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排序方式: 共有256条查询结果,搜索用时 31 毫秒
91.
Natural‐Antioxidant‐Inspired Benzo[b]selenophenes: Synthesis,Redox Properties,and Antiproliferative Activity 下载免费PDF全文
Edgars Paegle Dr. Ilona Domracheva Dr. Baiba Turovska Dr. Marina Petrova Dr. Iveta Kanepe‐Lapsa Anita Gulbe Dr. Edvards Liepinsh Dr. Pavel Arsenyan 《化学:亚洲杂志》2016,11(13):1929-1938
The cyclization of arylalkynes under selenobromination conditions, combined with an acid‐induced 3,2‐aryl shift, was elaborated as a general synthetic pathway for the preparation of polyhydroxy‐2‐ and ‐3‐arylbenzo[b]selenophenes from the same starting materials. The redox properties, free‐radical‐scavenging ability, and cytotoxicity against malignant cell lines (MCF‐7, MDA‐MB‐231, HepG2, and 4T1) of the synthesized compounds were explored, and the obtained results were used to consider the structure–activity relationships (SARs) in these compounds. Consequently, the structural features that were responsible for the highly potent peroxyl‐radical‐scavenging activity were established. 相似文献
92.
Adipic and malonic acid aqueous solutions: surface tensions and saturation vapor pressures 总被引:1,自引:0,他引:1
Riipinen I Koponen IK Frank GP Hyvärinen AP Vanhanen J Lihavainen H Lehtinen KE Bilde M Kulmala M 《The journal of physical chemistry. A》2007,111(50):12995-13002
The surface tension of adipic aqueous solutions was measured as a function of temperature (T=278-313 K) and adipic acid mole fraction (X=0.000-0.003) using the Wilhelmy plate method. A parametrization fitted to these data is presented. The evaporation rates of binary water-malonic and water-adipic acid droplets were measured with a TDMA technique at different temperatures (T=293-300 K) and relative humidities (58-80%), and the saturation vapor pressures of subcooled liquid malonic and adipic acids were derived from the data using a binary evaporation model. The temperature dependence of the vapor pressures was obtained as least-squares fits to the derived vapor pressures: ln(Psat,l) (Pa)=220.2389-22634.96/T (K)-26.66767 ln T (K) for malonic acid and ln(Psat,l) (Pa)=140.6704-18230.97/T (K)-15.48011 ln T (K) for adipic acid. 相似文献
93.
Andrea Rnavri Nra Igaz Dra I. Adamecz Bettina Szerencss Csaba Molnar Zoltn Knya Ilona Pfeiffer Monika Kiricsi 《Molecules (Basel, Switzerland)》2021,26(4)
The nanomaterial industry generates gigantic quantities of metal-based nanomaterials for various technological and biomedical applications; however, concomitantly, it places a massive burden on the environment by utilizing toxic chemicals for the production process and leaving hazardous waste materials behind. Moreover, the employed, often unpleasant chemicals can affect the biocompatibility of the generated particles and severely restrict their application possibilities. On these grounds, green synthetic approaches have emerged, offering eco-friendly, sustainable, nature-derived alternative production methods, thus attenuating the ecological footprint of the nanomaterial industry. In the last decade, a plethora of biological materials has been tested to probe their suitability for nanomaterial synthesis. Although most of these approaches were successful, a large body of evidence indicates that the green material or entity used for the production would substantially define the physical and chemical properties and as a consequence, the biological activities of the obtained nanomaterials. The present review provides a comprehensive collection of the most recent green methodologies, surveys the major nanoparticle characterization techniques and screens the effects triggered by the obtained nanomaterials in various living systems to give an impression on the biomedical potential of green synthesized silver and gold nanoparticles. 相似文献
94.
Evaluation of the Synthetic Potential of an AHBA Knockout Mutant of the Rifamycin Producer Amycolatopsis mediterranei 下载免费PDF全文
Ilona Bułyszko Dr. Gerald Dräger Anja Klenge Prof. Dr. Andreas Kirschning 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(52):19231-19242
Supplementing an AHBA(?) mutant strain of Amycolatopsis mediterranei, the rifamycin producer, with a series of benzoic acid derivatives yielded new tetraketides containing different phenyl groups. These mutasynthetic studies revealed unique reductive properties of A. mediterranei towards nitro‐ and azidoarenes, leading to the corresponding anilines. In selected cases, the yields of mutaproducts (fermentation products isolated after feeding bacteria with chemically prepared analogs of natural building blocks) obtained are in a range (up to 118 mg L?1) that renders them useful as chiral building blocks for further synthetic endeavors. The configuration of the stereogenic centers at C6 and C7 was determined to be 6R,7S for one representative tetraketide. Importantly, processing beyond the tetraketide stage is not always blocked when the formation of the bicyclic naphthalene precursor cannot occur. This was proven by formation of a bromo undecaketide, an observation that has implications regarding the evolutionary development of rifamycin biosynthesis. 相似文献
95.
Roumen L Van Hoof B Pieterse K Hilbers PA Custers EM Plate R De Gooyer M Beugels IP Emmen JM Leysen D Smits JF Ottenheijm HC Hermans JJ 《Journal of computational chemistry》2011,32(11):2441-2448
The biosynthesis of the mineralocorticoid hormone aldosterone involves a multistep hydroxylation of 11-deoxycorticosterone at the 11- and 18-positions, resulting in the formation of corticosterone and 18-hydroxycorticosterone, the final precursor of aldosterone. Two members of the cytochrome P450 11B family, CYP11B1 and CYP11B2, are known to catalyze these 11- and 18-hydroxylations, however, only CYP11B2 can oxidize 18-hydroxycorticosterone to aldosterone. It is unknown what sequence of hydroxylations leads to the formation of 18-hydroxycorticosterone. In this study we have investigated which of the possible conversion paths towards formation of 18-hydroxycorticosterone and aldosterone are most likely from the ligand perspective. Therefore, we combined quantum mechanical investigations on the steroid conformations of 11-deoxycorticosterone and its ensuing reaction intermediates with Fukui indices calculations to predict the reactivity of their carbon atoms for an attack by the iron-oxygen species. Both F(-) and F(0) were calculated to account for different mechanisms of substrate conversion. We show which particular initial conformations of 11-deoxycorticosterone and which conversion paths are likely to result in the successful synthesis of aldosterone, and thereby may be representative for the mechanism of aldosterone biosynthesis by CYP11B2. Moreover, we found that the most likely path for aldosterone synthesis coincides with the substrate conformation proposed in an earlier publication. To summarize, we show that on a theoretical and strictly ligand-directed basis only a limited number of reaction paths in the conversion of 11-deoxycorticosterone to aldosterone is possible. Despite its theoretical nature, this knowledge may help to understand the catalytic function of CYP11B1 and CYP11B2. 相似文献
96.
Joseph V Schulte F Rooch H Feldmann I Dörfel I Österle W Panne U Kneipp J 《Chemical communications (Cambridge, England)》2011,47(11):3236-3238
Silver nanoparticles were generated based on citrate reduction in the ultrastructure of the sporopollenin biopolymer of Ambrosia artemisiifolia (ragweed) and Secale cereale (rye). The nanoparticles enable the acquisition of SERS spectra and thereby a vibrational characterization of the local molecular structure of sporopollenin. 相似文献
97.
98.
An in-plane spin reorientation transition in thin ferromagnetic films is discussed in terms of the thermodynamics of inhomogeneous low-dimensional systems based on a Néel sublattices concept while using a spin 1 Heisenberg Hamiltonian. The model allows us to investigate in a straightforward manner the layer-dependent phenomena. In this context, we propose a model of noncollinear magnetization structure based on the appropriate distribution of the anisotropy parameters inside the Fe films on W(110). The spin reorientation transition originates at the Fe/W(110) interface and proceeds via noncollinear magnetization structure toward the surface with increasing film thickness in accordance with the experimental findings. The temperature-driven spin reorientation transition in freestanding Fe films and in Fe/W(110) systems is also discussed in detail. 相似文献
99.
Ilona Turowska‐Tyrk Karolina Grzeniak 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(2):o146-o148
Crystals of the 1‐chloroanthracene photodimer, viz. trans‐bi(1‐chloro‐9,10‐dihydro‐9,10‐anthracenediyl), C28H18Cl2, were obtained from the solid‐state [4+4]‐photodimerization of the monomer, C14H9Cl, followed by recrystallization. The symmetry of the product molecules is defined by the orientation of the reactant molecules in the crystal. The mutual orientation parameters calculated for adjacent monomers explain the reactivity of the compound. The molecules in the crystal of the monomer and the recrystallized photodimer pack differently and the photodimer has crystallographically imposed inversion symmetry. 相似文献
100.
Dmytro M. Khomenko Roman O. Doroshchuk Ilona V. Raspertova Jesús García López Fernando López Ortiz Sergiu Shova Oleg A. Iegorov Rostyslav D. Lampeka 《Tetrahedron letters》2019,60(39):151089
The regioselective cyclocondensation of aminoethyl-1,2,4-triazoles and glyoxal provides pentacyclic heterocycles in which two 7,8-dihydro-5H-6λ2-[1,2,4]triazolo[1,5-c]pyrimidine systems are connected through CH(OH) bridges generating a central piperazine-2,5-diol ring. The structure of the new compounds was elucidated based on 1H, 13C and 15N NMR spectroscopic methods. The molecular structure of the parent compound generated from aminoethyl-1,2,4-triazole was established by single crystal X-ray diffraction. 相似文献