Phosphorus oxychloride → 2-Chloro-7-fluoroquinoxaline

HRID 2279300Notes

Reaction equation

HRID 2279300 reaction equation
[F:1][C:2]1[CH:11]=[C:10]2[C:5]([N:6]=[CH:7][C:8](O)=[N:9]2)=[CH:4][CH:3]=1.P(Cl)(Cl)([Cl:15])=O>C(OCC)(=O)C>[Cl:15][C:8]1[CH:7]=[N:6][C:5]2[C:10](=[CH:11][C:2]([F:1])=[CH:3][CH:4]=2)[N:9]=1

Participants

4

Reactant 2

HCID 24813Phosphorus oxychlorideHCID 178516721HCID 178516721, compound

Product 1

HCID 714639612-Chloro-7-fluoroquinoxalineYield 86.4%

Reagents, catalysts & solvents 1

HCID 8857Ethyl AcetateSolvent

Procedure

A mixture of 7-fluoro-quinoxalin-2-ol (2.60 g, 15.84 mmol, 1.0 eq) and phosphorus oxychloride (50 mL, 536.4 mmol, 34.0 eq) is refluxed for 1 hour, then concentrated, diluted with water (60 mL), basified to pH 7 by adding saturated sodium hydrogen carbonate aqueous solution, and extracted with ethyl acetate (3×100 mL). The combined organic layers are dried over sodium sulfate, filtered and concentrated to give a crude that is purified by column chromatography (silica gel, eluent: ethyl acetate:petroleum ether, 1:20, v/v) to afford 2-chloro-7-fluoro-quinoxaline as a white solid (2.50 g, 84% yield).

Workup

  1. temperatureis refluxed for 1 hour
  2. concentrationconcentrated
  3. additiondiluted with water (60 mL)
  4. additionby adding saturated sodium hydrogen carbonate aqueous solution
  5. extractionextracted with ethyl acetate (3×100 mL)
  6. dry with materialThe combined organic layers are dried over sodium sulfate
  7. filtrationfiltered
  8. concentrationconcentrated
  9. customto give a crude that
  10. customis purified by column chromatography (silica gel, eluent

Sources & evidence

ORD record
ord-d52f1ed8328d4742aa62e7cfca4e2da5
Source dataset
uspto-grants-2015_09
Patent number
US09133219B2

Reaction notes

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