Multicomponent cascade reaction: dual role of copper in the synthesis of 1,2,3-triazole tethered benzimidazo[1,2-a]quinoline and their photophysical studies

Abstract

One-pot synthesis of 1,2,3-triazole tethered benzimidazo[1,2-a]quinolines through a multi-component reaction is demonstrated. Overall one C–C bond and three C–N bonds are formed in a single step.

Recent Progress of Cu-Catalyzed Azide-Alkyne Cycloaddition Reactions (CuAAC) in Sustainable Solvents: Glycerol, Deep Eutectic Solvents, and Aqueous Media

“…Apart from glycerol, other biosourced alcohol-type solvents like polyethylene glycol (PEG) have been employed in CuAAC reactions [36][37][38][39][40][41][42][43]. In this sense, PEG-400 has been used as environmentally friendly and inexpensive solvent thanks to its: (i) low toxicity; (ii) non-volatility; (iii) recyclability and biodegradability; (iv) thermal stability; and (v) commercial availability [44].…”

Copper‐Catalysed Multicomponent Syntheses of Heterocycles

“…An efficient and appealing synthetic route for 1,2,3‐triazole anchored benzimidazole[1,2‐ a ]quinolines via a one‐pot domino/cascade multicomponent reaction employing low loading of CuI catalyst and PEG‐400 as an environmentally benign solvent has been reported . The reaction proceeds via a click reaction, in which 1,2,3‐triazole motif being moderately electron‐withdrawing activates the adjacent methylene group to undergo Knoevenagel condensation forming the benzimidazole[1,2‐ a ]quinoline with the formation of one C−C bond and three C−N bonds in a single step.…”

Multicomponent Syntheses of Fluorophores Initiated by Metal Catalysis

“…1,2,3‐Triazoles are readily synthesized by regiospecific Cu I ‐catalyzed alkyne–azide cycloaddition (CuAAC), an approach that can also be conducted in a multicomponent fashion to open access to a multitude of diversity‐oriented syntheses . Chandra Sekhar and co‐workers used the reaction of benzimidazolyl methyl azides 37 , terminal alkynes 26 , and ortho ‐halo benzaldehydes 38 to prepare 1,2,3‐triazolyl‐substituted benzimidazo[1,2‐ a ]quinolines 39 (Scheme ) . The proposed mechanism for this domino three‐component reaction comprises CuAAC, copper‐catalyzed Ullmann‐type coupling, and Knoevenagel condensation for the final cyclization to furnish the benzimidazo[1,2‐ a ]quinolines 39 .…”