Transition Metal-Catalyzed Transformations of Chalcones

Chalcones are a class of naturally occurring flavonoid compounds associated to a variety of biological and pharmacological properties. Several reviews have been published describing the synthesis and biological properties of a vast array of analogues. However, overviews on the reactivity of chalcones has only been explored in a few accounts. To fill this gap, a systematic survey on the most recent developments in the transition metal-catalyzed transformation of chalcones was performed. The chemistry of copper, palladium, zinc, iron, manganese, nickel, ruthenium, cobalt, rhodium, iridium, silver, indium, gold, titanium, platinum, among others, as versatile catalysts will be highlighted, covering the literature from year 2000 to 2023, in more than 380 publications.

Exploration of chalcones and related heterocycle compounds as ligands of adenosine receptors: therapeutics development

Adenosine receptors (ARs) are ubiquitously distributed throughout the mammalian body where they are involved in an extensive list of physiological and pathological processes that scientists have only begun to decipher. Resultantly, AR agonists and antagonists have been the focus of multiple drug design and development programmes within the past few decades. Considered to be a privileged scaffold in medicinal chemistry, the chalcone framework has attracted a substantial amount of interest in this regard. Due to the potential liabilities associated with its structure, however, it has become necessary to explore other potentially promising compounds, such as heterocycles, which have successfully been obtained from chalcone precursors in the past. This review aims to summarise the emerging therapeutic importance of adenosine receptors and their ligands, especially in the central nervous system (CNS), while highlighting chalcone and heterocyclic derivatives as promising AR ligand lead compounds.

Synthesis, characterization and application of copper oxide chitosan nanocomposite for green regioselective synthesis of [1,2,3]triazoles

Chitosan copper (II) oxide nanocomposite was synthesized, characterized and used to synthesize [1,2,3]triazoles. Nanocomposite was characterized by using FTIR, XRD, FESEM, and EDS techniques, which reflected rough morphology. The powerful catalytic activity of hybrid nanocomposite was utilized to synthesize chalcones (3a-p) in relatively high yields (82%-98%) and multicomponent regio-selective cycloaddition of chalones, aryl halides (4), and sodium azide to afford the expected N-2-aryl[1,2,3]triazoles (5a-h) (80%-95% yield) rather than N-1-aryl[1,2,3]-triazoles (6a-h). The performance of nanomaterial was optimized by several variables. The capability of the nanocomposite was compared with previous work and the nanocomposite was found more efficient, economic and reproducible. The hybrid nanocomposite could be easily isolated form the reaction mixture and recycled four times without any significant loss of its catalytic activity. The reported catalyst is an inexpensive for good yields of the triazoles and may be used at industrial production for the reported compounds.

The recent development of efficient Earth-abundant transition-metal nanocatalysts

Whereas noble metal compounds have long been central in catalysis, Earth-abundant metal-based catalysts have in the same time remained undeveloped. Yet the efficacy of Earth-abundant metal catalysts was already shown at the very beginning of the 20th century with the Fe-catalyzed Haber-Bosch process of ammonia synthesis and later in the Fischer-Tropsch reaction. Nanoscience has revolutionized the world of catalysis since it was observed that very small Au nanoparticles (NPs) and other noble metal NPs are extraordinarily efficient. Therefore the development of Earth-abundant metals NPs is more recent, but it has appeared necessary due to their "greenness". This review highlights catalysis by NPs of Earth-abundant transition metals that include Mn, Fe, Co, Ni, Cu, early transition metals (Ti, V, Cr, Zr, Nb and W) and their nanocomposites with emphasis on basic principles and literature reported during the last 5 years. A very large spectrum of catalytic reactions has been successfully disclosed, and catalysis has been examined for each metal starting with zero-valent metal NPs followed by oxides and other nanocomposites. The last section highlights the catalytic activities of bi- and trimetallic NPs. Indeed this later family is very promising and simultaneously benefits from increased stability, efficiency and selectivity, compared to monometallic NPs, due to synergistic substrate activation.

Total Synthesis of the Flavonoid Natural Product Houttuynoid A

The first total synthesis of the antiviral flavonoid houttuynoid A (1) has been achieved from aryl ketone 6 and benzofuran aldehyde 5 in nine linear steps. The C₆-C₃-C₆ structure of the flavonoid was synthesized by an I₂-catalyzed oxa-Michael addition of a chalcone intermediate, generated by the Claisen-Schmidt condensation of 5 and 6. This work provides a method for the synthesis of houttuynoids and provides a reference for the synthesis of the remaining members of the houttuynoid family.

The recent development of efficient Earth-abundant transition-metal nanocatalysts

This review presents the recent remarkable developments of efficient Earth-abundant transition-metal nanocatalysts.

Copper immobilized ferromagnetic nanoparticle triazine dendrimer (FMNP@TD–Cu(ii))-catalyzed regioselective synthesis of 1,4-disubstituted 1,2,3-triazoles

The synthesis, characterisation and catalytic activity of FMNP@TD–Cu(ii) for the synthesis of 1,4-disubstituted 1,2,3-triazoles are reported.

Synthesis of heterocycles and fused heterocycles catalyzed by nanomaterials

The application of nanomaterials as heterogeneous catalyst for the synthesis of different heterocyclic systems is reviewed.

A new paradigm of copper oxide nanoparticles catalyzed reactions: synthesis of 1,2,3-triazoles through oxidative azide-olefin cycloaddition

Oxidative [3 + 2] cycloaddition of activated olefins and azides is reported with readily available CuO nanoparticles. 1,4-Disubsitituted and 1,4,5-trisubstituted 1,2,3-triazoles have been achieved without use of base or additives in a shorter time.

Synthesis and anti-cancer evaluation of steroidal diglycoside–pyrazoline hybrids

A new series of pyrazoline-steroidal diglycoside hybrids were synthesized via catalyzed cyclocondensation of the corresponding chalcones, screened for in vitro cytotoxic activity and the SAR deduced.

ZrO2-supported Cu(ii)–β-cyclodextrin complex: construction of 2,4,5-trisubstituted-1,2,3-triazoles via azide–chalcone oxidative cycloaddition and post-triazole alkylation

The ZrO₂–Cu₂–β-CD complex is an excellent catalyst for the synthesis of N-2-alkylated-1,2,3-triazoles.

Synthesis of medicinally important quinazolines decorated with 1,4-disubstituted-1,2,3-triazoles using CuSO4·5H2O–Et3N catalytic system

The direct use of Cu(ii) sulfate pentahydrate in the presence of triethylamine afforded 1,4-disubstituted-1,2,3-triazoles via 1,3-dipolar cycloaddition of terminal alkyne(s) to azide(s) at room temperature.