-
Molecules (Basel, Switzerland) Jul 2023The chemistry of hypervalent iodine reagents has now become quite valuable due to the reactivity of these compounds under mild reaction conditions and their resemblance... (Review)
Review
The chemistry of hypervalent iodine reagents has now become quite valuable due to the reactivity of these compounds under mild reaction conditions and their resemblance in chemical properties to transition metals. The environmentally friendly nature of these reagents makes them suitable for Green Chemistry. Reagents with a dual nature, such as iodine(III) reagents, are capable electrophiles, while iodine(V) reagents are known for their strong oxidant behavior. Various iodine(V) reagents including IBX and DMP have been used as oxidants in organic synthesis either in stoichiometric or in catalytic amounts. In this review article, we describe various oxidation reactions induced by iodine(V) reagents reported in the past decade.
Topics: Iodine; Oxidants; Oxidation-Reduction; Indicators and Reagents; Catalysis
PubMed: 37446912
DOI: 10.3390/molecules28135250 -
International Journal of Molecular... May 2022The paper presents synthesis and characterization of nine new thiazolyl-(phenyldiazenyl)-2-chromen-2-one dyes. The impact of substituent structure in thiazole ring in...
The paper presents synthesis and characterization of nine new thiazolyl-(phenyldiazenyl)-2-chromen-2-one dyes. The impact of substituent structure in thiazole ring in the synthesized azocoumarin derivatives on electrochemical properties, photoisomerization process and photovoltaic response was examined. The dyes were electrochemically active and undergo reduction and oxidation processes. They showed low electrochemically estimated energy band gap in the range of 1.71-2.13 eV. Photoisomerization process of the synthesized molecules was studied in various solvents such as ethanol, chloroform and ,-dimethylformamide (DMF) upon the UV illumination. It was found that novel azodyes showed reversible -- isomerization and exhibited long thermal back to the trans form, that was even 7 days in DMF. Selected azocoumarin were molecularly dispersed in polystyrene for preparation of guest-host azopolymer systems to study the - thermal isomerization of obtained dyes in solid state. The photovoltaic activity of the azochromophores was tested in bulk-heterojunction solar cells. They acting as weak donors in device with structure ITO/PEDOT:PSS/dye:PC70BM/Al. No photovoltaic response of cells with azocoumarin derivatives bearing 4-fluorobenzene, 3,4-dichlorobenzene, or 4-(1-adamantyl) unit was found. Additionally, dye which showed the best activity was examined in three-component solar cells ITO/PEDOT:PSS/PTB7:PC70BM:dye/PFN/Al.
Topics: Coloring Agents; Oxidation-Reduction
PubMed: 35628586
DOI: 10.3390/ijms23105767 -
Chemical Communications (Cambridge,... Jun 2023Natural product chemistry is constantly challenged by newly discovered, complex molecules. Elements of complexity arise from unprecedented frameworks, with a large... (Review)
Review
Natural product chemistry is constantly challenged by newly discovered, complex molecules. Elements of complexity arise from unprecedented frameworks, with a large amount of densely packed stereogenic centres and different functional groups along with a generally high oxidation state. As a prime example, rearranged triterpenoids possess all these elements. For their total synthesis, a limit of what is considered sensible in terms of steps and yield is frequently reached. As an alternative, semisynthetic approaches have gained a great amount of attention in recent years. In this featured article, we present our and others' contributions towards the development of efficient and economic syntheses of complex terpenoid natural products and elaborate on the underlying rationale of biogenetic space-guided synthetic analysis.
Topics: Terpenes; Triterpenes; Plant Extracts; Oxidation-Reduction; Biological Products
PubMed: 37162324
DOI: 10.1039/d3cc01009k -
Redox Biology May 2021Zinc and cellular oxidants such as reactive oxygen species (ROS) each participate in a multitude of physiological functions. There is considerable overlap between the... (Review)
Review
Zinc and cellular oxidants such as reactive oxygen species (ROS) each participate in a multitude of physiological functions. There is considerable overlap between the affected events, including signal transduction. While there is no obvious direct connection between zinc and ROS, mainly because the bivalent cation zinc does not change its oxidation state in biological systems, these are linked by their interaction with sulfur, forming the remarkable triad of zinc, ROS, and protein thiols. First, zinc binds to reduced thiols and can be released upon oxidation. Thereby, redox signals are translated into changes in the free zinc concentration, which can act as zinc signals. Second, zinc affects oxidation of thiols in several ways, directly as well as indirectly. A protein incorporating many of these interactions is metallothionein (MT), which is rich in cysteine and capable of binding up to seven zinc ions in its fully reduced state. Zinc binding is diminished after (partial) oxidation, while thiols show increased reactivity in the absence of bound metal ions. Adding still more complexity, the MT promoter is controlled by zinc (via metal regulatory transcription factor 1 (MTF-1)) as well as redox (via nuclear factor erythroid 2-related factor 2 (NRF2)). Many signaling cascades that are important for cell proliferation or apoptosis contain protein thiols, acting as centers for crosstalk between zinc- and redox-signaling. A prominent example for shared molecular targets for zinc and ROS are active site cysteine thiols in protein tyrosine phosphatases (PTP), their activity being downregulated by oxidation as well as zinc binding. Because zinc binding also protects PTP thiols form irreversible oxidation, there is a multi-faceted reciprocal interaction, illustrating that zinc- and redox-signaling are intricately linked on multiple levels.
Topics: Metallothionein; Oxidation-Reduction; Reactive Oxygen Species; Signal Transduction; Zinc
PubMed: 33662875
DOI: 10.1016/j.redox.2021.101916 -
Advanced Science (Weinheim,... Apr 2022The ability to control interfacial tension electrochemically is uniquely available for liquid metals (LMs), in particular gallium-based LM alloys. This imparts them with...
The ability to control interfacial tension electrochemically is uniquely available for liquid metals (LMs), in particular gallium-based LM alloys. This imparts them with excellent locomotion and deformation capabilities and enables diverse applications. However, electrochemical oxidation of LM is a highly dynamic process, which often induces Marangoni instabilities that make it almost impossible to elongate LM and manipulate its morphology directly and precisely on a 2D plane without the assistance of other patterning methods. To overcome these limitations, this study investigates the use of an LM-iron (Fe) particle mixture that is capable of suppressing instabilities during the electrochemical oxidation process, thereby allowing for superelongation of the LM core of the mixture to form a thin wire that is tens of times of its original length. More importantly, the elongated LM core can be manipulated freely on a 2D plane to form complex patterns. Eliminating Marangoni instabilities also allows for the effective spreading and filling of the LM-Fe mixture into molds with complex structures and small features. Harnessing these excellent abilities, a channel-less patterning method for fabricating elastomeric wearable sensors is demonstrated to detect motions. This study shows the potential for developing functional and flexible structures of LM with superior performance.
Topics: Oxidation-Reduction; Surface Tension
PubMed: 35128845
DOI: 10.1002/advs.202105289 -
Advances in Cancer Research 2023Protein disulfide isomerase (PDI) and its superfamilies are mainly endoplasmic reticulum (ER) resident proteins with essential roles in maintaining cellular homeostasis,... (Review)
Review
Protein disulfide isomerase (PDI) and its superfamilies are mainly endoplasmic reticulum (ER) resident proteins with essential roles in maintaining cellular homeostasis, via thiol oxidation/reduction cycles, chaperoning, and isomerization of client proteins. Since PDIs play an important role in ER homeostasis, their upregulation supports cell survival and they are found in a variety of cancer types. Despite the fact that the importance of PDI to tumorigenesis remains to be understood, it is emerging as a new therapeutic target in cancer. During the past decade, several PDI inhibitors has been developed and commercialized, but none has been approved for clinical use. In this review, we discuss the properties and redox regulation of PDIs within the ER and provide an overview of the last 5 years of advances regarding PDI inhibitors.
Topics: Humans; Protein Disulfide-Isomerases; Neoplasms; Carcinogenesis; Cell Survival; Oxidation-Reduction
PubMed: 37704292
DOI: 10.1016/bs.acr.2023.06.001 -
BioMed Research International 2022
Topics: Oxidation-Reduction; Oxidative Stress
PubMed: 35434128
DOI: 10.1155/2022/9813486 -
Biochemistry Oct 2022Cysteine side chains can exist in distinct oxidation states depending on the pH and redox potential of the environment, and cysteine oxidation plays important yet... (Review)
Review
Cysteine side chains can exist in distinct oxidation states depending on the pH and redox potential of the environment, and cysteine oxidation plays important yet complex regulatory roles. Compared with the effects of post-translational modifications such as phosphorylation, the effects of oxidation of cysteine to sulfenic, sulfinic, and sulfonic acid on protein structure and function remain relatively poorly characterized. We present an analysis of the role of cysteine reactivity as a regulatory factor in proteins, emphasizing the interplay between electrostatics and redox potential as key determinants of the resulting oxidation state. A review of current computational approaches suggests underdeveloped areas of research for studying cysteine reactivity through molecular simulations.
Topics: Biophysics; Cysteine; Oxidation-Reduction; Proteins; Sulfenic Acids; Sulfonic Acids
PubMed: 36161872
DOI: 10.1021/acs.biochem.2c00349 -
Frontiers in Endocrinology 2022Ferroptosis, an iron-dependent form of programmed cell death marked by phospholipid peroxidation, is regulated by complex cellular metabolic pathways including lipid... (Review)
Review
Ferroptosis, an iron-dependent form of programmed cell death marked by phospholipid peroxidation, is regulated by complex cellular metabolic pathways including lipid metabolism, iron balance, redox homeostasis, and mitochondrial activity. Initial research regarding the mechanism of ferroptosis mainly focused on the solute carrier family 7 member 11/glutathione/glutathione peroxidase 4 (GPX4) signal pathway. Recently, novel mechanisms of ferroptosis, independent of GPX4, have been discovered. Numerous pathologies associated with extensive lipid peroxidation, such as drug-resistant cancers, ischemic organ injuries, and neurodegenerative diseases, are driven by ferroptosis. Ferroptosis is a new therapeutic target for the intervention of IVDD. The role of ferroptosis in the modulation of intervertebral disc degeneration (IVDD) is a significant topic of interest. This is a novel research topic, and research on the mechanisms of IVDD and ferroptosis is ongoing. Herein, we aim to review and discuss the literature to explore the mechanisms of ferroptosis, the relationship between IVDD and ferroptosis, and the regulatory networks in the cells of the nucleus pulposus, annulus fibrosus, and cartilage endplate to provide references for future basic research and clinical translation for IVDD treatment.
Topics: Humans; Ferroptosis; Intervertebral Disc Degeneration; Lipid Peroxidation; Oxidation-Reduction; Iron
PubMed: 36339421
DOI: 10.3389/fendo.2022.1042060 -
Metal Ions in Life Sciences Mar 2020In biological nitrogen fixation, the enzyme nitrogenase mediates the reductive cleavage of the stable triple bond of gaseous N2at ambient conditions, driven by the...
In biological nitrogen fixation, the enzyme nitrogenase mediates the reductive cleavage of the stable triple bond of gaseous N2at ambient conditions, driven by the hydrolysis of ATP, to yield bioavailable ammonium (NH4+). At the core of nitrogenase is a complex, ironsulfur based cofactor that in most variants of the enzyme contains an additional, apical heterometal (Mo or V), an organic homocitrate ligand coordinated to this heterometal, and a unique, interstitial carbide. Recent years have witnessed fundamental advances in our understanding of the atomic and electronic structure of the nitrogenase cofactor. Spectroscopic studies have succeeded in trapping and identifying reaction intermediates and several inhibitor- or intermediate- bound structures of the cofactors were characterized by high-resolution X-ray crystallography. Here we summarize the current state of understanding of the cofactors of the nitrogenase enzymes, their interplay in electron transfer and in the six-electron reduction of nitrogen to ammonium and the actual theoretical and experimental conclusion on how this challenging chemistry is achieved.
Topics: Nitrogen; Nitrogen Fixation; Nitrogenase; Oxidation-Reduction
PubMed: 32851829
DOI: 10.1515/9783110589757-014