The Experts below are selected from a list of 273 Experts worldwide ranked by ideXlab platform
Ferenc Faigl - One of the best experts on this subject based on the ideXlab platform.
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Resolution of 1-[2-carboxy-6-(trifluoromethyl)phenyl]-1H-Pyrrole-2-Carboxylic Acid with methyl (R)-2-phenylglycinate, reciprocal resolution and second order asymmetric transformation
Tetrahedron-asymmetry, 2011Co-Authors: Ferenc Faigl, Mátyás Czugler, Béla Mátravölgyi, Tamás Holczbauer, János MadarászAbstract:Abstract A novel, highly efficient method has been developed for the separation of the optical isomers of 1-[2-carboxy-6-(trifluoromethyl)phenyl]-1 H -Pyrrole-2-Carboxylic Acid with methyl ( R )-2-phenylglycinate. The structural aspects of chiral discrimination have been discussed via comparison of the molecular structures and the packing energies of the diastereoisomeric salts determined by single crystal X-ray diffraction measurements. Reciprocal resolution and a new, highly efficient second order asymmetric transformation of racemic methyl 2-phenylglycinate with the pure enantiomer of the previously resolved atropisomeric carboxylic Acid are also reported.
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Efficient synthesis of optically active 1-(2-carboxymethyl-6-ethylphenyl)-1H-Pyrrole-2-Carboxylic Acid: a novel atropisomeric 1-arylpyrrole derivative
Tetrahedron: Asymmetry, 2009Co-Authors: Ferenc Faigl, Gábor Tárkányi, Bernadett Vas-feldhoffer, Krisztina Pál, Miklós Kubinyi, Mátyás CzuglerAbstract:Abstract An efficient synthesis and resolution of (±)-1-(2-carboxymethyl-6-ethylphenyl)- 1H -Pyrrole-2-Carboxylic Acid has been developed for the preparation of novel optically active atropisomers. The ee values were measured by a 1 H NMR spectroscopic method using quinidine as the chiral complexing agent. Absolute configurations of the separated enantiomers were determined using single crystal X-ray diffraction measurements of both the disodium salt and the ( R )-1-phenylethylamine salt of the enantiomerically pure dicarboxylic Acid, separately. The analysis of the CD spectra with the aid of TD-DFT quantum chemical calculations confirmed the assignment of configurations.
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Synthesis and optical resolution of 1-[(3-carboxy-1,1′-biphenyl)-2- yl]-1H-Pyrrole-2-Carboxylic Acid
Chirality, 2009Co-Authors: Ferenc Faigl, Bernadett Vas-feldhoffer, Veronika Kudar, Mátyás Czugler, Krisztina Pál, Miklós KubinyiAbstract:Site selective mono- and dimetalation methods have been developed for the functionalization of 1-[(1,1′-biphenyl)-2-yl]-1H-pyrrole. Optical resolution of the prepared 1-[(3-carboxy-1,1′-biphenyl)-2-yl]Pyrrole-2-Carboxylic Acid provided new atropisomeric 1-arylpyrrole derivatives. The absolute configuration of the pure dicarboxylic Acid enantiomers was determined by single crystal X-ray diffraction and CD spectroscopy. Chirality 2009. © 2009 Wiley-Liss, Inc.
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Efficient synthesis and resolution of (±)-1-[2-carboxy-6-(trifluoromethyl)phenyl]Pyrrole-2-Carboxylic Acid
Tetrahedron: Asymmetry, 2000Co-Authors: Katalin Fogassy, Veronika Harmat, Zsolt Böcskei, Gábor Tárkányi, László Tőke, Ferenc FaiglAbstract:Abstract A novel, efficient synthesis and resolution of (±)-1-[2-carboxy-6-(trifluoromethyl)-phenyl]Pyrrole-2-Carboxylic Acid has been developed for the preparation of new members of optically active atropisomers. The e.e. values were determined by a highly sensitive 19F NMR spectroscopic method using β-cyclodextrin as chiral complexing agent. Single-crystal X-ray structures of the two diastereoisomeric salts and consequently, the absolute configurations of the enantiomers are also reported.
Tushar Kanti Chakraborty - One of the best experts on this subject based on the ideXlab platform.
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Synthesis and characterization of Boc-protected 4-amino- and 5-amino-Pyrrole-2-Carboxylic Acid methyl esters
Tetrahedron Letters, 2006Co-Authors: Tushar Kanti Chakraborty, Sandip P. Udawant, Saumya Roy, Bajjuri Krishna Mohan, Kolla Srinivasa Rao, Samit Kumar Dutta, Ajit C. KunwarAbstract:Syntheses of Boc-protected 4-amino- and 5-amino-Pyrrole-2-Carboxylic Acid methyl esters have been achieved and the structures of these compounds have been fully characterized by detailed NMR studies.
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Synthesis and DNA binding properties of pyrrole amino Acid-containing peptides
Tetrahedron Letters, 2005Co-Authors: Tushar Kanti Chakraborty, Bajjuri Krishna Mohan, Muthaiah Gnanamani, Souvik MaitiAbstract:Dimers of the pyrrole amino Acid (Paa), 5-(aminomethyl)Pyrrole-2-Carboxylic Acid, and its derivatives having Lys anchored on N- and C-termini bind in the minor groove of DNA with considerable apparent binding affinities. When the Lys unit is attached to the C-terminus, the resulting ligand binds to ds-DNA with twice the affinity, of the order of 10 5 , than the one carrying two positive charges at the same end.
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Development of 5-(aminomethyl)Pyrrole-2-Carboxylic Acid as a constrained surrogate of Gly-ΔAla and its application in peptidomimetic studies
Tetrahedron Letters, 2002Co-Authors: Tushar Kanti Chakraborty, B. Krishna Mohan, S. Kiran Kumar, Ajit C. KunwarAbstract:A new peptidomimetic scaffold based on 5-(aminomethyl)Pyrrole-2-Carboxylic Acid (1) is developed for the first time and used as a conformationally constrained surrogate of the Gly-ΔAla dipeptide isostere (2) to prepare peptides 3 and 4.
Jerzy Leszczynski - One of the best experts on this subject based on the ideXlab platform.
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dimers of formic Acid acetic Acid formamide and pyrrole 2 carboxylic Acid an ab initio study
Journal of Physical Chemistry A, 2005Co-Authors: Robert W Gora, Sławomir J. Grabowski, Jerzy LeszczynskiAbstract:The intermolecular hydrogen bonds in dimers of formic Acid, acetic Acid, and formamide were investigated. Additionally, three configurations of the Pyrrole-2-Carboxylic Acid (PCA) dimer were studied to analyze how the pyrrole π-electron system influences the carboxylic groups connected by double O−H···O hydrogen bonds. The ab initio calculations for the systems investigated were performed at MP2/6-311++G(d,p), MP2/aug-cc-pVDZ, and MP2/aug-cc-pVTZ//MP2/aug-cc-pVDZ levels of theory. The “atoms in molecules” theory of Bader was used and the analysis of the critical points was performed to study the nature of hydrogen bonds. The decomposition of the total interaction energy applied here reveals that the delocalization energy term is a particularly important attractive contribution in these systems, more important in the case of systems forming homonuclear O−H···O double hydrogen bonds than in the case of those connected through heteronuclear N−H···O bonds. Because the systems analyzed may be formally classifi...
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Crystal and Molecular Structure of Pyrrole-2-Carboxylic Acid; π-Electron Delocalization of Its Dimers−DFT and MP2 Calculations
The Journal of Physical Chemistry A, 2004Co-Authors: Sławomir J. Grabowski, Alina T. Dubis, Dariusz Martynowski, Marek L. Główka, And Marcin Palusiak, Jerzy LeszczynskiAbstract:The crystal and molecular structure of Pyrrole-2-Carboxylic Acid (PCA) determined by single-crystal X-ray diffraction is presented. Intermolecular H-bonds for this structure are analyzed. The DFT calculations at the B3LYP/6-311++G(d,p) level of theory and ab initio calculations at the MP2/6-311++G(d,p) level are performed for dimers of Pyrrole-2-Carboxylic Acid and for similar model species. The X-ray data and calculations show that the pyrrole moiety within Pyrrole-2-Carboxylic Acid influences the π-electron delocalization and hence the strength of the hydrogen bonds. The geometrical and energetic features of H-bonds of PCA dimers and of model complexes are analyzed. Additionally, the Bader theory is applied, and the characteristics of the bond critical points and ring critical points confirm the influence of the pyrrole moiety on the strength of H-bond interactions.
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Pyrrole-2-Carboxylic Acid and Its Dimers: Molecular Structures and Vibrational Spectrum
The Journal of Physical Chemistry A, 2002Co-Authors: Alina T. Dubis, Sławomir J. Grabowski, Dorota B. Romanowska, Tomasz Misiaszek, Jerzy LeszczynskiAbstract:The infrared and Raman spectroscopic study of Pyrrole-2-Carboxylic Acid (PCA) confirms the formation of the cyclic Acid dimer species in the solid state. The molecular structure, vibrational frequencies, and binding energies of cyclic dimers have been also examined using the density functional theory (DFT) at the B3LYP/6-311+G(d) level. In addition, a complete vibrational assignment is proposed for the both s-cis and s-trans PCA conformers. The vibrational assignments are supported by normal coordinate calculations utilizing force constants predicted using the DFT method. The “atoms in molecules” theory of Bader is also used to characterize hydrogen bonds.
Paul Purkiss - One of the best experts on this subject based on the ideXlab platform.
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High urinary excretion of N‐(pyrrole‐2‐carboxyl) glycine in type II hyperprolinemia
Clinical genetics, 2008Co-Authors: Moacir Wajner, Clovis Milton Duval Wannmacher, Paul PurkissAbstract:A case report of type II hyperprolinemia in a 5-year-old boy and its biochemical investigation is presented. The child has mild developmental delay, recurrent seizures of the grand mal type and EEG alterations. Although this disorder has been recently considered a benign condition, variants accompanied by characteristic symptomatology cannot be fully ruled out. The urinary excretion of high concentrations of N-(Pyrrole-2-Carboxylic Acid)-glycine conjugate is stressed, since it appears that only one previous report in the literature described this compound in the urine of two patients affected by this disturbance.
Arunas Ramanavicius - One of the best experts on this subject based on the ideXlab platform.
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Reagent-less amperometric glucose biosensor based on nanobiocomposite consisting of poly(1,10-phenanthroline-5,6-dione), poly(Pyrrole-2-Carboxylic Acid), gold nanoparticles and glucose oxidase
Microchemical Journal, 2020Co-Authors: Asta Kausaite-minkstimiene, Almira Ramanaviciene, Laura Glumbokaite, Arunas RamanaviciusAbstract:Abstract In this work, a novel reagent-less amperometric glucose biosensor based on nanobiocomposite consisting of poly(1,10-phenanthroline-5,6-dione), poly(Pyrrole-2-Carboxylic Acid) (PPCA), gold nanoparticles (AuNP) and glucose oxidase (GOx) was designed. To achieve this, the graphite rod electrode with adsorbed 1,10-phenanthroline-5,6-dione (PD) was immersed into electrochemical cell filled with a buffer solution containing Pyrrole-2-Carboxylic Acid (PCA) and colloidal AuNP and electrochemical polymerization of PD and PCA was performed by cyclic voltammetry. During this process AuNP were encapsulated into PPCA layer. Carboxylic groups of the PPCA enabled the covalent immobilization of GOx. Optimal conditions for the biosensor working electrode preparation were elaborated and are discussed. The biosensor was characterized by wide linear range (0.2 –150.0 mM), relatively low detection limit (0.08 mM), good reproducibility (RSD 4.22 %, 2.34 % and 1.67 %, respectively for 5.0, 50.0 and 100.0 mM of glucose) and repeatability (RSD 6.93 %, 2.23 % and 1.17 %, respectively for 5.0, 50.0 and 100.0 mM of glucose), excellent stability (only 3.98 % loss of its initial activity over 14 days, when stored at 4 °C), high anti-interference ability to uric Acid, acetaminophen and acetylsalicylic Acid and demonstrated good accuracy in the analysis of pharmaceutical preparations Orsalit Drink and Rehydron Optim and human serum.
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Evaluation of poly(Pyrrole-2-Carboxylic Acid) particles synthesized by enzymatic catalysis
RSC Advances, 2015Co-Authors: Asta Kausaite-minkstimiene, Almira Ramanaviciene, R. Simanaityte, D. Gabrielaitis, Laura Glumbokaite, Arunas RamanaviciusAbstract:In this study an environmentally friendly synthesis of poly(Pyrrole-2-Carboxylic Acid) (PCPy) particles dispersed in water–ethanol medium using enzymatic catalysis is proposed. The polymerization of Pyrrole-2-Carboxylic Acid was initiated by the oxidant hydrogen peroxide resulting from the redox enzyme glucose oxidase (GOx) catalyzed glucose oxidation reaction. The main evidence of the polymerization process was the origin and increase of the absorption peak at 465 nm indicating the presence of PCPy oligomers. The PCPy formation rate in different pH medium was investigated and compared with the formation rate of the PCPy synthesized by chemical oxidative polymerization. The best medium for the enzymatic polymerization was determined at pH 5.0, while for the chemical method it was at pH 2.0. The GOx had a significant positive impact on the outcome of the polymerization reaction and colloidal stability of the formed PCPy particles. The GOx catalyzed polymerization reaction was faster than that based on chemical oxidative polymerization but the precipitation of insoluble precipitate was observed after a longer period of polymerization. The morphology of the PCPy particles was characterized by SEM. Additionally, the presence of carboxylic groups in the formed PCPy particles was confirmed by FTIR spectroscopy and potentiometric back-titration.
