An efficient protocol for the synthesis of pyridines and hydroquinolones using IRMOF-3/GO/CuFe2O4 composite as a magnetically separable heterogeneous catalyst

This study reports a facile and cost-effective technique for preparing magnetic copper ferrite nanoparticles supported on IRMOF-3/GO [IRMOF-3/GO/CuFe₂O₄]. The synthesized IRMOF-3/GO/CuFe₂O₄ was characterized with IR, SEM, TGA, XRD, BET, EDX, VSM, and elemental mapping. The prepared catalyst revealed higher catalytic behavior in synthesizing heterocyclic compounds through a one-pot reaction between various aromatic aldehydes, diverse primary amines, malononitrile, and dimedone under ultrasound irradiations. Among the notable features of this technique are higher efficiency, easy recovery from the reaction mixture, removal of a heterogeneous catalyst, and uncomplicated route. In this catalytic system, the activity level was almost constant after various stages of reuse and recovery.

Eucalyptol, an All-Purpose Product

Eucalyptus plants have attracted the attention of researchers and environmentalists worldwide because they are a rapidly growing source of wood and a source of oil used for multiple purposes. The main and the most important oil component is 1,8-cineole (eucalyptol: 60–85%). This review summarizes the literature reported to date involving the use of 1,8-cineole for the treatment of disorders. Additionally, we describe our efforts in the use of eucalyptol as a solvent for the synthesis of O,S,N-heterocycles. Solvents used in chemistry are a fundamental element of the environmental performance of processes in corporate and academic laboratories. Their influence on costs, safety and health cannot be neglected. Green solvents such as bio-based systems hold considerable additional promise to reduce the environmental impact of organic chemistry. The first section outlines the process leading to our discovery of an unprecedented solvent and its validation in the first coupling reactions. This section continues with the description of its properties and characteristics and its reuse as reported in the various studies conducted. The second section highlights the use of eucalyptol in a series of coupling reactions (i.e., Suzuki–Miyaura, Sonogashira–Hagihara, Buchwald–Hartwig, Migita–Kosugi–Stille, Hiyama and cyanation) that form O,S,N-heterocycles. We describe the optimization process applied to reach the ideal conditions. We also show that eucalyptol can be a good alternative to build heterocycles that contain oxygen, sulfur and nitrogen. These studies allowed us to demonstrate the viability and potential that bio solvents can have in synthesis laboratories.

Metal-free multicomponent reactions: a benign access to monocyclic six-membered N-heterocycles

The advent of multicomponent reactions in the synthesis of heterocycles and their ever burgeoning applications in drug development, materials chemistry, and catalysis, have attracted a great deal of current scientific interest. In particular, the metal-free multicomponent synthesis of six membered N-heterocycles has undergone intensive research over the last two decades offering an environmentally benevolent means contrary to traditional metal catalysed reactions. To the best of our knowledge, there exists no exclusive review on the metal-free multicomponent synthesis of six membered N-heterocyles, and hence the present report highlights the progress on metal-free multicomponent reactions with their advantages and mechanistic insights to access monocyclic six-membered N-heterocycles including pyridine, pyrimidine, pyrazine, triazine and their hydrogenated derivatives. The literature is covered since 2000, and the contents offer not only striking methods for divergent synthesis of six-membered N-heterocycles but also put forward some new insights into the exploration of metal-free multicomponent chemistry.

Eucalyptol: A Bio-Based Solvent for the Synthesis of O,S,N-Heterocycles. Application to Hiyama Coupling, Cyanation, and Multicomponent Reactions

We report here the use of eucalyptol as a bio-based solvent for Hiyama coupling, cyanation, and multicomponent reactions on O,S,N-heterocycles. These heterocycles were chosen as targets or as starting materials given their biological potential; they play an important role in therapeutically active compounds. Once again, eucalyptol proved to be a credible and sustainable alternative to common solvents.

Multicomponent Reactions, Solvent-Free Synthesis of 2-Amino-4-aryl-6-substituted Pyridine-3,5-dicarbonitrile Derivatives, and Corrosion Inhibitors Evaluation

A number of 2-amino-4-aryl-6-substituted pyridine-3,5-dicarbonitrile derivatives were synthesized via one-pot multicomponent condensation reactions of different aromatic aldehydes with malononitrile and different primary amines, using different molecular ratios and different reaction conditions to achieve considerable product yields. Moreover, we succeed, for the first time to develop a new method to synthesize the aforementioned under the fusion condition without using solvent and catalysts. With this method, a wide range of novel 2-amino-3,5-dicyano-4-aryl-6-substituted aminopyridine derivatives were synthesized with high yields and board substrate of functional groups. The synthesized pyridine derivatives were found to have a corrosion inhibition efficiency, the rate of which increased with the increasing concentration of the derivatives. The structures of the new compounds were elucidated by spectroscopic data and elemental analyses.

[TEATNM] and [TEATCM] as novel catalysts for the synthesis of pyridine-3,5-dicarbonitriles via anomeric-based oxidation

The synthesis of 2-amino-4-aryl-6-(arylamino)pyridine-3,5-dicarbonitriles was carried out using [TEATNM] and [TEATCM] as catalysts via anomeric-based oxidation.

In-water facile synthesis of poly-substituted 6-arylamino pyridines and 2-pyrrolidone derivatives using tetragonal nano-ZrO2 as reusable catalyst

Green synthesis of functionalized 6-arylamino pyridines and 2-pyrrolidinone derivatives using tetragonal ZrO₂ nanoparticles as reusable catalyst in aqueous ethanol.

Beyond conventional routes, an unprecedented metal-free chemoselective synthesis of anthranilate esters via a multicomponent reaction (MCR) strategy

A hitherto unreported route for the synthesis of anthranilate esters is demonstrated using 2-nitrobenzaldehyde, malonitrile and an alcohol or amine via a metal and oxidant free multicomponent reaction (MCR) strategy.

Domino synthesis of functionalized 1,6-naphthyridines and their in vitro anti-inflammatory and anti-oxidant efficacies

One-pot and multicomponent reaction of ketones with malononitrile and pyrrolidine in ethanol affords 1,6-naphthyridines.