One-Pot, Two-Step Synthesis of Imidazo[1,2‑a]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.本研究通过2-氨基苯并咪唑类化合物、芳香醛与异腈的三组分反应，成功实现了咪唑并[1,2-a]苯并咪唑（imidazo[1,2-a]benzimidazoles）的一锅两步法合成。该反应中，2-氨基苯并咪唑与醛的缩合步骤在碱性条件下通过微波活化进行，生成亚胺中间体；随后该亚胺中间体与异腈发生[4+1]环加成反应。