Supported Cu(II)-Schiff base: novel heterogeneous catalyst with extremely high activity for eco-friendly, one-pot and multi-component C-S bond-forming reaction toward a wide range of thioethers as biologically active cores

Antimicrobial activity of metal-based nanoparticles: a mini-review

The resistance of pathogenic microorganisms to antibiotics is one of the main problems of world health. Of particular concern are multidrug-resistant (MDR) bacteria. Infections caused by these microorganisms affect the appearance of acute or chronic diseases. In this regard, modern technologies, such as nanomaterials (NMs), especially promising nanoparticles (NPs), can possess antimicrobial properties or improve the effectiveness and delivery of known antibiotics. Their diversity and characteristics, combined with surface functionalization, enable multivalent interactions with microbial biomolecules. This article presents an overview of the most current research on replacing antibiotics with NPs, including the prospects and risks involved.

Alkylated Sulfonium Modification of Low Molecular Weight Polyethylenimine to Form Lipopolymers as Gene Vectors

Hydrophobic modification of low molecular weight polyethylenimine (PEI) is an efficient method to form ideal gene-transfer carriers. Sulfonium-a combination of three different functional groups, was conjugated onto PEI 1.8k at a conjugation ratio of 1:0.1 to form a series of sulfonium PEI (SPs). These SPs were hydrophobically modified and characterized by Fourier transform infrared and HNMR. DNA-condensing abilities of SPs were tested with gel retardation experiment, and their cytotoxicity was evaluated via the MTT assay. The particle size and zeta potential of SP/DNA nanoparticles were measured and evaluated for cellular uptake and transfection ability on HepG2 cell line. The results showed that the sulfonium moiety was attached to PEI 1.8k with a high yield at a conjugation ratio of 1:0.1. SPs containing longer alkyl chains condensed DNA completely at an SP/DNA weight ratio of 2:1. The formed nanoparticle size was in the range of 168-265 nm, and the zeta potential was +16-45 mV. The IC50 values of SPs were 6.5-43.2 μg/mL. The cytotoxicity of SPs increased as the hydrophobic chain got longer. SP/DNA showed much stronger cellular uptakes than PEI 25k; however, pure SPs presented almost no gene transfection on cells. Heparin release experiment showed that SP's strong binding of DNA resulted in low release of DNA and thus hindered the gene transfection process. By mixing SP with PEI 1.8k, the mixture presented adjustable DNA binding and releasing. The mixture formed by 67% SP and 33% PEI 1.8k showed strong gene transfection. In conclusion, sulfonium is an effective linkage to carry hydrophobic groups to adjust cell compatibilities and gene transfection capabilities of PEI.

Nano-CuFe2O3-catalyzed green synthesis of novel quinazolinone-tetrazole hybrids as anti-cancer agents

A novel green protocol has been developed for the synthesis of quinazolinone-tetrazole conjugates (7a-g, 8a-g and 9a-g) using recyclable nano-CuFe₂O₃ catalyst in water. Initially, 2-mercapto-3-substituted phenethylquinazolin-4(3H)-one (5a-c) was prepared by using nano-CuFe₂O₃ catalyst in water. Then, compounds (5a-c) were reacted with 1-bromo-3-chloropropane under nano-CuFe₂O₃ catalyst in water solvent to give S-alkylated quinazolinone core intermediate (6a-c), which was subsequently reacted with 1-substituted-1H-tetrazole-5-thiol (2a-g) by employing the similar reaction conditions to afford the final target compounds. The regioselective formation of C-S bond was unambiguously confirmed by single-crystal X-ray diffraction. The anti-cancer activity of the derivatives on various cancer cell lines such as SIHA, MD-AMB-231 and HepG2 was evaluated. Remarkably, compounds, 7f, 8f, 9a, 9d and 9f, showed potent activity in MD-AMB-231 cancer cell line (IC₅₀: 9.13-10.3 µM), while the same derivatives showed significant potent activity in SiHa and HepG2 cancer cell lines (IC₅₀: 17.46-27.0 µM). Most significantly, compound 7o (IC₅₀: 8.15 µM) showed potent activity, compared to the drug etoposide (IC₅₀: 18.11 µM) against MD-AMB-231 cell line. Flow cytometry analysis revealed that compounds 7f, 8f, 9a, 9d and 9f arrested the cell growth in the G1 phase in MD-AMB-231 cell line.

One-pot multicomponent synthesis of benzophenazine tethered tetrahydropyridopyrimidine derivatives

A simple, facile, and efficient green methodology has been developed for the synthesis of benzophenazine tethered tetrahydropyridopyrimidine derivatives by the one-pot four-component reaction of cinnamaldehyde/crotonaldehyde, 2-hydroxy-1,4-naphthoquinone, 1,3-dimethyl-6-amino uracil, and o-phenylenediamine in ethanol medium under reflux conditions using p-TSA as a catalyst. In this environmentally benign methodology, three C-N and two C-C bonds are formed in one pot. The hybrid products have three bioactive moieties such as benzophenazine, tetrahydropyridine, and pyrimidine. Operational simplicity, metal-free conditions, wide substrate scope, readily available starting materials, moderate to good yields of the desired products, presence of pharmaceutically active moieties, and easy purification process are the notable features of this methodology.

Progress on the natural asphalt applications as a new class of carbonious heterogeneous support; synthesis of Na[Pd-NAS] and study of its catalytic activity in the formation of carbon-carbon bonds

In continuation of our recent research on introducing natural asphalt as a new carbonious, eco-friendly, highly economical support, and also in addition to our plan to develop its application in heterogeneous catalyst chemistry, palladium grafted on natural asphalt sulfonate (Na [Pd-NAS]), was prepared and characterized using usual spectroscopy techniques. This new carbon-based heterogeneous nanocatalyst was successfully applied as an efficient catalyst for the Suzuki, Stille and Heck reactions under mild and sustainable conditions. The reaction of various aryl halides with triphenyltin chloride, phenylboronic acid or n-butyl acrylate provided the corresponding products with moderate to good yields. Na [Pd-NAS] was characterized by FT-IR spectroscopy, scanning electron microscopy, energy-dispersive spectroscopy, X-ray diffraction, inductively coupled plasma, thermogravimetric analysis techniques and N₂ adsorption-desorption measurement. SEM image illustrated that the Na [Pd-NAS] has vermicular and flaky shapes. According to the IUPAC classiication, the sample exhibited IV type curves. More importantly, this ligand-free catalyst is stable under the reaction conditions. Besides, the catalyst was separated by simple filtration and reused for the several times without any deterioration in its activity. In this research we report Na[Pd-NAS] as a versatile and reusable nanocatalyst for the C-C coupling reactions.