Phosphorus oxybromide → 2,5-Dibromo-3-methylpyrazine

HRID 441739Notes

Reaction equation

HRID 441739 reaction equation
O[C:2]1[C:7]([CH3:8])=[N:6][C:5]([Br:9])=[CH:4][N:3]=1.P(Br)(Br)([Br:12])=O>>[Br:12][C:2]1[C:7]([CH3:8])=[N:6][C:5]([Br:9])=[CH:4][N:3]=1

Participants

3

Reactant 2

HCID 24613Phosphorus oxybromideHCID 178432449HCID 178432449, compound

Product 1

HCID 205289252,5-Dibromo-3-methylpyrazine

Conditions

Temperature
175 °C

Procedure

A mixture of 2-hydroxy-3-methyl-5-bromopyrazine and phosphorus oxybromide is heated at about 175° C. for several hours with constant stirring. After hydrolysis of the solution on ice the crude product is extracted with ether and distilled. The distillate is refluxed with phosphorus tribromide for several hours and, after cooling, the solution is hydrolyzed on ice and the product extracted with ether, the ether removed in vacuo to give 2,5-dibromo-3-methylpyrazine.

Workup

  1. extractionis extracted with ether
  2. distillationdistilled
  3. temperatureThe distillate is refluxed with phosphorus tribromide for several hours
  4. temperatureafter cooling
  5. extractionthe product extracted with ether
  6. customthe ether removed in vacuo

Sources & evidence

ORD record
ord-b9ab9e6526bc4d44a67587a462c9af2a
Source dataset
uspto-grants-1977_08
Patent number
US04042586

Reaction notes

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