Hydrochloric Acid → Quinoxaline

HRID 1806002Notes

Reaction equation

HRID 1806002 reaction equation
Br[C:2]1[CH:11]=[CH:10][C:9](Br)=[C:8]2[C:3]=1[N:4]=[CH:5][CH:6]=[N:7]2.C(=O)([O-])[O-].[K+].[K+].Cl.C1C(=O)N(Br)C(=O)C1>C1COCC1.[Pd].C(Cl)(Cl)Cl.C(O)(=O)C>[N:4]1[C:3]2[C:8](=[CH:9][CH:10]=[CH:11][CH:2]=2)[N:7]=[CH:6][CH:5]=1

Participants

9

Reactant 4

HCID 313Hydrochloric AcidHCID 11430Potassium CarbonateHCID 67184N-bromobutanimideHCID 115147635,8-Dibromoquinoxaline

Product 1

HCID 7045QuinoxalineYield 72%

Reagents, catalysts & solvents 4

HCID 23938PalladiumCatalystHCID 176Acetic AcidSolventHCID 6212ChloroformSolventHCID 8028TetrahydrofuranSolvent

Procedure

In a reactor in a nitrogen atmosphere, while a solution (about 25 ml) of about 3.5 g (about 5.0 mmol) of 5,8-dibromoquinoxaline derivative synthesized in Preparative Example 1 (see: T. Yamamoto, et al. J. Am. Chem. Soc, 1996, Vol. 118, pp. 3930˜3937) and an excess of 2-thiophene borane derivative (about 15.0 mmol) in anhydrous THF was stirred, aqueous potassium carbonate (K2CO3, about 20 g, about 150 mmol) and about 10 mol % (about 578 mg, about 0.5 mmol) of a palladium catalyst (Pd(PPh3)4), based on the monomer, were added, and then the solution was allowed to react at about 80° C.˜about 85° C. for about 24 hours. The resultant reaction solution was treated with dilute aqueous hydrochloric acid and then extracted with chloroform. The obtained organic layer was distilled under reduced pressure, slightly washed with methanol, and dried, to thus prepare a thiophene-quinoxaline trimer, which was then reacted with NBS in a mixture of chloroform and acetic acid, thereby obtaining an orange solid thiophene-quinoxaline derivative (Yield: about 72%).

Workup

  1. additionwere added
  2. customto react at about 80° C.˜about 85° C. for about 24 hours
  3. customThe resultant reaction solution
  4. extractionextracted with chloroform
  5. distillationThe obtained organic layer was distilled under reduced pressure
  6. washslightly washed with methanol
  7. customdried
  8. customto thus prepare a thiophene-quinoxaline trimer, which

Sources & evidence

ORD record
ord-793b3adaf1164f6faff7df446a4baf72
Source dataset
uspto-grants-2013_01
Patent number
US08354666B2

Reaction notes

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