Facile synthesis of ZnAl₂O₄nanoparticles: efficient and reusable porous nano ZnAl₂O₄and copper supported on ZnAl₂O₄catalysts for one pot green synthesis of propargylamines and imidazo[1,2-a]pyridines by A³coupling reactions

Abstract

A simple, facile and efficient route was developed for the synthesis of nano ZnAl2O4using ethanolamine.

Tunable Prussian blue analogues for the selective synthesis of propargylamines through A3 coupling

“…The TOF obtained with the Cu-Co PBA was two orders of magnitude higher than the one obtained with Zn-Co PBA for the hydration of phenylacetylene. Contrary to previous reports 13,39 claiming that the formation of the iminium ion between the aldehyde and the amine occurs almost spontaneously above 353 K, our results show that a specific site -Zn 2+ in this case is needed for this reaction to occur considerably. Without Zn, the rapid activation of phenylacetylene (on Cu sites) yields considerable amounts of acetophenone, whereas without Cu in the structure, this activation takes place too slowly and the coupling of phenylacetylene, piperidine and benzaldehyde does not occur substantially.…”

A Review on Recent Advances in the Application of Nanocatalysts in A3 Coupling Reactions

“…The excellent catalytic ability of the nano porous ZnAl 2 O 4 with large surface area for the one‐pot synthesis of propargylamines via A 3 coupling of different aromatic aldehydes, piperidine and phenyl acetylene (Scheme ) was demonstrated by Sathiyanarayanan and co‐workers in 2016 . The porous nano ZnAl 2 O 4 was prepared by ethanolamine as complexing and precipitating agent between zinc nitrate and aluminium nitrate under calcinations.…”

“…It is important to stress that despite huge advancements of the reported works in the literature, another important challenges in the A 3 coupling reactions is nature of solvent and kind of the catalyst. A number of nanocatalysts, including copper, silver, gold, nickel, magnetic nanocatalysts and Co 3 O 4 , ZnS and nanopowder zinc titanate were successfully applied for A 3 coupling reactions with yields ranging from good to excellent in appropriate times in organic solvents or aqueous medium . The authors ascribed high catalytic activity of nanocatalysts to the particles size.…”

Indium-based metal–organic frameworks as catalysts: synthesis of 2-nitro-3-arylimidazo[1,2-a]pyridines via oxidative amination under air using MIL-68(In) as an effective heterogeneous catalyst

“…14 Radical reduction through single electron transfer (SET) subsequently occurred in the presence of the indium catalyst to form intermediate (2). 39 Next, radical dehydrogenation of (2) proceeded to generate (3), which was further oxidized to afford the radial cation (5) through the formation of cyclic (4). 40 Another single electron transfer from (5) generated the indium catalyst to the catalytic cycle and provided the desired product.…”

“…Imidazo [1,2-a]pyridines are a prominent collection of biologically active nitrogen-containing heterocycles that exhibit universal applications in medicinal chemistry, agro chemistry, and materials science. [1][2][3][4][5][6] A variety of synthetic strategies, including multicomponent condensation, oxidative coupling, and tandem reaction protocols, have been developed to produce imidazo [1,2-a]pyridine derivatives with numerous substituents at the 2 and 3-positions of this moiety. [7][8][9] Gryko et al reported a productive path to a wide range of imidazo [1,2-a]pyridines via the condensation of acetophenones with 2-aminopyridines.…”