Highly efficient, one-pot, solvent-free synthesis of 2,4,6-triarylpyridines using a Brønsted-acidic ionic liquid as reusable catalyst

Convenient one-pot synthesis of 1,2,4-oxadiazoles and 2,4,6-triarylpyridines using graphene oxide (GO) as a metal-free catalyst: importance of dual catalytic activity

A convenient and efficient process for the synthesis of 3,5-disubstituted 1,2,4-oxadiazoles and 2,4,6-triarylpyridines has been described using an inexpensive, environmentally benign, metal-free heterogeneous carbocatalyst, graphene oxide (GO). GO plays a dual role of an oxidizing agent and solid acid catalyst for synthesizing 1,2,4-oxadiazoles and triarylpyridines. This dual catalytic activity of GO is due to the presence of oxygenated functional groups which are distributed on the nanosheets of graphene oxide. A broad scope of substrate applicability and good sustainability is offered in this developed protocol. The results of a few control experiments reveal a plausible mechanism and the role of GO as a catalyst was confirmed by FTIR, XRD, SEM, and HR-TEM analysis.

One-Pot Synthesis of 1,5-Diketones under a Transition-Metal-Free Condition: Application in the Synthesis of 2,4,6-Triaryl Pyridine Derivatives

We developed a facile and green one-pot synthetic method for substituted 1,3,5-triaryl-1,5-diketones by Claisen-Schmidt condensation following Michael addition reaction of aryl ketones and aryl aldehydes under a transition-metal-free condition. This convenient one-pot synthetic strategy has several advantages, including being transition-metal-free, having no extra additives or reagents, having a broad substrate scope, having a high isolated yield, having a minimum amount of base employment, having a shorter reaction time, use of cheap starting materials, cost-effectiveness, and being environment friendly. Some of the chemical structures of 1,5-diketones were confirmed by X-ray single-crystal diffraction analysis. The application of 1,5-diketones was demonstrated in the preparation of 2,4,6-triaryl pyridine derivatives under a catalyst-free system using ammonium acetate as a nitrogen source.

Retracted Article: An efficient one pot three-component synthesis of 2,4,6-triarylpyridines using triflimide as a metal-free catalyst under solvent-free conditions

A simple and efficient protocol developed for one pot three-component synthesis of 2,4,6-triarylpyridines from aromatic aldehydes, substituted acetophenones and ammonium acetate using the versatile super Brønsted acid triflimide (HNTf₂) as an effective catalyst is described. The reactions proceed well in the presence of 1 mol% of HNTf₂ at 80 °C under solvent-free conditions and provide the corresponding triarylpyridines in good to excellent yields. The method reported has several advantages such as a metal-free and commercially available catalyst, mild reaction conditions and lower loading of catalyst.

A simple and efficient protocol developed for one pot three-component synthesis of 2,4,6-triarylpyridines from aromatic aldehydes, substituted acetophenones and ammonium acetate using triflimide (HNTf₂) as an effective catalyst is described.

L-Proline functionalized magnetic nanoparticles: A novel magnetically reusable nanocatalyst for one-pot synthesis of 2,4,6-triarylpyridines

In this work, an efficient method for the immobilization of L-proline on magnetic nanoparticles was offered and evaluated as a recoverable magnetic nanocatalyst for synthesis of 2,4,6-triarylpyridines through one-pot three-component reaction of acetophenone, aryl aldehydes and ammonium acetate. This article is the first report of the catalytic application of L-proline functionalized magnetic nanoparticles in organic reactions as a magnetic nanocatalyst. This novel magnetic nanocatalyst proved to be effective and provided the products in high to excellent yield under solvent-free conditions. The structure of obtained nanoparticles was characterized by Fourier transform infrared spectrophotometry (FT-IR), field-emission scanning electron microscopy (FE-SEM), thermogravimetric analysis (TGA) and energy-dispersive X-ray spectroscopy (EDX). TGA result revealed that it is stable up to 200 °C for using as a catalyst in organic reactions. FE-SEM image of the synthesized nanocatalyst showed that it has nearly core-shell spherical shape and uniform size distribution with an average size about 80 nm. Moreover, the catalyst could be easily recovered by facile separation by magnetic forces and recycled for several times without significant loss of its catalytic activity. The benefits of this study are simplicity, nontoxicity, low cost, simple workup, and an environmentally benign nature.

Synthesis and application of chitosan supported vanadium oxo in the synthesis of 1,4-dihydropyridines and 2,4,6-triarylpyridines via anomeric based oxidation

1,4-Dihydropyridines and 2,4,6-triarylpyridines were synthesized via anomeric based oxidation using chitosan supported vanadium oxo.

Two new pyrrolo[2,3-d]pyrimidines (7-deazapurines): ultrasonic-assisted synthesis, experimental and theoretical characterizations as well as antibacterial evaluation

Two new pyrrolo[2,3-d]pyrimidines (7-deazapurines) were synthesized in high yields by the reaction of 2-amino-1-methyl-4,5-diphenyl-1H-pyrrole-3-carbonitrile with triethyl orthoformate followed by cyclocondensation with methyl or benzyl amine in refluxing glacial acetic acid or using ultrasonic irradiation containing a catalytic amount of glacial acetic acid at 60°C. For each product, the correct structural isomer was identified using the FT-IR, 1H NMR, 13C NMR, 2D nuclear Overhauser effect spectroscopy spectral and microanalytical data together with comparison of the experimental and calculated chemical shifts at the B3LYP/6-31+G(d,p) level of theory. Furthermore, the synthesized compounds were evaluated for their antibacterial activity against Gram-positive bacteria (Staphylococcus aureus and Micrococcus luteus) and Gram-negative bacteria (Escherichia coli) by the agar dilution method using 24-well microtiter plates.

Ultrasonic synthesis, characterization, and antibacterial evaluation of novel heterocycles containing hexahydroquinoline and pyrrole moieties

Condensation reaction of dimedone with 2-amino-1-methyl-4,5-diphenyl-1

Magnetic MIL-101-SO3H: a highly efficient bifunctional nanocatalyst for the synthesis of 1,3,5-triarylbenzenes and 2,4,6-triaryl pyridines

A magnetic MIL-101-SO₃H was synthesized and successfully used as a highly active nanocatalyst for the synthesis of 1,3,5-triarylbenzenes and 2,4,6-triaryl pyridines.

A green one-pot three-component synthesis of tetrahydrobenzo[b]pyran and 3,4-dihydropyrano[c]chromene derivatives using a Fe3O4@SiO2–imid–PMAn magnetic nanocatalyst under ultrasonic irradiation or reflux conditions

Green synthesis of tetrahydrobenzo[b]pyran and dihydropyrano[3,2-c]chromene derivatives.

Solvent-free, one-pot synthesis of 2,4,6-triarylpyridines using trichloroisocyanuric acid or N-bromosuccinimide as a novel and neutral catalyst

A simple and benign protocol has been explored for the preparation of 2,4,6-triarylpyridines by a one-pot reaction between aryl aldehydes, enolizable ketones and ammonium acetate in the presence of N-bromosuccinimide or trichloroisocyanuric acid as green and neutral catalysts. The reactions proceed smoothly at 130 °C under solvent-free conditions to provide 2,4,6-triarylpyridines in good yields.