Potassium Carbonate → 1-Boc-4-(2-chloro-6-nitrophenyl)piperazine

HRID 970128Notes

Reaction equation

HRID 970128 reaction equation
[Cl:1][C:2]1[CH:7]=[CH:6][CH:5]=[C:4]([N+:8]([O-:10])=[O:9])[C:3]=1Cl.[C:12]([O:16][C:17]([N:19]1[CH2:24][CH2:23][NH:22][CH2:21][CH2:20]1)=[O:18])([CH3:15])([CH3:14])[CH3:13].C([O-])([O-])=O.[K+].[K+]>C(#N)C>[C:12]([O:16][C:17]([N:19]1[CH2:24][CH2:23][N:22]([C:3]2[C:4]([N+:8]([O-:10])=[O:9])=[CH:5][CH:6]=[CH:7][C:2]=2[Cl:1])[CH2:21][CH2:20]1)=[O:18])([CH3:15])([CH3:13])[CH3:14]

Participants

5

Reactant 3

HCID 11430Potassium CarbonateHCID 185552,3-DichloronitrobenzeneHCID 143452tert-Butyl piperazine-1-carboxylate

Product 1

HCID 587677041-Boc-4-(2-chloro-6-nitrophenyl)piperazineYield 70.2%

Reagents, catalysts & solvents 1

HCID 6342AcetonitrileSolvent

Procedure

To a stirred solution of 0.96 g (5.0 mmol) of 1,2-dichloro-3-nitrobenzene and 0.93 g (5.0 mmol, 1 eq) of 1-tert-butyloxycarbonylpiperazine in acetonitrile (5 mL) was added 1.38 g (10 mmol, 2 eq) 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 1.2 g (70%) of 4-(2-chloro-6-nitro-phenyl)-piperazine-1-carboxylic acid tert-butyl ester. TLC (silica, 20% EtOAc/hexanes): Rf=0.45. 1H NMR (400 MHz, CDCl3): 7.56 (dd, J=8.2, 1.4 Hz, 1H), 7.50 (dd, J=8.2, 1.4 Hz, 1H), 7.13 (t, J=8.2 Hz, 1H), 3.56-3.38 (m, 4H), 3.10-3.00 (m, 4H), 1.48 (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-e2ff990f3a1443469c751347dcf69cae
Source dataset
uspto-grants-2007_12
Patent number
US07309703B2

Reaction notes

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