Potassium Carbonate → 4-Boc-1-(5-bromo-2-pyridyl)piperazine

HRID 1640405Notes

Reaction equation

HRID 1640405 reaction equation
[N:1]1([C:7]([O:9][C:10]([CH3:13])([CH3:12])[CH3:11])=[O:8])[CH2:6][CH2:5][NH:4][CH2:3][CH2:2]1.Br[C:15]1[CH:20]=[CH:19][C:18]([Br:21])=[CH:17][N:16]=1.C(=O)([O-])[O-].[K+].[K+]>CS(C)=O.C(OCC)(=O)C>[Br:21][C:18]1[CH:19]=[CH:20][C:15]([N:4]2[CH2:5][CH2:6][N:1]([C:7]([O:9][C:10]([CH3:13])([CH3:12])[CH3:11])=[O:8])[CH2:2][CH2:3]2)=[N:16][CH:17]=1

Participants

6

Reactant 3

HCID 11430Potassium CarbonateHCID 693532,5-DibromopyridineHCID 143452tert-Butyl piperazine-1-carboxylate

Product 1

HCID 112447754-Boc-1-(5-bromo-2-pyridyl)piperazineYield 81.9%

Reagents, catalysts & solvents 2

HCID 679Dimethyl SulfoxideSolventHCID 8857Ethyl AcetateSolvent

Conditions

Temperature
150 °C

Procedure

29.2 g (157 mmol) of 1,1-dimethylethyl 1-piperazinecarboxylate, 37 g (157 mmol) of 2,5-dibromopyridine and 21.7 g (157 mmol) of potassium carbonate suspended in 27 ml of dimethyl sulfoxide (DMSO) are introduced into an autoclave. The mixture is then heated at 150° C. for 21 hours. The reaction mixture is allowed to cool to room temperature, it is taken up in ethyl acetate and water and the insoluble material is then separated out by filtration. The aqueous phase is separated out and extracted twice with ethyl acetate, the combined organic phases are washed with saturated aqueous sodium chloride solution and dried over sodium sulfate, and the filtrate is concentrated under reduced pressure. The residue obtained is purified by chromatography on silica gel, eluting with a 99/1 mixture of dichloromethane and methanol. 44 g of product are thus obtained in the form of a white solid.

Workup

  1. additionare introduced into an autoclave
  2. temperatureto cool to room temperature
  3. customwater and the insoluble material is then separated out by filtration
  4. customThe aqueous phase is separated out
  5. extractionextracted twice with ethyl acetate
  6. washthe combined organic phases are washed with saturated aqueous sodium chloride solution
  7. dry with materialdried over sodium sulfate
  8. concentrationthe filtrate is concentrated under reduced pressure
  9. customThe residue obtained
  10. customis purified by chromatography on silica gel
  11. washeluting with a 99/1 mixture of dichloromethane and methanol

Sources & evidence

ORD record
ord-a70cf85d4b68485689c040dc2c710c68
Source dataset
uspto-grants-2012_02
Patent number
US08114866B2

Reaction notes

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