Benzimidazole → 1H-Benzimidazole-1-acetic acid, ethyl ester

HRID 2257027Notes

Reaction equation

HRID 2257027 reaction equation
[H-].[Na+].[N:3]1[C:7]2[CH:8]=[CH:9][CH:10]=[CH:11][C:6]=2[NH:5][CH:4]=1.Br[CH2:13][C:14]([O:16][CH2:17][CH3:18])=[O:15].[NH4+].[Cl-]>CN(C=O)C.O>[CH2:17]([O:16][C:14]([CH2:13][N:3]1[C:7]2[CH:8]=[CH:9][CH:10]=[CH:11][C:6]=2[N:5]=[CH:4]1)=[O:15])[CH3:18]

Participants

7

Reactant 4

HCID 5798BenzimidazoleHCID 7748Ethyl bromoacetateHCID 24758Sodium hydrideHCID 25517Ammonium Chloride

Product 1

HCID 1714171H-Benzimidazole-1-acetic acid, ethyl esterYield 39.2%

Reagents, catalysts & solvents 2

HCID 962WaterSolventHCID 6228DimethylformamideSolvent3×

Procedure

A suspension of 97% NaH (3.0 g, 0.12 mol) in DMF (100 mL) was stirred for 0.5 hours, then benzimidazole (11.8 g, 0.1 mol) in DMF (50 mL) was added over 30 minutes, followed by ethyl bromoacetate (20 g, 0.12 mol) in DMF (50 mL). The reaction mixture was stirred at room temperature overnight, NH4Cl was added, and the reaction mixture was stipped. Water was added to the residue, and it was extracted with CH2Cl2 (3×200mL). The organic layer was dried over MgSO4, filtered and concentrated in vacuo. The residue was treated with ethyl acetate, a white solid was collected by filtration and the filtrate was concentrated in vacuo and the residue was recrystallized from water to afford 8.0 g of 1-(ethoxycarbonylmethyl)benzimidazole, m.p. 63°-64° C.

Workup

  1. stirringThe reaction mixture was stirred at room temperature overnight
  2. extractionwas extracted with CH2Cl2 (3×200mL)
  3. dry with materialThe organic layer was dried over MgSO4
  4. filtrationfiltered
  5. concentrationconcentrated in vacuo
  6. additionThe residue was treated with ethyl acetate
  7. filtrationa white solid was collected by filtration
  8. concentrationthe filtrate was concentrated in vacuo
  9. customthe residue was recrystallized from water

Sources & evidence

ORD record
ord-e0ec565cc3ce419b8667138f167b2223
Source dataset
uspto-grants-1997_08
Patent number
US05656629

Reaction notes

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