Novel amide derivatives of 3-phenylglutaric acid as potent soluble epoxide hydrolase inhibitors

Molecular Diversity - Soluble epoxide hydrolase (sEH) enzyme plays an important role in the metabolism of endogenous chemical mediators, epoxyeicosatrienoic acids, which are involved in the...     

k-torsionless modules with finite Gorenstein dimension

Let R be a commutative Noetherian ring. It is shown that the finitely generated R-module M with finite Gorenstein dimension is reflexive if and only if M _p is reflexive for p ∈ Spec(R) with depth(R _p) ? 1, and $G - {\dim _{{R_p}}}$ (M _p) ? depth(R _p) ? 2 for p ∈ Spec(R) with depth(R _p) ? 2. This gives a generalization of Serre and Samuel’s results on reflexive modules over a regular local ring and a generalization of a recent result due to Belshoff. In addition, for n ? 2 we give a characterization of n-Gorenstein rings via Gorenstein dimension of the dual of modules. Finally it is shown that every R-module has a k-torsionless cover provided R is a k-Gorenstein ring.     

Synthesis and Antimicrobial Activity of New Pyridothienopyrimidines and Pyridothienotriazines

5‐Acetyl‐3‐amino‐4‐aryl‐6‐methylthieno[2,3‐b]pyridine‐2‐carboxamides ( 5a,b ) were reacted with triethyl orthoformate or nitrous acid to give the corresponding pyrimidinones 6a,b and triazinones 7a,b . The reaction of 5a,b with acetic anhydride was carried out and its products were identified as a mixture of 8‐acetyl‐9‐aryl‐2,7‐dimethylpyrido[3′,2′:4,5]thieno[3,2‐d]pyrimidine‐4(3H)‐one ( 9a,b ) and related 5‐acetyl‐4‐aryl‐3‐biacetylamino‐6‐methylthieno[2,3‐b]pyridine‐2‐carbonitrile ( 10a,b ). Reaction of 7a with some halocompounds afforded the N‐alkylated triazinones 8a‐c . Chlorination of 6a,b and 9a,b with phosphorus oxychloride produced 4‐chloropyrimidines 11a‐d which were used as precursors for the rest of the target heterocycles. Some of the prepared compounds were tested in vitro for their antimicrobial activities.     

Solvation numbers and hydration constant for thorium(IV) in ethanol-water medium

The solvation number and hydration constant of Th⁴⁺ in ethanol-water medium were determined at 25°C using UV-spectral and electrochemical measurements. A solvate formation equilibrium is demonstrated and characterized. Three molecules of ethanol (S) can bond to the metal cation with strengths comparable to that for H₂O to form ThS₃(H₂O) ₃ ⁴⁺ Formation of thorium monochelate with lawsone (2-hydroxy-1,4-naphthoquinone) eliminates bonding with alcohol molecules. The dissociation constant of the chelating agent_sK_a and the formation contant of the monochelated metal ion_sK _f ^* that are essentially independent of the solution composition are evaluated. Hydration titrations involving thorium-lawsone monochelate are performed and the data obtained from the changes of pH with solvent composition are analyzed. The solution independent constant,_sK _f ^* for thorium-lawsone complex formation in mixed aqueous ethanol is given by $$log_s K_f * = vpK_a + log_s K_h - log[LH] - vpH + 3logv$$ where vpK_a is the dissociation constant of the chelating agent LH in the solvent system of ν volume fraction of water and_sK_h is the solution-independent hydration constant of thorium (IV) in the solvent system. Log-values for the constants_sK_h,_sK _f ^* and_sK _a ^* are found to be 7.8±0.02, 11.38±0.04 and ?0.753, respectively.     

Synthesis of new water soluble diorganotin(IV) complexes with hydrazones derived from Girard-T reagent as antibacterial and anticancer agents

Three new water-soluble organotin complexes R₂Sn(5-BrSalGT)Cl [R = Ph, Me] and Ph₂Sn(2-OHNaphGT)Cl have been synthesized by the reaction of R₂SnCl₂ (R = Ph or Me) with Schiff bases derived from condensation of Girard-T reagent with 5-bromosalicylaldehyde and 2-naphthaldehyde, (5-BrH₂SalGT)Cl (1) and (2-OHH₂NaphGT)Cl (2). The synthesized compounds have been investigated by elemental analysis, conductometric measurements, IR, ¹H NMR, and ¹¹⁹Sn NMR spectroscopy. These data show that the deporotonated ligand is coordinated to Sn(IV) via ONO atoms and six-coordinate zwitterionic complexes are formed. The ligands and their complexes were investigated for their in vitro toxicity against Gram-positive (Bacillus subtilis and Staphylococcus aureus) and Gram-negative (Escherichia coli and Pseudomonas aeruginosa) bacteria. The results show remarkable antibacterial activity against the studied bacteria. All complexes exhibit more inhibitory effects than the parent ligand. The anticancer activity of all compounds were also performed on HN5 cell line and (2-OHH₂NaphGT)Cl with concentration of 1 mg mL^?1 was found to show higher anticancer activity than other compounds.     

Surfactant effects on the particle size,zeta potential,and stability of starch nanoparticles and their use in a pH-responsive manner

Storage conditions seem to be important in the long-term stability of nanoparticles (NPs). This work studies the effects of surfactants and storage container on particle size distribution and zeta potential during long-term storage of acid hydrolyzed potato starch NPs. The NPs were prepared from potato starch using acid hydrolysis and high-intensity ultrasonication. During the ultrasonic treatment, the surfactants were added dropwise to the solutions to reduce the size and stabilize the formed NPs. Particle size distribution, zeta potential, and FE-SEM were used to characterize the ensuing NPs. Additionally, a 5-month stability study was performed to evaluate the maintenance of potato starch NPs over time at different storage conditions. Then, NPs from corn starch were produced by the same procedure and were used for preparing pH-responsive nanocarriers containing NaHCO₃ for delivery of an anti-cancer drug, FTY720. These NPs were able to release the drug at pH 5.0 because of CO₂ generated from NaHCO₃ in acidic pH and released from the NPs by the production of pores, which accelerate drug release.     

Green synthesis of silver nanoparticles by pepper extracts reduction and its electocatalytic and antibacterial activity

Stable silver nanoparticles were synthesized with the aid of a novel, non-toxic, eco-friendly biological material namely, green pepper extract. The aqueous pepper extract was used for reducing silver nitrate. The synthesized silver nanoparticles were analyzed with transmission electron microscopy (TEM), X-ray diffraction (XRD) and energy dispersive spectrometer (EDS). TEM image shows the formation of silver nanoparticles with average particle size of 20 nm which agrees well with the XRD data. The main advantage of using pepper extract as a stabilizing agent is that it provides long-term stability for nanoparticles by preventing particles agglomeration. To investigate the electrocatalytic efficiency of silver nanoparticles, silver nanoparticles modified carbon-paste electrode (AgNPs–CPE) displayed excellent electrochemical catalytic activities towards hydrogen peroxide (H₂O₂) and hydrogen evolution reaction (HER). The reduction overpotential of H₂O₂ was decreased significantly compared with those obtained at the bare CPE. An abrupt increase of the cathodic current for HER was observed at modified electrode. Also, the antibacterial activity of silver nanoparticle was performed using Escherichia coli and Salmonellae. The approach of plant-mediated synthesis appears to be cost efficient, eco-friendly and easy methods.     

CuI-catalyzed Coupling Reactions of Aryl Iodides with Amides Using L-Proline and KF/Al2O3

An efficient experimentally simple and inexpensive catalyst system for the selective amidation of aryl iodides using 15 mol% of CuI as catalyst, 15 mol% of L-proline as ligand and KF/Al2O3 as a base in toluene is described.     

Recent strategies in the synthesis of thiophene derivatives: highlights from the 2012–2020 literature

Molecular Diversity - Thiophene-based analogs have been fascinated by a growing number of scientists as a potential class of biologically active compounds. Furthermore, they play a vital role for...