Hydrochloric Acid → Methyl 3,6-dichloropyrazine-2-carboxylate

HRID 392325Notes

Reaction equation

HRID 392325 reaction equation
N[C:2]1[C:3]([C:9]([O:11][CH3:12])=[O:10])=[N:4][C:5]([Cl:8])=[CH:6][N:7]=1.N([O-])=O.[Na+].C(OCC)(=O)C.O.[ClH:24]>O1CCCC1>[Cl:24][C:2]1[C:3]([C:9]([O:11][CH3:12])=[O:10])=[N:4][C:5]([Cl:8])=[CH:6][N:7]=1

Participants

7

Reactant 5

HCID 313Hydrochloric Acid2×HCID 962WaterHCID 8857Ethyl AcetateHCID 824637Methyl 3-amino-6-chloropyrazine-2-carboxylateHCID 23668193Sodium Nitrite

Product 1

HCID 22662770Methyl 3,6-dichloropyrazine-2-carboxylate

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Procedure

In a mixture of 14 mL of 12 mol/L hydrochloric acid and 14 mL of tetrahydrofuran was suspended 8.0 g of methyl 3-amino-6-chloro-2-pyrazinecarboxylate. After adding 5.9 g of sodium nitrite at 5-12° C., the mixture thus obtained was stirred at an ice-cooled temperature for 50 minutes. Then, 8.4 g of cuprous (I) chloride suspended in 6 mol/L hydrochloric acid was added and stirred at the same temperature as above for 10 minutes. The reaction mixture was poured into a mixture of 100 mL of ethyl acetate and 100 mL of water, and the organic layer was separated. The organic layer thus obtained was washed successively with 50 mL of water and 50 mL of saturated aqueous solution of sodium chloride and dried on anhydrous magnesium sulfate, and the solvent was removed under reduced pressure. The residue was purified by silica gel chromatography [eluent: n-hexane:ethyl acetate=6:1] to obtain 6.0 g of methyl 3,6-dichloro-2-pyrazinecarboxylate as a colorless oily product.

Workup

  1. customthe mixture thus obtained
  2. temperaturecooled temperature for 50 minutes
  3. additionwas added
  4. customthe organic layer was separated
  5. customThe organic layer thus obtained
  6. washwas washed successively with 50 mL of water and 50 mL of saturated aqueous solution of sodium chloride
  7. dry with materialdried on anhydrous magnesium sulfate
  8. customthe solvent was removed under reduced pressure
  9. customThe residue was purified by silica gel chromatography [eluent: n-hexane:ethyl acetate=6:1]

Sources & evidence

ORD record
ord-64f1ef843adf4f268c5ae1398e2da251
Source dataset
uspto-grants-2004_10
Patent number
US06800629B2

Reaction notes

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