1
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Raczyńska ED. On Prototropy and Bond Length Alternation in Neutral and Ionized Pyrimidine Bases and Their Model Azines in Vacuo. Molecules 2023; 28:7282. [PMID: 37959699 PMCID: PMC10648772 DOI: 10.3390/molecules28217282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Revised: 10/21/2023] [Accepted: 10/22/2023] [Indexed: 11/15/2023] Open
Abstract
In this review, the complete tautomeric equilibria are derived for disubstituted pyrimidine nucleic acid bases starting from phenol, aniline, and their model compounds-monosubstituted aromatic azines. The differences in tautomeric preferences for isolated (gaseous) neutral pyrimidine bases and their model compounds are discussed in light of different functional groups, their positions within the six-membered ring, electronic effects, and intramolecular interactions. For the discussion of tautomeric preferences and for the analysis of internal effects, recent quantum-chemical results are taken into account and compared to some experimental ones. For each possible tautomer-rotamer of the title compounds, the bond length alternation, measured by means of the harmonic oscillator model of electron delocalization (HOMED) index, is examined. Significant HOMED similarities exist for mono- and disubstituted derivatives. The lack of parallelism between the geometric (HOMED) and energetic (ΔG) parameters for all possible isomers clearly shows that aromaticity is not the main factor that dictates tautomeric preferences for pyrimidine bases, particularly for uracil and thymine. The effects of one-electron loss (positive ionization) and one-electron gain (negative ionization) on prototropy and bond length alternation are also reviewed for pyrimidine bases and their models.
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Affiliation(s)
- Ewa Daniela Raczyńska
- Department of Chemistry, Warsaw University of Life Sciences (SGGW), ul. Nowoursynowska 159c, 02-776 Warszawa, Poland
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2
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Shao BR, Shi L, Zhou YG. Asymmetric hydrogenation of O-/N-functional group substituted arenes. Chem Commun (Camb) 2021; 57:12741-12753. [PMID: 34762082 DOI: 10.1039/d1cc04722a] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Asymmetric hydrogenation of aromatic compounds represents one of the most straightforward synthetic methods to construct important chiral cyclic skeletons that are often found in biologically active agents and natural products. So far, the most successful examples in this field are largely limited to aromatics containing alkyl and aryl substituted groups due to the poor functional-group tolerance of hydrogenation. Direct asymmetric hydrogenation of functionalized aromatics provides enormous potential for expanding the structural diversity of reductive products of planar aromatic compounds, which is highly desirable and has not been well studied. This feature article focuses on the progress in catalytic asymmetric hydrogenation and transfer hydrogenation of O/N substituted arenes.
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Affiliation(s)
- Bing-Ru Shao
- State Key Lab of Fine Chemicals, School of Chemical Engineering, Dalian University of Technology, Dalian, 116024, P. R. China.
| | - Lei Shi
- State Key Lab of Fine Chemicals, School of Chemical Engineering, Dalian University of Technology, Dalian, 116024, P. R. China.
| | - Yong-Gui Zhou
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, P. R. China.
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3
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Yao S, Brahmi R, Portier F, Putaux JL, Chen J, Halila S. Hierarchical Self-Assembly of Amphiphilic β-C-Glycosylbarbiturates into Multiresponsive Alginate-Like Supramolecular Hydrogel Fibers and Vesicle Hydrogel. Chemistry 2021; 27:16716-16721. [PMID: 34622999 DOI: 10.1002/chem.202102950] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Indexed: 01/03/2023]
Abstract
Ordered molecular self-assembly of glycoamphiphiles has been regarded as an attractive, practical and bottom-up approach to obtain stable, structurally well-defined, and functional mimics of natural polysaccharides. This study describes a versatile and rational design of carbohydrate-based hydrogelators through N,N'-substituted barbituric acid-mediated Knoevenagel condensation onto unprotected carbohydrates in water. Amphiphilic N-substituted β-C-maltosylbarbiturates self-assembled into pH- and calcium-triggered alginate-like supramolecular hydrogel fibers with a multistimuli responsiveness to temperature, pH and competitive metal chelating agent. In addition, amphiphilic N,N'-disubstituted β-C-maltosylbarbiturates formed vesicle gels in pure water that were scarcely observed for glyco-hydrogelators. Finally, barbituric acid worked as a multitasking group allowing chemoselective ligation onto reducing-end carbohydrates, structural diversity, stimuli-sensitiveness, and supramolecular interactions by hydrogen bonding.
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Affiliation(s)
- Shun Yao
- Univ. Grenoble Alpes, CNRS, CERMAV, 38000, Grenoble, France
| | - Robin Brahmi
- Univ. Grenoble Alpes, CNRS, CERMAV, 38000, Grenoble, France
| | | | | | - Jing Chen
- Zhejiang International Scientific and, Technological Cooperative Base of Biomedical Materials and Technology, Zhejiang Engineering Research Center for Biomedical Materials, Cixi Institute of Biomedical Engineering, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315300, P. R. China
| | - Sami Halila
- Univ. Grenoble Alpes, CNRS, CERMAV, 38000, Grenoble, France
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4
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Mohammadnezhad G, Farrokhpour H, Görls H, Plass W. Tautomerism in carbohydrate-derived salicylidene schiff bases: Solution, solid-state, and theoretical investigations. J Mol Struct 2021. [DOI: 10.1016/j.molstruc.2020.129853] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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5
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Büchner R, Fondell M, Mascarenhas EJ, Pietzsch A, Vaz da Cruz V, Föhlisch A. How Hydrogen Bonding Amplifies Isomeric Differences in Pyridones toward Strong Changes in Acidity and Tautomerism. J Phys Chem B 2021; 125:2372-2379. [PMID: 33562959 PMCID: PMC7957858 DOI: 10.1021/acs.jpcb.0c10873] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
Steric hindrance
of hydration and hydrogen bond enhancement by
localized charges have been identified as key factors for the massive
chemical differences between the hydroxypyridine/pyridone isomers
in aqueous solution. While all isomers occur mainly in the hydroxypyridine
form in the gas phase, they differ by more than 3 orders of magnitude
both in their acidity and tautomeric equilibrium constants upon hydration.
By monitoring the electronic and solvation structures as a function
of the protonation state and the O– substitution
position on the pyridine ring, the amplification of the isomeric differences
in aqueous solution has been investigated. Near-edge X-ray absorption
fine structure (NEXAFS) measurements at the N K-edge served as the
probe of the chemical state. The combination of molecular dynamics
simulations, complete active space self-consistent field (CASSCF),
and time-dependent density functional theory (TD-DFT) spectral calculations
contributes to unraveling the principles of tautomerism and acidity
in multiple biochemical systems based on tautomerism.
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Affiliation(s)
- Robby Büchner
- Institute of Physics and Astronomy, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam, Germany
| | - Mattis Fondell
- Institute for Methods and Instrumentation for Synchrotron Radiation Research, Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Str. 15, 12489 Berlin, Germany
| | - Eric J Mascarenhas
- Institute of Physics and Astronomy, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam, Germany.,Institute for Methods and Instrumentation for Synchrotron Radiation Research, Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Str. 15, 12489 Berlin, Germany
| | - Annette Pietzsch
- Institute for Methods and Instrumentation for Synchrotron Radiation Research, Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Str. 15, 12489 Berlin, Germany
| | - Vinícius Vaz da Cruz
- Institute for Methods and Instrumentation for Synchrotron Radiation Research, Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Str. 15, 12489 Berlin, Germany
| | - Alexander Föhlisch
- Institute of Physics and Astronomy, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam, Germany.,Institute for Methods and Instrumentation for Synchrotron Radiation Research, Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Str. 15, 12489 Berlin, Germany
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6
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Obydennov DL, Simbirtseva AE, Piksin SE, Sosnovskikh VY. 2,6-Dicyano-4-pyrone as a Novel and Multifarious Building Block for the Synthesis of 2,6-Bis(hetaryl)-4-pyrones and 2,6-Bis(hetaryl)-4-pyridinols. ACS OMEGA 2020; 5:33406-33420. [PMID: 33403303 PMCID: PMC7774280 DOI: 10.1021/acsomega.0c05357] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 12/02/2020] [Indexed: 05/08/2023]
Abstract
In this work, a three-stage and easily scalable synthesis of 2,6-dicyano-4-pyrone (overall yield of 45%) as a new convenient building block has been developed from diethyl acetonedioxalate. It was shown that the transformation with hydroxylamine and [3 + 2]-cycloaddition, in contrast to the reactions with hydrazines, selectively proceed through the attack at the cyano groups without the pyrone ring-opening to give symmetrical and unsymmetrical pyrone-bearing heterocyclic triads containing 1,2,4- and 1,3,4-oxadiazoles as well as tetrazole moieties. The reaction of 2,6-bis(hetaryl)-4-pyrones with ammonia afforded 2,6-bis(hetaryl)pyridines in 63-87% yields. The 4-pyridone/4-pyridinol tautomerism of 2,6-bis(hetaryl)pyridinols and the influence of the nature of adjacent azolyl moieties on this equilibrium have been discussed.
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7
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Desens W, Jiao H, Langer P, Michalik D. NMR Spectroscopic and Theoretical Studies on Tautomerism and Isomerism of Perfluoroalkyl‐Substituted 1,5‐Benzodiazepines. ChemistrySelect 2020. [DOI: 10.1002/slct.201904639] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Willi Desens
- Institut für ChemieUniversität Rostock Albert-Einstein-Str. 3a Rostock 18059 Germany
| | - Haijun Jiao
- Leibniz-Institut für Katalyse (LIKAT) Albert-Einstein-Str. 29a Rostock 18059 Germany
| | - Peter Langer
- Institut für ChemieUniversität Rostock Albert-Einstein-Str. 3a Rostock 18059 Germany
- Leibniz-Institut für Katalyse (LIKAT) Albert-Einstein-Str. 29a Rostock 18059 Germany
| | - Dirk Michalik
- Institut für ChemieUniversität Rostock Albert-Einstein-Str. 3a Rostock 18059 Germany
- Leibniz-Institut für Katalyse (LIKAT) Albert-Einstein-Str. 29a Rostock 18059 Germany
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8
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Synthesis, Characterization, and Biological Evaluation of Novel 7-Oxo-7 H-thiazolo[3,2- b]-1,2,4-triazine-2-carboxylic Acid Derivatives. Molecules 2020; 25:molecules25061307. [PMID: 32182992 PMCID: PMC7144117 DOI: 10.3390/molecules25061307] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 03/04/2020] [Accepted: 03/11/2020] [Indexed: 01/03/2023] Open
Abstract
A series of novel 7-oxo-7H-thiazolo[3,2-b]-1,2,4-triazine-2-carboxylic acid derivatives was synthesized in good yields by a multi-step procedure that included the generation of the S-alkylated derivatives from 6-substituted arylmethyl-3-mercapto-1,2,4-triazin-5-ones with ethyl 2-chloroacetoacetate, intramolecular cyclization with microwave irradiation, hydrolysis and amidation. All of the target compounds were fully characterized through 1H-NMR, 13C-NMR and HRMS spectra. The intramolecular cyclization occurred regioselectively at the N2-position of 1,2,4-triazine ring, which was confirmed by compound 3e using single-crystal X-ray diffraction analysis. The antibacterial and antitubercular activities of the target compounds were evaluated. Compared with Ciprofloxacin and Rifampicin, compounds 5d, 5f and 5g containing the terminal amide fragment exhibited broad spectrum antibacterial activity, and carboxylic acid derivatives or its corresponding ethyl esters had less effect on antibacterial properties. The most potent compound 5f also displayed excellent in vitro antitubercular activity against Mycobacterium smegmatis (minimum inhibitory concentration (MIC) = 50 μg/mL) and better growth inhibition activity of leucyl-tRNA synthetase (78.24 ± 4.05% at 15 μg/mL).
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9
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Desens W, Jiao H, Langer P, Michalik D. NMR spectroscopic and theoretical studies on the isomerism of 1,5-benzodiazepin-2-one derivatives containing a perfluorinated side chain. J Mol Struct 2019. [DOI: 10.1016/j.molstruc.2019.06.044] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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10
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Singh M, Baruah JB. Combinations of Tautomeric Forms and Neutral-Cationic Forms in the Cocrystals of Sulfamethazine with Carboxylic Acids. ACS OMEGA 2019; 4:11609-11620. [PMID: 31460268 PMCID: PMC6682086 DOI: 10.1021/acsomega.9b01437] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Accepted: 06/24/2019] [Indexed: 05/15/2023]
Abstract
The cocrystals of sulfamethazine with different acids, namely, 2-mercaptophenylcarboxylic acid, 2,6-pyridinedicarboxylic acid, 4-(4-hydroxyphenylazo)phenylcarboxylic acid, 3-(4-hydroxyphenyl)propanoic acid, and 4-(phenyl)phenylcarboxylic acid, are studied here. Each has distinct notable supramolecular features. The pyrimidin-2-amine unit of the sulfamethazine provided unique examples of cocrystals in which amidine and imidine forms or neutral and protonated forms of sulfamethazine are observed in 2:2 ratios. Hence, this study provides avenues to explore cocrystals with tautomeric forms together in a cocrystal and also neutral and protonated cocrystal partners as apparent multicomponents in cocrystals. Among the cocrystals, three of them have the amidine form of the sulfamethazine in respective self-assembly. The cocrystal of 2-mercapto-phenylcarboxylic acid with sulfamethazine has the amidine form and it has the distinction of having S-H···π interactions. The cocrystal of sulfamethazine with 2,6-pyridinecarboxylic acid is a rare example of a 1:1 cocrystal of sulfmethazine with dicarboxylic acid. It has methanol molecules as a solvent of crystallization. Sulfamethazine forms a hydrated cocrystal with 4-(4-hydroxyphenylazo)-phenylcarboxylic acid that has conventional R 2 2(8) synthons of amidine hydrogen-bonding with carboxylic acid. The phenolic part of the acid component is anchored to the water molecule and provides a robust self-assembly. The hydrated cocrystal of sulfamethazine with 3-(4-hydroxyphenyl)propanoic acid (2:2 cocrystal) has two independent molecules of sulfamethazine, one in amidine form and the other in imidine form. It has two neutral carboxylic acids anchored through complementary hydrogen bonds and also has two water molecules of crystallization. The cocrystal of sulfamethazine with 4-(phenyl)phenylcarboxylic acid is also a 2:2 cocrystal. It is a di-hydrate, which has a neutral and protonated form of sulfamethazine. The neutral form is hydrogen-bonded to a neutral carboxylic acid, whereas the protonated form is charge-assisted hydrogen-bonded to the corresponding carboxylate anion.
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Affiliation(s)
- Munendra
Pal Singh
- Department of Chemistry, Indian
Institute of Technology Guwahati, Guwahati 781 039 Assam, India
| | - Jubaraj B. Baruah
- Department of Chemistry, Indian
Institute of Technology Guwahati, Guwahati 781 039 Assam, India
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11
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Antonov L. Tautomerism in Azo and Azomethyne Dyes: When and If Theory Meets Experiment. Molecules 2019; 24:molecules24122252. [PMID: 31212924 PMCID: PMC6631587 DOI: 10.3390/molecules24122252] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 06/13/2019] [Accepted: 06/14/2019] [Indexed: 12/15/2022] Open
Abstract
The performance of 26 hybrid density functionals was tested against a tautomeric dataset (TautData), containing experimental information for the keto-enol tautomeric equilibrium in 16 tautomeric azodyes and Schiff bases in cyclohexane, carbon tetrachloride and acetonitrile. The results have shown that MN12-SX, BHandH and M06-2X can be used to describe the tautomeric state of the core structures in the frame of ~0.5 kcal/mol error and correctly predict the tautomeric state in respect of dominating tautomeric form. Among them MN12-SX is the best performer, although it fails to describe the nonplanarity of some of the enol tautomers. The same experimental dataset was used to develop and test a special DFT functional (TautLYP) aimed at describing the tautomeric state in azo- and azomethyne compounds in solution when nonspecific solvents are used.
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Affiliation(s)
- Liudmil Antonov
- Institute of Organic Chemistry with Centre of Phytochemistry, Bulgarian Academy of Sciences, Sofia 1113, Bulgaria.
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12
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Proton tautomerism in 2-nitramino-C-nitropyridine derivatives - Experimental and quantum chemical study. J Mol Struct 2019. [DOI: 10.1016/j.molstruc.2019.03.040] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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13
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Raczyńska ED, Juras W. Effects of ionization and proton-transfer on bond length alternation in favored and rare isomers of isocytosine. COMPUT THEOR CHEM 2019. [DOI: 10.1016/j.comptc.2018.12.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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14
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Oyarzo J, Bosque R, Toro P, Silva CP, Arancibia R, Font-Bardía M, Artigas V, Calvis C, Messeguer R, Klahn AH, López C. A novel type of organometallic 2-R-2,4-dihydro-1H-3,1-benzoxazine with R = [M(η5-C5H4)(CO)3] (M = Re or Mn) units. Experimental and computational studies of the effect of substituent R on ring-chain tautomerism. Dalton Trans 2019; 48:1023-1039. [DOI: 10.1039/c8dt03265c] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Novel 2-cyrhetrenyl and cymantrenyl-2,4-dihydro-1H-3,1-benzoxazines.
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15
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Feng GS, Chen MW, Shi L, Zhou YG. Facile Synthesis of Chiral Cyclic Ureas through Hydrogenation of 2-Hydroxypyrimidine/Pyrimidin-2(1H
)-one Tautomers. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201801485] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- Guang-Shou Feng
- State Key Laboratory of Catalysis; Dalian Institute of Chemical Physics, Chinese Academy of Sciences; Dalian 116023 China
- University of Chinese Academy of Sciences; Beijing 100049 China
| | - Mu-Wang Chen
- State Key Laboratory of Catalysis; Dalian Institute of Chemical Physics, Chinese Academy of Sciences; Dalian 116023 China
| | - Lei Shi
- State Key Laboratory of Catalysis; Dalian Institute of Chemical Physics, Chinese Academy of Sciences; Dalian 116023 China
| | - Yong-Gui Zhou
- State Key Laboratory of Catalysis; Dalian Institute of Chemical Physics, Chinese Academy of Sciences; Dalian 116023 China
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16
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Feng GS, Chen MW, Shi L, Zhou YG. Facile Synthesis of Chiral Cyclic Ureas through Hydrogenation of 2-Hydroxypyrimidine/Pyrimidin-2(1H
)-one Tautomers. Angew Chem Int Ed Engl 2018; 57:5853-5857. [DOI: 10.1002/anie.201801485] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2018] [Revised: 03/14/2018] [Indexed: 12/18/2022]
Affiliation(s)
- Guang-Shou Feng
- State Key Laboratory of Catalysis; Dalian Institute of Chemical Physics, Chinese Academy of Sciences; Dalian 116023 China
- University of Chinese Academy of Sciences; Beijing 100049 China
| | - Mu-Wang Chen
- State Key Laboratory of Catalysis; Dalian Institute of Chemical Physics, Chinese Academy of Sciences; Dalian 116023 China
| | - Lei Shi
- State Key Laboratory of Catalysis; Dalian Institute of Chemical Physics, Chinese Academy of Sciences; Dalian 116023 China
| | - Yong-Gui Zhou
- State Key Laboratory of Catalysis; Dalian Institute of Chemical Physics, Chinese Academy of Sciences; Dalian 116023 China
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18
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Iguchi M, Zhong H, Himeda Y, Kawanami H. Effect of the ortho-Hydroxyl Groups on a Bipyridine Ligand of Iridium Complexes for the High-Pressure Gas Generation from the Catalytic Decomposition of Formic Acid. Chemistry 2017; 23:17788-17793. [PMID: 28960487 DOI: 10.1002/chem.201703766] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Indexed: 11/10/2022]
Abstract
The hydroxyl groups of a 2,2'-bipyridine (bpy) ligand near the metal center activated the catalytic performance of the Ir complex for the dehydrogenation of formic acid at high pressure. The position of the hydroxyl groups on the ligand affected the catalytic durability for the high-pressure H2 generation through the decomposition of formic acid. The Ir complex with a bipyridine ligand functionalized with para-hydroxyl groups shows a good durability with a constant catalytic activity during the reaction even under high-pressure conditions, whereas deactivation was observed for an Ir complex with a bipyridine ligand with ortho-hydroxyl groups (2). In the presence of high-pressure H2 , complex 2 decomposed into the ligand and an Ir trihydride complex through the isomerization of the bpy ligand. This work provides the development of a durable catalyst for the high-pressure H2 production from formic acid.
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Affiliation(s)
- Masayuki Iguchi
- Research Institute for Chemical Process Technology, Department of Material and Chemistry, National Institute of Advanced Industrial Science and Technology, Sendai, Miyagi, 983-8551, Japan
| | - Heng Zhong
- Research Institute for Chemical Process Technology, Department of Material and Chemistry, National Institute of Advanced Industrial Science and Technology, Sendai, Miyagi, 983-8551, Japan
| | - Yuichiro Himeda
- Research Institute of Energy Frontier, Department of Energy and Environment, National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki, 305-8565, Japan
| | - Hajime Kawanami
- Research Institute for Chemical Process Technology, Department of Material and Chemistry, National Institute of Advanced Industrial Science and Technology, Sendai, Miyagi, 983-8551, Japan
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19
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20
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Karalkar NB, Khare K, Molt R, Benner SA. Tautomeric equilibria of isoguanine and related purine analogs. NUCLEOSIDES NUCLEOTIDES & NUCLEIC ACIDS 2017; 36:256-274. [PMID: 28332916 DOI: 10.1080/15257770.2016.1268694] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Nucleobase pairs in DNA match hydrogen-bond donor and acceptor groups on the nucleobases. However, these can adopt more than one tautomeric form, and can consequently pair with nucleobases other than their canonical complements, possibly a source of natural mutation. These issues are now being re-visited by synthetic biologists increasing the number of replicable pairs in DNA by exploiting unnatural hydrogen bonding patterns, where tautomerism can also create mutation. Here, we combine spectroscopic measurements on methylated analogs of isoguanine tautomers and tautomeric mixtures with statistical analyses to a set of isoguanine analogs, the complement of isocytosine, the 5th and 6th "letters" in DNA.
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Affiliation(s)
- Nilesh B Karalkar
- a Foundation for Applied Molecular Evolution (FfAME) , Alachua , FL , USA
| | - Kshitij Khare
- b Department of Statistics , University of Florida , Gainesville FL , USA
| | - Robert Molt
- c Department of Chemistry and Chemical Biology , Indiana University-Purdue University, Indianapolis , Indianapolis , IN , USA.,d ENSCO, Inc. , Melbourne , FL , USA
| | - Steven A Benner
- a Foundation for Applied Molecular Evolution (FfAME) , Alachua , FL , USA
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21
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Calabrese C, Maris A, Uriarte I, Cocinero EJ, Melandri S. Effects of Chlorination on the Tautomeric Equilibrium of 2‐Hydroxypyridine: Experiment and Theory. Chemistry 2016; 23:3595-3604. [DOI: 10.1002/chem.201604891] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Indexed: 11/08/2022]
Affiliation(s)
- Camilla Calabrese
- Dipartimento di Chimica “G. Ciamician” Università degli Studi di Bologna Via Selmi 2 40126 Bologna Italy
| | - Assimo Maris
- Dipartimento di Chimica “G. Ciamician” Università degli Studi di Bologna Via Selmi 2 40126 Bologna Italy
| | - Iciar Uriarte
- Dpto. Química Física Universidad del País Vasco (UPV/EHU) Apartado 644 48080 Bilbao Spain
| | - Emilio J. Cocinero
- Dpto. Química Física Universidad del País Vasco (UPV/EHU) Apartado 644 48080 Bilbao Spain
| | - Sonia Melandri
- Dipartimento di Chimica “G. Ciamician” Università degli Studi di Bologna Via Selmi 2 40126 Bologna Italy
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22
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Giovannoni MP, Schepetkin IA, Crocetti L, Ciciani G, Cilibrizzi A, Guerrini G, Khlebnikov AI, Quinn MT, Vergelli C. Cinnoline derivatives as human neutrophil elastase inhibitors. J Enzyme Inhib Med Chem 2015; 31:628-39. [PMID: 26194018 DOI: 10.3109/14756366.2015.1057718] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Compounds that can effectively inhibit the proteolytic activity of human neutrophil elastase (HNE) represent promising therapeutics for treatment of inflammatory diseases. We present here the synthesis, structure-activity relationship analysis, and biological evaluation of a new series of HNE inhibitors with a cinnoline scaffold. These compounds exhibited HNE inhibitory activity but had lower potency compared to N-benzoylindazoles previously reported by us. On the other hand, they exhibited increased stability in aqueous solution. The most potent compound, 18a, had a good balance between HNE inhibitory activity (IC50 value = 56 nM) and chemical stability (t1/2 = 114 min). Analysis of reaction kinetics revealed that these cinnoline derivatives were reversible competitive inhibitors of HNE. Furthermore, molecular docking studies of the active products into the HNE binding site revealed two types of HNE inhibitors: molecules with cinnolin-4(1H)-one scaffold, which were attacked by the HNE Ser195 hydroxyl group at the amido moiety, and cinnoline derivatives containing an ester function at C-4, which is the point of attack of Ser195.
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Affiliation(s)
- Maria Paola Giovannoni
- a NEUROFARBA, Sezione di Farmaceutica e Nutraceutica, Università degli Studi di Firenze , Sesto Fiorentino , Italy
| | - Igor A Schepetkin
- b Department of Immunology and Infectious Diseases , Montana State University , Bozeman , MT , USA
| | - Letizia Crocetti
- a NEUROFARBA, Sezione di Farmaceutica e Nutraceutica, Università degli Studi di Firenze , Sesto Fiorentino , Italy
| | - Giovanna Ciciani
- a NEUROFARBA, Sezione di Farmaceutica e Nutraceutica, Università degli Studi di Firenze , Sesto Fiorentino , Italy
| | - Agostino Cilibrizzi
- c Department of Chemistry , Imperial College London , South Kensington , London , UK
| | - Gabriella Guerrini
- a NEUROFARBA, Sezione di Farmaceutica e Nutraceutica, Università degli Studi di Firenze , Sesto Fiorentino , Italy
| | - Andrei I Khlebnikov
- d Department of Biotechnology and Organic Chemistry , Tomsk Polytechnic University , Tomsk , Russia , and.,e Department of Chemistry , Altai State Technical University , Barnaul , Russia
| | - Mark T Quinn
- b Department of Immunology and Infectious Diseases , Montana State University , Bozeman , MT , USA
| | - Claudia Vergelli
- a NEUROFARBA, Sezione di Farmaceutica e Nutraceutica, Università degli Studi di Firenze , Sesto Fiorentino , Italy
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Kharabayev NN, Starikov AG, Minkin VI. Quantum-chemical simulation of structure of bischelate Ni(II) complexes based on cyclic analogs of azomethines. RUSS J GEN CHEM+ 2015. [DOI: 10.1134/s1070363215070221] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Electron delocalization and relative stabilities for the favored and rare tautomers of hydroxyazines in the gas phase – A comparison with aminoazines. COMPUT THEOR CHEM 2014. [DOI: 10.1016/j.comptc.2014.04.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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25
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An experimental and theoretical study of the structure of Lamotrigine in its neutral and protonated forms: evidence of Lamotrigine enantiomers. Tetrahedron 2014. [DOI: 10.1016/j.tet.2014.02.075] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Todorov AR, Nieger M, Helaja J. Tautomeric switching and metal-cation sensing of ligand-equipped 4-hydroxy-/4-oxo-1,4-dihydroquinolines. Chemistry 2012; 18:7269-77. [PMID: 22517539 DOI: 10.1002/chem.201103868] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2011] [Revised: 02/21/2012] [Indexed: 11/11/2022]
Abstract
Novel 4-hydroxyquinoline (4HQ) based tautomeric switches are reported. 4HQs equipped with coordinative side arms (8-arylimino and 3-piperidin-1-ylmethyl groups) were synthesized to access O- or N-selective chelation of Zn(2+) and Cd(2+) ions by 4HQ. In the case of the monodentate arylimino group, O chelation of metal ions induces concomitant switching of phenol tautomer to the keto form in nonpolar or aprotic media. This change is accompanied by selective and highly sensitive fluorometric sensing of Zn(2+) ions. In the case of the bidentate 8-(quinolin-8-ylimino)methyl side arm, NMR studies in CD(3) OD indicated that both Cd(2+) and Zn(2+) ions afford N chelation for 4HQ, coexisting with tautomeric switching from quinolin-4(1H)-one to quinolin-4-olate. In corroboration, UV/Vis-monitored metal-ion titrations in toluene and methanol implied similar structural changes. Additionally, fluorescence measurements indicated that the metal-triggered tautomeric switching is associated with compound signaling properties. The results are supported by DFT calculations at the B3LYP 6-31G* level. Several X-ray structures of metal-free and metal-chelating 4HQ are presented to support the solution studies.
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Affiliation(s)
- Aleksandar R Todorov
- Laboratory of Organic Chemistry, Department of Chemistry, University of Helsinki, A.I.Virtasen aukio 1, P.O. Box. 55, University of Helsinki, 00014 Helsinki, Finland
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Rubčić M, Užarević K, Halasz I, Bregović N, Mališ M, Dilović I, Kokan Z, Stein RS, Dinnebier RE, Tomišić V. Desmotropy, polymorphism, and solid-state proton transfer: four solid forms of an aromatic o-hydroxy Schiff base. Chemistry 2012; 18:5620-31. [PMID: 22447516 DOI: 10.1002/chem.201103508] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2011] [Indexed: 11/06/2022]
Abstract
The Schiff base derived from salicylaldehyde and 2-amino-3-hydroxypyridine affords a diversity of solid forms, two polymorphic pairs of the enol-imino (D1 a and D1 b) and keto-amino (D2 a and D2 b) desmotropes. The isolated phases, identified by IR spectroscopy, X-ray crystallography, and (13)C cross-polarization/magnetic angle spinning (CP/MAS) NMR spectroscopy, display essentially planar molecular conformations characterized by strong intramolecular hydrogen bonds of the O-H⋅⋅⋅N (D1) or N-H⋅⋅⋅O (D2) type. A change in the position of the proton within this O⋅⋅⋅H⋅⋅⋅N system is accompanied by substantially different molecular conformations and, subsequently, by divergent supramolecular architectures. The appearance and interconversion conditions for each of the four phases have been established on the basis of a number of solution and solvent-free experiments, and evaluated against the results of computational studies. Solid phases readily convert into the most stable form (D1 a) upon exposure to methanol vapor, heating, or by mechanical treatment, and these transformations are accompanied by a change in the color of the sample. The course of thermally induced transformations has been monitored in detail by means of temperature-resolved powder X-ray diffraction and infrared spectroscopy. Upon dissolution, all forms equilibrate immediately, as confirmed by NMR and UV/Vis spectroscopy in several solvents, with the equilibrium shifted far towards the enol tautomer. This study reveals the significance of peripheral groups in the stabilization of metastable tautomers in the solid state.
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Affiliation(s)
- Mirta Rubčić
- Department of Chemistry, Faculty of Science, University of Zagreb, Croatia.
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Feyer V, Plekan O, Kivimäki A, Prince KC, Moskovskaya TE, Zaytseva IL, Soshnikov DY, Trofimov AB. Comprehensive Core-Level Study of the Effects of Isomerism, Halogenation, and Methylation on the Tautomeric Equilibrium of Cytosine. J Phys Chem A 2011; 115:7722-33. [DOI: 10.1021/jp2017506] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Vitaliy Feyer
- Sincrotrone Trieste, in Area Science Park, Basovizza (Trieste) I-34149, Italy
| | - Oksana Plekan
- Sincrotrone Trieste, in Area Science Park, Basovizza (Trieste) I-34149, Italy
| | - Antti Kivimäki
- Laboratorio TASC, CNR-IOM, Basovizza (Trieste) I-34149, Italy
| | - Kevin C. Prince
- Sincrotrone Trieste, in Area Science Park, Basovizza (Trieste) I-34149, Italy
- Laboratorio TASC, CNR-IOM, Basovizza (Trieste) I-34149, Italy
| | | | - Irina L. Zaytseva
- Laboratory of Quantum Chemistry, Irkutsk State University, 664003 Irkutsk, Russia
| | | | - Alexander B. Trofimov
- Laboratory of Quantum Chemistry, Irkutsk State University, 664003 Irkutsk, Russia
- Favorsky Institute of Chemistry, SB RAS, 664033 Irkutsk, Russia
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Angelova SE, Spassova MI, Deneva VV, Rogojerov MI, Antonov LM. Aggregation of 2-Aminobenzimidazole-A Combined Experimental and Theoretical Investigation. Chemphyschem 2011; 12:1747-55. [DOI: 10.1002/cphc.201100002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2011] [Revised: 03/27/2011] [Indexed: 11/09/2022]
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Spectroscopic and structural studies of 6-(1-methylbenzimidazol-2-yl)-1H-pyridin-2-one and of an unusual T4(2)7(2)6(2)7(2) water tape stabilized by the copper(II) coordination polymer. Inorganica Chim Acta 2011. [DOI: 10.1016/j.ica.2011.02.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Belen’kii L, Gramenitskaya V, Evdokimenkova Y. The Literature of Heterocyclic Chemistry, Part X, 2005–2007. ADVANCES IN HETEROCYCLIC CHEMISTRY 2011. [DOI: 10.1016/b978-0-12-385464-3.00001-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Alkorta I, Elguero J. A theoretical NMR study of ortho and para-substituted benzenes compared with silabenzenes, pyridines and phosphabenzenes. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2010; 48 Suppl 1:S32-S37. [PMID: 20306517 DOI: 10.1002/mrc.2586] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Calculations of absolute shieldings and nuclear-independent chemical shift [NICS(1)] values of 84 compounds (benzenes, silabenzenes, pyridines and phosphabenzenes) allowed to discuss the absolute shieldings in the function of Brown σ(p)(+) substituent constant and to predict 71 new chemical shifts. The NICS(1) analysis of the aromaticity leads to the unexpected result for the silabenzenes that it is almost insensitive to substituent effects. In these set of compounds, it can be concluded that the aromaticity and its sensitivity to substituent effects are orthogonal.
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Giuliano BM, Feyer V, Prince KC, Coreno M, Evangelisti L, Melandri S, Caminati W. Tautomerism in 4-Hydroxypyrimidine, S-Methyl-2-thiouracil, and 2-Thiouracil. J Phys Chem A 2010; 114:12725-30. [DOI: 10.1021/jp106883s] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Barbara M. Giuliano
- Departamento de Química da Universidade de Coimbra, 3004-535 Coimbra, Portugal, Sincrotrone Trieste, in Area Science Park, I-34149 Basovizza, Trieste, Italy, CNR-IMIP, I-00016 Montelibretti (Rome), Italy, Dipartimento di Chimica “G. Ciamician” dell’Università, Via Selmi 2, I-40126 Bologna, Italy, and IOM, CNR, Area Science Park, I-34149 Basovizza, Trieste, Italy
| | - Vitaliy Feyer
- Departamento de Química da Universidade de Coimbra, 3004-535 Coimbra, Portugal, Sincrotrone Trieste, in Area Science Park, I-34149 Basovizza, Trieste, Italy, CNR-IMIP, I-00016 Montelibretti (Rome), Italy, Dipartimento di Chimica “G. Ciamician” dell’Università, Via Selmi 2, I-40126 Bologna, Italy, and IOM, CNR, Area Science Park, I-34149 Basovizza, Trieste, Italy
| | - Kevin C. Prince
- Departamento de Química da Universidade de Coimbra, 3004-535 Coimbra, Portugal, Sincrotrone Trieste, in Area Science Park, I-34149 Basovizza, Trieste, Italy, CNR-IMIP, I-00016 Montelibretti (Rome), Italy, Dipartimento di Chimica “G. Ciamician” dell’Università, Via Selmi 2, I-40126 Bologna, Italy, and IOM, CNR, Area Science Park, I-34149 Basovizza, Trieste, Italy
| | - Marcello Coreno
- Departamento de Química da Universidade de Coimbra, 3004-535 Coimbra, Portugal, Sincrotrone Trieste, in Area Science Park, I-34149 Basovizza, Trieste, Italy, CNR-IMIP, I-00016 Montelibretti (Rome), Italy, Dipartimento di Chimica “G. Ciamician” dell’Università, Via Selmi 2, I-40126 Bologna, Italy, and IOM, CNR, Area Science Park, I-34149 Basovizza, Trieste, Italy
| | - Luca Evangelisti
- Departamento de Química da Universidade de Coimbra, 3004-535 Coimbra, Portugal, Sincrotrone Trieste, in Area Science Park, I-34149 Basovizza, Trieste, Italy, CNR-IMIP, I-00016 Montelibretti (Rome), Italy, Dipartimento di Chimica “G. Ciamician” dell’Università, Via Selmi 2, I-40126 Bologna, Italy, and IOM, CNR, Area Science Park, I-34149 Basovizza, Trieste, Italy
| | - Sonia Melandri
- Departamento de Química da Universidade de Coimbra, 3004-535 Coimbra, Portugal, Sincrotrone Trieste, in Area Science Park, I-34149 Basovizza, Trieste, Italy, CNR-IMIP, I-00016 Montelibretti (Rome), Italy, Dipartimento di Chimica “G. Ciamician” dell’Università, Via Selmi 2, I-40126 Bologna, Italy, and IOM, CNR, Area Science Park, I-34149 Basovizza, Trieste, Italy
| | - Walther Caminati
- Departamento de Química da Universidade de Coimbra, 3004-535 Coimbra, Portugal, Sincrotrone Trieste, in Area Science Park, I-34149 Basovizza, Trieste, Italy, CNR-IMIP, I-00016 Montelibretti (Rome), Italy, Dipartimento di Chimica “G. Ciamician” dell’Università, Via Selmi 2, I-40126 Bologna, Italy, and IOM, CNR, Area Science Park, I-34149 Basovizza, Trieste, Italy
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Annular tautomerism: experimental observations and quantum mechanics calculations. J Comput Aided Mol Des 2010; 24:575-86. [PMID: 20364360 DOI: 10.1007/s10822-010-9345-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2010] [Accepted: 03/17/2010] [Indexed: 10/19/2022]
Abstract
The use of MP2 level quantum mechanical (QM) calculations on isolated heteroaromatic ring systems for the prediction of the tautomeric propensities of whole molecules in a crystalline environment was examined. A Polarisable Continuum Model was used in the calculations to account for environment effects on the tautomeric relative stabilities. The calculated relative energies of tautomers were compared to relative abundances within the Cambridge Structural Database (CSD) and the Protein Data Bank (PDB). The work was focussed on 84 annular tautomeric forms of 34 common ring systems. Good agreement was found between the calculations and the experimental data even if the quantity of these data was limited in many cases. The QM results were compared to those produced by much faster semiempirical calculations. In a search for other sources of the useful experimental data, the relative numbers of known compounds in which prototropic positions were often substituted by heavy atoms were also analysed. A scheme which groups all annular tautomeric transformations into 10 classes was developed. The scheme was designed to encompass a comprehensive set of known and theoretically possible tautomeric ring systems generated as part of a previous study. General trends across analogous ring systems were detected as a result. The calculations and statistics collected on crystallographic data as well as the general trends observed should be useful for the better modelling of annular tautomerism in the applications such as computer-aided drug design, small molecule crystal structure prediction, the naming of compounds and the interpretation of protein-small molecule crystal structures.
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Ghiviriga I, El-Gendy BEDM, Steel PJ, Katritzky AR. Tautomerism of guanidines studied by 15N NMR: 2-hydrazono-3-phenylquinazolin-4(3H)-ones and related compounds. Org Biomol Chem 2009; 7:4110-9. [DOI: 10.1039/b907577a] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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37
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Lippert B, Gupta D. Promotion of rare nucleobase tautomers by metal binding. Dalton Trans 2009:4619-34. [DOI: 10.1039/b823087k] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Volle JN, Mävers U, Schlosser M. The Tautomeric Persistence of Electronically and Sterically Biased 2-Quinolinones. European J Org Chem 2008. [DOI: 10.1002/ejoc.200800123] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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Holzer W, A. Eller G, Sch嗜berger S. On the Tautomerism of Cinnolin-4-ol, Cinnolin-4-thiol, and Cinnolin-4-amine. HETEROCYCLES 2008. [DOI: 10.3987/com-07-11177] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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