Bis-adducts formed by nickel(II) and zinc(II) chelates of pyridine-2-(1H)thiones with nitrogen donors

Summary The bis-adducts formed by nickel(II) and zinc(II) chelates of 3-cyano-4-aryl-6-phenyl pyridine-2-(1H)thiones with pyridine and N-methylimidazole have been prepared and characterized by microelemental analyses, i.r., u.v., vis., and ¹Hn.m.r. spectra and magnetic measurements. Owing to Lewis acid-base interactions, the diamagnetic square planar nickel(II) or zinc(II) chelates interact with two molecules of pyridine or N-methylimidazole in the two axial positions forming the corresponding octahedral bis-adducts.     

The influence of solvent structure on the solvolysis of a ruthenium(II) complex in water–acetonitrile mixtures

The solvent effect on the rate of aquation of trans-[Ru(py)₄Cl₂] has been investigated by u.v. spectroscopy in the 40–55 °C range in MeCN–H₂O media. The thermodynamic activation parameters are calculated and discussed in terms of solvation effects. Log k was correlated with the reciprocal of the dielectric constant. A non-linear correlation was obtained and is discussed on the basis of specific solvation.     

Synthesis and antimicrobial activities of some newly 2,4,6-tri-substituted pyridine derivatives

A series of novel 2-(2-(substituted benzylidene)hydrazinyl)-N′-(substituted benzylidene)-6-chloropyridine-4-carbohydrazide (5a–e), 2-(2-cycloalkylidenehydrazinyl)-6-chloro-N’-cyclo-alkylidenepyridine-4-carbohydrazide (6a,b), 2-(2-(1-(4-substituted phenyl)ethylidene)hydrazinyl)-6-chloro-N′-(1-(4-substituted phenyl)ethylidene)pyridine-4-carbohydrazide (7a,b) and 2-(2-(1-(pyridinyl)ethylidene)hydrazinyl)-6-chloro-N′-(1-(pyridinyl) ethylidene)pyridine-4-carbo-hydrazide (8a–c) derivatives have been synthesized by treating treating 2-chloro-6-hydrazinoisonicotinic acid hydrazide 4 with selected active reagents. Their structures were confirmed by spectral and analytical data. The synthesized compounds were investigated for antimicrobial activities. The antimicrobial screening showed that many of these obtained compounds have good activities comparable to Streptomycin and Fusidic acid as reference drugs.     

Synthesis and Pharmacological Investigations of Novel Pyrazolyl and Hydrazonoyl Cyanide Benzimidazole Entities

Various novel benzimidazole entities linked to pyrazolyl and hydrazonoyl cyanide substrates carrying aryl and heteroaryl groups ( 8a – e to 10a – e ) were synthesized using new route syntheses and were focused on their pharmacological evaluation as one of the most important factors for the determination of the activity of these synthesized compounds. The obtained benzimidazoles' series were fully characterized and exhibited remarkable pharmacological activity upon in vitro screening for their antibacterial activity against strains of selected pathogenic Gram‐positive bacteria (Staphylococcus aureus) and Gram‐negative bacteria (Escherichia coli) comparing with Ampicillin and Kanamycin as standard antibacterial agents and against human liver cancer cell lines (HepG2) as antitumor agents as well.     

Synthesis and characterization of novel 1-[(2-hydroxyethoxy)methyl]-6-(phenylthio)thymine (HEPT) and dihydro-alkylthio-benzyloxopyrimidine (S-DABO) analogs containing a benzo[<Emphasis Type="Italic">d</Emphasis>]thiazol moiety

A series of novel dihydro-alkylthio-benzyloxopyrimidine (S-DABO) and 1-[(2-hydroxyethoxy) methyl]-6-(phenylthio)thymine (HEPT) analogs bearing a (benzo[d]thiazol-2-yl)methyl moiety at the C⁶ position of the pyrimidine core have been synthesized. 5-Allyl-6-{(benzo[d]thiazol-2-yl)methyl}-2-thiouracil and 5-allyl-6-{(benzo-[d]thiazol-2-yl)methyl}uracil were alkylated to give, respectively, S²- and N¹- ethoxymethyl and -methylthiomethyl uracil derivatives. 5-Allyl-6-[(benzo[d]thiazol-2-yl)methyl]-2-thiouracil was also alkylated by S² with methyl bromoacetate and hydrolyzed to the corresponding acid.     

Docking Analysis of Some Bioactive Compounds from Traditional Plants against SARS-CoV-2 Target Proteins

COVID-19 is still a global pandemic that has not been stopped. Many traditional medicines have been demonstrated to be incredibly helpful for treating COVID-19 patients while fighting the disease worldwide. We introduced 10 bioactive compounds derived from traditional medicinal plants and assessed their potential for inhibiting viral spike protein (S-protein), Papain-like protease (PLpro), and RNA dependent RNA polymerase (RdRp) using molecular docking protocols where we simulate the inhibitors bound to target proteins in various poses and at different known binding sites using Autodock version 4.0 and Chimera 1.8.1 software. Results found that the chicoric acid, quinine, and withaferin A ligand strongly inhibited CoV-2 S -protein with a binding energy of −8.63, −7.85, and −7.85 kcal/mol, respectively. Our modeling work also suggested that curcumin, quinine, and demothoxycurcumin exhibited high binding affinity toward RdRp with a binding energy of −7.80, −7.80, and −7.64 kcal/mol, respectively. The other ligands, namely chicoric acid, demothoxycurcumin, and curcumin express high binding energy than the other tested ligands docked to PLpro with −7.62, −6.81, and −6.70 kcal/mol, respectively. Prediction of drug-likeness properties revealed that all tested ligands have no violations to Lipinski’s Rule of Five except cepharanthine, chicoric acid, and theaflavin. Regarding the pharmacokinetic behavior, all ligand predicted to have high GI-absorption except chicoric acid and theaflavin. At the same way chicoric acid, withaferin A, and withanolide D predicted to be substrate for multidrug resistance protein (P-gp substrate). Caffeic acid, cepharanthine, chicoric acid, withaferin A, and withanolide D also have no inhibitory effect on any cytochrome P450 enzymes. Promisingly, chicoric acid, quinine, curcumin, and demothoxycurcumin exhibited high binding affinity on SARS-CoV-2 target proteins and expressed good drug-likeness and pharmacokinetic properties. Further research is required to investigate the potential uses of these compounds in the treatment of SARS-CoV-2.     

Mixed ligand extraction of cobalt(II) by thenoyltrifluoroacetone and triphenylphosphine or triphenylarsine oxides in chloroform

Extraction of Co(II) from perchlorate aqueous media by mixtures of thenoyltrifluoroacetone and triphenylarsine oxide or triphenylphosphine oxide in chloroform has been studied. It is found that the presence of these oxides enhances the extraction of Co(II). Synergic factors and formation constants were calculated and interpreted in the light of the electron donating properties of these oxides.     

Ab initio study of oxygen point defects on tungsten trioxide surface

The gas response of tungsten trioxide (WO3) based sensors strongly depends on the surface properties. Reconstructed surfaces and oxygen point defects at the surface of the monoclinic WO3 are studied using a self-consistent scheme based on first-principle. The oxygen vacancy is found to be the predominant defect independently of the oxygen partial pressure. Indeed, under rich oxygen atmosphere the formation enthalpies are found to be 1.45 eV in LDA (1.28 eV in GGA) for the oxygen vacancy instead of 2.70 eV (2.42 eV) for the oxygen adatom. When the oxygen partial pressure is lowered, the oxygen vacancy formation enthalpy decreases and becomes exothermic under very O-poor condition (? 1.65 eV in LDA and ? 1.36 eV in GGA). On the other hand, the formation enthalpy of an oxygen adatom rises. Finally, the oxygen vacancy formation acts as a n-doping by introducing negative charge carriers at the bottom of the conduction band. All these results can be very helpful in order to explain the electrical resistivity measurements.