2,6-Dichlorobenzaldehyde → 2-(2,6-Dichloro-phenyl)-3H-benzoimidazole-5-carboxylic acid

HRID 1514854Notes

Reaction equation

HRID 1514854 reaction equation
C([O:3][C:4](=[O:13])[C:5]1[CH:10]=[CH:9][C:8]([NH2:11])=[C:7]([NH2:12])[CH:6]=1)C.[Cl:14][C:15]1[CH:22]=[CH:21][CH:20]=[C:19]([Cl:23])[C:16]=1[CH:17]=O.[NH4+].[OH-]>CS(C)=O.C(S([O-])(=O)=O)(F)(F)F.C(S([O-])(=O)=O)(F)(F)F.C(S([O-])(=O)=O)(F)(F)F.[Sc+3].C(S([O-])(=O)=O)(F)(F)F.C(S([O-])(=O)=O)(F)(F)F.[Cu+2]>[Cl:14][C:15]1[CH:22]=[CH:21][CH:20]=[C:19]([Cl:23])[C:16]=1[C:17]1[NH:12][C:7]2[CH:6]=[C:5]([C:4]([OH:3])=[O:13])[CH:10]=[CH:9][C:8]=2[N:11]=1

Participants

7

Reactant 3

HCID 67372,6-DichlorobenzaldehydeHCID 14923Ammonium HydroxideHCID 458855Ethyl 3,4-Diaminobenzoate

Product 1

HCID 433492922-(2,6-Dichloro-phenyl)-3H-benzoimidazole-5-carboxylic acid

Reagents, catalysts & solvents 3

HCID 2734571Scandium(III) triflateCatalystHCID 2734996copper(II) trifluoromethanesulfonateCatalystHCID 679Dimethyl SulfoxideSolvent

Procedure

To a solution of 3,4-diamino-benzoic acid ethyl ester (0.9 g) and 2,6-dichlorobenzaldehyde (1.2 g) in DMSO (20 mL) was added Sc(OTf)3 (0.1 g) and Cu(OTf)2 (0.07 g). The mixture was stirred in an open flask at ambient temperature overnight, before it was poured into aqueous NH4OH. Resulting precipitate was collected by filtration and the wet solid was dissolved in MeOH (20 mL). To it was added 1N NaOH (12 mL) and the mixture was heated to reflux overnight, when it was cooled to ambient temperature, diluted by water, and washed with ether. The aqueous phase was then carefully acidified to pH 3-4 and resulting precipitate was filtered and air dried to give crude 2-(2,6-dichloro-phenyl)-3H-benzoimidazole-5-carboxylic acid as tan solid: 1H NMR (400 MHz, CD3OD) 8.4 (br s, 1H), 8.0 (d, 1H), 7.7 (s, 1H), 7.6 (m, 3H).

Workup

  1. customResulting precipitate
  2. filtrationwas collected by filtration
  3. dissolutionthe wet solid was dissolved in MeOH (20 mL)
  4. additionTo it was added 1N NaOH (12 mL)
  5. temperaturethe mixture was heated
  6. temperatureto reflux overnight
  7. temperaturewhen it was cooled to ambient temperature
  8. additiondiluted by water
  9. washwashed with ether
  10. customresulting precipitate
  11. filtrationwas filtered
  12. customair dried

Sources & evidence

ORD record
ord-abfd0a2424cd42e1bcf88f39f7d84649
Source dataset
uspto-grants-2012_07
Patent number
US08222248B2

Reaction notes

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