Browsing by Subject "ONE-POT SYNTHESIS"

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  • Verma, Arvind; Laakso, Into; Seppanen-Laakso, Tuulikki; Huhtikangas, Aarre; Riekkola, Marja-Liisa (2007)
  • Miliutina, Elena; Guselnikova, Olga; S. Soldatova, Natalia; Bainova, Polina; Elashnikov, Roman; Fitl, Přemysl; Kurten, Theo; S. Yusubov, Mekhman; Švorčík, Václav; Valiev, Rashid; M. Chehimi, Mohamed; Lyutakov, Oleksiy; S. Postnikov, Pavel (2020)
    Plasmon-assisted transformations of organic compounds represent a novel opportunity for conversion of light to chemical energy at room temperature. However, the mechanistic insights of interaction between plasmon energy and organic molecules is still under debate. Herein, we proposed a comprehensive study of the plasmon-assisted reaction mechanism using unsymmetric iodonium salts (ISs) as an organic probe. The experimental and theoretical analysis allow us to exclude the possible thermal effect or hot electron transfer. We found that plasmon interaction with unsymmetrical ISs led to the intramolecular excitation of electron followed by the regioselective cleavage of C–I bond with the formation of electron-rich radical species, which cannot be explained by the hot electron excitation or thermal effects. The high regioselectivity is explained by the direct excitation of electron to LUMO with the formation of a dissociative excited state according to quantum-chemical modeling, which provides novel opportunities for the fine control of reactivity using plasmon energy.
  • Stotani, Silvia; Gatta, Viviana; Medarametla, Prasanthi; Padmanaban, Mohan; Karawajzyk, Anna; Giordanetto, Fabrizio; Tammela, Päivi; Laitinen, Tuomo; Poso, Antti; Tzalis, Dimitrios; Collina, Simona (2019)
    Antibiotic resistance is posing a continuous threat to global public health and represents a huge burden for society as a whole. In the past decade, the interference with bacterial quorum sensing (QS) (i.e., cell cell communication) mechanisms has extensively been investigated as a valid therapeutic approach in the pursuit of a next generation of antimicrobials. (S)-4,5-Dihydroxy-2,3-pentanedione, commonly known as (S)-DPD, a small signaling molecule that modulates QS in both Gram-negative and Gram-positive bacteria, is phosphorylated by LsrK, and the resulting phospho-DPD activates QS. We designed and prepared a small library of DPD derivatives, characterized by five different scaffolds, and evaluated their LsrK inhibition in the context of QS interference. SAR studies highlighted the pyrazole moiety as an essential structural element for LsrK inhibition. Particularly, four compounds were found to be micromolar LsrK inhibitors (IC50 ranging between 100 mu M and 500 mu M) encouraging further exploration of novel analogues as potential new antimicrobials.
  • Maleki, Aziz; Shahbazi, Mohammad-Ali; Alinezhad, Vajiheh; Santos, Hélder A. (2020)
    The progressive development of zeolitic imidazolate frameworks (ZIFs), as a subfamily of metal‐organic frameworks (MOFs), and their unique features, including tunable pore size, large surface area, high thermal stability, and biodegradability/biocompatibility, have made them attractive in the field of biomedicine, especially for drug delivery and biomineralization applications. The high porosity of ZIFs gives them the opportunity for encapsulating a high amount of therapeutic drugs, proteins, imaging cargos, or a combination of them to construct advanced multifunctional drug delivery systems (DDSs) with combined therapeutic and imaging capabilities. This review summarizes recent strategies on the design and fabrication of ZIF‐based nansystems and their exploration in the biomedical field. First, recent developments for the adjustment of particle size, functionality, and morphology of ZIFs are discussed, which are important for achieving optimized therapeutic/theranostic nanosystems. Second, recent trends on the application of ZIF nanocarriers for the loading of diverse cargos, including anticancer medicines, antibiotic drugs, enzymes, proteins, photosensitizers, as well as imaging and photothermal agents, are investigated in order to understand how multifunctional DDSs can be designed based on the ZIF nanoparticles to treat different diseases, such as cancer and infection. Finally, prospects on the future research direction and applications of ZIF‐based nanomedicines are discussed.
  • Baddam, Vikram; Valinen, Lauri; Tenhu, Heikki (2021)
    Poly [(vinylbenzyl) trimethylammonium chloride] (PVBTMAC) has been used as a stabilizer in the polymerization-induced self-assembly polymerizations of diacetone acrylamide (DAAM). A whole spectrum of particle morphologies was obtained simply by adjusting the ionic strength of the reaction mixtures; no dilution of the cationic charges with noncharged comonomers or with noncharged polymers was needed. In addition to the ionic strength, the effects of solid content and the length of the PDAAM block on the morphologies of the particles were studied in detail. The experiments are a continuation to previous studies on solution properties of PVBTMAC. It has been shown earlier that the solubility of the polycation may be tuned with counterions. Hydrophobic triflate ions induce an upper critical solution temperature behavior. In the present case, the chains bound to hydrophobic cores of the particles show either a one-step phase separation in aqueous triflate solutions or under certain conditions, a two-step transition. The step-wise transition is typical for responsive polymers with limited mobility.
  • Figueiredo, Joana; Serrano, João L.; Cavalheiro, Eunice; Keurulainen, Leena; Yli-Kauhaluoma, Jari Tapani; Moreira, Vânia M.; Ferreira, Susana; Domingues, Fernanda C.; Silvestre, Samuel; Almeida, Paulo (2018)
    Barbituric and thiobarbituric acid derivatives have become progressively attractive to medicinal chemists due to their wide range of biological activities. Herein, different series of 1,3,5-trisubstituted barbiturates and thiobarbiturates were prepared in moderate to excellent yields and their activity as xanthine oxidase inhibitors, antioxidants, antibacterial agents and as anti-proliferative compounds was evaluated in vitro. Interesting bioactive barbiturates were found namely, 1,3-dimethyl-5-[1-(2-phenylhydrazinyl)ethylidene]pyrimidine-2,4,6(1H,3H,5H)-trione (6c) and 1,3-dimethyl-5-[1-[2-(4-nitrophenyl)hydrazinyl]ethylidene]pyrimidine-2,4,6(1H,3H,5H)-trione (6e), which showed concomitant xanthine oxidase inhibitory effect (IC50 values of 24.3 and 27.9 mu M, respectively), and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity (IC50 values of 18.8 and 23.8 mu M, respectively). In addition, 5-[1-(2-phenylhydrazinyl)ethylidene]pyrimidine-2,4,6(1H,3H,5H)-trione (6d) also revealed DPPH radical scavenger effect, with an IC50 value of 20.4 mu M. Moreover, relevant cytotoxicity against MCF-7 cells (IC50 = 13.3 mu M) was observed with 5-[[(2-chloro-4-nitrophenyl)amino]methylene]-2-thioxodihydropyrimidine-4,6(1H,5H)-dione (7d). Finally, different 5-hydrazinylethylidenepyrimidines revealed antibacterial activity against Acinetobacter baumannii (MIC values between 12.5 and 25.0 mu M) which paves the way for developing new treatments for infections caused by this Gram-negative coccobacillus bacterium, known to be an opportunistic pathogen in humans with high relevance in multidrug-resistant nosocomial infections. The most promising bioactive barbiturates were studied in silico with emphasis on compliance with the Lipinski's rule of five as well as several pharmacokinetics and toxicity parameters. (C) 2017 Elsevier Masson SAS. All rights reserved.