Ethyl Acetate → 3-Chloro-6-methoxy-2-methylquinoxaline

HRID 1422799Notes

Reaction equation

HRID 1422799 reaction equation
[CH3:1][O:2][C:3]1[CH:12]=[C:11]2[C:6]([N:7]=[C:8]([CH3:14])[C:9](=O)[NH:10]2)=[CH:5][CH:4]=1.C(OCC)(=O)C.P(Cl)(Cl)([Cl:23])=O>>[Cl:23][C:9]1[C:8]([CH3:14])=[N:7][C:6]2[C:11]([N:10]=1)=[CH:12][C:3]([O:2][CH3:1])=[CH:4][CH:5]=2

Participants

4

Reactant 3

HCID 8857Ethyl AcetateHCID 24813Phosphorus oxychlorideHCID 217964227-Methoxy-3-methylquinoxalin-2(1H)-one

Product 1

HCID 467413403-Chloro-6-methoxy-2-methylquinoxalineYield 34%

Procedure

A solution of 7-methoxy-3-methyl-1H-quinoxalin-2-one (125 g, 631 mmol, 1.0 eq) in phosphorus oxychloride (800 mL) is heated under reflux for 1 hour. Then the reaction mixture is cooled down to room temperature and the solvent is evaporated. The residue is poured into ice water and the resulting mixture is neutralized with 20% sodium hydroxide aqueous solution. The resulting precipitate is collected by filtration, washed with water to give a crude product that is purified by column chromatography (silica gel, eluent: petroleum ether:ethyl acetate, 100:1, v/v) to afford 3-chloro-6-methoxy-2-methyl-quinoxaline as a white solid (44.4 g, 34% yield).

Workup

  1. temperatureunder reflux for 1 hour
  2. customthe solvent is evaporated
  3. additionThe residue is poured into ice water
  4. filtrationThe resulting precipitate is collected by filtration
  5. washwashed with water
  6. customto give a crude product that
  7. customis purified by column chromatography (silica gel, eluent

Sources & evidence

ORD record
ord-3cf54bae67e44121b168ba53c739279c
Source dataset
uspto-grants-2015_01
Patent number
US08927542B2

Reaction notes

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