A convenient method of accessing imidazole 2-halo derivatives is proposed, comprising O-acylation of imidazole N-oxide fluoroborate complexes with tosyl halogenides which further undergo cine-substitution of 3-tosyl group with a halogen anion. In conjunction with a previously proposed method of synthesizing N-oxides of 2-unsubstituted 1-arylimidazoles this method enables one to substantially expand the range of accessible compounds.

Considerable attention holds on the chemistry and application of heterocyclic N-oxides due to their advantages as building-blocks in organic synthesis and importance in biomedical research. On the other hand, in recent years the development of selective methods for constructing C

The reaction of 2-unsubstituted imidazole N-oxides with ethyl cyanoacetate and aromatic aldehydes leads to the formation of ethyl 2-cyano-2-(1,3-dihydro-2H-imidazole-2-ylidene)acetates. The reaction proceeds through an initial [3+2] cycloaddition, followed by cleavage of the cycloadduct and regeneration of the aldehyde, which essentially plays a catalytic role.

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