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161.
Dijana Pei Ivana Ozimec Landek Renata Rup
i Marina Modri Iva Dapo Rudolf Trojko Mladen Merep Milan Mesi 《Journal of heterocyclic chemistry》2012,49(2):243-252
The present review focuses on dibenzo[b,f]oxepin‐10(11H)‐one ( I , X = O) and dibenzo[b,f]thiepin‐10(11H)‐one ( I , X = S) as common synthons in the efficient synthesis of various dibenzoxepino[4,5‐ and dibenzothiepino[4,5]‐fused five‐membered heterocycles: [2,3] fused thiophene ( II ), [3,4] fused thiophene ( III ), furan ( IV ), pyrrole ( V ), imidazole ( VI ), pyrazole ( VII ), oxazole ( VIII ), and thiazole ( IX ). The potential of I to be converted into reactive intermediates that readily undergo heteroaromatic annulation reactions by cyclocondensation with proper binucleophiles allows formation of a range of enumerated functionalized dibenzo[e,h]azulene [4] structures ( II , III , IV , V , VI , VII , VIII , IX ). Dibenzo[e,h]azulenes as heterotetracyclic scaffold can be exploited in further modifications to obtain compounds with altered physicochemical and biological profile. J. Heterocyclic Chem., (2012). 相似文献
162.
Separation and characterization of oxidized isomeric lipid–peptide adducts by ion mobility mass spectrometry 下载免费PDF全文
Ivana Milic Marc Kipping Ralf Hoffmann Maria Fedorova 《Journal of mass spectrometry : JMS》2015,50(12):1386-1392
Phospholipids are major components of cell membranes and lipoprotein complexes. They are prone to oxidation by endogenous and exogenous reactive oxygen species yielding a large variety of modified lipids including small aliphatic and phospholipid bound aldehydes and ketones. These carbonyls are strong electrophiles that can modify proteins and, thereby, alter their structures and functions triggering various pathophysiological conditions. The analysis of lipid–protein adducts by liquid chromatography‐MS is challenged by their mixed chemical nature (polar peptide and hydrophobic lipid), low abundance in biological samples, and formation of multiple isomers. Thus, we investigated traveling wave ion mobility mass spectrometry (TWIMS) to analyze lipid–peptide adducts generated by incubating model peptides corresponding to the amphipathic β1 sheet sequence of apolipoprotein B‐100 with 1‐palmitoyl‐2‐(oxo‐nonanoyl)‐sn‐glycerophosphatidylcholine (PONPC). The complex mixture of peptides, lipids, and peptide–lipid adducts was separated by TWIMS, which was especially important for the identification of two mono‐PONPC‐peptide isomers containing Schiff bases at different lysine residues. Moreover, TWIMS separated structural conformers of one peptide–lipid adduct possessing most likely different orientations of the hydrophobic sn‐1 fatty acyl residue and head group of PONPC, relative to the peptide backbone. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
163.
Study of carbon black obtained by pyrolysis of waste scrap tyres 总被引:1,自引:0,他引:1
Zuzana Mikulova Ivana Sedenkova Lenka Matejova Marek Večeř Václav Dombek 《Journal of Thermal Analysis and Calorimetry》2013,111(2):1475-1481
Waste scrap tyres were thermally decomposed under various conditions. Decompositions were followed by the TGA method. Specific heating regimes were tested to obtain optimal structural properties of resulting pyrolytic carbon black produced by pyrolysis of scrap tyres and the process was characterized in temperature interval from 380 to 1,200 °C and heating rate 10, 20 and 50 °C min?1 under nitrogen atmosphere. The original scrap tyres and pyrolytic carbon black were characterized by Raman and Fourier transform infrared spectroscopy methods. Textural properties were also determined. Effect of temperature and heating rate on process of pyrolysis of scrap tyres was observed. Shifting of temperature of maximum pyrolysis rate to lower value and spreading of DTG peak is caused by increasing heating rate. Temperature 570 °C was sufficient for total scrap tyres pyrolysis. Graphitic and disordered structure was distinguished in the formed carbon black by Raman spectroscopy. With increasing temperature, heating rate and weight loss, the amount of the graphitic structure was reduced at the expense of disordered structure. Destruction of nonporous scrap tyres and formation of porous structure took place at higher temperature. Porous carbon black is formed above 380 °C, specific surface area increased up to 88 m2 g?1 . 相似文献
164.
Petr Holý Jií Zvada Ivana Císaov Jaroslav Podlaha 《Angewandte Chemie (International ed. in English)》1999,38(3):381-383
D 4 ‐symmetric chiral hydrogen‐bonded cyclotetramers (see the structure in the picture) are present in the self‐assembled achiral title compound in the solid state. The unilayered network set up from the chiral “square” blocks is achiral as a consequence of the crystal symmetry. 相似文献
165.
Lubomír Machu?a Roman Jambor Robert Jirásko Ivana Císa?ová 《Journal of organometallic chemistry》2007,692(18):3969-3975
The reactions of organoantimony chlorides L1,2SbCl21 and 2 ([2,6-(ROCH2)2C6H3]−, R = Me; L1 and R = t-Bu; L2) with silver salts of selected carboxylic acids resulted to corresponding organoantimony carboxylates L1,2Sb(OOCR′)2, 1a-c (for L1) and 2a-c (for L2), where R′ = CH3 for 1a, 2a; R′ = CHCH2 for 1b, 2b and R′ = CF3 for 1c, 2c. All compounds were characterized by the help of elemental analysis, ESI-MS, 1H and 13C NMR spectroscopy. The solid state structure investigation using single crystal X-ray diffraction techniques (2a, c) and IR spectroscopy revealed significant differences in coordination mode of both O,C,O chelating ligand and carboxylic groups in this set of compounds. The structure of all compounds in solution of non-coordinating solvent (CDCl3) was determined by means of variable temperature 1H, 13C, 19F NMR spectroscopy and IR spectroscopy. 相似文献
166.
The methanol, ethyl acetate and chloroform extracts of selected Croatian plants were tested for their acetylcholinesterase (AChE) inhibition and antioxidant activity. Assessment of AChE inhibition was carried out using microplate reader at 1?mg?mL?1. Antioxidant capacities were determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging test and ferric reducing/antioxidant power assay (FRAP). Total phenol content (TPC) of extracts were determined using Folin-Ciocalteu colorimetric method. Out of 48 extracts, only methanolic extract of the Salix alba L. cortex exerted modest activity towards AChE, reaching 50.80% inhibition at concentration of 1?mg?mL?1. All the other samples tested had activity below 20%. The same extract performed the best antioxidative activity using DPPH and FRAP method, too. In essence, among all extracts used in the screening, methanolic extracts showed the best antioxidative activity as well as highest TPC. 相似文献
167.
Ivana Bochicchio 《Ricerche di matematica》2011,60(2):179-192
The existence and physical uniqueness is proved for the restricted evolution problem in general relativity. Precisely, the Einstein equations for the gravitational field are analyzed in harmonic and generic adapted coordinates in order to prove the existence and uniqueness of solution in both systems of coordinates. 相似文献
168.
Klmov Martina Krausov Ivana Orsk Maty Chvtil David 《Journal of Radioanalytical and Nuclear Chemistry》2022,331(7):3195-3201
Journal of Radioanalytical and Nuclear Chemistry - The mass fractions of V, Cr, Co, Ni, Cu, Zn, As, Br, Mo, Cd, W, Hg, and Pb in soil of the Czech dump-side were measured by instrumental neutron... 相似文献
169.
Juan Luis Vázquez Ivan Velazco-Cabral Dr. Marcos Flores-Álamo Gleb Turlakov Geraldina Rodríguez Dr. Ivana Moggio Dr. Eduardo Arias Dr. Eduardo Peña-Cabrera Dr. Miguel A. Vázquez 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(71):e202202446
A series of new symmetrical highly substituted BODIPYs 6 a – l was synthesized through a prefunctionalization approach in 35 %–89 % yields from the pyrrole core. This strategy allowed modulation of the substituents at the different positions based on the choice of Fischer's alkynyl carbenes, oxazolones and aldehydes used as precursors. The substituent variation at positions 2, 6, 3 and 5 had the greatest effect on the modulation of their photophysical properties such as absorption (λabs) and emission (λem) wavelengths, extinction coefficient (ϵ), quantum yields (ϕ), Stokes shifts (Δν), fluorescence decay, radiative (krad) and non-radiative (knr) constants and the CIE 1931 coordinates. Theoretical calculations allowed to corroborate the effect of the substituents of meso-position on the modification of the dihedral angles. Cyclic voltammetry studies revealed that the BODIPY series presents similar redox potential behavior, being electrochemically active even in successive cycles, which suggests that transport by diffusion is the dominant process. 相似文献
170.
Perković Ivana Beus Maja Schols Dominique Persoons Leentje Zorc Branka 《Molecular diversity》2022,26(1):1-14
Molecular Diversity - In this paper, we report the synthesis of novel hybrids 2–14 based on itaconic acid and fluoroaniline, pyridine, indole and quinoline scaffolds. Itaconic acid is a... 相似文献