Elemental Sulfur Disproportionation in the Redox Condensation Reaction between o‐Halonitrobenzenes and Benzylamines

The disproportionation of elemental sulfur at moderate temperatures is investigated in the redox condensation involving o‐halonitrobenzenes 1 and benzylamines 2 . As a redox moderator, elemental sulfur plays the dual role of both electron donor and acceptor, generating its lowest and highest oxidation states: S^?2 (sulfide equivalent) in benzothiazole 3 and S⁺⁶ (sulfate equivalent) in sulfamate 4 , and filling the electron gap of the global redox condensation process. Along with this process, a cascade of reactions of reduction of the nitro group of 1 , oxidation of the aminomethyl group of 2 , metal‐free aromatic halogen substitution, and condensation finally led to 2‐arylbenzothiazoles 3 .     

Single oscillator model and refractive index dispersion properties of ternary ZnO films by sol gel method

The optical constants of the NiMnZnO thin films prepared by spin-coating method were determined using transmittance and reflectance spectra. The optical band gap of the NiMnZnO thin films was found to be in the range of 3.20–3.35 eV. The refractive index dispersion of the NiMnZnO films obeys the single oscillator model. The dispersion energy and oscillator energy values of the NiMnZnO films were found to be in the range of 6.46–9.85 and 4.82–5.54 eV, respectively. The real and imaginary parts of the dielectric constants of the NiMnZnO films were determined. The reflectance spectra of the NiMnZnO films give a peak and the presence of this peak is due to the photoexcitation process, in which, the electrons are excited from valence band to the conduction band. The obtained results suggest that the optical constants and refractive dispersion energy parameters of the films are controlled by the molar ratios of NiMnZnO films.     

Deposition of Phosphate Nanoparticles onto Textile Fabrics via Sol-gel Method and Their Kinetics Desorption Studies

In this paper, phosphate nanoparticles were coated on cotton(CO) and polyester(PES) textile surfaces by sol-gel method using tetraethylorthosilicate(TEOS) and chloropropyltriethoxysilane(CPTS) as silica precursors. The deposited nanoparticles were observed with scanning electronic microscopy energy-dispersive X-ray spectroscopy (SEM-EDX). The release kinetics of phosphorus(P) from these textiles into the aqueous medium(Aq), acid(Ac), and basic(Ba) artificial sweats were then studied. The released amount of phosphorus was evaluated by the inductively coupled plasma(ICP) according to ISO NF EN 16711-2 procedure. The results revealed that the release of P into the aqueous medium is lower than in the artificial sweat. The kinetics data[the phosphorus desorption amount(mg/g) as a function of time] were modeled according to five models:the first order, the second order, the third order, simple Elovich and parabolic diffusion. The suitable model was chosen based on the coefficient of determination(R²) and the calculation of the sum of the absolute errors(EABS), which describes the error between the theoretical and experimental values. SEM observations were also carried out on the fabrics after desorption in order to show the impact of desorption on their morphology. Furthermore, the impact of P release on the tensile strength of CO and PES fabrics was investigated using a uniaxial tensile test. The thermal stability of all samples before and after desorption was assessed by thermogravimetric analysis(ATG).     

Entrapment of organic fluorophores in calcium phosphate nanoparticles with slow release

Two organic fluorophores, fluorescein (F) and rhodamine B (Rd), were entrapped in calcium phosphate nanoparticles. The as-obtained nanoparticles can be used for biological release applications. For this aim, calcium phosphate nanoparticles were synthesized using the precipitation method. Structural analysis of these nanoparticles was performed using XRD, FTIR, and Raman spectroscopy, confirming that the synthesized nanoparticles were hydroxyapatite. TEM and SEM analyses demonstrated that these nanoparticles had a size of 20 nm and a well-defined morphology. F and Rd (about 0.5 wt.%) were entrapped in these nanoparticles and their release, as a function of time, was studied via UV-Vis spectroscopy. The obtained results showed that the release of both fluorophores was progressive over time. The trapping efficiencies of the fluorophores were 67.15% and 90.76% for F and Rd, respectively.     

Divergent Strain‐Release Amino‐Functionalization of [1.1.1]Propellane with Electrophilic Nitrogen‐Radicals

Herein we report the development of a photocatalytic strategy for the divergent preparation of functionalized bicyclo[1.1.1]pentylamines. This approach exploits, for the first time, the ability of nitrogen‐radicals to undergo strain‐release reaction with [1.1.1]propellane. This reactivity is facilitated by the electrophilic nature of these open‐shell intermediates and the presence of strong polar effects in the transition‐state for C?N bond formation/ring‐opening. With the aid of a simple reductive quenching photoredox cycle, we have successfully harnessed this novel radical strain‐release amination as part of a multicomponent cascade compatible with several external trapping agents. Overall, this radical strategy enables the rapid construction of novel amino‐functionalized building blocks with potential application in medicinal chemistry programs as p‐substituted aniline bioisosteres.     

Extending the Sensitivity of CEST NMR Spectroscopy to Micro‐to‐Millisecond Dynamics in Nucleic Acids Using High‐Power Radio‐Frequency Fields

Biomolecules undergo motions on the micro‐to‐millisecond timescale to adopt low‐populated transient states that play important roles in folding, recognition, and catalysis. NMR techniques, such as Carr–Purcell–Meiboom–Gill (CPMG), chemical exchange saturation transfer (CEST), and R_1ρ are the most commonly used methods for characterizing such transitions at atomic resolution under solution conditions. CPMG and CEST are most effective at characterizing motions on the millisecond timescale. While some implementations of the R_1ρ experiment are more broadly sensitive to motions on the micro‐to‐millisecond timescale, they entail the use of selective irradiation schemes and inefficient 1D data acquisition methods. Herein, we show that high‐power radio‐frequency fields can be used in CEST experiments to extend the sensitivity to faster motions on the micro‐to‐millisecond timescale. Given the ease of implementing high‐power fields in CEST, this should make it easier to characterize micro‐to‐millisecond dynamics in biomolecules.     

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.     

Promoting Effect of Soluble Polysaccharides Extracted from Ulva spp. on Zea mays L. Growth

Seaweeds can play a vital role in plant growth promotion. Two concentrations (5 and 10 mg/mL) of soluble polysaccharides extracted from the green macroalgae Ulva fasciata and Ulva lactuca were tested on Zea mays L. The carbohydrate and protein contents, and antioxidant activities (phenols, ascorbic, peroxidase, and catalase) were measured, as well as the protein banding patterns. The soluble polysaccharides at 5 mg/mL had the greatest effect on the base of all of the parameters. The highest effects of soluble polysaccharides on the Zea mays were 38.453, 96.76, 4, 835, 1.658, 7.462, and 38615.19, mg/mL for carbohydrates, proteins, phenol, µg ascorbic/mL, mg peroxidase/g dry tissue, and units/g tissue of catalase, respectively. The total number of protein bands (as determined by SDS PAGE) was not changed, but the density of the bands was correlated to the treatments. The highest band density and promoting effect were correlated to 5 mg/mL soluble polysaccharide treatments extracted from Ulva fasciata in Zea mays, which can be used as a biofertilizer.     

Development of Sustained Release Baricitinib Loaded Lipid-Polymer Hybrid Nanoparticles with Improved Oral Bioavailability

Baricitinib (BTB) is an orally administered Janus kinase inhibitor, therapeutically used for the treatment of rheumatoid arthritis. Recently it has also been approved for the treatment of COVID-19 infection. In this study, four different BTB-loaded lipids (stearin)-polymer (Poly(d,l-lactide-co-glycolide)) hybrid nanoparticles (B-PLN1 to B-PLN4) were prepared by the single-step nanoprecipitation method. Next, they were characterised in terms of physicochemical properties such as particle size, zeta potential (ζP), polydispersity index (PDI), entrapment efficiency (EE) and drug loading (DL). Based on preliminary evaluation, the B-PLN4 was regarded as the optimised formulation with particle size (272 ± 7.6 nm), PDI (0.225), ζP (−36.5 ± 3.1 mV), %EE (71.6 ± 1.5%) and %DL (2.87 ± 0.42%). This formulation (B-PLN4) was further assessed concerning morphology, in vitro release, and in vivo pharmacokinetic studies in rats. The in vitro release profile exhibited a sustained release pattern well-fitted by the Korsmeyer–Peppas kinetic model (R² = 0.879). The in vivo pharmacokinetic data showed an enhancement (2.92 times more) in bioavailability in comparison to the normal suspension of pure BTB. These data concluded that the formulated lipid-polymer hybrid nanoparticles could be a promising drug delivery option to enhance the bioavailability of BTB. Overall, this study provides a scientific basis for future studies on the entrapment efficiency of lipid-polymer hybrid systems as promising carriers for overcoming pharmacokinetic limitations.     

Polyphenolics with Strong Antioxidant Activity from Acacia nilotica Ameliorate Some Biochemical Signs of Arsenic-Induced Neurotoxicity and Oxidative Stress in Mice

Neurotoxicity is a serious health problem of patients chronically exposed to arsenic. There is no specific treatment of this problem. Oxidative stress has been implicated in the pathological process of neurotoxicity. Polyphenolics have proven antioxidant activity, thereby offering protection against oxidative stress. In this study, we have isolated the polyphenolics from Acacia nilotica and investigated its effect against arsenic-induced neurotoxicity and oxidative stress in mice. Acacia nilotica polyphenolics prepared from column chromatography of the crude methanol extract using diaion resin contained a phenolic content of 452.185 ± 7.879 mg gallic acid equivalent/gm of sample and flavonoid content of 200.075 ± 0.755 mg catechin equivalent/gm of sample. The polyphenolics exhibited potent antioxidant activity with respect to free radical scavenging ability, total antioxidant activity and inhibition of lipid peroxidation. Administration of arsenic in mice showed a reduction of acetylcholinesterase activity in the brain which was counteracted by Acacia nilotica polyphenolics. Similarly, elevation of lipid peroxidation and depletion of glutathione in the brain of mice was effectively restored to normal level by Acacia nilotica polyphenolics. Gallic acid methyl ester, catechin and catechin-7-gallate were identified in the polyphenolics as the major active compounds. These results suggest that Acacia nilotica polyphenolics due to its strong antioxidant potential might be effective in the management of arsenic induced neurotoxicity.