Phosphorus oxychloride → Methyl 6-bromo-5-chloro-2-pyrazinecarboxylate

HRID 639314Notes

Reaction equation

HRID 639314 reaction equation
[CH3:1][O:2][C:3]([C:5]1[CH:10]=[N:9][C:8](O)=[C:7]([Br:12])[N:6]=1)=[O:4].O=P(Cl)(Cl)[Cl:15]>>[CH3:1][O:2][C:3]([C:5]1[CH:10]=[N:9][C:8]([Cl:15])=[C:7]([Br:12])[N:6]=1)=[O:4]

Participants

3

Reactant 2

HCID 24813Phosphorus oxychlorideHCID 178498844methyl 5-bromo-6-oxo-1H-pyrazine-3-carboxylate

Product 1

HCID 59254839Methyl 6-bromo-5-chloro-2-pyrazinecarboxylateYield 29%

Procedure

A mixture of 6-bromo-5-hydroxy-pyrazine-2-carboxylic acid methyl ester and 9.75 mL (10.7 mmol) POCl3 was refluxed for 3 h and subsequently quenched with 200 g ice. The mixture was extracted with DCM, the combined organic phases were dried with MgSO4 and evaporated to dryness the residue was purified by column chromatography on silica eluting with a gradient formed from ethyl acetate and heptane. The product fractions were combined and evaporated to dryness to yield 0.95 g (29%) of the title compound as light yellow solid. 300-MHz-1H-NMR (DMSO): δ=9.00 (s, 1H, 3-H), d=4.04 (s, 3H, OMe).

Workup

  1. temperaturewas refluxed for 3 h
  2. customsubsequently quenched with 200 g ice
  3. extractionThe mixture was extracted with DCM
  4. dry with materialthe combined organic phases were dried with MgSO4
  5. customevaporated to dryness the residue
  6. customwas purified by column chromatography on silica eluting with a gradient
  7. customformed from ethyl acetate and heptane
  8. customevaporated to dryness

Sources & evidence

ORD record
ord-29a7cb4baa244f32a906050c867d8a84
Source dataset
uspto-grants-2010_04
Patent number
US07691863B2

Reaction notes

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