Diethyl Sulfate → 2-Bromo-1-ethyl-1H-benzo[d]imidazole

HRID 495264Notes

Reaction equation

HRID 495264 reaction equation
[Br:1][C:2]1[NH:6][C:5]2[CH:7]=[CH:8][CH:9]=[CH:10][C:4]=2[N:3]=1.[H-].[Na+].S(OCC)(O[CH2:17][CH3:18])(=O)=O>O1CCCC1>[Br:1][C:2]1[N:6]([CH2:17][CH3:18])[C:5]2[CH:7]=[CH:8][CH:9]=[CH:10][C:4]=2[N:3]=1

Participants

5

Reactant 3

HCID 6163Diethyl SulfateHCID 24758Sodium hydrideHCID 27762812-Bromobenzimidazole

Product 1

HCID 666281632-Bromo-1-ethyl-1H-benzo[d]imidazoleYield 91.9%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Procedure

To a flask were added 4 g 2-bromo-1H-benzimidazole and 60 ml tetrahydrofuran, and the mixture was cooled to 10 C. To this mixture was added 1.2 g of 60% sodium hydride in mineral oil in small portions, and after stirring at 10 C for ten minutes, 4.7 g of diethyl sulfate were added. The reaction mixture was heated to 40 C for several hours, then cooled to 22 C and quenched with 100 ml water. The product was extracted twice with 50 ml ethyl acetate and following removal of the solvent, the product was purified by silica gel chromatography using a gradient from 100% hexane to 25% ethyl acetate in hexane. An oil was obtained that crystallized on standing which was dried resulting in 4.2 g of a white solid.

Workup

  1. temperaturethe mixture was cooled to 10 C
  2. temperatureThe reaction mixture was heated to 40 C for several hours
  3. temperaturecooled to 22 C
  4. customquenched with 100 ml water
  5. extractionThe product was extracted twice with 50 ml ethyl acetate
  6. customremoval of the solvent
  7. customthe product was purified by silica gel chromatography
  8. customAn oil was obtained
  9. customthat crystallized on standing which
  10. customwas dried

Sources & evidence

ORD record
ord-4f73e2a575d34788ab986ce92e5942b7
Source dataset
uspto-grants-2009_05
Patent number
US07538931B2

Reaction notes

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