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

HRID 500955Notes

Reaction equation

HRID 500955 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 1,2-dichloro-3-nitrobenzene (0.96 g, 5.0 mmol) and piperazine-1-carboxylic acid tert-butyl ester (0.93 g, 5.0 mmol) in acetonitrile (5 mL) was added of K2CO3 (1.38 g, 10 mmol). The mixture was heated at reflux for 48 h. The solvent was removed under reduced pressure. The crude material was partitioned between EtOAc (100 mL) and H2O (20 mL). The organic layer was washed with H2O (2×20 mL), dried over Na2SO4 and concentrated. Column chromatography (silica, 10-20% EtOAc/hexanes) provided 4-(2-chloro-6-nitro-phenyl)-piperazine-1-carboxylic acid tert-butyl ester (1.2 g, 70%). TLC (silica, 20% EtOAc/hexanes): Rf=0.45. MS (electrospray): exact mass calculated for C15H20ClN3O4, 341.1; m/z found, 364.1 [M+Na]+. 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), 3.38-3.56 (m, 4H), 3.06 (m, 4H), 1.48 (s, 9H).

Workup

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

Sources & evidence

ORD record
ord-31292c49aff545cfb49ae376fd3b3b24
Source dataset
uspto-grants-2010_08
Patent number
US07772236B2

Reaction notes

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