Phosphorus oxybromide → 2-Bromo-7-(1-ethylpropyl)-1-methyl-1H-benzimidazole

HRID 1665222Notes

Reaction equation

HRID 1665222 reaction equation
[CH2:1]([CH:3]([C:6]1[C:11]2[N:12]([CH3:16])[C:13](=O)[NH:14][C:10]=2[CH:9]=[CH:8][CH:7]=1)[CH2:4][CH3:5])[CH3:2].P(Br)(Br)([Br:19])=O>C1(C)C=CC=CC=1>[Br:19][C:13]1[N:12]([CH3:16])[C:11]2[C:6]([CH:3]([CH2:4][CH3:5])[CH2:1][CH3:2])=[CH:7][CH:8]=[CH:9][C:10]=2[N:14]=1

Participants

4

Reactant 2

HCID 24613Phosphorus oxybromideHCID 672726137-(1-Ethylpropyl)-1-methyl-1,3-dihydro-2H-benzimidazol-2-one

Product 1

HCID 592020912-Bromo-7-(1-ethylpropyl)-1-methyl-1H-benzimidazoleYield 11.1%

Reagents, catalysts & solvents 1

HCID 1140TolueneSolvent

Procedure

A mixture of 7-(1-ethylpropyl)-1-methyl-1,3-dihydro-2H-benzimidazol-2-one (2.10 g, 10.0 mmol), phosphoric tribromide (5.73 g, 20.0 mmol) and toluene (10 mL) was heated under reflux for 16 hr. The reaction mixture was concentrated in vacuo. The residue was dissolved in saturated sodium hydrogen carbonate solution and ethyl acetate, and extracted. The organics were dried over anhydrous magnesium sulfate, filtered, and concentrated in vacuo. The residue was purified by silica gel column chromatography eluting with a 10-50% ethyl acetate/n-hexane gradient mixture to give the title compound (312 mg, 1.11 mmol, 11%) as colorless oil.

Workup

  1. temperaturewas heated
  2. temperatureunder reflux for 16 hr
  3. concentrationThe reaction mixture was concentrated in vacuo
  4. dissolutionThe residue was dissolved in saturated sodium hydrogen carbonate solution
  5. extractionethyl acetate, and extracted
  6. dry with materialThe organics were dried over anhydrous magnesium sulfate
  7. filtrationfiltered
  8. concentrationconcentrated in vacuo
  9. customThe residue was purified by silica gel column chromatography
  10. washeluting with a 10-50% ethyl acetate/n-hexane gradient mixture

Sources & evidence

ORD record
ord-3b04253d347d4b26831f8578a25edaef
Source dataset
uspto-grants-2011_10
Patent number
US08039500B2

Reaction notes

Loading…