One-Pot, Two-Step Synthesis of Imidazo[1,2‑<i>a</i>]benzimidazoles via A Multicomponent [4 + 1] Cycloaddition Reaction

A one-pot,
two-step synthesis of imidazo­[1,2-a]­benzimidazoles
has been achieved by a three-component reaction of
2-aminobenzimidazoles with an aromatic aldehyde and an isocyanide.
The reaction involving condensation of 2-aminobenzimidazole with an
aldehyde is run under microwave activation to generate an imine intermediate
under basic conditions which then undergoes [4 + 1] cycloaddition
with an isocyanide.