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

HRID 1600798Notes

Reaction equation

HRID 1600798 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 (3×200 mL) . 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 (3×200 mL)
  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-e509a73d9ff640d4a11e1d26c57aad65
Source dataset
uspto-grants-1999_11
Patent number
US05977118

Reaction notes

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