Ethanol → 6,7-Dichloro-2,3-dimethoxy-5-(4-pyridyl)quinoxaline

HRID 842665Notes

Reaction equation

HRID 842665 reaction equation
[Cl:1][C:2]1[C:11]([Cl:12])=[CH:10][C:9]2[N:8]=[C:7]([O:13][CH3:14])[C:6]([O:15][CH3:16])=[N:5][C:4]=2[C:3]=1B(O)O.Br[C:21]1[CH:26]=[CH:25][N:24]=[CH:23][CH:22]=1.C(O)C.C1(C)C=CC=CC=1>C(=O)([O-])[O-].[Na+].[Na+].C1C=CC(P(C2C=CC=CC=2)C2C=CC=CC=2)=CC=1.C1C=CC(P(C2C=CC=CC=2)C2C=CC=CC=2)=CC=1.C1C=CC(P(C2C=CC=CC=2)C2C=CC=CC=2)=CC=1.C1C=CC(P(C2C=CC=CC=2)C2C=CC=CC=2)=CC=1.[Pd]>[Cl:1][C:2]1[C:3]([C:21]2[CH:26]=[CH:25][N:24]=[CH:23][CH:22]=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

7

Reactant 4

HCID 702EthanolHCID 1140TolueneHCID 142684-BromopyridineHCID 120471116,7-Dichloro-2,3-dimethoxyquinoxaline-5-boronic acid

Product 1

HCID 108606436,7-Dichloro-2,3-dimethoxy-5-(4-pyridyl)quinoxalineYield 38%

Reagents, catalysts & solvents 2

HCID 11979704Tetrakis(triphenylphosphine)palladiumCatalystHCID 10340Sodium CarbonateSolvent

Procedure

A mixture of 6,7-dichloro-2,3-dimethoxyquinoxaline-5-boronic acid (0.27 g, 0.89 mmol), 4-bromopyridine (0.14 g, 0.89 mmol) and tetrakis(triphenylphosphine)palladium(O) (0.031 g, 0.026 mmol) in a mixture of 2M aqueous sodium carbonate solution (1 mL), ethanol (0.5 mL) and toluene (10 mL) was heated under nitrogen under reflux for 24 hours. After being cooled the mixture was partitioned between water (20 mL) and dichloromethane (20 mL). The phases were separated and the aqueous phase was extracted with dichloromethane (3×50 mL). The combined organic extracts were dried (MgSO4) and concentrated under reduced pressure to give a brown solid which was purified by flash chromatography on silica gel, eluting with hexane:ethyl acetate (3:1, by volume) to afford the title compound (0.113 g, 38%) as a beige solid.

Workup

  1. temperaturewas heated under nitrogen
  2. temperatureunder reflux for 24 hours
  3. temperatureAfter being cooled the mixture
  4. customwas partitioned between water (20 mL) and dichloromethane (20 mL)
  5. customThe phases were separated
  6. extractionthe aqueous phase was extracted with dichloromethane (3×50 mL)
  7. dry with materialThe combined organic extracts were dried (MgSO4)
  8. concentrationconcentrated under reduced pressure
  9. customto give a brown solid which
  10. customwas purified by flash chromatography on silica gel
  11. washeluting with hexane:ethyl acetate (3:1, by volume)

Sources & evidence

ORD record
ord-b4a1541fb67844119aaee761c7cbf989
Source dataset
uspto-grants-2002_04
Patent number
US06376490B1

Reaction notes

Loading…