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Toxics May 2024Zirconium is recognized as one of the main impurities of the rare earth element scandium during purification. It presents significant challenges due to its similar...
Zirconium is recognized as one of the main impurities of the rare earth element scandium during purification. It presents significant challenges due to its similar chemical properties, making separating it difficult. This study used trialkyl phosphine oxide (TRPO) as a functional ligand, and the effects of carrier type and acidity on adsorption performance were first investigated. Among these, the novel extraction resin SiO-P as a carrier for TRPO demonstrated more prominent separation performance in 0.2 M HSO and 5 M HCl solutions. The kinetic and isotherm data were consistent with the pseudo-secondary kinetics and Langmuir model, respectively, and the adsorption process could be regarded as homogeneous monolayer adsorption subject to the dual effects of chemisorption and internal diffusion. In addition, thermodynamic analysis showed that the adsorption process of zirconium under the experimental conditions was a spontaneous endothermic process. Combined with the results of SEM-EDS, FT-IR, and XPS analyses, scandium and zirconium were successfully adsorbed by the resin and uniformly distributed on its surface, and the greater affinity of the P=O groups on the resin for zirconium was the critical factor contributing to the separation of scandium and zirconium. Finally, scandium and zirconium in sulfuric acid and hydrochloric acid media were extracted and separated by column experiments, and the purity of scandium could reach 99.8% and 99.99%, respectively.
PubMed: 38787129
DOI: 10.3390/toxics12050350 -
Current Issues in Molecular Biology May 2024Osteosarcoma malignancy currently represents a major health problem; therefore, the need for new therapy approaches is of great interest. In this regard, the current...
Osteosarcoma malignancy currently represents a major health problem; therefore, the need for new therapy approaches is of great interest. In this regard, the current study aims to evaluate the anti-neoplastic potential of a newly developed phosphinic acid derivative (2-carboxyethylphenylphosphinic acid) and, subsequently, to outline its pharmaco-toxicological profile by employing two different in vitro human cell cultures (keratinocytes-HaCaT-and osteosarcoma SAOS-2 cells), employing different techniques (MTT assay, cell morphology assessment, LDH assay, Hoechst staining and RT-PCR). Additionally, the results obtained are compared with three commercially available phosphorus-containing compounds (P1, P2, P3). The results recorded for the newly developed compound (P4) revealed good biocompatibility (cell viability of 77%) when concentrations up to 5 mM were used on HaCaT cells for 24 h. Also, the HaCaT cultures showed no significant morphological alterations or gene modulation, thus achieving a biosafety profile even superior to some of the commercial products tested herein. Moreover, in terms of anti-osteosarcoma activity, 2-carboxyethylphenylphosphinic acid expressed promising activity on SAOS-2 monolayers, the cells showing viability of only 55%, as well as apoptosis features and important gene expression modulation, especially downregulation. Therefore, the newly developed compound should be considered a promising candidate for further in vitro and in vivo research related to osteosarcoma therapy.
PubMed: 38785558
DOI: 10.3390/cimb46050290 -
Chemical Science May 2024Nickel-catalyzed cross-couplings of (hetero)aryl electrophiles with a diversity of nucleophiles (nitrogen, oxygen, carbon, and others) have evolved into competitive... (Review)
Review
Nickel-catalyzed cross-couplings of (hetero)aryl electrophiles with a diversity of nucleophiles (nitrogen, oxygen, carbon, and others) have evolved into competitive alternatives to well-established palladium- and copper-based protocols for the synthesis of (hetero)aryl products, including (hetero)anilines and (hetero)aryl ethers. A survey of the literature reveals that the use of cage phosphine (CgP) 'DalPhos' (DALhousie PHOSphine) bisphosphine-type ligands operating under thermal conditions currently offers the most broad substrate scope in nickel-catalyzed cross-couplings of this type, especially involving (hetero)aryl chlorides and phenol-derived electrophiles. The development and application of these DalPhos ligands is described in a ligand-specific manner that is intended to serve as a guide for the synthetic chemistry end-user.
PubMed: 38784740
DOI: 10.1039/d4sc01253d -
Frontiers in Chemistry 2024Asymmetric catalysis stands at the forefront of modern chemistry, serving as a cornerstone for the efficient creation of enantiopure chiral molecules characterized by... (Review)
Review
Asymmetric catalysis stands at the forefront of modern chemistry, serving as a cornerstone for the efficient creation of enantiopure chiral molecules characterized by their high selectivity. In this review, we delve into the realm of asymmetric catalytic reactions, which spans various methodologies, each contributing to the broader landscape of the enantioselective synthesis of chiral molecules. Transition metals play a central role as catalysts for a wide range of transformations with chiral ligands such as phosphines, -heterocyclic carbenes (NHCs), etc., facilitating the formation of chiral C-C and C-X bonds, enabling precise control over stereochemistry. Enantioselective photocatalytic reactions leverage the power of light as a driving force for the synthesis of chiral molecules. Asymmetric electrocatalysis has emerged as a sustainable approach, being both atom-efficient and environmentally friendly, while offering a versatile toolkit for enantioselective reductions and oxidations. Biocatalysis relies on nature's most efficient catalysts, i.e., enzymes, to provide exquisite selectivity, as well as a high tolerance for diverse functional groups under mild conditions. Thus, enzymatic optical resolution, kinetic resolution and dynamic kinetic resolution have revolutionized the production of enantiopure compounds. Enantioselective organocatalysis uses metal-free organocatalysts, consisting of modular chiral phosphorus, sulfur and nitrogen components, facilitating remarkably efficient and diverse enantioselective transformations. Additionally, unlocking traditionally unreactive C-H bonds through selective functionalization has expanded the arsenal of catalytic asymmetric synthesis, enabling the efficient and atom-economical construction of enantiopure chiral molecules. Incorporating flow chemistry into asymmetric catalysis has been transformative, as continuous flow systems provide precise control over reaction conditions, enhancing the efficiency and facilitating optimization. Researchers are increasingly adopting hybrid approaches that combine multiple strategies synergistically to tackle complex synthetic challenges. This convergence holds great promise, propelling the field of asymmetric catalysis forward and facilitating the efficient construction of complex molecules in enantiopure form. As these methodologies evolve and complement one another, they push the boundaries of what can be accomplished in catalytic asymmetric synthesis, leading to the discovery of novel, highly selective transformations which may lead to groundbreaking applications across various industries.
PubMed: 38783896
DOI: 10.3389/fchem.2024.1398397 -
Beilstein Journal of Organic Chemistry 2024Nucleoside and polynucleotide cytidine deaminases (CDAs), such as CDA and APOBEC3, share a similar mechanism of cytosine to uracil conversion. In 1984, phosphapyrimidine...
Nucleoside and polynucleotide cytidine deaminases (CDAs), such as CDA and APOBEC3, share a similar mechanism of cytosine to uracil conversion. In 1984, phosphapyrimidine riboside was characterised as the most potent inhibitor of human CDA, but the quick degradation in water limited the applicability as a potential therapeutic. To improve stability in water, we synthesised derivatives of phosphapyrimidine nucleoside having a CH group instead of the N3 atom in the nucleobase. A charge-neutral phosphinamide and a negatively charged phosphinic acid derivative had excellent stability in water at pH 7.4, but only the charge-neutral compound inhibited human CDA, similar to previously described 2'-deoxyzebularine ( = 8.0 ± 1.9 and 10.7 ± 0.5 µM, respectively). However, under basic conditions, the charge-neutral phosphinamide was unstable, which prevented the incorporation into DNA using conventional DNA chemistry. In contrast, the negatively charged phosphinic acid derivative was incorporated into DNA instead of the target 2'-deoxycytidine using an automated DNA synthesiser, but no inhibition of APOBEC3A was observed for modified DNAs. Although this shows that the negative charge is poorly accommodated in the active site of CDA and APOBEC3, the synthetic route reported here provides opportunities for the synthesis of other derivatives of phosphapyrimidine riboside for potential development of more potent CDA and APOBEC3 inhibitors.
PubMed: 38774272
DOI: 10.3762/bjoc.20.96 -
ACS Omega May 2024Fluorinated compounds are a staple of modern-day chemical innovation, and efficient strategies for their synthesis are highly valuable. In this chemical space,...
Fluorinated compounds are a staple of modern-day chemical innovation, and efficient strategies for their synthesis are highly valuable. In this chemical space, fluoroalkenes continue to be the object of much interest across diverse fields, including drug development and pharmaceuticals with active roles as bioisosteres. Herein, in expanding chemists' synthetic toolbox for constructing valuable organofluorine compounds, we report a "pipeline" strategy for the synthesis of fluorinated olefins, ., -difluoroalkenyl and monofluoroalkenyl arenes with high -isomeric selectivity. The advantages of this streamlined synthetic protocol include mild reaction conditions, operational simplicity, broad substrate scope, and good to excellent yields, even at gram scales. Critical to this robust procedure is the use of widely available and inexpensive "scavenger" solid-support Merrifield peptide resin for removing phosphine impurities. Further computational investigations offering clarity into this reactivity are disclosed.
PubMed: 38764685
DOI: 10.1021/acsomega.4c01055 -
International Journal of... 2024: Aluminum phosphide (AlP) poisoning is prevalent in numerous countries, resulting in high mortality rates. Phosphine gas, the primary agent responsible for AlP...
: Aluminum phosphide (AlP) poisoning is prevalent in numerous countries, resulting in high mortality rates. Phosphine gas, the primary agent responsible for AlP poisoning, exerts detrimental effects on various organs, notably the heart, liver and kidneys. Numerous studies have documented the advantageous impact of Coenzyme Q (CoQ) in mitigating hepatic injuries. The objective of this investigation is to explore the potential protective efficacy of CoQ against hepatic toxicity arising from AlP poisoning. : The study encompassed distinct groups receiving almond oil, normal saline, exclusive CoQ (at a dosage of 100 mg/kg), AlP at 12 mg/kg; LD (lethal dose for 50%), and four groups subjected to AlP along with CoQ administration (post-AlP gavage). CoQ was administered at 10, 50, and 100 mg/kg doses via Intraparietal (ip) injections. After 24 h, liver tissue specimens were scrutinized for mitochondrial complex activities, oxidative stress parameters, and apoptosis as well as biomarkers such as aspartate transaminase (AST) and alanine transaminase (ALT). : AlP induced a significant decrease in the activity of mitochondrial complexes I and IV, as well as a reduction in catalase activity, Ferric Reducing Antioxidant Power (FRAP), and Thiol levels. Additionally, AlP significantly elevated oxidative stress levels, indicated by elevated reactive oxygen species (ROS) production, and resulted in the increment of hepatic biomarkers such as AST and ALT. Administration of CoQ led to a substantial improvement in the aforementioned biochemical markers. Furthermore, phosphine exposure resulted in a significant reduction in viable hepatocytes and an increase in apoptosis. Co-treatment with CoQ exhibited a dose-dependent reversal of these observed alterations. : CoQ preserved mitochondrial function, consequently mitigating oxidative damage. This preventive action impeded the progression of heart cells toward apoptosis.
Topics: Phosphines; Ubiquinone; Chemical and Drug Induced Liver Injury; Animals; Oxidative Stress; Male; Liver; Apoptosis; Antioxidants; Rats; Aspartate Aminotransferases; Aluminum Compounds; Alanine Transaminase; Reactive Oxygen Species; Rats, Wistar
PubMed: 38764158
DOI: 10.1177/03946320241250286 -
Organometallics May 2024Rh complexes of a tridentate PPP ligand bearing 1,2-pyrrolediyl linkers have been prepared, including examples with the central P donor being either a phosphine or a...
Rh complexes of a tridentate PPP ligand bearing 1,2-pyrrolediyl linkers have been prepared, including examples with the central P donor being either a phosphine or a phosphide. Three bimetallic Rh complexes containing the diamandoid RhP core (P = phosphido) have been structurally and spectroscopically characterized. The Rh-Rh interaction in these three dimers was examined by way of structural comparisons and DFT investigations.
PubMed: 38756991
DOI: 10.1021/acs.organomet.3c00492 -
Nature Communications May 2024Despite recent developments on the design of dynamic catalysts, none of them have been exploited for the in-situ control of multiple stereogenic centers in a single...
Despite recent developments on the design of dynamic catalysts, none of them have been exploited for the in-situ control of multiple stereogenic centers in a single molecular scaffold. We report herein that it is possible to obtain in majority any amongst the four possible stereoisomers of an amino alcohol by means of a switchable asymmetric catalyst built on supramolecular helices. Hydrogen-bonded assemblies between a benzene-1,3,5-tricarboxamide (BTA) achiral phosphine ligand coordinated to copper and a chiral BTA comonomer are engaged in a copper-hydride catalyzed hydrosilylation and hydroamination cascade process. The nature of the product stereoisomer is related to the handedness of the helices and can thus be directed in a predictable way by changing the nature of the major enantiomer of the BTA comonomer present in the assemblies. The strategy allows all stereoisomers to be obtained one-pot with similar selectivities by conducting the cascade reaction in a concomitant manner, i.e. without inverting the handedness of the helices, or sequentially, i.e. by switching the handedness of the supramolecular helices between the hydrosilylation and hydroamination steps. Supramolecular helical catalysts appear as a unique and versatile platform to control the configuration of molecules or polymers embedding several stereogenic centers.
PubMed: 38750046
DOI: 10.1038/s41467-024-48412-z -
Molecules (Basel, Switzerland) Apr 2024The addition of Na[BArF] (BArF = tetrakis(3,5-bis(trifluoromethyl)phenyl)borate) to [Pd(PP)Cl] (PP = 1,1'-bis(phosphino)ferrocene ligands) compounds results in the loss...
The addition of Na[BArF] (BArF = tetrakis(3,5-bis(trifluoromethyl)phenyl)borate) to [Pd(PP)Cl] (PP = 1,1'-bis(phosphino)ferrocene ligands) compounds results in the loss of a chloride ligand and the formation of the dimeric species [Pd(PP)(-Cl)][BArF]. In most cases, the addition of a monodentate phosphine, PR, to these dimeric species leads to cleaving of the dimer and formation of [Pd(PP)(PR)Cl][BArF]. While these reactions are readily observed via a significant color change, the P{H} NMR spectra offer more significant support, as the singlet for the dimer is replaced with three doublets of doublets. The reaction seems to take place for a wide range of PR ligands, although there do appear to be steric limitations to the reaction. The compounds were thoroughly characterized by NMR, and X-ray crystal structures of several of the compounds were obtained. In addition, the ferrocenyl backbone of the 1,1'-bis(phosphino)ferrocene ligands provides an opportunity to examine the oxidative electrochemistry of these compounds. In general, the potential at which oxidations of these compounds occurs shows a dependence on the phosphine substituents.
PubMed: 38731539
DOI: 10.3390/molecules29092047