Ligand-free copper-catalyzed O-arylation of nitroarenes with phenols

Transition-metal-catalyzed one-pot selenylation of electrophilic arylating agents using triphenyltin chloride/Se as a phenylselenating agent

Three novel and efficient protocols for the synthesis of phenyl aryl selenides through a three-component coupling reaction of triphenyltin chloride with aryl halides, phenolic esters or nitroarenes, and Se powder catalyzed by CuI or Cu(OAc)₂ in the presence of a base in PEG200 at 90-100 °C have been developed. Also, NiFe₂O₄ as a magnetically reusable nanocatalyst was applied in these reactions under similar reaction conditions. The present methods are superior to other currently available methods due to the use of triphenyltin chloride/Se as a phenylselenating agent and phenolic esters and nitroarenes as a coupling partner for C-Se-C bond formation for the first time, a green solvent and inexpensive and reusable catalysts, and avoidance of any toxic and expensive arylselenating reagents.

Synthesis and Electrochemistry of Novel Dumbbell-Shaped Bis-pyrazolino[60]fullerene Derivatives Formed Using Microwave Radiation

The design of covalently linked [60]fullerene dimers has gained increased attention, as the linked electron donors or acceptors are in close proximity to the surface of the C60, providing a valuable approach to novel molecular electronic devices. Herein, new compounds involving C60 dumbbells covalently connected by the π-conjugated system from azobenzene and diaryl ether linkers were synthesized following the bifunctional cycloaddition reactions to C60 using microwave radiation. The structural identity of the fullerene dimers has been determined using spectroscopic techniques including Fourier transform infrared (FT-IR), matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF), and NMR spectroscopy, and the photophysical and the electrochemical properties for the new dumbbells have been examined using UV-vis spectroscopy, fluorescence spectroscopy, cyclic voltammetry, and square wave voltammetry. Both new dimers show electronic interaction with the fullerene cage and higher electron affinity than the pristine C60.

Highly Efficient Heterogeneous Copper-Catalysed O-Arylation of Phenols by Nitroarenes Leading to Diaryl Ethers

The heterogeneous O-arylation of phenols by nitroarenes was achieved in DMF at 100 °C by using an MCM-41-immobilised bidentate nitrogen copper(II) complex [MCM-41-2N-Cu(OAc)2] as catalyst, yielding a variety of unsymmetrical diaryl ethers in good to excellent yields. This heterogeneous copper catalyst can be easily prepared by a simple procedure from commercially readily available and inexpensive reagents, recovered by filtration of the reaction solution and recycled at least seven times without significant loss of activity.

A Recyclable Cu-MOF-74 Catalyst for the Ligand-Free O-Arylation Reaction of 4-Nitrobenzaldehyde and Phenol

The activity and recyclability of Cu-MOF-74 as a catalyst was studied for the ligand-free C–O cross-coupling reaction of 4-nitrobenzaldehyde (NB) with phenol (Ph) to form 4-formyldiphenyl ether (FDE). Cu-MOF-74 is characterized by having unsaturated copper sites in a highly porous metal-organic framework. The influence of solvent, reaction temperature, NB/Ph ratio, catalyst concentration, and basic agent (type and concentration) were evaluated. High conversions were achieved at 120 °C, 5 mol % of catalyst, NB/Ph ratio of 1:2, DMF as solvent, and 1 equivalent of K₂CO₃ base. The activity of Cu-MOF-74 material was higher than other ligand-free copper catalytic systems tested in this study. This catalyst was easily separated and reused in five successive runs, achieving a remarkable performance without significant porous framework degradation. The leaching of copper species in the reaction medium was negligible. The O-arylation between NB and Ph took place only in the presence of Cu-MOF-74 material, being negligible without the solid catalyst. The catalytic advantages of using nanostructured Cu-MOF-74 catalyst were also proven.

Heterogeneous O-arylation of nitroarenes with substituted phenols over a copper immobilized mesoporous silica catalyst

Highly efficient heterogeneous mesoporous silica based Cu-catalyst has been designed forO-arylation of phenol using nitroarene to afford unsymmetrical diarylethers. It can be recycled up to 5 times without any significant loss of catalytic activity.

Chimeric derivatives of functionalized amino acids and α-aminoamides: compounds with anticonvulsant activity in seizure models and inhibitory actions on central, peripheral, and cardiac isoforms of voltage-gated sodium channels

Six novel 3″-substituted (R)-N-(phenoxybenzyl) 2-N-acetamido-3-methoxypropionamides were prepared and then assessed using whole-cell, patch-clamp electrophysiology for their anticonvulsant activities in animal seizure models and for their sodium channel activities. We found compounds with various substituents at the terminal aromatic ring that had excellent anticonvulsant activity. Of these compounds, (R)-N-4'-((3″-chloro)phenoxy)benzyl 2-N-acetamido-3-methoxypropionamide ((R)-5) and (R)-N-4'-((3″-trifluoromethoxy)phenoxy)benzyl 2-N-acetamido-3-methoxypropionamide ((R)-9) exhibited high protective indices (PI=TD50/ED50) comparable with many antiseizure drugs when tested in the maximal electroshock seizure test to mice (intraperitoneally) and rats (intraperitoneally, orally). Most compounds potently transitioned sodium channels to the slow-inactivated state when evaluated in rat embryonic cortical neurons. Treating HEK293 recombinant cells that expressed hNaV1.1, rNaV1.3, hNaV1.5, or hNaV1.7 with (R)-9 recapitulated the high levels of sodium channel slow inactivation.

O-Arylation with nitroarenes: metal-catalyzed and metal-free methodologies

Emergence of nitroarene as an alternative to aryl halides inO-arylation of arylboronic acid or phenols has been highlighted.

A family of ligand and anion dependent structurally diverse Cu(ii) Schiff-base complexes and their catalytic efficacy in an O-arylation reaction in ethanolic media

Catalytic O-arylation reactions have been studied by employing a variety of copper(ii) Schiff-base complexes under environmentally benign conditions.