151
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Acetamidines and acetamidoximes containing an electron-withdrawing group at the α-carbon atom: their use in the synthesis of nitrogen heterocycles (review)*. Chem Heterocycl Compd (N Y) 2013. [DOI: 10.1007/s10593-013-1277-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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152
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Korotaev VY, Barkov AY, Sosnovskikh VY. Synthesis of 5-(trifluoromethyl)-5H-chromeno[3,4-b]pyridines from 3-nitro-2-(trifluoromethyl)-2H-chromenes and aminoenones derived from acetylacetone and cyclic amines. Tetrahedron Lett 2013. [DOI: 10.1016/j.tetlet.2013.03.137] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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153
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Chenov’yants MS, Burykin IV, Erofeev NE. Electrophoretic determination of thioamides, pyridine and pyrimidine derivatives. JOURNAL OF ANALYTICAL CHEMISTRY 2013. [DOI: 10.1134/s106193481306004x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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154
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Patni M, Gupta R, Kotikalapudi R, Kumara Swamy K, Bansal RK. Nitrenium ion induced tandem S–S coupling, 1,2-prototropic shift and reduction. Tetrahedron Lett 2013. [DOI: 10.1016/j.tetlet.2013.02.035] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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155
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Oziminski WP. Theoretical study on the solvent influence on 1,2,3-triazole tautomeric equilibrium. A comparison of incremental microsolvation and continuum solvation model approaches. Tetrahedron 2013. [DOI: 10.1016/j.tet.2013.02.057] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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156
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Huang YW, Srinivasadesikan V, Chen WH, Lee SL. The failure of UMP2 on the keto–enol tautomerization of β-radical compounds: The effect of spin contamination. Chem Phys Lett 2013. [DOI: 10.1016/j.cplett.2013.02.034] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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157
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Rozas I, Sánchez-Sanz G, Alkorta I, Elguero J. Solvent effects on guanidinium-anion interactions and the problem of guanidinium Y-aromaticity. J PHYS ORG CHEM 2013. [DOI: 10.1002/poc.3099] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Isabel Rozas
- School of Chemistry; Trinity Biomedical Sciences Institute, Trinity College Dublin; 154-160 Pearse St. Dublin 2 Ireland
| | - Goar Sánchez-Sanz
- Instituto de Química Médica (IQM-CSIC); Juan de la Cierva, 3 28006 Madrid Spain
| | - Ibon Alkorta
- Instituto de Química Médica (IQM-CSIC); Juan de la Cierva, 3 28006 Madrid Spain
| | - José Elguero
- Instituto de Química Médica (IQM-CSIC); Juan de la Cierva, 3 28006 Madrid Spain
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158
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Ajaj I, Mijin D, Maslak V, Brković D, Milčić M, Todorović N, Marinković A. A simple and convenient synthesis of tautomeric (6 or 2)-hydroxy-4-methyl-(2 or 6)-oxo-1-(substituted phenyl)-(1,2 or 1,6)-dihydropyridine-3-carbonitriles. MONATSHEFTE FUR CHEMIE 2013. [DOI: 10.1007/s00706-012-0911-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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159
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Skotnicka A, Kolehmainen E, Czeleń P, Valkonen A, Gawinecki R. Synthesis and structural characterization of substituted 2-phenacylbenzoxazoles. Int J Mol Sci 2013; 14:4444-60. [PMID: 23439552 PMCID: PMC3634406 DOI: 10.3390/ijms14034444] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2013] [Revised: 02/04/2013] [Accepted: 02/16/2013] [Indexed: 11/16/2022] Open
Abstract
1H and 13C NMR spectra of eleven 2-phenacylbenzoxazoles (ketimine form) show that their CDCl3-solutions contains also (Z)-2-(benzo[d]oxazol-2-yl)-1-phenylethenols (enolimine form). Intramolecular hydrogen bonding in the latter tautomer was found to be significantly weaker than that one in respective (Z)-2-(2-hydroxy-2-phenylvinyl)pyridines. Integrals of the 1H NMR signals were used to evaluate the molar ratio of the tautomers. Strong electron-donating substituents were found to stabilize the ketimine tautomer. pKT (negative logarithm of the equilibrium constant, KT = [ketimine]/[enolimine]) was found to be linearly dependent on the Hammett substituent constant σ. The results of the MP2 ab initio calculations reveal enolimine including an intramolecular OH···N hydrogen bond to be the most stable form both with electron-donor and electron-acceptor substituents. The stability of ketimines is an intermediate of those found for enolimines and enaminones i.e., (E)-2-(benzo[d]oxazol-2(3H)-ylidene)-1-phenylethanones. 13C CPMAS NMR spectral data reveal that in the crystalline state the ketimine tautomer is predominant in p-NMe2 substituted congener. On the other hand, enolimine forms were detected there when the substituent has less electron-donating character or when it is an electron-acceptor by character.
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Affiliation(s)
- Agnieszka Skotnicka
- Department of Chemistry, University of Technology and Life Sciences, Seminaryjna 3, PL-85-326 Bydgoszcz, Poland; E-Mail:
| | - Erkki Kolehmainen
- Department of Chemistry, P.O. Box 35, FI-40014 University of Jyväskylä, Finland; E-Mails: (E.K.); (A.V.)
| | - Przemysław Czeleń
- Department of Physical Chemistry, Collegium Medicum, N. Copernicus University, Kurpińskiego 5, 85-950 Bydgoszcz, Poland; E-Mail:
| | - Arto Valkonen
- Department of Chemistry, P.O. Box 35, FI-40014 University of Jyväskylä, Finland; E-Mails: (E.K.); (A.V.)
| | - Ryszard Gawinecki
- Department of Chemistry, University of Technology and Life Sciences, Seminaryjna 3, PL-85-326 Bydgoszcz, Poland; E-Mail:
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +48-52-374-90-70; Fax: +48-52-374-90-05
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160
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Yamaji M, Kida M. Photothermal Tautomerization of a UV Sunscreen (4-tert-Butyl-4′-methoxydibenzoylmethane) in Acetonitrile Studied by Steady-State and Laser Flash Photolysis. J Phys Chem A 2013; 117:1946-51. [DOI: 10.1021/jp312774e] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Minoru Yamaji
- Department of Chemistry and Chemical Biology, Graduate
School of Engineering, Gunma University, Kiryu, Gunma 376-8515, Japan
| | - Mayumi Kida
- Department of Chemistry and Chemical Biology, Graduate
School of Engineering, Gunma University, Kiryu, Gunma 376-8515, Japan
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161
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Raczyńska ED, Makowski M, Zientara-Rytter K, Kolczyńska K, Stępniewski TM, Hallmann M. Quantum-Chemical Studies on the Favored and Rare Tautomers of Neutral and Redox Adenine. J Phys Chem A 2013; 117:1548-59. [DOI: 10.1021/jp3081029] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Ewa D. Raczyńska
- Department of Chemistry, Warsaw University of Life Sciences (SGGW), ul. Nowoursynowska
159 c, 02-776 Warszawa, Poland
| | - Mariusz Makowski
- Faculty of Chemistry, Univeristy of Gdańsk, ul. Sobieskiego 18, 80-952
Gdańsk, Poland
| | - Katarzyna Zientara-Rytter
- Interdisciplinary
Department of
Biotechnology, Warsaw University of Life Sciences (SGGW), ul. Nowoursynowska 166, 02-776 Warszawa, Poland
| | - Katarzyna Kolczyńska
- Interdisciplinary
Department of
Biotechnology, Warsaw University of Life Sciences (SGGW), ul. Nowoursynowska 166, 02-776 Warszawa, Poland
| | - Tomasz M. Stępniewski
- Interdisciplinary
Department of
Biotechnology, Warsaw University of Life Sciences (SGGW), ul. Nowoursynowska 166, 02-776 Warszawa, Poland
| | - Małgorzata Hallmann
- Department of Chemistry, Warsaw University of Life Sciences (SGGW), ul. Nowoursynowska
159 c, 02-776 Warszawa, Poland
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162
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Photochemical behaviors of a tethered 1,3-diketone derivative studied by transient absorption and time-resolved EPR measurements. Chem Phys Lett 2013. [DOI: 10.1016/j.cplett.2012.10.067] [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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163
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Stability and aromaticity of tautomers and kinetics of proton transfer in 6-methylpentafulvene and its exo-substituted derivatives: a computational study. Struct Chem 2012. [DOI: 10.1007/s11224-012-0125-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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164
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Karabulut S, Namlı H. An FT-IR and DFT based new approach for the detection of tautomer proportions in solution. J Mol Struct 2012. [DOI: 10.1016/j.molstruc.2012.05.029] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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165
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Esteruelas MA, García-Raboso J, Oliván M. Reactions of an Osmium-Hexahydride Complex with Cytosine, Deoxycytidine, and Cytidine: The Importance of the Minor Tautomers. Inorg Chem 2012; 51:9522-8. [DOI: 10.1021/ic3013238] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Miguel A. Esteruelas
- Departamento de Química Inorgánica-Instituto
de Síntesis Química y Catálisis Homogénea
(ISQCH), Universidad de Zaragoza-CSIC,
50009 Zaragoza, Spain
| | - Jorge García-Raboso
- Departamento de Química Inorgánica-Instituto
de Síntesis Química y Catálisis Homogénea
(ISQCH), Universidad de Zaragoza-CSIC,
50009 Zaragoza, Spain
| | - Montserrat Oliván
- Departamento de Química Inorgánica-Instituto
de Síntesis Química y Catálisis Homogénea
(ISQCH), Universidad de Zaragoza-CSIC,
50009 Zaragoza, Spain
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166
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Raczyńska ED. Quantum-chemical studies of the consequences of one-electron oxidation and one-electron reduction for imidazole in the gas phase and water. COMPUT THEOR CHEM 2012. [DOI: 10.1016/j.comptc.2012.05.036] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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167
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Deng ZP, Kang W, Zhu ZB, Huo LH, Zhao H, Gao S. Cation radii induced structural variation in fluorescent alkaline earth networks constructed from tautomers of a nucleobase analogue. Dalton Trans 2012; 41:8354-60. [PMID: 22635055 DOI: 10.1039/c2dt12353c] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Nucleobase tautomers and their metal complexes have attracted considerable attention due to their fascinating architectures along with wide applications. In this paper, 4,6-dihydroxypyrimidine (H(2)DHP), an analogue of uracil and thymine, was employed to react with the vital elements of alkaline earth metals in an aqueous solution and lead to the formation of four novel complexes, [Mg(HDHP)(2) (H(2)O)(4)] (1), [Ca(HDHP)(2)(H(2)O)(3)](n)·nH(2)O (2), [Sr(HDHP)(2)(H(2)O)(3)](n)·nH(2)O (3), and [Ba(HDHP)(2)(H(2)O)(2)](n)·nH(2)O (4), which have been characterized by elemental analysis, IR, TG, UV-Vis, PL, powder and single-crystal X-ray diffraction and progressively evolve from zero-dimensional (0D) mononuclear, one-dimensional (1D) zig-zag double chain, two-dimensional (2D) double layer, to a three-dimensional (3D) porous network along with the increase of cation radii. This tendency in dimensionality follows salient crystal engineering principles and can be explained by considering factors such as hard-soft acid-base principles and cation radii. The deprotonated H(2)DHP ligand exhibits four new coordination modes, namely, O-monodentate (complex 1), N,O-chelating (complexes 2 and 3), O,O-bridging (complexes 2 and 3), and κ(1)O:κ(2)O-bridging mode (complex 4). Interestingly, the structural investigation indicates that the HDHP(-) monoanion shows three unusual types of tautomers, which are essential for the diagnosis of disease and investigation of medicine. Furthermore, the four complexes exhibit strong blue emission compared to free H(2)DHP ligand at room temperature and may be potential candidates for blue fluorescent biological materials used in organisms.
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Affiliation(s)
- Zhao-Peng Deng
- Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education, Heilongjiang University, Harbin 150080, People's Republic of China
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168
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Giussi JM, Allegretti PE, Cortizo MS. New copolymers of a tautomerizable β-ketonitrile monomer: Synthesis, characterization and solution tautomerism. ACTA ACUST UNITED AC 2012. [DOI: 10.1002/pola.26238] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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169
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Imashiro F. DFT Study on Hydrogen-Bond-Enhanced Aromaticity/Antiaromaticity of the Rings Involved in the π-Conjugated Hydrogen-Bond System: 3-Hydroxy-2H-benzocyclo(propen and penten)-2-ones and 6-Hydroxy-5H-benzocyclohepten-5-one. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2012. [DOI: 10.1246/bcsj.20120050] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Fumio Imashiro
- Department of Chemistry, Graduate School of Science, Kyoto University
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170
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DFT studies on one-electron oxidation and one-electron reduction for 2- and 4-aminopyridines. J Mol Model 2012; 18:4367-80. [PMID: 22585356 PMCID: PMC3429776 DOI: 10.1007/s00894-012-1446-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2012] [Accepted: 04/23/2012] [Indexed: 11/28/2022]
Abstract
Quantum-chemical calculations {DFT(B3LYP)/6-311+G(d,p)} were performed for all possible tautomers (aromatic and nonaromatic) of neutral 2- and 4-aminopyridines and their oxidized and reduced forms. One-electron oxidation has no important effect on the tautomeric preference for 2-aminopyridine. The amine tautomer is favored. However, oxidation increases the stability of the imine NH tautomer, and its contribution in the tautomeric mixture cannot be neglected. In the case of 4-aminopyridine, one-electron oxidation increases the stability of both the amine and imine NH tautomers. Consequently, they possess very close energies. As major tautomers, they dictate the composition of the tautomeric mixture. The CH tautomers may be considered as very rare forms for both neutral and oxidized aminopyridines. A reverse situation takes place for the reduced forms of aminopyridines. One-electron reduction favors the C3 atom for the labile proton for both aminopyridines. This may partially explain the origin of the CH tautomers for the anionic states of nucleobases containing the exo NH2 group.
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171
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Karton A, O’Reilly RJ, Radom L. Assessment of Theoretical Procedures for Calculating Barrier Heights for a Diverse Set of Water-Catalyzed Proton-Transfer Reactions. J Phys Chem A 2012; 116:4211-21. [DOI: 10.1021/jp301499y] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Amir Karton
- School of
Chemistry and ARC Centre of Excellence for
Free Radical Chemistry and Biotechnology, University of Sydney, Sydney, NSW 2006, Australia
| | - Robert J. O’Reilly
- School of
Chemistry and ARC Centre of Excellence for
Free Radical Chemistry and Biotechnology, University of Sydney, Sydney, NSW 2006, Australia
| | - Leo Radom
- School of
Chemistry and ARC Centre of Excellence for
Free Radical Chemistry and Biotechnology, University of Sydney, Sydney, NSW 2006, Australia
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172
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Stasyuk OA, Szatyłowicz H, Krygowski TM. Effect of the H-bonding on aromaticity of purine tautomers. J Org Chem 2012; 77:4035-45. [PMID: 22448684 DOI: 10.1021/jo300406r] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Four tautomers of purine (1-H, 3-H, 7-H, and 9-H) and their equilibrium H-bonded complexes with F(-) and HF for acidic and basic centers, respectively, were optimized by means of the B3LYP/6-311++G(d,p) level of theory. Purine tautomer stability increases in the following series: 1-H < 3-H < 7-H < 9-H, consistent with increasing aromaticity. Furthermore, the presence of a hydrogen bond with HF does not change this order. For neutral H-bonded complexes, the strongest and the weakest intermolecular interactions occur (-14.12 and -10.49 kcal/mol) for less stable purine tautomers when the proton acceptor is located in the five- and six-membered rings, respectively. For 9-H and 7-H tautomers the order is reversed. The H-bond energy for the imidazole complex with HF amounts to -14.03 kcal/mol; hence, in the latter case, the fusion of imidazole to pyrimidine decreases its basicity. The ionic H-bonds of N(-)···HF type are stronger by ~10 kcal/mol than the neutral N···HF intermolecular interactions. The hydrogen bond N(-)···HF energies in pyrrole and imidazole are -32.28 and -30.03 kcal/mol, respectively, and are substantially stronger than those observed in purine complexes. The aromaticity of each individual ring and of the whole molecule for all tautomers in ionic complexes is very similar to that observed for the anion of purine. This is not the case for neutral complexes and purine as a reference. The N···HF bonds perturb much more the π-electron structure of five-membered rings than that of the six-membered ones. The H-bonding complexes for 7-H and 9-H tautomers are characterized by higher aromaticity and a much lower range of HOMA variability.
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Affiliation(s)
- Olga A Stasyuk
- Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland
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173
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Consequences of one-electron oxidation and one-electron reduction for 4-aminopyrimidine—DFT studies. J Mol Model 2012; 18:3523-33. [DOI: 10.1007/s00894-012-1358-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2011] [Accepted: 01/08/2012] [Indexed: 10/14/2022]
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174
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Ośmiałowski B, Kolehmainen E, Kowalska M. 2-Acylamino-6-pyridones: Breaking of an Intramolecular Hydrogen Bond by Self-association and Complexation with Double and Triple Hydrogen Bonding Counterparts. Uncommon Steric Effect on Intermolecular Interactions. J Org Chem 2012; 77:1653-62. [DOI: 10.1021/jo201800u] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- Borys Ośmiałowski
- Faculty of Chemical Technology
and Engineering, University of Technology and Life Sciences, Seminaryjna 3, PL-85-326 Bydgoszcz, Poland
| | - Erkki Kolehmainen
- Department of Chemistry, University of Jyväskylä, P.O. Box 35,
FI-40014 Finland
| | - Magdalena Kowalska
- Faculty of Chemical Technology
and Engineering, University of Technology and Life Sciences, Seminaryjna 3, PL-85-326 Bydgoszcz, Poland
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175
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Hidalgo A, Jiménez LPA, Ramos LA, Mroginski MA, Jios JL, Ulic SE, Echeverría GA, Piro OE, Castellano E. Spectroscopic, structural, and conformational properties of (Z)-4,4,4-trifluoro-3-(2-hydroxyethylamino)-1-(2-hydroxyphenyl)-2-buten-1-one, C12H12F3NO3: a trifluoromethyl-substituted β-aminoenone. J Phys Chem A 2012; 116:1110-8. [PMID: 22242788 DOI: 10.1021/jp211536q] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The (Z)-4,4,4-trifluoro-3-(2-hydroxyethylamino)-1-(2-hydroxyphenyl)-2-buten-1-one (C(12)H(12)F(3)NO(3)) compound was thoroughly studied by IR, Raman, UV-visible, and (13)C and (19)F NMR spectroscopies. The solid-state molecular structure was determined by X-ray diffraction methods. It crystallizes in the P2(1)/c space group with a = 12.1420(4) Å, b = 7.8210(3) Å, c = 13.8970(5) Å, β = 116.162(2)°, and Z = 4 molecules per unit cell. The molecule shows a nearly planar molecular skeleton, favored by intramolecular OH···O and NH···O bonds, which are arranged in the lattice as an OH···O bonded polymer coiled around crystallographic 2-fold screw-axes. The three postulated tautomers were evaluated using quantum chemical calculations. The lowest energy tautomer (I) calculated with density functional theory methods agrees with the observed crystal structure. The structural and conformational properties are discussed considering the effect of the intra- and intermolecular hydrogen bond interactions.
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Affiliation(s)
- A Hidalgo
- CEQUINOR (CONICET-UNLP), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, República Argentina
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176
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Oziminski WP. Tautomeric equilibria and aromaticity of phosphodiazoles: An ab initio study. COMPUT THEOR CHEM 2012. [DOI: 10.1016/j.comptc.2011.11.018] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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177
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Martyniak A, Lipkowski P, Boens N, Filarowski A. Electron-topological, energetic and π-electron delocalization analysis of ketoenamine-enolimine tautomeric equilibrium. J Mol Model 2012; 18:257-63. [PMID: 21523531 PMCID: PMC3249559 DOI: 10.1007/s00894-011-1075-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2010] [Accepted: 03/28/2011] [Indexed: 11/30/2022]
Abstract
The ketoenamine-enolimine tautometic equilibrium has been studied by the analysis of aromaticity and electron-topological parameters. The influence of substituents on the energy of the transition state and of the tautomeric forms has been investigated for different positions of chelate chain. The quantum theory of atoms in molecules method (QTAIM) has been applied to study changes in the electron-topological parameters of the molecule with respect to the tautomeric equilibrium in intramolecular hydrogen bond. Dependencies of the HOMA aromaticity index and electron density at the critical points defining aromaticity and electronic state of the chelate chain on the transition state (TS), OH and HN tautomeric forms have been obtained.
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Affiliation(s)
- Agata Martyniak
- Faculty of Chemistry, University of Wrocław, 14 F. Joliot-Curie str., 50–383 Wrocław, Poland
| | - Pawel Lipkowski
- Theoretical Chemistry Group, Institute of Physical and Theoretical Chemistry, Wrocław University of Technology, Wyb. Wyspiańskiego 27, 50–370 Wrocław, Poland
| | - Noel Boens
- Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200f – bus 02404, 3001 Leuven, Belgium
| | - Aleksander Filarowski
- Faculty of Chemistry, University of Wrocław, 14 F. Joliot-Curie str., 50–383 Wrocław, Poland
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178
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Pagar VV, Jadhav AM, Liu RS. Gold-catalyzed formal [3 + 3] and [4 + 2] cycloaddition reactions of nitrosobenzenes with alkenylgold carbenoids. J Am Chem Soc 2011; 133:20728-31. [PMID: 22128862 DOI: 10.1021/ja209980d] [Citation(s) in RCA: 169] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We report two new formal cycloaddition reactions between nitrosobenzenes and alkenylgold carbenoids. We obtained quinoline oxides 3 in satisfactory yields from the gold-catalyzed [3 + 3]-cycloadditions between nitrosobenzenes and alkenyldiazo esters 1. For propargyl esters 5, its resulting gold carbenes react with nitrosobenzene to give alkenylimine 8, followed by a [4 + 2]-cycloaddition with nitrosobenzene.
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Affiliation(s)
- Vinayak Vishnu Pagar
- Department of Chemistry, National Tsing-Hua University, Hsinchu, Taiwan 30013, ROC
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179
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Chernov'yants MS, Khohlov EV, Bondarenko GI, Burykin IV. Estimation of σ- and π-donor properties of heterocyclic thioamides by spectroscopic and magnetic resonance methods. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2011; 81:640-644. [PMID: 21788156 DOI: 10.1016/j.saa.2011.06.067] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2010] [Revised: 06/23/2011] [Accepted: 06/26/2011] [Indexed: 05/31/2023]
Abstract
The charge-transfer complexes (CTC) of few thioamide: 1-methylimidazoline-2-thione (MMI), 3-methyl-1-ethoxycarbonilimidazoline-2-thione (Carb), 5-methylbenzimidazoline-2-thione (BIZ), benzothiazoline-2-thione (BTZ), benzoxazoline-2-thione (BOZ) as σ-donors and diiodine as σ-acceptor were studied by spectroscopic methods (UV/Vis, (1)H NMR). CTC formation constants of thioamides with diiodine were determined using the function of the average-iodine number. The charge-transfer complexes of thioamides as π-donors with tetracyanoethylene (TCNE) as π-electron acceptor, were studied by UV-spectroscopy in dichloromethane and chloroform solutions. The mechanism of interaction MMI and Carb with TCNE have been studied by EPR spectroscopy. Spectral characteristics and formation constants are discussed in the terms of electron donor affinity of thioamides and the nature of the organic solvent used. The ionization potentials of donors were estimated from the CT transition energies of their complexes. The photolytic equilibrium constants of five thioamides are determined using pH-metric titrations.
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180
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Balabin RM. The keto-enol equilibrium in substituted acetaldehydes: focal-point analysis and ab initiolimit. Mol Phys 2011. [DOI: 10.1080/00268976.2011.587457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2022]
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181
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Karpińska G, Mazurek AP, Dobrowolski JC. Hydroxyquinolines: Constitutional isomers and tautomers. COMPUT THEOR CHEM 2011. [DOI: 10.1016/j.comptc.2011.06.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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182
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183
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Korotaev VY, Barkov AY, Slepukhin PA, Kodess MI, Sosnovskikh VY. Unexpected spontaneous ring-contraction rearrangement of trifluoromethylated 1,2-oxazine N-oxides to 1-pyrroline N-oxides. MENDELEEV COMMUNICATIONS 2011. [DOI: 10.1016/j.mencom.2011.09.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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184
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Minkin VI, Tsukanov AV, Dubonosov AD, Bren VA. Tautomeric Schiff bases: Iono-, solvato-, thermo- and photochromism. J Mol Struct 2011. [DOI: 10.1016/j.molstruc.2011.05.029] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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185
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Milione S, Bertolasi V. Tautomerism in bis(oxazolines): an experimental and theoretical study of proton transfer in 1,1-bis(4,4-dimethyl-1,3-oxazolin-2-yl)-ethane. Tetrahedron Lett 2011. [DOI: 10.1016/j.tetlet.2011.04.107] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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186
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Li H, Jiang J, Lu G, Huang F, Wang ZX. On the “Reverse Gear”Mechanism of the Reversible Dehydrogenation/Hydrogenation of a Nitrogen Heterocycle Catalyzed by a Cp*Ir Complex: A Computational Study. Organometallics 2011. [DOI: 10.1021/om200222j] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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187
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Machiguchi T, Hasegawa T, Saitoh H, Yamabe S, Yamazaki S. Solid-State Thiotropolone: An Extremely Rapid Intramolecular Proton Transfer. J Org Chem 2011; 76:5457-60. [DOI: 10.1021/jo2005796] [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)
| | - Toshio Hasegawa
- Department of Chemistry, Saitama University, Saitama, 338-8570, Japan
| | - Hideki Saitoh
- Department of Chemistry, Saitama University, Saitama, 338-8570, Japan
| | - Shinichi Yamabe
- Department of Chemistry, Nara University of Education, Takabatake-cho, Nara 630-8528, Japan
| | - Shoko Yamazaki
- Department of Chemistry, Nara University of Education, Takabatake-cho, Nara 630-8528, Japan
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188
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Sachdeva N, Dolzhenko AV, Chui WK. Synthesis and tautomerism study of 6-benzoylmethyl-1,3,5-triazin-2,4-diamine. CR CHIM 2011. [DOI: 10.1016/j.crci.2010.10.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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189
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Su Y, Song G, Han K, Li X. Theoretical studies of iridium-mediated tautomerization of substituted pyridines. J Organomet Chem 2011. [DOI: 10.1016/j.jorganchem.2011.01.029] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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190
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Consequence of one-electron oxidation and one-electron reduction for aniline. J Mol Model 2011; 17:3229-39. [PMID: 21369938 PMCID: PMC3224217 DOI: 10.1007/s00894-011-1001-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2010] [Accepted: 01/28/2011] [Indexed: 11/17/2022]
Abstract
Quantum-chemical calculations were performed for all possible isomers of neutral aniline and its redox forms, and intramolecular proton-transfer (prototropy) accompanied by π-electron delocalization was analyzed. One-electron oxidation (PhNH2 – e → [PhNH2]+•) has no important effect on tautomeric preferences. The enamine tautomer is preferred for oxidized aniline similarly as for the neutral molecule. Dramatical changes take place when proceeding from neutral to reduced aniline. One-electron reduction (PhNH2 + e → [PhNH2]-•) favors the imine tautomer. Independently on the state of oxidation, π- and n-electrons are more delocalized for the enamine than imine tautomers. The change of the tautomeric preferences for reduced aniline may partially explain the origin of the CH tautomers for reduced nucleobases (cytosine, adenine, and guanine).
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191
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Theoretical investigations on the structure and relative stabilities of the tautomeric forms of 6-amino-5-nitrosouracil and violuric acid derivatives (PM3-COSMO calculation). COMPUT THEOR CHEM 2011. [DOI: 10.1016/j.comptc.2010.12.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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192
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Raczyńska ED, Hallmann M, Duczmal K. Quantum-chemical studies of amide–iminol tautomerism for inhibitor of lactate dehydrogenase: Oxamic acid. COMPUT THEOR CHEM 2011. [DOI: 10.1016/j.comptc.2011.01.017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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193
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Heteroaromatic thioamides: Structure and stability of charge transfer complexes with iodine, antithyroid activity. J STRUCT CHEM+ 2011. [DOI: 10.1007/s10947-010-0178-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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194
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Gaspar A, Teixeira F, Uriarte E, Milhazes N, Melo A, Cordeiro MNDS, Ortuso F, Alcaro S, Borges F. Towards the discovery of a novel class of monoamine oxidase inhibitors: structure-property-activity and docking studies on chromone amides. ChemMedChem 2011; 6:628-32. [PMID: 21442758 DOI: 10.1002/cmdc.201000452] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2010] [Revised: 12/23/2010] [Indexed: 11/08/2022]
Affiliation(s)
- Alexandra Gaspar
- CIQUP, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua Campo Alegre 687, 4169-007 Porto, Portugal
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195
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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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196
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Raczyńska E, Kolczyńska K, Stępniewski T. Tautomeric preferences and π-electron delocalization for redox forms of phenol. COMPUT THEOR CHEM 2011. [DOI: 10.1016/j.comptc.2010.10.022] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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197
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DFT studies on tautomeric preferences of 1-(pyridin-2-yl)-4-(quinolin-2-yl)butane-2,3-dione in the gas phase and in solution. Struct Chem 2010. [DOI: 10.1007/s11224-010-9674-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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198
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Milletti F, Vulpetti A. Tautomer preference in PDB complexes and its impact on structure-based drug discovery. J Chem Inf Model 2010; 50:1062-74. [PMID: 20515065 DOI: 10.1021/ci900501c] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Tautomer enrichment is a key step of ligand preparation prior to virtual screening. In this paper, we have investigated how tautomer preference in various media (water, gas phase, and crystal) compares to tautomer preference at the active site of the protein by analyzing the different possible H-bonding contacts for a set of 13 tautomeric structures. In addition, we have explored the impact of four different protocols for the enumeration of tautomers in virtual screening by using Flap, Glide, and Gold as docking tools on seven targets of the DUD data set. Excluding targets in which the binding does not involve tautomeric atoms (HSP90, p38, and VEGFR2), we found that the average receiver operating characteristic curve enrichment at 10% was 0.25 (Gold), 0.24 (Glide), and 0.50 (Flap) by considering only tautomers predicted to be unstable in water versus 0.41 (Gold), 0.56 (Glide), 0.51 (Flap) by limiting the enumeration process only to the predicted most stable tautomer. The inclusion of all tautomers (stable and unstable) yielded slightly poorer results than considering only the most stable form in water.
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Affiliation(s)
- Francesca Milletti
- CADD, Global Discovery Chemistry, Novartis Institutes for Biomedical Research, CH4002 Basel, Switzerland
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199
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Paasche A, Schiller M, Schirmeister T, Engels B. Mechanistic study of the reaction of thiol-containing enzymes with alpha,beta-unsaturated carbonyl substrates by computation and chemoassays. ChemMedChem 2010; 5:869-80. [PMID: 20401893 PMCID: PMC7162195 DOI: 10.1002/cmdc.201000020] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
We investigated the reactions between substituted α,β‐unsaturated carbonyl compounds (Michael systems) and thiols by computations as well as chemoassays. The results give insight into variations in the underlying mechanisms as a function of the substitution pattern. This is of interest for the mechanisms of inhibition of the SARS coronavirus main protease (SARS‐CoV Mpro) by etacrynic acid derivatives as well as for the excess toxicity of substituted α,β‐unsaturated carbonyl compounds. This study compares possible reaction courses including 1,4‐addition followed by a ketonization step, and underscores the importance of a base‐catalyzed step for the reactivity of thiol groups in enzymes. Phenyl and methyl substituents at the Michael system decrease the reactivity of the electrophilic compound, but chlorophenyl substituents partly recover the reactivity. Computations also indicate that electron‐pushing substituents lead to a change in the reaction mechanism. The conformation of the Michael system is also found to significantly influence reactivity: the s‐cis conformation leads to higher reactivity than the s‐trans conformation. The computed data explain the trends in measured inhibition potencies of substituted α,β‐unsaturated carbonyl compounds and of reaction rates in chemical assays. They also indicate that the reversibility of inhibition does not stand in contrast to the formation of a new covalent bond between inhibitor and protease.
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Affiliation(s)
- Alexander Paasche
- Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
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200
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Paul BK, Samanta A, Kar S, Guchhait N. Lactim–lactam tautomerism is favoured over enol–keto tautomerism in 2-hydroxy-5-(4-fluorophenyl)nicotinic acid: Experimental and quantum chemical approach. J Photochem Photobiol A Chem 2010. [DOI: 10.1016/j.jphotochem.2010.06.028] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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