Diversely functionalized imidazole-4-carboxylates were synthesized by microwave-assisted 1,5-eletrocyclization of 1,2-diaza-1,3-diene-derived azavinyl azomethine ylides. 1,2-Diaza-1,3-dienes were treated with primary aliphatic or aromatic amines and subjected to microwave irradiation in the presence of aldehydes. 3-Alkyl- and 3-arylimidazole-4-carboxylates were prepared in good yields through a one-pot multicomponent procedure. Modulation of the substituents at C-2, N-3 and C-5 was possible, and 2-unsubstituted imidazoles were obtained when paraformaldehyde was used.
Keywords: Azomethine ylides; Electrocyclic reactions; Microwave chemistry; Multicomponent reactions; Nitrogen heterocycles.