Hydroxyapatite supported copper catalyst for effective three-component coupling

W/HAP catalysed N-oxidation of tertiary amines with H2O2 as an oxidant

Synthesis of several N-oxides with tungsten exchanged hydroxyapatite (W/HAP) in the presence of 30% hydrogen peroxide (H₂O₂) as an oxidant is presented. A process with aqueous H₂O₂, a cheap and clean oxidant with an active catalyst is developed to reduce waste production and meet the requirements of green chemistry. Several tertiary amines have been efficiently oxidized to their corresponding N-oxides with excellent yields. The as-synthesized catalyst (W/HAP) is characterized using BET, FTIR, SEM, ICP-OES and XRD. Effect of catalyst loading , temperature and oxidants were studied. A kinetic model has been developed to determine the reaction rate at different temperatures and activation energy for the model reaction.

A decennary update on applications of metal nanoparticles (MNPs) in the synthesis of nitrogen- and oxygen-containing heterocyclic scaffolds

Heterocycles have been found to be of much importance as several nitrogen- and oxygen-containing heterocycle compounds exist amongst the various USFDA-approved drugs. Because of the advancement of nanotechnology, nanocatalysis has found abundant applications in the synthesis of heterocyclic compounds. Numerous nanoparticles (NPs) have been utilized for several organic transformations, which led us to make dedicated efforts for the complete coverage of applications of metal nanoparticles (MNPs) in the synthesis of heterocyclic scaffolds reported from 2010 to 2019. Our emphasize during the coverage of catalyzed reactions of the various MNPs such as Ag, Au, Co, Cu, Fe, Ni, Pd, Pt, Rh, Ru, Si, Ti, and Zn has not only been on nanoparticles catalyzed synthetic transformations for the synthesis of heterocyclic scaffolds, but also provide an inherent framework for the reader to select a suitable catalytic system of interest for the synthesis of desired heterocyclic scaffold.

Shedding light on the use of Cu(ii)-salen complexes in the A3 coupling reaction

One Cu(ii) complex, {Cu(ii)L} (1S), has been synthesised, in two high yielding steps under ambient conditions, and characterised by single-crystal X-Ray diffraction (SXRD), IR, UV-Vis, circular dichroism (CD), elemental analysis, thermogravimetric analysis (TGA) and electron spray ionization mass spectroscopy (ESI-MS). This air-stable compound enables the generation, at room temperature and in open-air, of twenty propargylamines, nine new, from secondary amines, aliphatic aldehydes and alkynes with a broad scope with yields up to 99%. Catalyst loadings can be as low as 1 mol%, while the recovered material retains its structural integrity and can be used up to 5 times without loss of its activity. Control experiments, SXRD, cyclic voltammetry and theoretical studies shed light on the mechanism revealing that the key to success is the use of phenoxido salen based ligands. These ligands orchestrate topological control permitting alkyne binding with concomitant activation of the C-H bond and simultaneously acting as a template temporarily accommodating the abstracted acetylenic proton, and continuously generating, via in situ formed radicals and a Single Electron Transfer (SET) mechanism, a transient Cu(i) active site to facilitate this transformation. The scope and limitations of this protocol are discussed and presented.

Two inorganic–organic hybrid silver-polyoxometalates as reusable catalysts for one-pot synthesis of propargylamines via a three-component coupling reaction at room temperature

Two silver-polyoxometalates [Ag₃L₂(DMSO)₂][PW₁₂O₄₀]·4DMSO (1) and [(Ag₂L₂)₂][SiW₁₂O₄₀]·10DMSO·2H₂O (2) are made and 1 shows good catalytic activities for three-component coupling reaction.

Green synthesis of Au nanoparticles using an aqueous extract ofStachys lavandulifoliaand their catalytic performance for alkyne/aldehyde/amine A3coupling reactions

High reaction rate and easy availability make green synthesis of metal nanoparticles noticeable.

Post-synthetically modified MOF for the A3-coupling reaction of aldehyde, amine, and alkyne

A new heterogeneous NHC catalyst (Ag-NHC-MOF) was synthesized by the post-synthetic modification of an azolium-containing metal–organic framework.

Magnetically recoverable graphene-based nanocomposite material as an efficient catalyst for the synthesis of propargylamines via A3 coupling reaction

The magnetically separable Au NPs–Fe₃O₄–rGO catalyst provides a robust and efficient route for the A³ coupling reaction of secondary amines, terminal alkynes and aldehyde with tolerance of diverse functional groups for the synthesis of propargylamine in high yields.

Zn(ii) anchored onto the magnetic natural hydroxyapatite (ZnII/HAP/Fe3O4): as a novel, green and recyclable catalyst for A3-coupling reaction towards propargylamine synthesis under solvent-free conditions

In this paper, Zn(ii) anchored onto the magnetic natural hydroxyapatite (Zn^II/HAP/Fe₃O₄), as a new and magnetically recoverable catalyst, was prepared and characterized using different techniques such as FT-IR, XRD, TGA, TEM, EDX, VSM and ICP.

Copper(ii) carboxymethylcellulose (CMC-CuII) as an efficient catalyst for aldehyde–alkyne–amine coupling under solvent-free conditions

A novel heterogeneous Cu(ii) carboxymethylcellulose catalyst was prepared and successfully employed in the A3 coupling without using any co-catalyst, other additives, bases under solvent-free conditions.

Preparation of Au nanoparticles by Anthemis xylopoda flowers aqueous extract and their application for alkyne/aldehyde/amine A3-type coupling reactions

This paper reports on the green synthesis of gold nanoparticles (Au NPs) by Anthemis xylopoda flowers aqueous extract without the addition of surfactant agents and their application as stable catalysts for the synthesis of propargylamines.

Manganese(ii) chloride catalyzed highly efficient one-pot synthesis of propargylamines and fused triazoles via three-component coupling reaction under solvent-free condition

A one-pot green and highly efficient method for the synthesis of propargylamines and distereoselective synthesis of fused triazoles via three-component coupling in the presence of manganese(ii) chloride and a catalyst-free 1,3-dipolar cycloaddition reaction without using a co-catalyst is reported.

Copper modified spherical MCM-41 nano particles: an efficient catalyst for the three-component coupling of aldehydes, amines and alkynes in solvent-free conditions

Cu-MCM-41 nano particles have been shown to effectively catalyze the multi-component synthesis of propargylamines by the reaction of aldehydes, amines, and alkynes (A³ coupling) effectively at 100 °C under solvent-free conditions.