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991.
Matteo Lusardi Aldo Profumo Chiara Rotolo Erika Iervasi Camillo Rosano Andrea Spallarossa Marco Ponassi 《Molecules (Basel, Switzerland)》2022,27(18)
A small library of highly functionalized phenylaminopyrazoles, bearing different substituents at position 1, 3, and 4 of the pyrazole ring, was prepared by the one-pot condensation of active methylene reagents, phenylisothiocyanate, and substituted hydrazine (namely, methyl- and benzyl-hydrazine). The identified reaction conditions proved to be versatile and efficient. Furthermore, the evaluation of alternative stepwise protocols affected the chemo- and regio-selectivity outcome of the one-pot procedure. The chemical identities of two N-methyl pyrazole isomers, selected as prototypes of the whole series, were unambiguously identified by means of NMR and mass spectrometry studies. Additionally, semiempirical calculations provided a structural rationale for the different chromatographic behavior of the two isomers. The prepared tetra-substituted phenylaminopyrazoles were tested in cell-based assays on a panel of cancer and normal cell lines. The tested compounds did not show any cytotoxic effect on the selected cell lines, thus supporting their pharmaceutical potentials. 相似文献
992.
The hydrolytic behavior of antimonic acid, Sb(OH)5o, was experimentally investigated, at fixed temperatures within the range 10–40 °C, by both titration of dilute Na-antimonate
solutions with HClO4 and single-point pH measurements of diluted Sb(OH)5o solutions. The thermodynamic constants, K
a, for the reaction:
were derived at different controlled temperatures, based on pH measurements, applying suitable mass and electrical balances
and correcting the concentrations of ionic species for medium effects. From the resulting log 10
K
a values, those of the corresponding isocoulombic equilibrium reaction:
were computed and used to derive its thermodynamic properties. These were finally combined with the corresponding thermodynamic
properties of the water association reaction, to obtain robust estimations of ΔG
ro, ΔS
ro and ΔH
ro for the ionogenic reaction. These are the first thermodynamic data at temperatures different from 25 °C for the ionization
reaction of Sb(OH)5o. The results of the present work confirm that Sb(OH)5o is a moderately weak and monoprotic acid with a pK
a of 2.848 at 25 °C. 相似文献
993.
The presence of boron atoms has made carboranes, C(2)B(10)H(12), attractive candidates for boron neutron capture therapy. Because of their chemistry and possible conjugation with proteins, they can also be used to enhance interactions between pharmaceuticals and their targets and to increase the in vivo stability and bioavailability of compounds that are normally metabolized rapidly. Carboranes are isosteric to a rotating phenyl group, which they can substitute successfully in biologically active systems. A reverse ligand-protein docking approach was used in this work to identify binding proteins for carboranes. The screening was carried out on the drug target database PDTD that contains 1207 entries covering 841 known potential drug targets with structures taken from the Protein Data Bank. First, for validation, the protocol was applied to three crystal structures of proteins in which carborane derivatives are present. Then, the model was applied to systems for which the protein structure is available, but the binding site of carborane has not been reported. These systems were used for further validation of the protocol, while simultaneously providing new insight into the interactions between cage and protein. Finally, the screening was carried out on the database to reveal potential carborane binding targets of interest for biological and pharmacological activity. Carboranes are predicted to bind well to protease and metalloprotease enzymes. Other carborane pharmaceutical targets are also discussed, together with possible protein carriers. 相似文献
994.
Matteo Signorile Luca Braglia Valentina Crocell Piero Torelli Elena Groppo Gabriele Ricchiardi Silvia Bordiga Francesca Bonino 《Angewandte Chemie (International ed. in English)》2020,59(41):18145-18150
Ti silicates, and in particular, titanium silicalite‐1 (TS‐1), are nowadays important catalysts for several partial oxidation reactions in the presence of aqueous H2O2 as an oxidant. Despite the numerous studies dealing with this material, some fundamental aspects are still unclear. In particular, the structure and the catalytic role of defective Ti sites, other than perfect tetrahedral sites recognized as the main active species, has not been quantitatively discussed in the literature. We assess the structural features of defective Ti sites on the basis of outcomes of electronic spectroscopies, as interpreted through quantum mechanical simulation. Strong evidence is disclosed to support the fact that the most common defective Ti sites, often reported in the TS‐1 literature, are monomeric Ti centers that are embedded in the zeolite framework, and which have a distorted octahedral local symmetry. 相似文献
995.
Dr. Filippo Doria Dr. Erica Salvati Luca Pompili Dr. Valentina Pirota Carmen D'Angelo Francesco Manoli Dr. Matteo Nadai Prof. Sara N. Richter Dr. Annamaria Biroccio Dr. Ilse Manet Prof. Mauro Freccero 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(47):11085-11097
Naphthalene diimide (NDI) dyads exhibiting a different substitution pattern and linker length have been synthesised and evaluated as G-quadruplex (G4) ligands, by investigating their cytotoxicity in selected cell lines. The dyads with the long C7 linker exhibit extremely low IC50 values, below 10 nm , on different cancer cell lines. Contrary, the dyads with the shorter C4 linker were much less effective, with IC values increasing up to 1 μm . Among the three dyads with the longest linker, small differences in the IC50 values emerge, suggesting that the linker length plays a more important role than the substitution pattern. We have further shown that the dyads are able to induce cellular DNA damage response, which is not limited to the telomeric regions and is likely the origin of their cytotoxicity. Both absorption titration and dynamic light scattering of the most cytotoxic dyads in the presence of hTel22 highlight their ability to induce effective G4 aggregation, acting as non-covalent cross-linking agents. 相似文献
996.
Morozova Ksenia Armani Mariachiara Scampicchio Matteo 《Journal of Thermal Analysis and Calorimetry》2020,139(1):375-382
Journal of Thermal Analysis and Calorimetry - Isothermal microcalorimetry is often used to monitor microbiological activity and growth in various types of biological samples. Usually, it is useful... 相似文献
997.
Continuous-time quantum walk describes the propagation of a quantum particle (or an excitation) evolving continuously in time on a graph. As such, it provides a natural framework for modeling transport processes, e.g., in light-harvesting systems. In particular, the transport properties strongly depend on the initial state and specific features of the graph under investigation. In this paper, we address the role of graph topology, and investigate the transport properties of graphs with different regularity, symmetry, and connectivity. We neglect disorder and decoherence, and assume a single trap vertex that is accountable for the loss processes. In particular, for each graph, we analytically determine the subspace of states having maximum transport efficiency. Our results provide a set of benchmarks for environment-assisted quantum transport, and suggest that connectivity is a poor indicator for transport efficiency. Indeed, we observe some specific correlations between transport efficiency and connectivity for certain graphs, but, in general, they are uncorrelated. 相似文献
998.
999.
Lorenzo Lombardi Daniele Bellini Prof. Andrea Bottoni Prof. Matteo Calvaresi Prof. Magda Monari Dr. Alessandro Kovtun Dr. Vincenzo Palermo Dr. Manuela Melucci Prof. Marco Bandini 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(46):10427-10432
The site-selective allylative and allenylative dearomatization of indoles with alcohols was performed under carbocatalytic regime in the presence of graphene oxide (GO, 10 wt % loading) as the promoter. Metal-free conditions, absence of stoichiometric additive, environmentally friendly conditions (H2O/CH3CN, 55 °C, 6 h), broad substrate scope (33 examples, yield up to 92 %) and excellent site- and stereoselectivity characterize the present methodology. Moreover, a covalent activation model exerted by GO functionalities was corroborated by spectroscopic, experimental and computational evidences. Recovering and regeneration of the GO catalyst through simple acidic treatment was also documented. 相似文献
1000.
Manuela Simonato Francesca Ricci Chiara Catozzi Matteo Storti Sonia Giambelluca Alessio Correani Fabrizio Salomone Paola Cogo Virgilio Carnielli 《Journal of mass spectrometry : JMS》2022,57(2):e4808
Stable isotope tracing can be safely used for metabolic studies in animals and humans. The endogenous biosynthesis of lipids (lipogenesis) is a key process throughout the entire life but especially during brain and lung growth. Adequate synthesis of pulmonary surfactant lipids is indispensable for life. With this study, we report the use of deuterium-depleted water (DDW), suitable for human consumption, as metabolic precursor for lipogenesis. We studied 13 adult rabbits for 5 days. Four rabbits drank tap water (TW) and served as controls; in four animals, DDW was substituted to drinking water, whereas five drank deuterium-enriched water (DEW). After 5 days, a blood sample and a bronchoalveolar lavage (BAL) sample were collected. The 2H/1H (δ2H) of BAL palmitic acid (PA) desaturated phosphatidylcholine (DSPC), the major phospholipid of pulmonary surfactant, and of plasma water was determined by high-resolution mass spectrometry. We found that the δ2H values of DDW, DEW and TW were −984 ± 2‰, +757 ± 2‰ and −58 ± 1‰, respectively. After 5 days, plasma water values were −467 ± 87‰, +377 ± 56‰ and −53 ± 6‰, and BAL DSPC-PA was −401 ± 27‰, −96 ± 38‰ and −249 ± 9‰ in the DDW, DEW and TW, respectively. With this preliminary study, we demonstrated the feasibility of using DDW to label pulmonary surfactant lipids. This novel approach can be used in animals and in humans, and we speculate that it could be associated with more favourable study compliance than DEW in human studies. 相似文献