Piperazine → 2-Chloro-3-(piperazin-1-yl)pyrazine

HRID 493295Notes

Reaction equation

HRID 493295 reaction equation
Cl[C:2]1[C:7]([Cl:8])=[N:6][CH:5]=[CH:4][N:3]=1.[NH:9]1[CH2:14][CH2:13][NH:12][CH2:11][CH2:10]1.C([O-])([O-])=O.[K+].[K+]>C(#N)C.C(Cl)Cl>[Cl:8][C:7]1[C:2]([N:9]2[CH2:14][CH2:13][NH:12][CH2:11][CH2:10]2)=[N:3][CH:4]=[CH:5][N:6]=1

Participants

6

Reactant 3

HCID 4837PiperazineHCID 11430Potassium CarbonateHCID 785752,3-Dichloropyrazine

Product 1

HCID 140864382-Chloro-3-(piperazin-1-yl)pyrazineYield 69%

Reagents, catalysts & solvents 2

HCID 6342AcetonitrileSolventHCID 6344DichloromethaneSolvent

Conditions

Temperature
110 °C

Procedure

A mixture of 2,3-dichloropyrazine (1.35 g, 15.32 mmol), piperazine (2.34 g, 27.2 mmol) and K2CO3 (1.25 g, 9.04 mmol) in acetonitrile (5.5 mL) was stirred at 110° C. for 1.25 h in a sealed tube. The reaction mixture was diluted with CH2Cl2, filtered, and concentrated to give a yellowish semisolid residue which was purified by chromatography on silica gel using CHCl3/MeOH (9:1) as eluent. The obtained solid was redissolved in CHCl3 and applied to a short (3 cm) plug of alumina. Elution with ether/CHCl3 (9 1) afforded 1.24 g (69%) of the title product as a white solid: mp 47-53° C. HRMS m/z calcd for C8H11ClN4 (M)+ 198.0672, found 198.0673.

Workup

  1. filtrationfiltered
  2. concentrationconcentrated
  3. customto give a yellowish semisolid residue which
  4. customwas purified by chromatography on silica gel
  5. dissolutionThe obtained solid was redissolved in CHCl3
  6. washElution with ether/CHCl3 (9 1)

Sources & evidence

ORD record
ord-339e508f88dd4b85a5d13d2e2da715ab
Source dataset
uspto-grants-2009_05
Patent number
US07534794B2

Reaction notes

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