Supported Metal Catalysts for the Synthesis of N-Heterocycles

Abstract

Nitrogen-containing heterocycles are important scaffolds for a large number of compounds with biological, pharmaceutical, industrial and optoelectronic applications. A wide range of different methodologies for the preparation of N-heterocycles are based on metal-catalyzed cyclization of suitable substrates. Due to the growing interest in Green Chemistry criteria over the past two decades, the use of supported metal catalysts in the preparation of N-heterocycles has become a central topic in Organic Chemistry. Here we will give a critical overview of all the solid supported metal catalysts applied in the synthesis of N-heterocycles, following a systematic approach as a function of the type of support: (i) metal catalysts supported on inorganic matrices; (ii) metal catalysts supported on organic matrices; (iii) metal catalysts supported on hybrid inorganic-organic matrices. In particular, we will try to emphasize the effective heterogeneity and recyclability of the described metal catalysts, specifying which studies were carried out in order to evaluate these aspects.

Plant mediated synthesis of flower-like Cu2O microbeads from Artimisia campestris L. extract for the catalyzed synthesis of 1,4-disubstituted 1,2,3-triazole derivatives

“…These include copper ( De Nino et al, 2021 ), silver ( Sultana and Sarma, 2020 ), zinc ( Daraie et al, 2020 ), ruthenium ( Sharma et al, 2018 ), iridium ( Wu et al, 2020 ), nickel ( Choudhury et al, 2021 ), and gold ( Librando et al, 2021 ) providing alternatives to traditional homogeneous catalysts. The employment of these catalysts allows for straightforward separation from the reaction solution via simple filtration, promoting their reusability ( Aronica and Albano, 2022 ). This approach addresses the limitations associated with catalyst separation, enhancing the sustainability and efficiency of 1,4-disubstituted 1,2,3-triazole synthesis processes.…”

One–Pot Three–Component Synthesis of 2,4,5–Triaryl Imidazoles using Fe3O4@BisImid−CuBr Nanocomposite as an Ecofriendly and Efficient Magnetically Reusable Catalyst

“…[23][24][25][26] Imidazole derivatives are a valuable class of nitrogen-containing heterocycles, whose synthesis and activities are always an attractive challenge among synthetic chemists. [27][28][29] Ketoconazole, miconazole and clotrimazole are imidazole derivatives and are widely used in the treatment of fungal infections. [30][31][32] Molecules containing imidazole ring are used to treat duodenal and gastric ulcers, gastroesophageal reflux disease, and associated symptoms such as heartburn and pain.…”

“…Heterocyclic compounds in particular nitrogen heterocycles are abundantly seen in the structure of various medicinal compounds for veterinary and herbal medicine [23–26] . Imidazole derivatives are a valuable class of nitrogen–containing heterocycles, whose synthesis and activities are always an attractive challenge among synthetic chemists [27–29] . Ketoconazole, miconazole and clotrimazole are imidazole derivatives and are widely used in the treatment of fungal infections [30–32] .…”

Palladium Supported on Bioinspired Materials as Catalysts for C–C Coupling Reactions

“…Transition metal-catalyzed synthesis is probably the most important approach to the formation of polyfunctionalyzed compounds [1]. Copper, nickel, ruthenium, rhodium, platinum and palladium are the most employed metals.…”