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91.
Christoph M. Hendrich Sebastian Senn Lea Haas Marvin T. Hoffmann Dr. Ute Zschieschang Luca C. Greiner Dr. Frank Rominger Dr. Matthias Rudolph Dr. Hagen Klauk Prof. Dr. Andreas Dreuw Prof. Dr. A. Stephen K. Hashmi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(59):14778-14784
Herein, we describe a gold-catalyzed cascade cyclization of Boc-protected benzylamines bearing two tethered alkyne moieties in a domino reaction initiated by a 6-endo-dig cyclization. The reaction was screened intensively, and the scope was explored, resulting in nine new Boc-protected dihydrobenzo[c]phenanthridines with yields of up to 98 %; even a π-extension and two bidirectional approaches were successful. Furthermore, thermal cleavage of the Boc group and subsequent oxidation gave substituted benzo[c]phenanthridines in up to quantitative yields. Two bidirectional approaches under the optimized conditions were successful, and the resulting π-extended molecules were tested as organic semiconductors in organic thin-film transistors. 相似文献
92.
Dr. Ravi Yadav Martin Weber Dr. Akhil K. Singh Luca Münzfeld Johannes Gramüller Prof. Dr. Ruth M. Gschwind Prof. Dr. Manfred Scheer Prof. Dr. Peter W. Roesky 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(56):14128-14137
A series of molecular group 2 polyphosphides has been synthesized by using air-stable [Cp*Fe(η5-P5)] (Cp*=C5Me5) or white phosphorus as polyphosphorus precursors. Different types of group 2 reagents such as organo-magnesium, mono-valent magnesium, and molecular calcium hydride complexes have been investigated to activate these polyphosphorus sources. The organo-magnesium complex [(DippBDI−Mg(CH3))2] (DippBDI={[2,6-iPr2C6H3NCMe]2CH}−) reacts with [Cp*Fe(η5-P5)] to give an unprecedented Mg/Fe-supramolecular wheel. Kinetically controlled activation of [Cp*Fe(η5-P5)] by different mono-valent magnesium complexes allowed the isolation of Mg-coordinated formally mono- and di-reduced products of [Cp*Fe(η5-P5)]. To obtain the first examples of molecular calcium-polyphosphides, a molecular calcium hydride complex was used to reduce the aromatic cyclo-P5 ring of [Cp*Fe(η5-P5)]. The Ca-Fe-polyphosphide is also characterized by quantum chemical calculations and compared with the corresponding Mg complex. Moreover, a calcium coordinated Zintl ion (P7)3− was obtained by molecular calcium hydride mediated P4 reduction. 相似文献
93.
Qiang Liu Hubert Meissel Ilia Sadykov Simon Jones Nick Van Dijk Przemyslaw Rzepka Luca Artiglia Marco Ranocchiari Jeroen A. van Bokhoven 《Helvetica chimica acta》2021,104(7):e2100082
Stability studies on supported metal nanoparticles are essential for gaining insight into the design and optimization of high-performance materials. In this work, the dissolutions of Pt-based catalysts in HBr/Br2 mixture of various concentration regimes were studied and correlated with material structural properties. The dissolution of metal nanoparticles was enhanced by adding Br2 to the HBr solution. Comparing with commercial Pt/C catalyst, the well-alloyed PtIr/C catalyst was observed to exhibit high resistance towards dissolution. In addition, regulating the accessibility of the metal sites to dissolution-inducing species contributed to the marked stability of the nanoparticles in HBr/Br2 solutions, as shown for the surface-modified PtIr/C catalysts with organic diamine molecules. 相似文献
94.
Giuseppe Innorta Luca Pontoni Sandro Torroni 《Journal of the American Society for Mass Spectrometry》1998,9(4):314-319
The kinetics of gas phase reactions of the ion C5H5Fe+ with oxygen (Me2CO, Me2O, MeOH, iso-propanol, H2O) and nitrogen (NH3, NH2Me, NHMe2, NMe3) donor ligands have been studied by ion trap mass spectrometry. While in the literature reactions of the ion Fe+, with the same ligands, the principal reaction path involves fragmentation in almost all the reactions of the ion C5H5Fe+, formation of adduct ions is the major reaction path. The reactivity of these two ions is briefly compared in the ion trap conditions. Kinetic data for the ion C5H5Fe+ indicate that the reactions show a large range of efficiency and a linear correlation is found between the log of the reaction rate constants and the ionization energy of ligands with the same donor atom. 相似文献
95.
Dr. Pradeep Chopra Dr. Tejabhiram Yadavalli Francesco Palmieri Dr. Seino A. K. Jongkees Dr. Luca Unione Prof. Dr. Deepak Shukla Prof. Dr. Geert-Jan Boons 《Angewandte Chemie (International ed. in English)》2023,62(41):e202309838
Herpes simplex virus (HSV-1) employs heparan sulfate (HS) as receptor for cell attachment and entry. During late-stage infection, the virus induces the upregulation of human heparanase (Hpse) to remove cell surface HS allowing viral spread. We hypothesized that inhibition of Hpse will prevent viral release thereby representing a new therapeutic strategy for HSV-1. A range of HS-oligosaccharides was prepared to examine the importance of chain length and 2-O-sulfation of iduronic moieties for Hpse inhibition. It was found that hexa- and octasaccharides potently inhibited the enzyme and that 2-O-sulfation of iduronic acid is tolerated. Computational studies provided a rationale for the observed structure–activity relationship. Treatment of human corneal epithelial cells (HCEs) infected with HSV-1 with the hexa- and octasaccharide blocked viral induced shedding of HS which significantly reduced spread of virions. The compounds also inhibited migration and proliferation of immortalized HCEs thereby providing additional therapeutic properties. 相似文献
96.
Dr. Daniele Paderni Dr. Eleonora Macedi Dr. Larisa Lvova Dr. Gianluca Ambrosi Prof. Mauro Formica Prof. Luca Giorgi Prof. Roberto Paolesse Prof. Vieri Fusi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(49):e202201062
A new series of ligands containing the 2-(2-hydroxy-3- naphthyl)-4-methylbenzoxazole (HNBO) fluorophore showed selectivity for Mg2+ ions, without the interference of Ca2+. The most promising representative L3 resulted the best performing sensor for Mg2+ both in solution and embedded in an all-solid-state optode, especially towards real samples of drinkable water. 相似文献
97.
Joan J. Soldevila-Barreda Andrea Pettenuzzo Maria Azmanova Laia Rafols Amr A. A. Attia Alexandru Lupan Luca Ronconi Nicolas P. E. Barry Anaïs Pitto-Barry 《Helvetica chimica acta》2023,106(8):e202300064
The synthesis by transmetallation and in-depth characterisation by IR spectroscopy of five half-sandwich ruthenium and osmium dithiocarbamato isonipecotamide glycoconjugate complexes are presented herein. The evaluation of their in vitro cytotoxicity and of the zinc precursors’ in vitro cytotoxicity towards ovarian cancer (A2780 and A2780cisR) and normal prostate (PNT2) cells is reported. While the cytotoxicity of the compounds is rather limited, some selectivity is observed. 相似文献
98.
Giuseppe Guanti Luca Banfi Enrica Narisano Carlo Scolastico 《Tetrahedron letters》1984,25(41):4693-4696
threo-α-Dibenzylamino-?-hydroxyesters (2) have been synthesised with high diastereoselectivity through the NaBH4 reduction of α-dibenzylamino-β-oxoesters (4) and then tranformed into threo-α-amino-β-hydroxyacids. 相似文献
99.
Normal human dermal fibroblasts: proteomic analysis of cell layer and culture medium. 总被引:7,自引:0,他引:7
Federica Boraldi Luca Bini Sabrina Liberatori Alessandro Armini Vitaliano Pallini Roberta Tiozzo Ivonne Pasquali Ronchetti Daniela Quaglino 《Electrophoresis》2003,24(7-8):1292-1310
Proteins present within the cell layer and those released in the cell medium from in vitro cultured normal human dermal fibroblasts were separated and characterized in terms of their isoelectric point and molecular weight, by two-dimensional (2-D) gel electrophoresis. All spots in the synthetic gel were firstly analyzed by the Melanie 3 software and compared with those of breast cancer cells, colorectal epithelial cells, HL60, lymphoma cells, and platelets, already available on-line. From the identification of 144 spots from both the cell layer and the medium, we were able to recognize 89 different proteins, since a certain number of spots represented different isoforms of the same molecule. Identifications were performed by matching with on-line 2-D databases, and by matrix assisted laser-desorption/ionization-time of flight-mass spectrometry (MALDI-TOF-MS), in order to confirm the identification by matching, or to identify new proteins. The procedure we used allows (i) to design a highly reproducible reference map of the proteome of adult human normal fibroblasts in culture, (ii) to evaluate protein species produced in the cell layer as well as those released in the culture medium, and (iii) to compare data from gel matching with those obtained by MS. This work represents an essential step for a better knowledge of mesenchymal cells, given the widespread use of this cell type in both clinical and experimental investigations. 相似文献
100.
Amorati R Ferroni F Lucarini M Pedulli GF Valgimigli L 《The Journal of organic chemistry》2002,67(26):9295-9303
A systematic investigation is reported on the regeneration of alpha-tocopherol (alpha-TOH) in homogeneous solution by coantioxidants in order to better understand the mechanism and the factors responsible for the effectiveness of this process. The current availability of thermochemical data concerning the reactants involved in the regeneration reactions, as well as a large number of the kinetic constants for the various reactions involved, allowed us to rationalize the experimental observations collected so far. Three limiting cases have been considered. The first case is that of a coantioxidant irreversibly regenerating alpha-TOH, where the effectiveness of the recycling process depends on the magnitude of the rate constant k(r). The second case is that of a coantioxidant reversibly recycling alpha-TOH, where regeneration can only be observed if the bond dissociation enthalpy value of the coantioxidant is lower or at least close to that of the O-H bond of alpha-tocopherol. The third case is that of a catechol derivative (chosen as a model compound for polyphenolic antioxidants), where recycling of alpha-TOH is feasible even though the BDE value is significantly higher than that of vitamin E. In this case, the driving force for the recycling process is the removal of the semiquinone radical from the catechol derivative by the alpha-tocopheroxyl radical, which makes the regeneration of alpha-TOH practically irreversible. 相似文献