Eco-friendly synthesis of 3-aminoimidazo [1, 2-a] pyridines via a one-pot three-component reaction in PEG catalyzed by peptide nanofibers: as hydrogen-bonding organocatalyst

Abstract

Self-assembled peptide nanofibers have attracted extensive attention; they offer unique templating possibilities, which allow the synthesis of nanostructured materials with high surface areas, and also act as organocatalysts for various transformations in organic chemistry. In the present work, peptide nanofibers as hydrogen-bonding organocatalysts have been developed as efficient organocatalysts for three-component Groebke condensation reactions of aldehydes, isocyanides, and 2-aminopyridines in PEG to afford the corresponding 3-aminoimidazo [1, 2-a] pyridines in high yields without any additives. The key advantages of catalytic systems are (1) using peptide nanofibers as powerful hydrogen-bonding organocatalysts for the synthesis of 3-aminoimidazo [1, 2-a] pyridines, (2) having high catalytic activity, and (3) performing the reactions which can be carried out in PEG, as green solvent instead of the usually used organic solvents. This catalyst could be recycled and reused at least for four times without noteworthy loss of its activity.