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Search Results: 1 - 10 of 3413 matches for " Roman Lesyk "
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2-[N-(4-Methoxyphenyl)acetamido]-1,3-thiazol-4-yl acetate
Volodymyr Horishny,Roman Lesyk,Andrzej K. Gzella
Acta Crystallographica Section E , 2013, DOI: 10.1107/s1600536813004236
Abstract: The structural analysis of the title compound, C14H14N2O4S, particularly the presence of an acetyl group at the exocyclic N atom and the C(H)—C(O2CMe)—N acetoxy group in the thiazole ring, may indicate that one of the starting materials, i.e. 2-(4-methoxyanilino)-1,3-thiazol-4(5H)-one, exists in the reaction mixture, at least partially, as a tautomer with an exocyclic amine N atom and an enol group. The acetoxy and acetyl groups deviate from the thiazole plane by 69.17 (6) and 7.25 (19)°, respectively. The thiazole and benzene rings form a dihedral angle of 73.50 (4)°. In the crystal, centrosymmetrically related molecules are connected into dimeric aggregates via C—H...O interactions.
2-[N-(2,4-Dimethoxyphenyl)acetamido]-1,3-thiazol-4-yl acetate
Volodymyr Horishny,Roman Lesyk,Marcin Kowiel,Andrzej K. Gzella
Acta Crystallographica Section E , 2013, DOI: 10.1107/s1600536813003474
Abstract: The title compound, C15H16N2O5S, is a product of the reaction of 2-(2,4-dimethoxyphenylamino)-1,3-thiazol-4(5H)-one with acetic anhydride. The presence of the acetyl and acetoxy groups in the molecule indicates that the starting thiazole exists as a tautomer in the reaction mixture with exocyclic amino and enol moieties. The acetyl group is tilted slightly from the heterocyclic ring plane [dihedral angle = 4.46 (11)°], while the acetoxy group is almost perpendicular to this ring [dihedral angle = 88.14 (12)°]. An intramolecular acetyl–methoxy C—H...O interaction is noted. In the crystal, molecules are connected into a three-dimensional architecture by C—H...O interactions.
Structure–anticancer activity relationships among 4-azolidinone-3-carboxylic acids derivatives
Kaminskyy D. V.,Lesyk R. B.
Biopolymers and Cell , 2010,
Abstract: The aim of present research was investigation of anticancer activity of 4-azolidinone-3-carboxylic acids derivatives, and studies of structure–activity relationships (SAR) aspects. Methods. Organic synthesis; spectral methods; anticancer screening was performed according to the US NCI protocol (Developmental Therapeutic Program). Results. The data of new 4-thiazolidinone-3-alkanecarboxylic acids derivatives in vitro anticancer activity were described. The most active compounds which belong to 5-arylidene-2,4- thia(imida)zolidinone-3-alkanecarboxylic acids; 5-aryl(heteryl)idenerhodanine-3-succinic acids derivatives were selected. Determination of some SAR aspects which allowed to determine directions in lead- compounds structure optimization, as well as desirable molecular fragments for design of potential anticancer agents based on 4-azolidinone scaffold were performed. 5-Arylidenehydantoin-3-acetic acids amides were identified as a new class of significant selective antileukemic agents. Possible pharmacophore scaffold of 5-ylidenerhodanine-3-succinic acids derivatives was suggested. Conclusions. The series of active compounds with high anticancer activity and/or selectivity levels were selected. Some SAR aspects were determined and structure design directions were proposed.
2-[7-(3,5-Dibromo-2-hydroxyphenyl)-6-ethoxycarbonyl-2-oxo-5H-2,3,6,7-tetrahydrothiopyrano[2,3-d][1,3]thiazol-6-yl]acetic acid ethanol monosolvate
M. Kowiel,N. Zelisko,D. Atamanyuk,R. Lesyk
Acta Crystallographica Section E , 2012, DOI: 10.1107/s1600536812035325
Abstract: The title compound, C17H15Br2NO6S2·C2H5OH, is the esterification reaction product of 2-(8,10-dibromo-2,6-dioxo-3,5,5a,11b-tetrahydro-2H,6H-chromeno[4′,3′:4,5]thiopyrano[2,3-d]thiazol-5a-yl)acetic acid. Cleavage of the lactone ring and formation of ethoxycarbonyl and hydroxy groups from its structural elements were observed. On the other hand, the carboxymethyl group was not esterified. The H atom and carboxymethyl group, both at stereogenic centres, show a cis conformation. The six-membered dihydrothiopyran ring adopts a half-chair conformation. All NH and OH groups participate in the three-dimensional hydrogen-bond network, which is additionally strengthened by C—H...O and C—H...S interactions. Intramolecular O—H...Br and C—H...O interactions also occur.
Ni o de 4 días de vida con holoprocencefalia semilobar
Maximiliano Francabandiera,Sonia Lesyk,Juan Pablo Biosci,Fernando Abramzon
Revista Argentina de Radiología , 2012,
Thiazolidinone motif in anticancer drug discovery. Experience of DH LNMU medicinal chemistry scientific group
Lesyk R. B.,Zimenkovsky B. S.,Kaminskyy D. V.,Kryshchyshyn A. P.
Biopolymers and Cell , 2011,
Abstract: The aim was analysis of 4-thiazolidinones and related heterocyclic systems anticancer activity data and formation of some rational design directions of potential anticancer agents. Synthetic research carried out in Danylo Halytsky Lviv National Medical University (DH LNMU) allowed us to propose a whole number of new molecular design directions of biological active 4-thiazolidinones and related heterocyclic systems, as well as obtain directed library that numbers over 5000 of novel compounds. At the present time in vitro anticancer activity screening was carried out for more than 1000 compounds (US NCI protocol (Developmental Therapeutic Program), among them 167 compounds showed high antitumor activity level. For the purpose of optimization and rational design of highly active molecules with optimal drug-like characteristics and discovering of possible mechanism of action SAR, QSAR analysis and molecular docking were carried out. The ultimate aim of the project is creating of innovative synthetic drug with special mechanism of action and sufficient pharmacological and toxicological features. Some aspects of structure–activity relationships were determined and structure design directions were proposed. The series of active compounds with high anticancer activity and/or selectivity levels were selected.
Comparison of dual acting drugs and conventional NSAIDs towards parameters of NO-synthase system and oxidative stress in mucosal membrane of large intestine of rats with experimental ulcerative colitis
Sklyarov A. Ya.,Lesyk R. B.,Panasyuk N. B.,Fomenko I. S.
Biopolymers and Cell , 2011,
Abstract: Aim was to compare the action of 2A5DHT compound (dual COX-2/5-LOX inhibitor) and conventional non-steroidal anti-inflammatory drugs towards parameters of nitric oxide (NO) system and intensity of oxidative stress in the mucous membrane of the large intestine (MMLI) in rats with experimental ulcerative colitis. Methods. Ulcerative colitis was induced by administration of acetic acid. The activity of NO-synthases, content of NO, and parameters of lipoperoxidation processes were measured in MMLI. Results. COX-2/5-LOX inhibition by 2A5DHT compound did not cause considerable destructive changes of the MMLI of rats. The activity of inducible nitric oxide synthase (iNOS) declined more than 2 fold as compared to their activity in colitis. The intensity of lipoperoxidation processes was found to be much lower than under the separate effect of celecoxib or indomethacine. Conclusions. Dual COX-2/5-LOX inhibition by 2A5DHT has a significant cytoprotective effect in MMLI that is accompanied by reduction of oxidative stress and activity of NO-synthases. The substance 2A5DHT significantly overexceeds the cytoprotective effects of both selective and non-selective COX/LOX inhibitors and can be used in the treatment of inflammatory bowel disease
Mathematical Model of Embodied Symbols: Cognition and Perceptual Symbol System  [PDF]
Leonid Perlovsky, Roman Ilin
Journal of Behavioral and Brain Science (JBBS) , 2012, DOI: 10.4236/jbbs.2012.22024
Abstract: A mathematical model of perceptual symbol system is developed. This development requires new mathematical methods of dynamic logic (DL), which have overcome limitations of classical artificial intelligence and connectionist approaches. The paper discusses these past limitations, relates them to combinatorial complexity (exponential explosion) of algorithms in the past, and relates it further to the static nature of classical logic. DL is a process-logic; its salient property is evolution of vague representations into crisp. We first consider one aspect of PSS: situation learning from object perceptions. Next DL is related to PSS mechanisms of concepts, simulators, grounding, embodiment, productiveity, binding, recursion, and to the mechanisms relating embodied-grounded and amodal symbols. We discuss DL capability for modeling cognition on multiple levels of abstraction. PSS is extended toward interaction between cognition and language. Experimental predictions of the theory are discussed. They might influence experimental psychology and impact future theoretical developments in cognitive science, including knowledge representation, and mechanisms of interaction between perception, cognition, and language. All mathematical equations are also discussed conceptually, so mathematical understanding is not required. Experimental evidence for DL and PSS in brain imaging is discussed as well as future research directions.
Fractal Parametric Oscillator as a Model of a Nonlinear Oscillation System in Natural Mediums  [PDF]
Roman I. Parovik
Int'l J. of Communications, Network and System Sciences (IJCNS) , 2013, DOI: 10.4236/ijcns.2013.63016

The paper presents a model of fractal parametric oscillator. Showing that the solution of such a model exists and is unique. A study of the solution with the aid of diagrams Stratton-Ince. The regions of instability, which can occur parametric resonance. It is suggested that this solution can be any signal, including acoustic.

Working Time Reductions and Labour Force Participation in Unemployment Contexts: A Note  [PDF]
Angel Martin-Roman
Theoretical Economics Letters (TEL) , 2014, DOI: 10.4236/tel.2014.43025
Abstract: Work-sharing measures aim to reduce unemployment. When politicians are more interested in fostering this kind of measures is when the official unemployment rate published in statistics rises. There is already an important body of research addressing this issue, but it has mainly focused on the labour demand side. Nevertheless, it must not be forgotten that unemployment is determined both by demand and supply. The neoclassical model of labour supply predicts that a reduction of standard working hours encourages labour market participation. In this paper we show that this unambiguous result vanishes precisely when high unemployment makes that search transaction costs cannot be considered negligible.
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