Phenylacetylene → 6,7-Dichloro-2,3-dimethoxy-5-(2-phenylethynyl)quinoxaline

HRID 842687Notes

Reaction equation

HRID 842687 reaction equation
[Cl:1][C:2]1[C:3](I)=[C:4]2[C:9](=[CH:10][C:11]=1[Cl:12])[N:8]=[C:7]([O:13][CH3:14])[C:6]([O:15][CH3:16])=[N:5]2.[C:18]1([C:24]#[CH:25])[CH:23]=[CH:22][CH:21]=[CH:20][CH:19]=1>C(N(CC)CC)C.Cl[Pd](Cl)([P](C1C=CC=CC=1)(C1C=CC=CC=1)C1C=CC=CC=1)[P](C1C=CC=CC=1)(C1C=CC=CC=1)C1C=CC=CC=1.[Cu]I>[Cl:1][C:2]1[C:3]([C:25]#[C:24][C:18]2[CH:23]=[CH:22][CH:21]=[CH:20][CH:19]=2)=[C:4]2[C:9](=[CH:10][C:11]=1[Cl:12])[N:8]=[C:7]([O:13][CH3:14])[C:6]([O:15][CH3:16])=[N:5]2

Participants

6

Reactant 2

HCID 10821PhenylacetyleneHCID 10691461HCID 10691461, compound

Product 1

HCID 226148926,7-Dichloro-2,3-dimethoxy-5-(2-phenylethynyl)quinoxalineYield 77.1%

Reagents, catalysts & solvents 3

HCID 24350Copper(1+) iodide; Copper(I) iodide; Cuprous iodide; Cuprous iodide (CuI)CatalystHCID 178418476HCID 178418476, compoundCatalystHCID 8471TriethylamineSolvent

Procedure

A mixture of 6,7-dichloro-2,3-dimethoxy-5-iodoquinoxaline (Preparation 108, 5.0 g, 13 mmol), phenylacetylene (3.98 g, 39 mmol), bis(triphenylphosphine)palladium(II) chloride (0.913 g, 1.3 mmol) and copper(I) iodide (0.248 g, 1.3 mmol) in triethylamine (100 mL) was heated under reflux for 4 hours. After being cooled, the mixture was concentrated under reduced pressure and the residue partitioned between dichloromethane (200 mL) and brine (200 mL). The phases were separated and the aqueous phase extracted with dichloromethane (2×100 mL). The combined organic extracts were dried (MgSO4) and concentrated under reduced pressure. The residue was purified by flash chromatography on silica gel, by gradient elution using hexane:dichloromethane (1:0 changing to 1:1, by volume) to afford 6,7-dichloro-2,3-dimethoxy-5-(2-phenylethynyl)quinoxaline (3.60 g, 77%) as a yellow solid, mp 170-172° C.

Workup

  1. temperaturewas heated
  2. temperatureunder reflux for 4 hours
  3. temperatureAfter being cooled
  4. concentrationthe mixture was concentrated under reduced pressure
  5. customthe residue partitioned between dichloromethane (200 mL) and brine (200 mL)
  6. customThe phases were separated
  7. extractionthe aqueous phase extracted with dichloromethane (2×100 mL)
  8. dry with materialThe combined organic extracts were dried (MgSO4)
  9. concentrationconcentrated under reduced pressure
  10. customThe residue was purified by flash chromatography on silica gel, by gradient elution

Sources & evidence

ORD record
ord-425d72f438e14f929bb299420858b8d6
Source dataset
uspto-grants-2002_04
Patent number
US06376490B1

Reaction notes

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