Reaction #1528384

Reaction equation

benzimidazole

potassium hydroxide

α,α′-dibromo-m-xylene

→

1-[3-(1H-benzimidazole-1yl-methyl)benzyl]-1H-benzimidazole

Yield 18.8%

Solvents

acetone

Conditions

Workup

1. 1
   OtherTo a 1 L round bottom flask equipped with a stirbar
2. 2
   Temperatureat reflux
3. 3
   Temperatureat reflux for 6 hours
4. 4
   Otherfollowed by room temperature
5. 5
   workup.STIRRINGstirring for 72 hours
6. 6
   FiltrationThe cloudy solution was filtered
7. 7
   Washthe white solids rinsed with acetone
8. 8
   OtherThe resulting filtrate was dried on silica
9. 9
   Otherpartitioned on a silica gel column
10. 10
    OtherThe product fractions were evaporated of solvent

Procedure

To a 1 L round bottom flask equipped with a stirbar was added 26.8 g benzimidazole (227 mmol) and 12.7 g (227 mmol) finely pulverized potassium hydroxide. These were stirred in 500 mL acetone for 20 minutes at reflux. 20.0 g (78.5 mmol) α,α′-dibromo-m-xylene was then added, and the solution was stirred at reflux for 6 hours followed by room temperature stirring for 72 hours. The cloudy solution was filtered, and the white solids rinsed with acetone. The resulting filtrate was dried on silica and partitioned on a silica gel column using a gradient of 100% acetonitrile→90% acetronitrile/10% MeOH as eluent. The product fractions were evaporated of solvent to give 5 g 1-[3-(1H-benzimidazole-1yl-methyl)benzyl]-1H-benzimidazole as a white solid.

Source