Hydrochloric Acid → 5-Chloropyrazinoic acid

HRID 719895Notes

Reaction equation

HRID 719895 reaction equation
[Cl:1][C:2]1[N:3]=[CH:4][C:5]([C:8]([O:10]C)=[O:9])=[N:6][CH:7]=1.C(=O)([O-])[O-].[K+].[K+].Cl>O1CCCC1.O.[Cl-].[Na+]>[Cl:1][C:2]1[N:3]=[CH:4][C:5]([C:8]([OH:10])=[O:9])=[N:6][CH:7]=1

Participants

7

Reactant 3

HCID 313Hydrochloric AcidHCID 11430Potassium CarbonateHCID 406081Methyl 5-chloropyrazine-2-carboxylate

Product 1

HCID 4654725-Chloropyrazinoic acidYield 98.5%

Reagents, catalysts & solvents 3

HCID 962WaterSolventHCID 5234Sodium ChlorideSolventHCID 8028TetrahydrofuranSolvent

Conditions

Temperature
25 °C

Procedure

A solution of methyl 5-chloropyrazine-2-carboxylate (30.00 g, 0.17 mol) in tetrahydrofuran (87 mL) was treated with a solution of potassium carbonate (72.08 g, 0.52 mol) in water (261 mL). The resulting reaction mixture stirred at 25° C. for 42 h. The reaction mixture was then acidified to a pH=2 with concentrated hydrochloric acid, diluted with a saturated aqueous sodium chloride solution (300 mL), and was continuously extracted with ethyl acetate (4 L total) until no product was present in the aqueous layer. The combined organic layers were dried over sodium sulfate, filtered, and concentrated in vacuo to afford 5-chloro-pyrazine-2-carboxylic acid (26.54 g, 96%) as an off-white solid: mp 150–151° C.; EI-HRMS m/e calcd for C5H3ClN2O2 (M+) 157.9883, found 157.9877.

Workup

  1. customThe resulting reaction mixture
  2. extractionwas continuously extracted with ethyl acetate (4 L total) until no product
  3. dry with materialThe combined organic layers were dried over sodium sulfate
  4. filtrationfiltered
  5. concentrationconcentrated in vacuo

Sources & evidence

ORD record
ord-5242c561ee0d43a5a64605b15030673f
Source dataset
uspto-grants-2006_11
Patent number
US07132425B2

Reaction notes

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