Design and development of cyclohexane-based P,N-ligands for transition metal catalysis

[reaction: see text] A new class of cyclohexane-based P,N-ligands is readily obtained through aziridine ring opening with suitable phosphorus nucleophiles under acidic conditions. trans-1-Amino-2-diphenylphosphinocyclohexane is resolved with tartaric acid to give the final product in >99% ee. The new ligands show high stability toward oxidation at the phosphorus atom.     

Diammonium Hydrogen Phosphate as an Efficient and Inexpensive Catalyst for the Synthesis of Bis(indolyl)methanes under Solvent-Free Conditions

Bis(indolyl)methanes were synthesized by the reaction of indole derivatives and aromatic and aliphatic aldehydes in the presence of diammonium hydrogen phosphate as a solid catalyst under solvent-free conditions. This methodology offers significant improvements for the synthesis of bis(indolyl)methanes with regard to the yield of products, simplicity in operation, and green aspects by avoiding toxic catalysts and solvents.     

Transition metal-catalyzed synthesis and reactivity of N-alkenyl aziridines

[reaction: see text] Straightforward methods for palladium-catalyzed alkenylation of aziridines with alkenyl halides and copper-catalyzed alkenylation of aziridines with alkenyl boronic acids have been developed. This methodology offers attractive alternatives to the known methods requiring activated alkenyl halides and acetylenes. A wide variety of N-alkenyl aziridines containing substituents other than electron-withdrawing substituents such as cyano groups and sulfones have been synthesized in good yields. Furthermore, these N-alkenyl aziridines exhibit quite a different reactivity from conventional enamines, as demonstrated by their reactivity.     

Optimization of solid phase dispersive field‐assisted ultrasonication for the extraction of auramine O and crystal violet dyes using central composite design

Simultaneous preconcentration and determination of auramine o (AO) and crystal violet (CV) dyes from aqueous solution was conducted by ultrasound assisted (dispersive) solid phase microextraction (UASPME) based on SnO₂/SnS composite loaded activated carbon (SnO₂/SnS‐NCs‐AC). The prepared of SnO₂/SnS‐NCs‐AC was characterized by FESEM and XRD analysis. Main and interaction influences of operational parameters such as pH, sonication time, amounts of sorbent, and type of eluent on extraction efficiency were investigated by central composite design and optimized with desirability function approach (DFA). ANOVA was conducted and shows that optimized values were found at 15.33 min sonication time, 0.019 g SnO₂/SnS‐NCs‐AC mass, pH 5.46 and among different solvents, dimethyl formamide was selected as an efficient eluent. Under this conditions recoverees percentage were obtained 82.85% and 86.70% for AO and CV, respectively. Based on F‐test under ANOVA all main effect and interaction effect of understudy parameters has the significant effect on the responses. At optimum conditions, limit of detection (0.0015 and 0.001 mg/l), limit of quantitation (0.4 and 0.4 mg/l), limit of linearity (9.0 and 9.0 mg/l), enrichment factor (33.48 and 83.71) and percent relative standard deviation (3.44 and 4.20) were found to be for auramine o and crystal violet dyes, respectively. Finally, the method was successfully applied for the preconcentration and determination of AO and CV in water samples and ER% of 89.0‐97.0 and 96.2–98.0% as acceptable range were found to be for AO and CV samples, respectively.     

Preparation of chitosan functionalized end‐capped Ag‐NPs and composited with Fe3O4‐NPs: Controlled release to pH‐responsive delivery of progesterone and antibacterial activity against pseudomonas aeruginosa (PAO‐1)

In this work, functionalized chitosan end‐capped Ag nanoparticles (NPs) and composited with Fe₃O₄‐NPs was prepared as pH‐responsive controlled release carrier for gastric‐specific drug delivery. The structure of prepared material was characterized by FE‐SEM, XRD, EDS and FT‐IR analysis. The loading behavior of the progesterone onto this novel material was studied in aqueous medium at 25°C and their release was followed spectrophotometrically at 37°C in seven different buffer solutions (pH 1.2, 2.2, 3.2, 4.2, 5.2, 6.2 and 7.2) to simulate intestine and gastric media which experimental results reveal more release rate in pH 1.2 (gastric medium) with respect to other buffers. This observation is attributed to dependency of the CS‐IMBDO‐Ag‐Fe₃O₄‐NPs and progesterone structure with buffer pH that candidate this new material as prospective pH‐sensitive carrier for gastric‐targeted drug delivery. On the other hand, the antibacterial properties of this material against gram‐negative bacterium pseudomonas aeruginosa (PAO‐1) in agar plates was studied and accordingly based on broth micro dilution the minimum bactericidal concentration (MBC) and minimum inhibitory concentration (MIC) with respect to standard CLSI in different concentrations of CS‐IMBDO‐Ag‐Fe₃O₄‐NPs was calculated. The results reveal that MIC and MBC values are 50 and 1250 μg/mL, respectively. In addition, extracts of Portulaca oleracea leaves was prepared and its antibacterial activity in single and binary system with CS‐IMBDO‐Ag‐Fe₃O₄‐NPs as synergies effect against PAO‐1 was tested and results shown that these materials have significant synergistic effect for each other.     

Synthesis of Thio Analogues of Quinolone Antibacterials

A facile and rapid synthesis of thio compounds, analogues to ciprofloxacin, and norfloxacin is described.     

Supercritical CO2-assisted atomization for deposition of cellulose nanocrystals: an experimental and computational study

Nanoparticle spray deposition finds numerous applications in pharmaceutical, electronics, manufacturing, and energy industries and has shown great promises in engineering the functional properties of the coated parts. However, current spray deposition systems either lack the required precision in controlling the morphology of the deposited nanostructures or do not have the capacity for large-scale deposition applications. In this study, we introduce a novel spray system that uses supercritical CO₂ to assist the atomization process and create uniform micron-size water droplets that are used as cellulose nanocrystal (CNC) carriers. CNCs are selected in this study as they are abundant, possess superior mechanical properties, and contain hydroxyl groups that facilitate interaction with neighboring materials. We fundamentally investigate the effect of different process parameters, such as injection pressure, gas-to-liquid ratio, the axial distance between the nozzle and substrate, and CNC concentration on the final patterns left on the substrate upon evaporation of water droplets. To this end, we show how tuning process parameters control the size of carrier droplets, dynamics of evaporation, and self-assembly of CNCs, which in turn dictate the final architecture of the deposited nanostructures. We will particularly investigate the morphology of the nanostructures deposited after evaporation of micron-size droplets that has not been fully disclosed to date. Different characterization techniques such as laser diffraction, polarized microscopy, and high-resolution profilometry are employed to visualize and quantify the effect of each process parameter. Numerical simulations are employed to inform the design of experiments. Finally, it is shown that the fabricated nanostructures can be engineered based on the size of the carrier droplets controlled by adjusting spray parameters and the concentration of nanoparticles in the injected mixture. Process parameters can be selected such that nanoparticles form a ring, disk, or dome-shaped structure. Moderate operational conditions, simplicity, and time efficiency of the process, and use of abundant and biodegradable materials, i.e., water, CNCs, and CO₂ promote the scalability and sustainability of this method.

     

Cannabis-Derived Compounds Cannabichromene and Δ9-Tetrahydrocannabinol Interact and Exhibit Cytotoxic Activity against Urothelial Cell Carcinoma Correlated with Inhibition of Cell Migration and Cytoskeleton Organization

Cannabis sativa contains more than 500 constituents, yet the anticancer properties of the vast majority of cannabis compounds remains unknown. We aimed to identify cannabis compounds and their combinations presenting cytotoxicity against bladder urothelial carcinoma (UC), the most common urinary system cancer. An XTT assay was used to determine cytotoxic activity of C. sativa extracts on T24 and HBT-9 cell lines. Extract chemical content was identified by high-performance liquid chromatography (HPLC). Fluorescence-activated cell sorting (FACS) was used to determine apoptosis and cell cycle, using stained F-actin and nuclei. Scratch and transwell assays were used to determine cell migration and invasion, respectively. Gene expression was determined by quantitative Polymerase chain reaction (PCR). The most active decarboxylated extract fraction (F7) of high-cannabidiol (CBD) C. sativa was found to contain cannabichromene (CBC) and Δ9-tetrahydrocannabinol (THC). Synergistic interaction was demonstrated between CBC + THC whereas cannabinoid receptor (CB) type 1 and type 2 inverse agonists reduced cytotoxic activity. Treatments with CBC + THC or CBD led to cell cycle arrest and cell apoptosis. CBC + THC or CBD treatments inhibited cell migration and affected F-actin integrity. Identification of active plant ingredients (API) from cannabis that induce apoptosis and affect cell migration in UC cell lines forms a basis for pre-clinical trials for UC treatment.     

Electronic effects on atom tunneling: conformational isomerization of monomeric para-substituted benzoic acid derivatives

We present the first generation and spectroscopic identification of the higher-lying E conformer of the simplest aromatic carboxylic acid, benzoic acid (1a), as its O-deuterated isotopologue (E)-d(1)-1a using matrix-isolation techniques; the parent (E)-1a could not be observed because of fast H-tunneling to the more stable conformer (Z)-1a. Even deuterated (E)-d(1)-1a converts quickly back to (Z)-d(1)-1a through D-tunneling with a half-life (τ) of ～12 min in Ar at 11 K. Tunneling computations using an Eckart barrier in conjunction with a CCSD(T)/cc-pVTZ//MP2/cc-pVDZ + ZPVE intrinsic reaction path revealed that τ of (E)-1a is only ～10(-5) min, in marked contrast to those of simple aliphatic acids, which are in the range of minutes. The electronic substituent effects on D-tunneling in para-substituted benzoic acid derivatives (p-X-PhCOOD, d(1)-1) were systematically studied in Ar matrices at 11 K to derive the first Hammett relationships for atom tunneling. σ-Electron donors (X = alkyl) increase the half-life of d(1)-1, while σ-acceptor/π-donor groups (X = OD, NH(2), halogen) and to an even greater extent a σ-/π-acceptor group (X = NO(2)) decrease τ. The latter finding is in line with the smaller E-to-Z reaction barriers and narrower reaction widths for the isomerization. Tunneling substituent constants (σ(t)) for this conformational isomerization were derived experimentally and computationally.     

PVA-Based Sol–Gel Synthesis and Characterization of CdO–ZnO Nanocomposite

CdO–ZnO nanocomposite was fabricated by a sol–gel pyrrolysis method based on the poly vinyl alcohol (PVA) polymeric network. The prepared nanocomposite was carefully characterized using scanning electron microscopy, X-Ray dispersive energy analysis, ICP-atomic emission spectroscopy, X-Ray diffraction, transmission electron microscopy and UV–visible spectroscopy. The structure, composition, and morphology of this composite depend on a number of aspects: the amounts of cadmium salt, zinc salt, and PVA in the initial solution, the solvent composition, and the pyrrolysis temperature. The obtained results showed that the nanocomposite had excellent linear nanoclusters created from nanograins. Each nanograin was made of a CdO core, completely covered by ZnO layers. Total diameter of each nanograin was 70–90 nm.