Synthesis,Antiviral, and Antimicrobial Activity of N‐ and S‐Alkylated Phthalazine Derivatives

A series of N‐alkylphthalazinone were synthesized by the reaction of phthalazin‐1(2H)‐one derivatives 1a , 1b , 1c with alkylating agents namely, propargyl, allyl bromide, epichlorohydrin, 1,3‐dichloro‐2‐propanol, 4‐bromobutylacetate, and 1‐(bromomethoxy)ethyl acetate to give the corresponding N‐alkylphthalazinone 2a , 2b , 2c , 3a , 3b , 3c , 5a , 5b , 5c , 6a , 6b , 6c , 7a , 7b , 7c , and 9a , 9b , 9c . Alkylation of phthalazin‐1(2H)‐thione to give a series from S‐alkylphthalazine 12 , 13 , 14 and thioglycosides 15 and 17 was performed. Deprotection of compounds 7a , 7b , 7c , 9a , 9b , 9c , 15 , and 17 resulted in the formation of the corresponding products 8a , 8b , 8c , 10a , 10b , 10c , 16 , and 18 . The structure of newly synthesized compounds was assigned by IR, ¹H, ¹³C NMR, and elemental analysis. Some of these compounds were screened for antiviral and antimicrobial activity.     

Solanum elaeagnifolium Var. Obtusifolium (Dunal) Dunal: Antioxidant,Antibacterial, and Antifungal Activities of Polyphenol-Rich Extracts Chemically Characterized by Use of In Vitro and In Silico Approaches

The present work was designed to study the chemical composition and the antioxidant and antimicrobial properties of fruits (SFr) and leaf (SF) extracts from Solanum elaeagnifolium var. obtusifolium (Dunal) Dunal (S. elaeagnifolium). The chemical composition was determined using HPLC-DAD analysis. Colorimetric methods were used to determine polyphenols and flavonoids. Antioxidant capacity was assessed with DPPH, TAC, and FRAP assays. Antimicrobial activity was assessed using disk diffusion and microdilution assays against two Gram (+) bacteria (Staphylococcus aureus ATCC-6633 and Bacillus subtilis DSM-6333) and two Gram (-) bacteria (Escherichia coli K-12 and Proteus mirabilis ATCC-29906), while the antifungal effect was tested vs. Candida albicans ATCC-1023. By use of in silico studies, the antioxidant and antimicrobial properties of the studied extracts were also investigated. HPLC analysis showed that both fruits and leaf extracts from S. elaeagnifolium were rich in luteolin, quercetin, gallic acid, and naringenin. Both SFr and SF generated good antioxidant activity, with IC₅₀ values of 35.15 ± 6.09 μg/mL and 132.46 ± 11.73 μg/mL, respectively. The EC₅₀ of SFr and SF was 35.15 ± 6.09 μg/mL and 132.46 ± 11.73 μg/mL, respectively. SFr and SF also showed a good total antioxidant capacity of 939.66 ± 5.01 μg AAE/and 890.1 ± 7.76 μg AAE/g, respectively. SFr had important antibacterial activity vs. all tested strains—most notably B. subtilis DSM-6333 and E. coli, with MICs values of 2.5 ± 0.00 mg/mL and 2.50 ± 0.00 mg/mL, respectively. SFr demonstrated potent antifungal activity against C. albicans, with an inhibition diameter of 9.00 ± 0.50 mm and an MIC of 0.31 ± 0.00 mg/mL. The in silico approach showed that all compounds detected in SFr and SF had high activity (between −5.368 and 8.416 kcal/mol) against the receptors studied, including NADPH oxidase, human acetylcholinesterase, and beta-ketoacyl-[acyl carrier protein] synthase.     

Spray-drying as a tool to disperse conductive carbon inside Na<Subscript>2</Subscript>FePO<Subscript>4</Subscript>F particles by addition of carbon black or carbon nanotubes to the precursor solution

In this work, Na₂FePO₄F-carbon composite powders were prepared by spray-drying a solution of inorganic precursors with 10 and 20 wt% added carbon black (CB) or carbon nanotubes (CNTs). In order to compare the effect of CB and CNT when added to the precursor solutions, the structural, electrochemical, and morphological properties of the synthesized Na₂FePO₄F-xCB and Na₂FePO₄F-xCNT samples were systematically investigated. In both cases, X-ray diffraction shows that calcination at 600 °C in argon leads to the formation of Na₂FePO₄F as the major inorganic phase. ⁵⁷Fe Mössbauer spectroscopy was used as complementary technique to probe the oxidation states, local environment, and identify the composition of the iron-containing phases. The electrochemical performance is markedly better in the case of Na₂FePO₄F-CNT (20 wt%), with specific capacities of about 100 mAh/g (Na₂FePO₄F-CNT) at C/4 rate vs. 50 mAh/g for Na₂FePO₄F-CB (20 wt%). SEM characterization of Na₂FePO₄F-CB particles revealed different particle morphologies for the Na₂FePO₄F-CNT and Na₂FePO₄F-CB powders. The carbon-poor surface observed for Na₂FePO₄F-CB could be due to a slow diffusion of carbon in the droplets during drying. On the contrary, Na₂FePO₄F-CNT shows a better CNT dispersion inside and at the surface of the NFPF particles that improves the electrochemical performance.     

Antimicrobial Activity and DFT Studies of a Novel Set of Spiropyrrolidines Tethered with Thiochroman-4-one/Chroman-4-one Scaffolds

A novel series of 14 spiropyrrolidines bearing thiochroman-4-one/chroman-4-one, and oxindole/acenaphthylene-1,2-dione moieties were synthesized and characterized by spectroscopic techniques, as well as by three X-ray diffraction studies, corroborating the stereochemistry. Quantum chemical calculations studies, using the DFT approach, were performed to rationalize the stereochemical outcome. These N-heterocycles were evaluated for their antibacterial and antifungal activities against some pathogenic organisms. Several compounds displayed moderate to excellent activity towards the screened microbe strains in the study compared to Amoxicillin (AMX), Ampicillin (AMP), and Amphotericin B. Furthermore, a structural activity relationship (SAR) was established considering the synthesized compounds. Pharmacokinetic studies reveal that these derivatives exhibit an acceptable predictive ADMET profile (Absorption, Distribution, Metabolism, Excretion and Toxicity) and good drug-likeness.     

Hydrazidoyl halides in synthesis of Δ2-1,3,4-selenadiazolin-5-ones

Reaction of hydrazidoyl halides 1-5 with potassium selenocyanate in ethanol produces the corresponding 2,4-disubstituted-5-iminoδ²-1,3,4-selenadiazolines, 9-13 respectively. Nitrosation of the latter yields the N-nitroso derivatives 14-17 , which decompose upon refluxing in xylene to give 2,4-disubstituted Δ²-1,3,4-selenadiazolin-5-ones in good yield. Compounds 9-13 give the respective N-acetyl derivatives 22-26 and N-benzoyl derivatives 27-31 with acetic anhydride and benzoyl chloride in pyridine.     

Linear and weakly nonlinear variable viscosity convection in spherical shells

A theoretical study of linear and weakly nonlinear thermal convection in a spherical shell is performed. The Boussinesq fluid is of infinite Prandtl number and its viscosity is temperature dependent. The linear stability eigenvalue problem is derived and solved by a shooting method assuming isothermal, stress-free boundaries, a self-gravitating fluid, and corresponding to two heating models. The first is heating from below, and the second is a model of combined heating from below and within, such that convection is described by a self-adjoint linear stability formulation. In addition, nonlinear, hemispherical, axisymmetric convection is computed by a finite volume technique for a shell with 0.5 aspect ratio. It is shown that 2-cell convection occurs as transcritical bifurcation for a viscosity constrast across the shell up to about 150. Motions with four cells are also possible. As expected, the subcritical range is found to increase with increasing viscosity contrast, even when the linear operator is self-adjoint.This research was supported by the AT&T Foundation.     

A fluorogenic red fluorescent protein heterodimer

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Highlights? A dimerization-dependent red fluorescent protein (ddRFP) was engineered ? ddRFP fluorogenesis results from modulation of pK_a and quantum yield ? ddRFP-based biosensors exhibit reversible intensiometric responses ? ddRFP-based biosensors can detect Ca²⁺ dynamics and caspase-3 activity in live cells