C–N cross-coupling reaction catalysed by reusable CuCr₂O₄ nanoparticles under ligand-free conditions: a highly efficient synthesis of triarylamines

Abstract

A convenient, efficient and ligand-free method for the C-N coupling reaction of anilines and aryl iodides was performed using CuCr 2 O 4 nanoparticles. Copper chromite nanocatalyst improved rate and facility of the synthesis of triarylamines. The heterogeneous catalyst was fully characterized by scanning electron microscopy, IR and X-ray diffraction techniques. Recyclability, excellent yields of products and short reaction times are the important advantages of this ligand-free procedure by using the CuCr 2 O 4 nanoparticles.

An Efficient Buchwald–Hartwig/Reductive Cyclization for the Scaffold Diversification of Halogenated Phenazines: Potent Antibacterial Targeting, Biofilm Eradication, and Prodrug Exploration

“…One of the few synthetic methods known to regioselectively afford phenazine compounds is the reductive cyclization of 4-amino-2-nitrodiphenylamines under basic conditions using sodium borohydride. − This protocol has the potential to incorporate a multitude of commercially available anilines, nitrobenzenes, and aryl halides into the synthesis of the diarylamine intermediate via one of several well-described methods (e.g., Buchwald–Hartwig amination, Jourdan–Ullman coupling, nucleophilic aromatic substitution). − Thus, reductive cyclization was selected for the synthesis of halogenated phenazines to accommodate diverse substitution at the 6-, 7-, 8-, and 9-positions. We envisioned 1-methoxyphenazine intermediates could be obtained via reductive cyclization through two orientations of diarylamine intermediates: 2 and 3 (Figure B).…”

“…Our synthesis commenced with investigation into coupling conditions for the generation of diarylamine intermediates. A copper-catalyzed Ullmann coupling, although frequently used to couple anilines to aryl halides, yielded no desired product in the reaction between anilines and 2-bromo-1-methoxy-3-nitrobenzene ( 4 , Figure A). − With this shortcoming in mind, we then turned our attention toward a palladium-catalyzed Buchwald–Hartwig (BH) amination reaction as this chemistry has been very useful due to typical high yields and a broad substrate scope of coupling partners. , Initially, we attempted a BH cross-coupling between iodobenzene and 2-amino-1-methoxy-3-nitrobenzene ( 5 ) but observed no product formation (Figure B). We suspect this result is due to the electron-poor nature of the aniline coupling partner when positioned ortho to the nitro group on substrate 5 , although others have reported success with similar BH couplings using electron-poor anilines. , We also sought to design the synthesis such that a TBS-protected hydroxyphenazine could be generated from the reductive cyclization.…”

The Effect of Nitrogen on the Capacitive Properties of N-Doped rGO/CuCr₂O₄ Composites as Materials for Supercapacitors

“…The XRD pattern displayed similarities to that of graphite; however, it exhibited an amorphous structure characterized by low intensities and broadened peaks. The XRD peaks of CuCr2O4, marked with diamond symbols, indicate a tetragonal structure (JCPDS No 88-0110) [9]. Additionally, the XRD pattern reveals the presence of CuSO4.5H2O as an impurity (JCPDS No 01-072-2355) [10].…”

Recent advances in the application of nanocatalysts in C‐N coupling reactions

“…The use of copper chromite (CuCr 2 O 4 ) NPs, as a catalyst in the C‐N coupling reaction of aryl iodides and anilines, was described by Safaei‐Ghomi and co‐workers [ 147 ] in 2015 (Scheme 17). This nanocatalyst was synthesized by the coprecipitation method using and could improve the facility and rate of the preparation of triarylamines.…”