Methanol → 2-(2,4-dichloro-phenyl)-7-hydroxy-1H-benzoimidazole-4-carboxylic acid methyl ester

HRID 349479Notes

Reaction equation

HRID 349479 reaction equation
[Cl:1][C:2]1[CH:7]=[C:6]([Cl:8])[CH:5]=[CH:4][C:3]=1[C:9]1[NH:13][C:12]2[C:14]([OH:21])=[CH:15][CH:16]=[C:17]([C:18]([OH:20])=[O:19])[C:11]=2[N:10]=1.OS(O)(=O)=O.[CH3:27]O>>[CH3:27][O:19][C:18]([C:17]1[C:11]2[N:10]=[C:9]([C:3]3[CH:4]=[CH:5][C:6]([Cl:8])=[CH:7][C:2]=3[Cl:1])[NH:13][C:12]=2[C:14]([OH:21])=[CH:15][CH:16]=1)=[O:20]

Participants

4

Reactant 3

HCID 887MethanolHCID 1118Sulfuric AcidHCID 691199912-(2,4-dichloro-phenyl)-7-hydroxy-1H-benzoimidazole-4-carboxylic acid

Product 1

HCID 691323632-(2,4-dichloro-phenyl)-7-hydroxy-1H-benzoimidazole-4-carboxylic acid methyl esterYield 86%

Procedure

2-(2,4-dichloro-phenyl)-7-hydroxy-1H-benzoimidazole-4-carboxylic acid (1.63 g, 5.03 mmol) obtained in step 3 was dissolved in 30 ml of methanol, and H2SO4 (1.08 ml, 20.12 mmol) was added dropwise thereto and refluxed for 15 hours. The resulting solution was cooled to room temperature, concentrated under a reduced pressure to remove methanol, and the residue was neutralized with NaHCO3. Then, the neutralized residue was extracted with ethyl acetate and concentrated under a reduced pressure to obtain a residue which was purified by recrystallization from ethyl acetate/hexane to obtain the title compound (1.5 g, 3.62 mmol) in a yield of 86%.

Workup

  1. temperaturerefluxed for 15 hours
  2. concentrationconcentrated under a reduced pressure
  3. customto remove methanol
  4. extractionThen, the neutralized residue was extracted with ethyl acetate
  5. concentrationconcentrated under a reduced pressure
  6. customto obtain a residue which
  7. customwas purified by recrystallization from ethyl acetate/hexane

Sources & evidence

ORD record
ord-ad024f9c305749b28f8666dd3a937210
Source dataset
uspto-grants-2007_02
Patent number
US07179832B2

Reaction notes

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