Calcined oyster shell nanoparticles (COS NPs): a new,efficient and reusable catalyst for one-pot rapid preparation of 1,8-dioxo-octahydroxanthenes under solvent-free conditions

Research on Chemical Intermediates - Calcined oyster shell nanoparticles (COS NPs) as a novel heterogeneous nanocatalyst were prepared and fully characterized by X-ray fluorescence analysis,...     

HEXAMETHYLDISILAZANE IN THE PRESENCE OF N,N′,N″,N‴-TETRAMETHYLTETRA-2,3-PYRIDINOPORPHYRAZINATO COPPER (II) IS A NEW,MILD AND HIGHLY EFFICIENT REAGENT FOR SILYLATION OF ALCOHOLS AND PHENOLS

Alcohols and phenols are protected with hexamethyldisilazane in the presence of N,N′,N′,N?-tetramethyletra-2,3-pyridinoporphyrazinato copper (II) in good-to-excellent yields at room temperature.     

Influence of hybrid nano-structures on thermal performance of shear rate dependent viscosity fluid over a heated rotating cone with Hall and ion slip currents

Journal of Thermal Analysis and Calorimetry - The fluid of shear rate dependent viscosity has totally different rheology and exhibits dynamics which play a key role in heat transfer rate and...     

Middle East respiratory syndrome coronavirus: transmission,virology and therapeutic targeting to aid in outbreak control

Middle East respiratory syndrome coronavirus (MERS-CoV) causes high fever, cough, acute respiratory tract infection and multiorgan dysfunction that may eventually lead to the death of the infected individuals. MERS-CoV is thought to be transmitted to humans through dromedary camels. The occurrence of the virus was first reported in the Middle East and it subsequently spread to several parts of the world. Since 2012, about 1368 infections, including ~487 deaths, have been reported worldwide. Notably, the recent human-to-human ‘superspreading'' of MERS-CoV in hospitals in South Korea has raised a major global health concern. The fatality rate in MERS-CoV infection is four times higher compared with that of the closely related severe acute respiratory syndrome coronavirus infection. Currently, no drug has been clinically approved to control MERS-CoV infection. In this study, we highlight the potential drug targets that can be used to develop anti-MERS-CoV therapeutics.     

EFFICIENT CONVERSION OF TETRAHYDROPYRANYL (THP) ETHERS TO THEIR CORRESPONDING CYANIDES WITH TRIPHENYLPHOSPHINE/2,3-DICHLORO- 5,6-DICYANOBENZOQUINONE/n-Bu4 NCN

Tetrahydropyranyl ethers were converted to their corresponding alkyl cyanides efficiently by using the triphenylphosphine/ 2,3-dichloro-5,6-dicyanobenoquinone/n-Bu ₄ NCN system in refluxing acetonitrile with good-to-excellent yields.     

An Update on Synthesis of Coumarin Sulfonamides as Enzyme Inhibitors and Anticancer Agents

Coumarin is an important six-membered aromatic heterocyclic pharmacophore, widely distributed in natural products and synthetic molecules. The versatile and unique features of coumarin nucleus, in combination with privileged sulfonamide moiety, have enhanced the broad spectrum of biological activities. The research and development of coumarin, sulfonamide-based pharmacology, and medicinal chemistry have become active topics, and attracted the attention of medicinal chemists, pharmacists, and synthetic chemists. Coumarin sulfonamide compounds and analogs as clinical drugs have been used to cure various diseases with high therapeutic potency, which have shown their enormous development value. The diversified and wide array of biological activities such as anticancer, antibacterial, anti-fungal, antioxidant and anti-viral, etc. were displayed by diversified coumarin sulfonamides. The present systematic and comprehensive review in the current developments of synthesis and the medicinal chemistry of coumarin sulfonamide-based scaffolds give a whole range of therapeutics, especially in the field of oncology and carbonic anhydrase inhibitors. In the present review, various synthetic approaches, strategies, and methodologies involving effect of catalysts, the change of substrates, and the employment of various synthetic reaction conditions to obtain high yields is cited.     

Facile and direct synthesis of symmetrical acid anhydrides using a newly prepared powerful and efficient mixed reagent

An efficient mixed reagent for direct synthesis of symmetrical carboxylic anhydrides from carboxylic acids has been prepared. Carboxylic acids are converted to anhydrides using triphenylphosphine/trichloroisocyanuric acid under mild reaction conditions at room temperature. Short reaction time, excellent yields of products, low cost, availability of reagents, simple experimental procedure, and easy work-up of the products are the main advantages of the presented method.     

Magnetic Signatures of Hydroxyl- and Water-Terminated Neutral and Tetra-Anionic Mn12-Acetate

We investigate the energetics and magnetic signatures of the parent molecular magnet Mn₁₂-Acetate [Mn₁₂O₁₂(COOR)₁₆(H₂O)₄] and a chemically decomposed version of this structure, in which the four water molecules are converted to hydroxyl groups and hydrogen molecules. We determine electron addition and water decomposition energetics for this water-containing molecule using density-functional methods and include the recent Fermi-Löwdin-Orbital self-interaction correction. We find that it only costs 0.32 eV to add four electrons to the parent molecule. Furthermore, due to the strong Coulomb attractions between hydroxyl anions and the Mn cations, the energy cost for breaking the four coordinating water molecules into four coordinating hydroxyls and two hydrogen molecules is decreased in the tetra-anionic structure relative to the neutral structure. We calculate magnetic anisotropy barriers for the neutral molecule and the dehydrogenated tetra-anion and show that large changes in the magnetic anisotropy arise the strong attraction between the hydroxyl anions and four of the crown Mn cations. We suggest that the large changes in magnetic signals associated with the [Mn₁₂O₁₂(COOR)₁₆(HOH)₄] to [Mn₁₂O₁₂(COOR)₁₆(OH⁻)₄ + 2H₂] decomposition could provide a nondestructive spectroscopic method for learning about water decomposition mechanisms in a class of realizable model catalytic systems that have been synthesized recently. © 2019 Wiley Periodicals, Inc.     

Green Synthesis of CeO2 Nanoparticles from the Abelmoschus esculentus Extract: Evaluation of Antioxidant,Anticancer, Antibacterial,and Wound-Healing Activities

Metal oxide nanoparticles synthesized by the biological method represent the most recent research in nanotechnology. This study reports the rapid and ecofriendly approach for the synthesis of CeO₂ nanoparticles mediated using the Abelmoschus esculentus extract. The medicinal plant extract acts as both a reducing and stabilizing agent. The characterization of CeO₂ NPs was performed by scanning electron microscopy (SEM), X-ray diffraction (XRD), ultraviolet-visible spectroscopy (UV-Vis), and Fourier transform infrared spectroscopy (FTIR). The in vitro cytotoxicity of green synthesized CeO₂ was assessed against cervical cancerous cells (HeLa). The exposure of CeO₂ to HeLa cells at 10–125 µg/mL caused a loss in cellular viability against cervical cancerous cells in a dose-dependent manner. The antibacterial activity of the CeO₂ was assessed against S. aureus and K. pneumonia. A significant improvement in wound-healing progression was observed when cerium oxide nanoparticles were incorporated into the chitosan hydrogel membrane as a wound dressing.