ChemistrySelect最新文献

In this study, we have successfully developed an environmentally benign methodology for synthesizing para-nitrotoluene (p-NT) via catalytic nitration of toluene using nitrogen dioxide (NO₂) as the nitrating agent, with molecular oxygen (O₂) serving as an efficient promoter in the reaction system. The experimental results demonstrate that the Hβ zeolite-supported Lewis acid catalyst (AlCl₃) exhibits remarkable catalytic performance in the developed NO₂–O₂–Ac₂O system, achieving a toluene conversion of 78.5% with a p-NT selectivity of 62.5%. To elucidate the structure–activity relationship, the physicochemical properties of various catalysts were systematically characterized using multiple analytical techniques, including nitrogen physisorption (BET), x-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), temperature-programmed desorption of ammonia (NH₃-TPD), and scanning electron microscopy (SEM). On the basis of comprehensive catalytic characterization and density-functional theory (DFT) calculations, we propose a plausible reaction mechanism that accounts for the enhanced para-selectivity in the toluene nitration process within the NO₂–O₂–Ac₂O catalytic system.

Thermoplastic polyurethane (TPU) nanocomposites reinforced with hydroxylated multi-walled carbon nanotubes (MWCNTs) were synthesized via in situ polymerization of polycarbonate diol (PCDL), isophorone diisocyanate (IPDI), and chain extender. The MWCNTs were covalently integrated into the TPU matrix through reactions between surface hydroxyl groups and isocyanate. Systematic characterization revealed uniform MWCNT dispersion (SEM/XRD) without agglomeration up to 4 wt% loading. The nanocomposites exhibited enhanced hardness (80 to 89 Shore A), elevated thermal stability (5% weight loss temperature increased by 6 °C), and restricted soft-segment chain mobility (glass transition temperature rose from −37.34 to −26.26 °C). Critically, surface resistivity decreased dramatically from 10¹⁴ (pure TPU) to 3 × 10⁶ Ω (4 wt% MWCNTs), achieving antistatic performance (5 × 10¹¹ Ω) at only 1 wt% loading. This work demonstrates a robust strategy for developing high-performance antistatic TPU nanocomposites.

The rising global burden of cancer, coupled with the limitations and side effects of current treatments, necessitates the development of safer and more effective therapeutic strategies. Microbial nanotechnology offers an eco-friendly and innovative approach to address this challenge. Here, we report the green synthesis of biogenic gold nanoparticles (AuNP_008) using the extracellular supernatant of Bacillus sp. GB_SG_008. The nanoparticles, averaging 24.6 ± 7.7 nm, were synthesized without additional reducing agents and characterized by UV-visible spectroscopy, field-emission transmission electron microscope (FETEM), selected area electron diffraction (SAED), dynamic light scattering (DLS), x-ray diffraction (XRD), and Fourier transform infrared (FT-IR) spectroscopy. AuNPs_008 demonstrated potent anticancer activity against HeLa and MDA-MB-231 cells with minimal toxicity to normal HEK 293 cells, confirmed by cell proliferation and PI-FACS assays. Mechanistic studies revealed modulation of tumorigenesis-related proteins, including upregulation of pRB and p21 and downregulation of COX-2, Bcl-2, MMP9, and CXCR4. These findings emphasize the versatile role of bacterial-driven nanoparticles in modulating cellular processes and molecular signatures linked to cancer development. The present study highlights the promise of microbial nanotechnology as a novel strategy for advancing cancer therapeutics.

A solid polymer electrolyte based on chitosan was developed through solution casting, incorporating 1-propyl-1-methylpyrrolidinium bis(trifluoromethane sulfonylimide) ([PMP][TFSI]) ionic liquid (IL) as plasticizer and sodium iodide (NaI) as the salt. The formation of polymer–ion interactions was confirmed by Fourier-transform infrared (FTIR) spectroscopy. X-ray diffraction (XRD) and polarized optical microscopy (POM) have been used to carry out surface crystallinity and features. Thermal properties have been carried out using differential scanning calorimetry (DSC). Electrical characterization has been carried out using impedance spectroscopy, whereas ionic transference number (t_ion) was carried out using Wagner polarization method. Using maximum conducting IL-doped polymer electrolyte film sandwiched between two carbon electrodes, we have fabricated electric double-layer capacitor that shows a notable performance, which is confirmed by galvanostatic charge–discharge and cyclic voltammetry.

The era of generative artificial intelligence (AI) in drug design is here, and in this study, we applied a generative AI model to design potential non-nucleoside inhibitors of HIV-1 reverse transcriptase (RT). RT converts viral RNA into DNA, facilitating viral integration into a host's genome. Inhibiting RT is therefore critical in combating HIV-1. Using the REINVENT prior model, we fine-tuned it with classified RT inhibitors (pIC50 > 8.5) from ChEMBL, generating over 6000 compounds. These compounds underwent rigorous filtering, including classification by a Message Passing Neural Network (MPNN), PAINS filtering, pharmacophore modeling, structure-based screening, MMGBSA scoring, and ADMET prediction. We identified five top-performing compounds, which demonstrated superior docking scores (≤ −13.22 kcal/mol) and binding free energies (MMGBSA dG Bind ≤ −77.48 kcal/mol) compared to the reference ligand (−8.42 kcal/mol). Further ADMET predictions and molecular dynamics simulation at 500 ns revealed that these compounds had better drug-like properties and comparable stability at the active site compared to the reference ligand. These findings suggest that the identified compounds are promising candidates for further in vitro validation to confirm their therapeutic potential against HIV-related proteins. This study highlights the transformative role of AI-driven drug discovery in addressing HIV drug resistance.

In this study, we present our preliminary findings on the synthesis of racemosin B and its derivatives involving thermal electrocyclization of 3-vinylindolo triene, followed by concomitant intramolecular nitrene insertion of the resulting 1-(o-nitrophenyl)-carbazole/1-(o-azidophenyl)-carbazole.

Biogenic ZrO₂ nanoparticles (NPs) were synthesized using phytochemicals derived from the Allium cepa peel as a green source, and their possible inhibitory effect against the dengue virus's NS1 protein was examined using in silico analysis. On the basis of the x-ray diffraction (XRD) and FE-SEM analytical methods, the average NP size is about 21.58 nm, and the crystalline size is 17.74 nm. According to the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, the synthesized ZrO₂ NPs showed viable antioxidant properties with an IC₅₀ value of 10.23 µg/mL. The disc diffusion method demonstrated significant antifungal activity of the NPs against Pyricularia oryzae and Bipolaris sorokiniana, with the inhibition rates of 30.48% and 45%, respectively. The inhibitory qualities and drug-likeness of extracted phytochemicals have been assessed using in silico techniques such as molecular docking and molecular dynamics (MD) simulations, focusing on the DENV-2 envelope protein NS1 (PDB: 4O6B). To highlight the potential of A. cepa peel in the eco-friendly production of ZrO₂ NPs with encouraging antioxidant and antifungal properties, this study also offers a route for the development of antiviral medicines via in silico analysis.

Plants have recently become a valuable natural source of active ingredients in the cosmetic industry owing to their sustainability, low allergenicity, and ability to ensure environmental and ecological safety. Therefore, our research aims at assessing the cosmetic potential of Limonium thouinii (Algerian halophyte from the Plumbaginaceae family) as a natural cosmetic active ingredient with broad-spectrum UV protection, antioxidant, and antibacterial efficacy for sunscreen preparations. The study evaluates the in vitro antioxidant efficacy using eight assays, including radical scavenging and power reducing methods. An in silico analysis was performed to predict the possible biological activity and skin irritant effect of the hydromethanolic extract employing Prediction of Activity Spectra of Substances (PASS) and OSIRIS Property Explorer software. Additionally, UVB and broad-spectrum (UVB-UVA) protective efficacy were assessed using UV spectroscopic techniques, measuring SPF, UVAI/UV, UVA/UVB, and critical wavelength (CW) factors. Moreover, the antibacterial effect was evaluated through the agar diffusion method. HPLC-DAD analysis of the hydromethanolic extract revealed the presence of various phytoconstituents, including phenolic and nonphenolic acids. In silico antioxidant and antimicrobial activity of the hydromethanolic extract's main compounds, based on PASS software calculation, was confirmed. No in silico skin irritant effect was detected. The results indicate that the extract exhibits significant in vitro antioxidant efficiency, with IC₅₀ values ranging between 10.79 ± 0.49 and 74.09 ± 1.83 µgmL⁻¹. The antibacterial effect assessment revealed a moderate activity, with the highest inhibition against Porteus vulgaris strains (ZOI = 8.25 ± 0.04 mm). Furthermore, the studied extract shows promising efficacy in protecting against UVB, with a SPF value of 19 ± 0.5. The hydromethanolic extract showed broad-spectrum photoprotective efficacy, exhibiting UVA/UVB, UVAI/UV, and CW values of 0.67 ± 0.005, 0.81 ± 0.001. and 375.09 ± 0.01, respectively. The study reveals that L. thouinii hydromethanolic extract has potential as a natural cosmetic ingredient, exhibiting multiple functions, including sunscreening, antioxidant, and antibacterial efficacy.