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Topic Review
Aurilide Family
Aurilides are a class of depsipeptides occurring mainly in marine cyanobacteria. Members of the aurilide family have shown to exhibit strong cytotoxicity against various cancer cell lines. These compounds bear a pentapeptide, a polyketide, and an α-hydroxy ester subunit in their structure.
  • 813
  • 18 Mar 2021
Topic Review
Chikungunya Virus
Arboviruses, in general, are a global threat due to their morbidity and mortality, which results in an important social and economic impact. Chikungunya virus (CHIKV), one of the most relevant arbovirus currently known, is a re-emergent virus that causes a disease named chikungunya fever, characterized by a severe arthralgia (joint pains) that can persist for several months or years in some individuals. Until now, no vaccine or specific antiviral drug is commercially available. Nitrogen heterocyclic scaffolds are found in medications, such as aristeromycin, favipiravir, fluorouracil, 6-azauridine, thioguanine, pyrimethamine, among others. New families of natural and synthetic nitrogen analogous compounds are reported to have significant anti-CHIKV effects. In the present work, we focus on these nitrogen-based heterocyclic compounds as an important class with CHIKV antiviral activity.
  • 812
  • 16 Jan 2021
Topic Review
Leaves of Diospyros kaki (Persimmon)
Diospyros kaki (persimmon) leaves have long been utilized as traditional medicine for the treatment of ischemic stroke, angina, and hypertension and as a healthy beverage and cosmetic for anti-aging. This study aimed to isolate as many compounds as possible from an ethanol extract of the persimmon leaves to identify the biologically active compounds. The antioxidative effect of the ethyl acetate layer from the ethanol extract of the persimmon leaves was demonstrated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay and online high-performance liquid chromatography-2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (HPLC-ABTS) analysis. 
  • 811
  • 11 Nov 2021
Topic Review
Gold(I)-Catalyzed Approaches with Arylalkyne Activation
Gold catalysts possess the advantages of water and oxygen resistance, with the possibility of catalyzing many novel chemical transformations, especially in the syntheses of small-molecule skeletons, in addition to achieving the rapid construction of multiple chemical bonds and ring systems in one step.
  • 811
  • 14 Feb 2023
Topic Review
C,C- and C,N-Chelated Organocopper Compounds
Copper-catalyzed and organocopper-involved reactions are of great significance in organic synthesis. To have a deep understanding of the reaction mechanisms, the structural characterizations of organocopper intermediates become indispensable. Meanwhile, the structure-function relationship of organocopper compounds could advance the rational design and development of new Cu-based reactions and organocopper reagents. Compared to the mono-carbonic ligand, the C,N- and C,C-bidentate ligands better stabilize unstable organocopper compounds. Bidentate ligands can chelate to the same copper atom via η2-mode, forming a mono-cupra-cyclic compounds with at least one acute C-Cu-C angle. When the bidentate ligands bind to two copper atoms via η1-mode at each coordinating site, the bimetallic macrocyclic compounds will form nearly linear C-Cu-C angles. The anionic coordinating sites of the bidentate ligand can also bridge two metals via μ2-mode, forming organocopper aggregates with Cu-Cu interactions and organocuprates with contact ion pair structures. The reaction chemistry of some selected organocopper compounds is highlighted, showing their unique structure–reactivity relationships.
  • 810
  • 08 Oct 2021
Topic Review
Metal-Catalyzed Synthesis of the OSe Compounds
Organoselenium (OSe) compounds have recently gained considerable interest as a potential class of organic motifs due to their outstanding applications in synthetic organic and medicinal chemistry and their possible properties in materials science. These are attributed to the exceptional properties of the selenium (Se) element.
  • 801
  • 02 Jun 2022
Topic Review
Removal of Pesticides from Waters
Pesticides are pollutants found in wastewater due to increasing agricultural activities over the years. Inappropriate dosing of pesticides results in the dispersal of active ingredients in the environment. The complete removal of pesticides from wastewater is an immediate concern due to their high toxicity and mobility. At present, adsorption is one of the most widely used methods for pesticide removal, in which synthetic zeolites and mesoporous silica materials are extensively applied. This article presents a systematic and comparative review of the applications and comparison of these adsorbents, based on the data reported in the literature.
  • 797
  • 07 Jul 2021
Topic Review
Synthetic Hemorphin Analogs Containing Non-Natural Amino Acids
The endogenous hemorphins are bioactive peptides with activity on opioid receptors. Several research teams have synthesized, characterized, and pharmacologically evaluated synthetic hemorphin analogs containing unusual amino acids, D-amino acids, α-aminophosphonic acids, and their derivatives. Research focuses on the structure-activity relationship analysis, details on specific methods for their characterization, and the advantage of synthetic hemorphin analogs compared to endogenous peptides as potent biologically active compounds with a complex mechanism of action.
  • 794
  • 05 Dec 2022
Topic Review
Deep Eutectic Solvents as à-la-Carte Medium
Regarding the chemical industry, one of the most significant issues to be addressed is the use of volatile organic compounds (VOCs) as solvents because they are petrol-derived and most of them are toxic and flammable. Among the possible solutions, deep eutectic solvents (DESs) have emerged as sustainable alternatives to VOCs in organic catalyzed transformations and other fields. The advantages of these new reaction media are not only related to their more benign physical and chemical properties and, for most of them, their renewable sources but also due to the possibility of being recycled after their use, increasing the sustainability of the catalyzed process in which they are involved.
  • 792
  • 19 Dec 2022
Topic Review
(−)-Methyl-Oleocanthal, a New Oleocanthal Metabolite
The antioxidant and anti-inflammatory responses of (−)-methyl-oleocanthal (met-OLE), a new metabolite of the extra virgin olive oil (EVOO) phenolic oleocanthal (OLE), were explored in lipopolysaccharide (LPS)-induced murine peritoneal macrophages. Possible signaling pathways and epigenetic modulation of histones were studied. Met-OLE inhibited LPS-induced intracellular reactive oxygen species (ROS) and nitrite (NO) production and decreased the overexpression of the pro-inflammatory enzymes COX-2, mPGES-1 and iNOS in murine macrophages.
  • 791
  • 13 Jan 2022
Topic Review
Stereoselective Promiscuous Reactions Catalyzed by Lipases
The ability of lipases to display activity beyond their physiological reactions, so-called “catalytic promiscuity”, has gained increasing interest in the last two decades as an important tool for expanding the application of these enzymes in organic synthesis. Some lipases have been shown to be effective in catalyzing a variety of C-C bond formation reactions and most of the investigations have been directed to the optimization of the products yield through a careful tuning of the experimental parameters. Despite the fact that new stereogenic carbons are formed in many of the tested reactions, the target products have been often obtained in racemic form and examples of an efficient asymmetric induction by the used lipases are quite limited.
  • 789
  • 25 Mar 2022
Topic Review
Oxidative Catalytic Processes for APIs and Precursors Preparation
Active pharmaceutical ingredients (APIs) can be defined as those biological compounds used for the detection, prevention, and treatment of different types of diseases. Asymmetric oxidation processes have constituted a valuable tool for the synthesis of APIs, especially for the preparation of optically active sulfoxides, compounds with interesting biological properties. Biocatalyzed reactions usually occur with high efficiency, excellent selectivity, good yields, environmental sustainability, and lower costs, which make them more attractive from an industrial perspective. However, it must be taken into account that these procedures also present some drawbacks, such as the (relatively) high substrate specificity of biocatalysts or the low substrate loadings required due to their generally low solubility in water.
  • 788
  • 10 Apr 2023
Topic Review
Specific Bifunctionalization on the Phosphorus Dendrimers
Dendrimers are highly branched three-dimensional macromolecules, which properties are essentially dependent on the type of their terminal functions. Dendrimers are synthesized by iterative processes, which afford a new generation at the end of each sequence, characterized by a multiplication of the number of terminal functions. Such processes generate identical terminal functions on the surface of the dendrimers. However, it is sometimes desirable to have two types of surface functions in order to fulfil specific properties. Numerous properties have been explored already, most of them being related to catalysis, materials, or biology/nanomedicine. Strategies to get two types of terminal functions will be illustrated with polyphosphorhydrazone (PPH) dendrimers.
  • 787
  • 13 Sep 2022
Topic Review
PZT
The ligand, 4'-(4-(2,2,2-tris(1H-pyrazol-1-yl)ethoxymethyl)phenyl)-2,2':6',2"-terpyridine (PZT) contains a terpyridine fragment and a tris(pyrazolyl) fragment, which may allow synthetic differentiation between the tridentate binding sites as a result of the meridional and the facial coordination preferences of these groups around the octahedral metal centres. This designed bridging ligand may offer the benefits of polydentate ligands and minimisation of isomeric possibilities. The tris(pyrazolyl)methane fragment is of interest, because the coordination chemistry of such systems has also been studied. It, too, is easy to prepare, by reaction of pyrazole with chloroform, and to derivatise, for example by reaction with formaldehyde, to give a molecule, 2,2,2-tris(1H-pyrazol-1-yl)ethanol, that can be readily joined to the other binding site, a terpyridine containing synthon.
  • 785
  • 10 Feb 2021
Topic Review
Isothiocyanate Synthesis Using Elemental Sulfur
Isothiocyanates (ITCs) are biologically active molecules found in several natural products and pharmaceutical ingredients. Moreover, due to their high and versatile reactivity, they are widely used as intermediates in organic synthesis.This review considers the best practices for the synthesis of ITCs using elemental sulfur, highlighting recent developments. Additionally, we also reveal that in the catalyst‑free reaction of isocyanides and sulfur, two—until this time overlooked and not investigated—different mechanistic pathways exist.
  • 784
  • 28 Sep 2021
Topic Review
Benzimidazole and Their Derivatives
Heterocyclic compounds are significant lead drug candidates based on their various structure–activity relationships (SAR), and their use in pharmaceutics is constantly developing. Benzimidazole (BnZ) is synthesized by a condensation reaction between benzene and imidazole. The BnZ structure consists of two nitrogen atoms embedded in a five-membered imide ring which is fused with a benzene ring. 
  • 784
  • 23 Oct 2023
Topic Review
Classifications of Adsorptive Ultrafiltration Membrane
Adsorptive ultrafiltration mixed matrix membranes (MMMs) are a new strategy, developed in recent years, to remove harmful cations and small-molecule organics from wastewater and drinking water, which achieve ultrafiltration and adsorption functions in one unit and are considered to be among the promising technologies that have exhibited efficiency and competence in water reuse.
  • 779
  • 17 May 2022
Topic Review
Fluorescent Organic Small Molecule Probes
Fluorescence imaging technology provides a visual tool for medicine, showing great potential in the fields of molecular biology, cellular immunology and oncology. In recent years, organic fluorescent probes have attracted much attention in the bioanalytical field. Among various organic fluorescent probes, fluorescent organic small molecule probes (FOSMPs) have become a research hotspot due to their excellent physicochemical properties, such as good photostability, high spatial and temporal resolution, as well as excellent biocompatibility. FOSMPs have proved to be suitable for in vivo bioimaging and detection. 
  • 777
  • 17 Jan 2023
Topic Review
Salvigenin
Phytochemical analysis of the Iranian plant Achillea wilhelmsii led to the isolation of 17 pure secondary metabolites belonging to the classes of sesquiterpenoids and phenolics. Two of these compounds, named wilhemsin (7) and wilhelmsolide (9), are new sesquiterpenoids, and the first shows undescribed structural features. Their structures were elucidated through extensive spectroscopic analysis, mainly based on 1D and 2D NMR, and chemical derivatization. Starting from plant traditional use and previous reports on the activity of the plant extracts, all the pure compounds were evaluated on endpoints related to the treatment of metabolic syndrome. The sesquiterpene hanphyllin (8) showed a selective cholesterol-lowering activity (−12.7% at 30 µM), santoflavone (13) stimulated glucose uptake via the GLUT transporter (+16.2% at 30 µM), while the trimethoxylated flavone salvigenin (14) showed a dual activity in decreasing lipid levels (−22.5% palmitic acid biosynthesis at 30 µM) and stimulating mitochondrial functionality (+15.4% at 30 µM). 
  • 775
  • 13 Aug 2021
Topic Review
Stereoselective Synthesis of Chiral Molecules
Metal/lipase-combo catalyzed dynamic kinetic resolution (DKR) of racemic chiral alcohols is a general and practical process to obtain the corresponding enantiopure esters R with quantitative conversion. The use of known Ru-catalysts as well as newly developed homogeneous and heterogeneous metal catalysts (Fe, V) contributed to make the DKR process more sustainable and to expand the substrate scope of the reaction. In addition to classical substrates, challenging allylic alcohols, tertiary alcohols, C1-and C2-symmetric biaryl diols turned out to be competent substrates. Synthetic utility further emerged from the integration of this methodology into cascade reactions leading to linear/cyclic chiral molecules with high ee through the formation of multiple bonds, in a one-pot procedure. 
  • 773
  • 08 Oct 2021
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