Ammonia → 2-Bromo-6-(4-chlorophenyl)pyrazine

HRID 1269656Notes

Reaction equation

HRID 1269656 reaction equation
Cl[C:2]1[CH:7]=[N:6][CH:5]=[C:4]([C:8]2[CH:13]=[CH:12][C:11]([Cl:14])=[CH:10][CH:9]=2)[N:3]=1.P(Br)(Br)[Br:16].N>O>[Br:16][C:2]1[CH:7]=[N:6][CH:5]=[C:4]([C:8]2[CH:13]=[CH:12][C:11]([Cl:14])=[CH:10][CH:9]=2)[N:3]=1

Participants

5

Reactant 3

HCID 222AmmoniaHCID 24614Phosphorus tribromideHCID 214131582-Chloro-6-(4-chlorophenyl)pyrazine

Product 1

HCID 184483222-Bromo-6-(4-chlorophenyl)pyrazine

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Procedure

To a flask containing 2-chloro-6-(4-chlorophenyl)pyrazine (2.35 g, 10.4 mmol), was added phosphorus tribromide (17 mL) and the mixture heated at reflux for 6 h under nitrogen. The reaction mixture was cooled to room temperature prior to pouring carefully into iced water (600 mL) the resulting mixture was adjusted to pH 6–7 using aqueous ammonia and extracted with diethyl ether (2×250 mL). The organic solution was dried (MgSO4) and the solvent removed in vacuo. The reaction had not gone to completion so the residue was treated with added phosphorus tribromide (17 mL) and heated at reflux for a further 5 h under nitrogen. Work up as before afforded the title compound as a pale yellow solid (0.97 g).

Workup

  1. temperaturethe mixture heated
  2. temperatureat reflux for 6 h under nitrogen
  3. extractionextracted with diethyl ether (2×250 mL)
  4. dry with materialThe organic solution was dried (MgSO4)
  5. customthe solvent removed in vacuo
  6. additionwas treated with added phosphorus tribromide (17 mL)
  7. temperatureheated
  8. temperatureat reflux for a further 5 h under nitrogen

Sources & evidence

ORD record
ord-dbdf95888b044a12b9e2a98938b1abff
Source dataset
uspto-grants-2007_04
Patent number
US07199239B2

Reaction notes

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