Pyridine → Methyl 5-chloropyrazine-2-carboxylate

HRID 1174948Notes

Reaction equation

HRID 1174948 reaction equation
O[C:2]1[N:3]=C[C:5](C(O)=O)=[N:6][CH:7]=1.S(Cl)([Cl:13])=O.CN(C=O)C.N1C=CC=CC=1.[C:26]([O:29][CH2:30]C)(=[O:28])[CH3:27].CCCCCC>>[CH3:30][O:29][C:26]([C:27]1[CH:5]=[N:6][C:7]([Cl:13])=[CH:2][N:3]=1)=[O:28]

Participants

6

Reactant 5

HCID 1049PyridineHCID 6228DimethylformamideHCID 24386Thionyl ChlorideHCID 21226206Ethyl acetate hexaneHCID 1785247745-Hydroxypyrazine-2-carboxylic acid

Product 1

HCID 406081Methyl 5-chloropyrazine-2-carboxylateYield 91%

Procedure

Reflux a mixture of 5-Hydroxy-pyrazine-2-carboxylic acid (6.568 g, 46.88 mmol), thionyl chloride (51 mL, 703.2 mmol), and DMF (0.50 mL) for 4 h. Cool the mixture to room temperature, concentrate in vacuo, and pump on high vacuum for 3 h. Dilute the mixture with MeOH (25 mL) and add pyridine (4.5 mL, 55.7 mmol). Stir the mixture overnight at room temperature. Adsorb the reaction mixture onto silica gel and subject the mixture to flash column chromatography (330 g column, 25%-60% ethyl acetate/n-hexane) to yield the desired product (7.380 g, 91%). mass spectrum (m/e): 173.0 (M+1).

Workup

  1. temperatureReflux
  2. concentrationconcentrate in vacuo
  3. additionDilute the mixture with MeOH (25 mL)

Sources & evidence

ORD record
ord-959435c030fc417d87353d4a1da999fc
Source dataset
uspto-grants-2010_11
Patent number
US07838543B2

Reaction notes

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