1-[2-(Dimethylamino)ethyl]-1,3-dihydrobenzimidazol-2-one → 1,3-dihydro-1-(2-dimethylaminoethyl)-4,5,6-tribromo-2H-benzimidazol-2-one

HRID 373053Notes

Reaction equation

HRID 373053 reaction equation
[CH3:1][N:2]([CH3:15])[CH2:3][CH2:4][N:5]1[C:9]2[CH:10]=[CH:11][CH:12]=[CH:13][C:8]=2[NH:7][C:6]1=[O:14].[Br-:16].[Br-:17].[Br-:18].C([N+](C)(C)C)C1C=CC=CC=1.C([N+](C)(C)C)C1C=CC=CC=1.C([N+](C)(C)C)C1C=CC=CC=1>C(O)(=O)C.[Cl-].[Zn+2].[Cl-]>[CH3:1][N:2]([CH3:15])[CH2:3][CH2:4][N:5]1[C:9]2[CH:10]=[C:11]([Br:18])[C:12]([Br:17])=[C:13]([Br:16])[C:8]=2[NH:7][C:6]1=[O:14].[Br:16][C:12]1[C:11]([Br:17])=[CH:10][C:9]2[N:5]([CH2:4][CH2:3][N:2]([CH3:15])[CH3:1])[C:6](=[O:14])[NH:7][C:8]=2[CH:13]=1

Participants

6

Reactant 2

HCID 148946781-[2-(Dimethylamino)ethyl]-1,3-dihydrobenzimidazol-2-oneHCID 53442637Benzyltrimethylammoniumtribromide

Product 2

HCID 198113371,3-dihydro-1-(2-dimethylaminoethyl)-4,5,6-tribromo-2H-benzimidazol-2-oneHCID 198113505,6-dibromo-1,3-dihydro-1-(2-dimethylaminoethyl)-2H-benzimidazol-2-one

Reagents, catalysts & solvents 2

HCID 3007855ZincchlorideCatalystHCID 176Acetic AcidSolvent

Conditions

Temperature
70 °C

Procedure

To a solution of 1,3-dihydro-1-(2-dimethylaminoethyl)-2H-benzimidazol-2-one (0.63 g) in acetic acid (20 ml) were added zinc chloride (1.33 g) and benzyltrimethylammonium tribromide (2.64 g). The reaction mixture was stirred at 70° C. for 24 hours, after which the solvent was distilled off under reduced pressure. To the residue was added a saturated aqueous sodium hydrogen carbonate solution and the product was extracted with ethyl acetate. The organic layer was washed with saturated aqueous sodium chloride solution and dried over anhydrous sodium sulfate. The solvent was distilled off under reduced pressure and the residue was purified by silica gel chromatography (eluent: chloroform:methanol=15:1) to give 0.31 g of 1,3-dihydro-1-(2-dimethylaminoethyl)-4,5,6-tribromo-2H-benzimidazol-2-one (Compound C) and 0.45 g of 5,6-dibromo-1,3-dihydro-1-(2-dimethylaminoethyl)-2H-benzimidazol-2-one (Compound D).

Workup

  1. distillationafter which the solvent was distilled off under reduced pressure
  2. additionTo the residue was added a saturated aqueous sodium hydrogen carbonate solution
  3. extractionthe product was extracted with ethyl acetate
  4. washThe organic layer was washed with saturated aqueous sodium chloride solution
  5. dry with materialdried over anhydrous sodium sulfate
  6. distillationThe solvent was distilled off under reduced pressure
  7. customthe residue was purified by silica gel chromatography (eluent: chloroform:methanol=15:1)

Sources & evidence

ORD record
ord-eb133f6dad6b432785a950077caa1990
Source dataset
uspto-grants-1992_11
Patent number
US05162318

Reaction notes

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