5-Nitrobenzimidazole → HCID 178437240, compound

HRID 2299120Notes

Reaction equation

HRID 2299120 reaction equation
[N+:1]([C:4]1[CH:12]=[CH:11][C:7]2[N:8]=[CH:9][NH:10][C:6]=2[CH:5]=1)([O-:3])=[O:2].[CH3:13][CH2:14][Mg+].[Br-].ClC1C(=O)C(Cl)=C(Cl)C(=O)C=1Cl.CCOC(C)=O>C1COCC1>[CH2:13]([C:5]1[C:6]2[NH:10][CH:9]=[N:8][C:7]=2[CH:11]=[CH:12][C:4]=1[N+:1]([O-:3])=[O:2])[CH3:14]

Participants

6

Reactant 4

HCID 71955-NitrobenzimidazoleHCID 8371ChloranilHCID 8857Ethyl AcetateHCID 178461630HCID 178461630, compound

Product 1

HCID 178437240HCID 178437240, compoundYield 52.4%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent2×

Conditions

Temperature
-15 °C

Procedure

To a solution of 5-nitro-benzimidazole (2.8 g, 17 mmol) in THF was added 16 ml of EtMgBr solution (48 mmol) and reaction mixture was stirred for 2 h at −15° C. A solution of tetrachloro-1,4-benzoquinone (8.8 g, 36 mmol) in THF was added dropwise into reaction mixture, which was allowed to warm up to 25° C. over 1 h. Silica gel(20 g) was added into reaction mixture and solvent was removed in vacuo to provide a brown silica gel powder which was subjected to column chromatography (EtOAc, meat) to provide 1.7 g (8.9 mmol, 52%) of 4-ethyl-5-nitrobenzimidazole, which was subsequently subjected to hydrogenation (H2, Pd/c) to yield 1.32 g (8.2 mmol) of 4-ethyl-5-aminobenzimidazole.

Workup

  1. temperatureto warm up to 25° C. over 1 h
  2. additionSilica gel(20 g) was added into reaction mixture and solvent
  3. customwas removed in vacuo
  4. customto provide a brown silica gel powder which

Sources & evidence

ORD record
ord-b4514eec7c3a4d74af8510f05599d39c
Source dataset
uspto-grants-2002_12
Patent number
US06495583B1

Reaction notes

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