A Multicomponent Approach for the Synthesis of Indeno-Pyrrolido-Pyrimidino-Azoles: Access to Structurally Diverse Pseudo-Natural Products

A sustainable, multicomponent strategy has been developed for the efficient synthesis of structurally diverse pseudonatural products (pNPs). Using acetic acid as a catalyst, we have synthesized three distinct pNP families: indeno-pyrrolido-pyrimidino-benzimidazole (IPPBi), indeno-pyrrolido-pyrimidino-triazoles (IPPTa), and indeno-pyrrolido-pyrimidino-tetrazoles (IPPTt). The mechanism involved the formation of acetyl indenopyrrole as a key intermediate, which enables the divergent product formation. Interestingly, the reaction proceeded efficiently under microwave irradiation (MW), resulting in an enhanced overall reaction efficiency. Broad substrate scope, operational simplicity, excellent yields, and column chromatography-free purification are advantageous features of this methodology.