Acetic Acid → 2-Benzyl-5-ethoxy-carbonylbenzimidazole

HRID 1699613Notes

Reaction equation

HRID 1699613 reaction equation
[N+:1]([C:4]1[C:5]([CH2:23]C)=[C:6]([CH:10]=[CH:11][C:12]=1[NH:13][C:14](=O)[CH2:15][C:16]1[CH:21]=[CH:20][CH:19]=[CH:18][CH:17]=1)C([O-])=O)([O-])=O.[CH2:25]([OH:27])[CH3:26].C(O)(=[O:30])C>[Fe]>[CH2:15]([C:14]1[N:1]=[C:4]2[C:5](=[C:23]=[O:30])[C:6]([O:27][CH2:25][CH3:26])=[CH:10][CH:11]=[C:12]2[N:13]=1)[C:16]1[CH:17]=[CH:18][CH:19]=[CH:20][CH:21]=1

Participants

5

Reactant 3

HCID 176Acetic AcidHCID 702EthanolHCID 701409133-Nitro-4-phenylacetylamino-ethylbenzoate

Product 1

HCID 867577922-Benzyl-5-ethoxy-carbonylbenzimidazole

Reagents, catalysts & solvents 1

HCID 23925IronCatalyst

Procedure

A mixture of 3-nitro-4-phenylacetylamino-ethylbenzoate (3.60 g), ethanol (47 ml), acetic acid (23 ml) and iron (6.4 g) is refluxed by heating for four hours. Solids are separated through filtration and the filtrate is concentrated. Ethanol (50 ml) and 35% hydrochloric acid (5 g) are added to the residue and the solution is stirred for 40 hours as it is refluxed by heating. The solution is neutralized with sodium bicarbonate and chloroform extraction is performed. The organic layer is concentrated under reduced pressure and then purified using silica gel column chromatography. Thus, 2-benzyl-5-ethoxy-carbonylbenzimidazole (2.30 g) is obtained. 1H-NMR (CDCl3, δ): 1.39 (3H, t, J =7.1Hz), 4.26 (2H, s), 4.37 (2H, q, J=7.1Hz), 7.22-7.36 (5H, m), 7.50 (1H, d, J=8.6Hz), 7.94 (1H, dd, J=1.5 and 8.6Hz), 8.23 (1H, d, J=1.3Hz).

Workup

  1. temperatureis refluxed
  2. temperatureby heating for four hours
  3. customSolids are separated through filtration
  4. concentrationthe filtrate is concentrated
  5. additionEthanol (50 ml) and 35% hydrochloric acid (5 g) are added to the residue
  6. temperatureis refluxed
  7. temperatureby heating
  8. extractionThe solution is neutralized with sodium bicarbonate and chloroform extraction
  9. concentrationThe organic layer is concentrated under reduced pressure
  10. custompurified

Sources & evidence

ORD record
ord-ea9a9c3c3b7c41199bf454ff5c2f2e6a
Source dataset
uspto-grants-2002_02
Patent number
US06348032B1

Reaction notes

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