One-pot,three-component synthesis of 1-amidomethyl-imidazo[1,2-a]pyridines catalyzed by ytterbium triflate

A straightforward method has been developed for the synthesis of 1-amidomethyl-imidazo[1,2-a]pyridines by Yb(OTf)₃ catalyzed three-component reaction of aldehydes, acetamide, and imidazo[1,2-a]pyridines. A series of substituted 3-substituted imidazo[1,2-a]pyridines were synthesized in moderate to good yield (21–74%) under mild reaction condition and the catalyst was recycled for four cycles.     

Synthesis,characterization and microbiocidal studies of novel ionic liquid tagged Schiff bases

The synthesis of novel imidazolium ionic liquid, tagged Schiff, has been described. The synthesis was achieved in three steps from 2,4-dihydroxybenzaldehyde by selective alkylation with 1,3-dibromopropane, followed by reaction with 1-methylimidazole and Schiff base formation with aromatic amines. The compounds were evaluated for antibacterial and antifungal activities. The ionic liquid tagged Schiff base 4a showed the inhibition of both Gram positive and Gram negative bacteria. It also showed broad spectrum antifungal activity against all four tested fungi; however, 4f showed highest antifungal activity against A. niger.     

Synthesis of 3-aroylimidazo[1,2-a]pyridines via CuCl2 catalyzed tandem dual carbon–nitrogen bonding

A novel tandem approach has been demonstrated for the direct synthesis of bioactive 3-aroylimidazo[1,2-a]pyridines from chalcones and 2-aminopyridines. The reported tandem reaction is atom-economical and expected to proceed via 1,4-Michael addition followed by copper catalyzed oxidative C–N bonding. Catalytic amount of copper was found to be crucial for the success of tandem reaction and it altered the reaction pathway to furnish entirely new products. This protocol proved to be convenient as reaction proceeds smoothly without the necessity of any ligand in the presence of air as oxidant.     

Microwave assisted copper triflate-catalyzed rapid hydration of aryl acetylenes

An efficient microwave-assisted copper triflate-catalyzed reaction for the hydration of terminal aryl acetylenes to prepare substituted acetophenones has been developed. Significantly shorter reaction time, low catalyst loading, and wide range of functional group tolerance are salient features of this methodology.