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Chiral pincer complexes, characterized by their rigid tridentate coordination framework, have emerged as powerful catalysts in asymmetric synthesis. This review provides a comprehensive overview of recent advancements in the development of chiral pincer-type ligands and their corresponding transition metal complexes. We highlight the latest progress in their application across a range of catalytic asymmetric reactions, including the (transfer) hydrogenation of polar and non-polar bonds, hydrophosphination, alkynylation, Friedel-Crafts reactions, enantioselective reductive cyclization of alkynyl-tethered cyclohexadienones, enantioselective hydrosilylation, as well as Aza–Morita–Baylis–Hillman reactions. The structural rigidity and tunability of chiral pincer complexes enable precise control over stereoselectivity, resulting in high enantioselectivity and efficiency in complex molecular transformations. As the field advances, innovations in ligand design and the exploration of new metal centers are expected to expand the scope and utility of these catalysts, bearing significant implications for the synthesis of enantioenriched compounds in pharmaceuticals, materials science, and beyond. [ABSTRACT FROM AUTHOR]

In recent years, extensive research has focused on cannabidiol (CBD), a well-studied non-psychoactive component of the plant-derived cannabinoids. CBD has shown significant therapeutic potential for treating various diseases and disorders, including antioxidants and anti-inflammatory effects. Due to the promising therapeutic effect of CBD in a wide variety of diseases, synthetic derivatization of this compound has attracted the attention of drug discovery in both industry and academia. In the current research, we focused on the derivatization of CBD by introducing Schiff base moieties, particularly (thio)-semicarbazide and aminoguanidine motifs, at the 3-position of the olivetolic ring. We have designed, synthesized, and characterized new derivatives based on CBD's framework, specifically aminoguanylhydrazone- and (thio)-semicarbazones-CBD-aldehyde compounds. Their antioxidant potential was assessed using FRAP and DPPH assays, alongside an evaluation of their effect on LDL oxidation induced by Cu2+ and AAPH. Our findings suggest that incorporating the thiosemicarbazide motif into the CBD framework produces a potent antioxidant, warranting further investigation. [ABSTRACT FROM AUTHOR]

Simple Summary: Cancer cells often become resistant to treatment, making it harder to fight the disease effectively. This resistance can happen due to genetic changes, proteins that pump out drugs, or the environment around the tumor. Crizotinib is a drug that helps overcome this resistance in certain lung cancers and lymphomas by targeting specific proteins. It can also break down a harmful protein found in some cancers. Researchers have found that combining crizotinib with other drugs can improve its effectiveness, especially for cancers with specific genetic mutations. Chemoresistance is a major obstacle in cancer treatment, often leading to disease progression and poor outcomes. It arises through various mechanisms such as genetic mutations, drug efflux pumps, enhanced DNA repair, and changes in the tumor microenvironment. These processes allow cancer cells to survive despite chemotherapy, underscoring the need for new strategies to overcome resistance and improve treatment efficacy. Crizotinib, a first-generation multi-target kinase inhibitor, is approved by the FDA for the treatment of ALK-positive or ROS1-positive non-small cell lung cancer (NSCLC), refractory inflammatory (ALK)-positive myofibroblastic tumors (IMTs) and relapsed/refractory ALK-positive anaplastic large cell lymphoma (ALCL). Crizotinib exists in two enantiomeric forms: (R)-crizotinib and its mirror image, (S)-crizotinib. It is assumed that the R-isomer is responsible for the carrying out various processes reviewed here The S-isomer, on the other hand, shows a strong inhibition of MTH1, an enzyme important for DNA repair mechanisms. Studies have shown that crizotinib is an effective multi-kinase inhibitor targeting various kinases such as c-Met, native/T315I Bcr/Abl, and JAK2. Its mechanism of action involves the competitive inhibition of ATP binding and allosteric inhibition, particularly at Bcr/Abl. Crizotinib showed synergistic effects when combined with the poly ADP ribose polymerase inhibitor (PARP), especially in ovarian cancer harboring BRCA gene mutations. In addition, crizotinib targets a critical vulnerability in many p53-mutated cancers. Unlike its wild-type counterpart, the p53 mutant promotes cancer cell survival. Crizotinib can cause the degradation of the p53 mutant, sensitizing these cancer cells to DNA-damaging substances and triggering apoptosis. Interestingly, other reports demonstrated that crizotinib exhibits anti-bacterial activity, targeting Gram-positive bacteria. Also, it is active against drug-resistant strains. In summary, crizotinib exerts anti-tumor effects through several mechanisms, including the inhibition of kinases and the restoration of drug sensitivity. The potential of crizotinib in combination therapies is emphasized, particularly in cancers with a high prevalence of the p53 mutant, such as triple-negative breast cancer (TNBC) and high-grade serous ovarian cancer (HGSOC). [ABSTRACT FROM AUTHOR]

In recent years, research on mushrooms belonging to the Hericium genus has attracted considerable attention due to their unique appearance and well-known medicinal properties. These mushrooms are abundant in bioactive chemicals like polysaccharides, hericenones, erinacines, hericerins, resorcinols, steroids, mono- and diterpenes, and corallocins, alongside essential nutrients. These compounds demonstrate beneficial bioactivities which are related to various physiological systems of the body, including the digestive, immune, and nervous systems. Extensive research has been conducted on the isolation and identification of numerous bioactive chemicals, and both in vitro and in vivo studies have confirmed their antimicrobial, antioxidant, immunomodulatory, antidiabetic, anticholesterolemic, anticancer, and neuroprotective properties. Therefore, this review aims to provide a comprehensive summary of the latest scientific literature on the chemical composition and secondary metabolites profile of Hericium spp. through an introduction to their chemical characteristics, speculated biosynthesis pathways for key chemical families, potential toxicological aspects, and a detailed description of the recent updates regarding the bioactivity of these metabolites. [ABSTRACT FROM AUTHOR]

The high‐density lipoprotein (HDL)‐associated enzyme paraoxonase 1 (PON1) is expressed almost exclusively in the liver and is then transported by HDL to the peripheral tissues. The lipophilic nature of PON1 enables its easy exchange between the lipoprotein and cell membranes in a process that is dependent on the HDL receptor scavenger receptor class B, type 1 (SR‐B1). In endothelial cells, PON1 binding to the cell membrane leads to its internalization by endocytosis and subsequent lysosomal degradation. PON1 is a "promiscuous" enzyme with unusually broad substrate specificity in vitro, but its actual function and substrate are still unknown. The enzyme requires a lipid environment and becomes completely inactive upon delipidation. However, when PON1 binds HDL, its active site faces the lipoprotein's core and is inaccessible to external substrates. Hence, the HDL‐bound PON1 is inactive toward substrates outside the particle's lipid core and is rapidly degraded and becomes inactive upon internalization. Consequently, the enzyme is only active in the cell membrane during its transit from HDL to the cytoplasm. To assign a function to PON1, we investigated whether it is a palmitoyl‐protein thioesterase (PPT) that can hydrolyze the palmitoyl moieties of membrane proteins involved in HDL and cholesterol transport, such as SR‐B1, ABCA1, or their neighboring caveola proteins to facilitate the release of HDL or trigger its endocytosis. This study shows that PON1 can hydrolyze palmitoyl‐cysteine thioester bonds in vitro, has direct or indirect PPT activity in vivo, and can significantly decrease the presence of SR‐B1 in the endothelial membrane. [ABSTRACT FROM AUTHOR]

The manuscript describes the synthesis and coordination chemistry of a novel diphosphine pincer ligand based on a p-hydroquinone-functionalized dibenzobarrelene scaffold. The p-hydroquinone fragment of the ligand is oxidatively and coordinatively non-innocent and may render new reactivity to the metal center due to implied reversible redox behavior, tautomeric interconversion and metal–hydroxyl/alkoxide coordination switch of the pendant hydroxyl side-arm. Palladium, platinum and iridium complexes were prepared and characterized. Investigation of their coordination chemistry revealed that while tautomeric equilibrium exists in free ligands and in the chelate non-metalated complexes, it is essentially blocked in the corresponding C(sp3)-pincer compounds due to stabilizing hemilabile coordination of the hydroxyl group. However, its presence in close proximity to the metal center is essential for catalyzing acceptorless dehydrogenation of alcohols by the iridium complexes via the outer-sphere hydrogen transfer mechanism. Remarkably, we found a similar activity for the analogous palladium complexes, which is not characteristic of this metal. This unprecedented reactivity of palladium stresses the fact that besides the choice of an active metal, transformation-oriented design of the ligand is crucial for catalysis. [ABSTRACT FROM AUTHOR]

The manuscript describes an efficient protocol for the E-selective transfer semihydrogenation of internal alkynes employing a previously described bifunctional ruthenium-based PC( sp3)P complex, 20 mol% of sodium formate and nearly stoichiometric formic acid. Semihydrogenation of the terminal alkynes results in the formation of the corresponding styrenes. The mechanism of the reaction includes stepwise transfer of both the hydride and the proton of the formic acid to the substrate. This fact allowed for the development of a facile protocol for the synthesis of monodeuterated alkenes by simply applying formic acid/sodium formate/D2O mixture as a hydrogen source. High yields, selectivity and functional group compatibility have been generally achieved. [ABSTRACT FROM AUTHOR]

Ligand–metal cooperation: A new ligand–metal cooperating catalyst for the hydroformylation of olefins is described (see scheme). The mechanism of the H2 activation and CH bond formation of the catalyst involves an intramolecular cooperation between the structurally remote functionality and the metal center and proceeds without change of the oxidation state of the metal. [ABSTRACT FROM AUTHOR]

New air-stable ruthenium complex 1, bearing the dibenzobarrelene-basedcooperating ligand, was synthesized in 96% yield and fully characterized.The examination of its coordination chemistry revealed that the rutheniumcenter in 1is slightly distorted from octahedral geometry,and 31P NMR is consistent with the formation of trans-spannedpincer complexes bearing strongly bent dibenzobarrelene-based ligands.The catalytic activity of the new complex was examined in acceptorlessdehydrogenation of alcohols and acceptorless dehydrogenative couplingof alcohols with amines. [ABSTRACT FROM AUTHOR]

Abstract: We describe the synthesis, characterization and properties of the new electrophilic palladium and platinum complexes bearing electron-rich PC(sp3 )P pincer ligands. We found that Lewis acidity of the compounds is low due to the strong σ-donation of the sp3 -carbometalated ligand backbone. [Copyright &y& Elsevier]

Review: 105 refs. [ABSTRACT FROM AUTHOR]

The manuscript describes the synthesis and coordination chemistry of a novel diphosphine pincer ligand based on a p-hydroquinone-functionalized dibenzobarrelene scaffold. The p-hydroquinone fragment of the ligand is oxidatively and coordinatively non-innocent and may render new reactivity to the metal center due to implied reversible redox behavior, tautomeric interconversion and metal-hydroxyl/alkoxide coordination switch of the pendant hydroxyl side-arm. Palladium, platinum and iridium complexes were prepared and characterized. Investigation of their coordination chemistry revealed that while tautomeric equilibrium exists in free ligands and in the chelate non-metalated complexes, it is essentially blocked in the corresponding C(sp 3 )-pincer compounds due to stabilizing hemilabile coordination of the hydroxyl group. However, its presence in close proximity to the metal center is essential for catalyzing acceptorless dehydrogenation of alcohols by the iridium complexes via the outer-sphere hydrogen transfer mechanism. Remarkably, we found a similar activity for the analogous palladium complexes, which is not characteristic of this metal. This unprecedented reactivity of palladium stresses the fact that besides the choice of an active metal, transformation-oriented design of the ligand is crucial for catalysis.