3,4-Dichlorobenzeneboronic acid → 3-(3,4-dichloro-phenyl)-5-methyl-3H-imidazole-4-carboxylic acid ethyl ester

HRID 433577Notes

Reaction equation

HRID 433577 reaction equation
[Cl:1][C:2]1[CH:3]=[C:4](B(O)O)[CH:5]=[CH:6][C:7]=1[Cl:8].[CH3:12][C:13]1[N:14]=[CH:15][NH:16][C:17]=1[C:18]([O:20][CH2:21][CH3:22])=[O:19]>C(Cl)Cl.C([O-])(=O)C.[Cu+2].C([O-])(=O)C>[CH2:21]([O:20][C:18]([C:17]1[N:16]([C:4]2[CH:5]=[CH:6][C:7]([Cl:8])=[C:2]([Cl:1])[CH:3]=2)[CH:15]=[N:14][C:13]=1[CH3:12])=[O:19])[CH3:22].[CH2:21]([O:20][C:18]([C:17]1[N:16]=[CH:15][N:14]([C:4]2[CH:5]=[CH:6][C:7]([Cl:8])=[C:2]([Cl:1])[CH:3]=2)[C:13]=1[CH3:12])=[O:19])[CH3:22]

Participants

6

Reactant 2

HCID 27343303,4-Dichlorobenzeneboronic acidHCID 178470400HCID 178470400, compound

Product 2

HCID 690387013-(3,4-dichloro-phenyl)-5-methyl-3H-imidazole-4-carboxylic acid ethyl esterYield 22%HCID 690427491-(3,4-dichloro-phenyl)-5-methyl-1H-imidazole-4-carboxylic acid ethyl esterYield 8%

Reagents, catalysts & solvents 2

HCID 8895Cupric acetateCatalystHCID 6344DichloromethaneSolvent

Conditions

Temperature
20 °C

Procedure

A suspension of 3,4-dichlorophenylboronic acid (8.22 g, 43.1 mmol), ethyl 4-methyl-5-imidazolecarboxylate (6.64 g, 43.1 mmol) and copper(II) acetate (7.83 g, 43.1 mmol) in CH2Cl2 (86 ml) was stirred at 20° C. for 48 h. All solids were filtered, the organic phase diluted with AcOEt (500 ml) and stirred with saturated aqueous Seignette salt solution. After filtration and evaporation the residue was chromatographed (silica, eluation with gradient hexane to AcOEt) to obtain 2.8 g (22%) of 3-(3,4-dichloro-phenyl)-5-methyl-3H-imidazole-4-carboxylic acid ethyl ester [Mp. 135-136° C. (AcOEt/hexane), MS: m/e=298 (M+)] and 1.0 g (8%) of 1-(3,4-dichloro-phenyl)-5-methyl-1H-imidazole-4-carboxylic acid ethyl ester [Mp. 163-164° C. (AcOEt/hexane), MS: m/e=298 (M+)].

Workup

  1. filtrationAll solids were filtered
  2. additionthe organic phase diluted with AcOEt (500 ml)
  3. stirringstirred with saturated aqueous Seignette salt solution
  4. filtrationAfter filtration and evaporation the residue
  5. customwas chromatographed (silica, eluation with gradient hexane to AcOEt)

Sources & evidence

ORD record
ord-a8c2fd9325dc4943851c45a2248de602
Source dataset
uspto-grants-2003_12
Patent number
US06667335B2

Reaction notes

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