Amberlyst A-15: A recyclable and reusable catalyst for the green synthesis of multi-substituted indolylimidazole derivatives

Title : Amberlyst A-15: A recyclable and reusable catalyst for the green synthesis of multi-substituted indolylimidazole derivatives

Abstract:

A simple, efficient, and environmentally benign protocol has been developed for the green synthesis of multi-substituted indolylimidazole derivatives by one-pot four components condensation of indole-3-carbaldehyde, benzil, ammonium acetate using Amberlyst A-15 as a recyclable and reusable heterogeneous catalyst under microwave irradiation. Amberlyst A-15, a strongly acidic sulfonated polymeric resin, efficiently promotes the multicomponent condensation reaction under mild reaction conditions, affording the desired multi-substituted indolylimidazole derivatives in good to excellent yields. The use of a solid acid catalyst offers several advantages, including easy handling, simple product isolation, reduced reaction time, eco-friendly, cost-effectiveness with the reusability of catalyst, and avoidance of corrosive homogeneous mineral acids.

Moreover, the catalyst can be readily separated from the reaction mixture by simple filtration and reused for subsequent reaction cycles with only a minor decrease in catalytic activity. The developed methodology demonstrates good functional-group tolerance and provides a convenient approach toward structurally diverse multi-substituted indolylimidazole derivatives. The recyclability of Amberlyst A-15, together with its operational simplicity and reduced waste generation, makes this protocol attractive from the perspective of green and sustainable organic synthesis. The imidazole and indole are the most noteworthy rings in heterocycles because these ring-containing natural and synthesized compounds have shown significant biological activities. Due to the presence of both indole and imidazole rings in the same the synthesized compound multi-substituted indolylimidazole, the biological and pharmacological importance of this multi-substituted indolylimidazole compound has been enhanced. The structures of synthesized compounds were characterized by FTIR, 1H NMR, and Mass spectrometric studies. These compounds' antibacterial and antifungal activities were screened and compared with the standard drug.

Keywords: Amberlyst-15, Benzil, Indolylimidazole, microwave irradiation, green synthesis, one-pot synthesis

Biography:

Dr. Narendra Nirwan is an accomplished Professor of Chemistry at S.P.C. Government College, Ajmer. He holds a Ph.D. from MDS University, Ajmer, specializing in the synthesis, characterization and biological activities of nitrogen-containing heterocyclic compounds. With 17 years of undergraduate teaching, 15 years of postgraduate teaching and 13 years of research experience, he has made significant contributions to chemistry education and research. His interests include green chemistry, heterocyclic synthesis, environmental chemistry and sustainable technologies. Dr. Nirwan has authored numerous research publications, edited books and written book chapters, reflecting his dedication to scientific research, education and environmental sustainability.