Chemical Reviews
DOI: 10.1021/acs.chemrev.3c00058
Monthly Archives: September 2023
The potential protective effect of liraglutide on valproic acid induced liver injury in rats: Targeting HMGB1/RAGE axis and RIPK3/MLKL mediated necroptosis
Abstract
Valproic acid (VPA) is a commonly used drug for management of epilepsy. Prolonged VPA administration increases the risk of hepatotoxicity. Liraglutide is a glucagon-like peptide 1 receptor (GLP-1R) agonist that act as a novel antidiabetic drug with broad-spectrum anti-inflammatory and antioxidant effects. This study tested the protective effect of liraglutide against VPA-induced hepatotoxicity elucidating the possible underlying molecular mechanisms. Forty adult male rats were allocated in to four equally sized groups; Group I (control group) received oral distilled water and subcutaneous normal saline for 2 weeks followed by subcutaneous normal saline only for 2 weeks. Group II (liraglutide group) received subcutaneous liraglutide dissolved in normal saline daily for 4 weeks. Group III (valproic acid-treated group) received sodium valproate dissolved in distilled water for 2 weeks. Group IV (Combined valproic acid & liraglutide treated group) received valproic acid plus liraglutide daily for 2 weeks which was continued for additional 2 weeks after valproic acid administration. The hepatic index was calculated. Serum AST, ALT, GGT, and ALP activities were estimated. Hepatic tissue homogenate MDA, GSH, SOD, HMGB1, MAPK, RIPK1, and RIPK3 levels were evaluated using ELISA. However, hepatic RAGE and MLKL messenger RNA expression levels using the QRT-PCR technique. Hepatic NF-κB and TNF-α were detected immunohistochemically. Results proved that liraglutide coadministration significantly decreased liver enzymes, MDA, HMGB1, MAPK, RIPK1 RIPK3, RAGE, and MLKL with concomitant increased GSH and SOD in comparison to the correspondent values in VPA-hepatotoxicity group. Conclusions: Liraglutide's protective effects against VPA-induced hepatotoxicity are triggered by ameliorating oxidative stress, inflammation, and necroptosis.
Decarboxylative amination with nitroarenes via synergistic catalysis
Comprehensive Summary
In this paper, we have developed a decarboxylative amination of carboxylic acids with nitroarenes for the synthesis of secondary amines. The protocol is performed at mild conditions without the use of noble metals as catalysts. A wide range structurally diverse secondary amines could be obtained in good yields (up to 94%) with good functional group tolerance. This transformation shows good to excellent selectivity, avoiding the generation of overalkylated byproducts.
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Access to Electron‐Rich Dibenzofurans through NBu4OAc‐Mediated Palladium Catalysis
Dibenzofuran and its derivatives are ubiquitous and important medicinal and natural products. Many contain electron-donating substituents. Herein, we report a Pd-catalysed C−H functionalisation protocol that works with electron-rich arenes. We use tetrabutylammonium acetate (NBu4OAc), which we suspect can act as base and ligand, rendering this protocol a simple and efficient route to dibenzofurans.
Abstract
Dibenzofuran and its derivatives are ubiquitous and important medicinal and natural products. Many contain electron-rich aryl rings. Forming the key intramolecular Ar−Ar bond using traditional cross-coupling is difficult. The C−H functionalisation (C−H activation) approach is, in principle, far more useful. However, we previously found that the well-established conditions, which promote C−H functionalisation through Concerted Metalation-Deprotonation (CMD), proved unsatisfactory. Herein, we report a Pd-catalysed C−H functionalisation protocol that works with electron-rich arenes. We use tetrabutylammonium acetate (NBu4OAc), which we suspect can act as base, ligand and solvent, rendering this protocol a simple and efficient route to electron-rich dibenzofurans.
Distinct Heterocyclic Moieties Govern the Selectivity of Thiophene‐Vinylene‐Based Ligands towards Aβ or Tau Pathology in Alzheimer’s Disease
Tau be or not tau be. A variety of fluorescent thiophene-vinylene-based ligands was synthesized. Ligands with specific chemical composition displayed selectivity towards distinct protein aggregates in tissue sections with Alzheimer's disease pathology and distinct heterocyclic moieties governed the selectivity of the ligand towards Aβ or tau pathology. We foresee that these findings will aid in designing ligands towards disease-associated protein aggregates.
Abstract
Distinct aggregated proteins are correlated with numerous neurodegenerative diseases and the development of ligands that selectively detect these pathological hallmarks is vital. Recently, the synthesis of thiophene-based optical ligands, denoted bi-thiophene-vinyl-benzothiazoles (bTVBTs), that could be utilized for selective assignment of tau pathology in brain tissue with Alzheimer's disease (AD) pathology, was reported. Herein, we investigate the ability of these ligands to selectively distinguish tau deposits from aggregated amyloid-β (Aβ), the second AD associated pathological hallmark, when replacing the terminal thiophene moiety with other heterocyclic motifs. The selectivity for tau pathology was reduced when introducing specific heterocyclic motifs, verifying that specific molecular interactions between the ligands and the aggregates are necessary for selective detection of tau deposits. In addition, ligands having certain heterocyclic moieties attached to the central thiophene-vinylene building block displayed selectivity to aggregated Aβ pathology. Our findings provide chemical insights for the development of ligands that can distinguish between aggregated proteinaceous species consisting of different proteins and might also aid in creating novel agents for clinical imaging of tau pathology in AD.
Enhanced Cr(VI) Photocatalysis Reduction by Layered N‐doped TiO2 Sheets from Template Free Solvothermal Method
N-doped TiO2 with layered structure was obtained by solvothermal method using ethylene glycol as the sheet-structure linking agent, and pyridine as N source. N-doped TiO2 showed good catalytic performance for photocatalytic degradation of Cr(VI) to Cr(III) owing to its high surface area, high Ti3+ ratio and abundant N in the layered structure.
Abstract
Layered TiO2 sheets with high Cr(VI) photoreduction ability were prepared by template free solvothermal method using ethylene glycol (EG) as structure directing agent. EG linking function in the layered TiO2 structure were confirmed by SEM, TEM, FTIR, XPS and so on. Moreover, the obtained large sized TiO2 (20~50 μm in length, about 5~10 μm in width) were assembled by N-doped TiO2 thin sheets with about 1.2 nm gap in between, resulting in very high surface area (327.5 m2/g) and abundant Ti3+ sites for Cr(VI) adsorption and reduction. This structure can not only have good performance during Cr(VI) photocatalysis reduction application (Cr(VI) removal rate: 0.84 mg*g−1*min−1), but also endow the material with good cycle ability.
Synergistic Mechanism of 0D Internal and Surface Defects Regulation Coupled with Pyroelectric Effects for Optimizing the Photoelectrocatalytic Properties of CdS
This paper constructed internal and surface defects to modulate the crystal structure of CdS, and investigated the synergistic impact of 0D (0-dimensional) internal and surface defects regulation coupled with pyroelectric effects for optimizing the photoelectrocatalytic properties.
Abstract
Rational defect regulation is an effective way to enhance the performance of photoelectrocatalytic (PEC) water splitting. In this paper, we firstly constructed internal and surface defects to modulate the crystal structure of CdS, and investigated the synergistic impact of 0D (0-dimensional) internal and surface defects regulation coupled with pyroelectric effects for optimizing the photoelectrocatalytic properties of CdS. It was found that the synergistic impact had a significant enhancement effect on the carrier separation and transfer, and the current density reached 3.93 mA/cm2 at 1.23 V vs. RHE increased by 16.38 times, meanwhile, the stability of the photoelectrodes was greatly promoted. The advantages and intrinsic relationships are also described: the formation of 0D dual-type of defects alters the atomic arrangement in the crystal, optimizes the energy band structure, reduces carrier recombination, and increases carrier density. What's more, the introduction of defects induces electron redistribution and changes the state of dipoles inside the crystal, thus increasing built-in electric field and generating more thermally generated carriers to optimize the pyroelectric effect. This work demonstrates the feasibility of defect modulation for optimizing pyroelectric performance and photocatalytic performance and bringing new light to PEC water splitting.
High‐Resolution X‐ray Absorption and Emission Spectroscopy for Detailed Analysis of New CO2 Methanation Catalysts
A methodical approach to investigate Ni@C CO2 methanation catalysts obtained by thermal decomposition of nickel MOFs using hard X-rays is established and applied. The procedure involves high-energy-resolution X-ray absorption near-edge structure spectroscopy and X-ray emission spectroscopy in combination with ab initio FEFF calculations.
Abstract
A new approach for the characterization of CO2 methanation catalysts prepared by thermal decomposition of a nickel MOF by hard X-ray photon-in/photon-out spectroscopy in form of high energy resolution fluorescence detected X-ray absorption near edge structure spectroscopy (HERFD-XANES) and valence-to-core X-ray emission (VtC-XES) is presented. In contrast to conventional X-ray absorption spectroscopy, the increased resolution of both methods allows a more precise phase determination of the final catalyst, which is influenced by the conditions during MOF decomposition.
Ammonium and Tartrate Salts as Alternatives to Neutral Aqueous Electrolytes for Supercapacitors
Supercapacitors are interesting energy storage devices in terms of power density and lifetime. Organic electrolytes are frequently applied in commercial supercapacitor devices. However, their water-based counterparts are much more sustainable, cost-effective and safer. Therefore, aqueous energy storage devices are interesting alternatives. Here, aqueous Ammonium and tartrate-based electrolytes are introduced as possible candidates for applications in aqueous supercapacitors.
Abstract
Supercapacitors are promising energy storage devices in terms of power density and lifetime. Organic electrolytes are frequently applied in commercial supercapacitor devices. However, their water-based counterparts are much safer, more sustainable and cost-effective. In this study we therefore present, for the first time, aqueous tartrate-based electrolytes (sodium tartrate / ammonium tartrate) for supercapacitor applications, and relate them to well-known inorganic aqueous electrolytes like Na2SO4. Additionally, the influence of the cation on the electrochemical performance of supercapacitors is investigated using sodium and ammonium cations for comparison. We demonstrate the electrochemical performance and physicochemical properties of ammonium tartrate / sulfate and sodium tartrate / sulfate. An improvement of the conductivity in the range of 40–60 % was achieved by the exchange of sodium cation with ammonium cation. Carbon electrodes in newly introduced aqueous tartrate-based electrolytes deliver high specific capacitances up to 117 Fg−1. Furthermore, electrical double layer capacitors (EDLCs) containing 1 M ammonium tartrate display a high energy density at 0.1 Ag−1 and at 10 Ag−1 (9.88 Whkg−1 and 1.14 Whkg−1, respectively). Floating tests show excellent long-term performance. Tartrate-based EDLCs retain >80 % of their initial capacitance at 1.6 V cell voltage (120 h floating time). In the case of ammonium tartrate electrolyte, a novel metal-free and non-toxic concept for an eco-friendly supercapacitor device is proposed.
Amino Acid Residues Controlling Domain Interaction and Interdomain Electron Transfer in Cellobiose Dehydrogenase
Cellobiose dehydrogenase serves as an auxiliary enzyme donating electrons to lytic polysaccharide monooxygenase in biomass depolymerization, as well as a biorecognition element in biosensors due to its electron transfer capability. The involvement of two amino acids in the interdomain electron transfer process is investigated in depth with stopped-flow spectrophotometry, small-angle X-ray scattering, multistate modeling, and molecular dynamics simulations.
Abstract
The function of cellobiose dehydrogenase (CDH) in biosensors, biofuel cells, and as a physiological redox partner of lytic polysaccharide monooxygenase (LPMO) is based on its role as an electron donor. Before donating electrons to LPMO or electrodes, an interdomain electron transfer from the catalytic FAD-containing dehydrogenase domain to the electron shuttling cytochrome domain of CDH is required. This study investigates the role of two crucial amino acids located at the dehydrogenase domain on domain interaction and interdomain electron transfer by structure-based engineering. The electron transfer kinetics of wild-type Myriococcum thermophilum CDH and its variants M309A, R698S, and M309A/R698S were analyzed by stopped-flow spectrophotometry and structural effects were studied by small-angle X-ray scattering. The data show that R698 is essential to pull the cytochrome domain close to the dehydrogenase domain and orient the heme propionate group towards the FAD, while M309 is an integral part of the electron transfer pathway – its mutation reducing the interdomain electron transfer 10-fold. Structural models and molecular dynamics simulations pinpoint the action of these two residues on the domain interaction and interdomain electron transfer.