反应详情

Ethyl 1-(4-bromophenyl)-1H-imidazole-5-carboxylate (4) was constructed through the condensation of tosylmethyl isocyanide and hemi-aminal 3, which in turn was produced by the addition of 4-bromoaniline (2) to ethyl glyoxalate (1). Ester 4 was reduced with LiAlH4 at −40° C. and the resulting alcohol 5 oxidised with MnO2 to furnish 1-(4-bromophenyl)-1H-imidazole-5-carbaldehyde (6), which was condensed with ethyl azidoacetate to give the α,β-unsaturated ester 7. The pyrrolo[2,3-d]imidazole core 8 was then formed by thermal cyclisation of 7 in refluxing in p-xylene. Hydrolysis of 8 provided 1-(4-bromophenyl)-1,4-dihydropyrrolo[2,3-d]imidazole-5-carboxylic acid (9) which could be coupled with various amines, for example, with 2-methoxyethylamine to give amide 10.