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

Participants

Reaction Conditions

Reaction Steps

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+)].

Provenance & Evidence