:20])([CH3:17])([CH3:15])[CH3:16]

Participants

5

Reactant 3

HCID 11430Potassium CarbonateHCID 118141-Chloro-2,6-dinitrobenzeneHCID 143452tert-Butyl piperazine-1-carboxylate

Product 1

HCID 865848194-(2,6-Dinitro-phenyl)-piperazine-1-carboxylic acid tert-butyl esterYield 85%

Reagents, catalysts & solvents 1

HCID 6342AcetonitrileSolvent

Procedure

To a stirred solution of 1.01 g (5.0 mmol) of 1-chloro-2,6-dinitrobenzene and 0.93 g (5.0 mmol) of 1-tert-butyloxycarbonylpiperazine in acetonitrile (5 mL) was added 1.38 g (10 mmol) of K2CO3. The mixture was heated to reflux for 48 h. The solvent was removed under reduced pressure. The crude product was partitioned between EtOAc (100 mL) and 20 mL of H2O. The organic layer was washed with H2O (2×20 mL), dried over Na2SO4 and concentrated. Column chromatography (silica, 10-20% EtOAc/hexanes) provided 1.31 g (85%) of 4-(2,6-dinitro-phenyl)-piperazine-1-carboxylic acid tert-butyl ester TLC (silica, 20% EtOAc/hexanes): Rf=0.35. 1H NMR (400 MHz, CDCl3): 7.75 (d, J=8.2 Hz, 2H), 7.25 (t, J=8.2 Hz, 1H), 3.30 (m, 4H), 2.95 (m, 2H), 1.44 (s, 9H).

Workup

  1. temperatureThe mixture was heated
  2. temperatureto reflux for 48 h
  3. customThe solvent was removed under reduced pressure
  4. customThe crude product was partitioned between EtOAc (100 mL) and 20 mL of H2O
  5. washThe organic layer was washed with H2O (2×20 mL)
  6. dry with materialdried over Na2SO4
  7. concentrationconcentrated

Sources & evidence

ORD record
ord-40386c866a6849cabf4fde90082f91e1
Source dataset
uspto-grants-2008_07
Patent number
US07393850B2

Reaction notes

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