Quinone → 5,6-Dichloro-2-(4-formylphenyl)benzimidazole

HRID 1281120Notes

Reaction equation

HRID 1281120 reaction equation
CCO[CH:4]([O:13]CC)[C:5]1[CH:10]=[CH:9][C:8]([CH:11]=O)=[CH:7][CH:6]=1.[Cl:16][C:17]1[C:22]([Cl:23])=[CH:21][C:20]([NH2:24])=[C:19]([NH2:25])[CH:18]=1.C1(=O)C=CC(=O)C=C1>C(O)C>[Cl:16][C:17]1[C:22]([Cl:23])=[CH:21][C:20]2[N:24]=[C:11]([C:8]3[CH:7]=[CH:6][C:5]([CH:4]=[O:13])=[CH:10][CH:9]=3)[NH:25][C:19]=2[CH:18]=1

Participants

5

Reactant 3

HCID 4650QuinoneHCID 792974,5-Dichloro-1,2-phenylenediamineHCID 5959934-(Diethoxymethyl)benzaldehyde

Product 1

HCID 184267935,6-Dichloro-2-(4-formylphenyl)benzimidazoleYield 97%

Reagents, catalysts & solvents 1

HCID 702EthanolSolvent

Procedure

To a mixture of terephthalaldehyde mono-(diethyl acetal) (2.0 mL, 10 mmol), 4,5-dichloro-1,2-phenylenediamine (1.77 g, 10 mmol) and 1,4-benzoquinone (1.08 g, 10 mmol) in ethanol (50 mL) was heated to reflux for 6 h. The solvent was removed under reduced pressure. To the residue were added tetrahydrofuran (50 mL) and hydrochloric acid (1 mol/L, 10 mL), and the mixture was stirred at room temperature for 2 h. Water was added, and the mixture was extracted with ethyl acetate. The organic layer was washed with water and brine, and dried on anhydrous sodium sulfate. The solvent was removed under reduced pressure, and the residue was triturated with ether to afford 5,6-dichloro-2-(4-formylphenyl)benzimidazole (2.80 g, 97%).

Workup

  1. temperaturewas heated
  2. temperatureto reflux for 6 h
  3. customThe solvent was removed under reduced pressure
  4. additionTo the residue were added tetrahydrofuran (50 mL) and hydrochloric acid (1 mol/L, 10 mL)
  5. additionWater was added
  6. extractionthe mixture was extracted with ethyl acetate
  7. washThe organic layer was washed with water and brine
  8. dry with materialdried on anhydrous sodium sulfate
  9. customThe solvent was removed under reduced pressure
  10. customthe residue was triturated with ether

Sources & evidence

ORD record
ord-22cd26916360454f93852f42d36cb995
Source dataset
uspto-grants-2002_09
Patent number
US06452014B1

Reaction notes

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