1
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Emenike BU, Farshadmand A, Zeller M, Roman AJ, Sevimler A, Shinn DW. Electrostatic CH-π Interactions Can Override Fluorine Gauche Effects To Exert Conformational Control. Chemistry 2023; 29:e202203139. [PMID: 36286329 DOI: 10.1002/chem.202203139] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Indexed: 11/07/2022]
Abstract
Fluorine gauche effects are conformational properties of 2-fluoroethanes often applied in modern molecular designs. However, the physical origins of fluorine gauche effects are not well understood, with the consensus favoring the established hyperconjugation theory over an emerging electrostatic model. Using a series of model systems, we show that a shift to fluorine gauche effects can be influenced by intramolecular CH⋅⋅⋅π aromatic interactions, a through-space event. Modulating the π-ring (forming the aromatic interaction) with substituent groups resulted in a linear Hammett relationship, thus indicating that the CH⋅⋅⋅π interaction has electrostatic features. For instance, attaching a nitro group (an electron-withdrawing substituent) to the π-ring weakened the CH⋅⋅⋅π interaction and led to a gauche preference, whereas an anti conformer is preferred with amine as substituent. The experimental results performed by using proton NMR spectroscopy are corroborated by gas-phase DFT calculations and solid-state X-ray crystallography.
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Affiliation(s)
- Bright U Emenike
- Department of Chemistry & Physics, State University of New York, Old Westbury, 223 Store Hill Road, Old Westbury, NY 11568, USA
| | - Amiel Farshadmand
- Department of Chemistry & Physics, State University of New York, Old Westbury, 223 Store Hill Road, Old Westbury, NY 11568, USA
| | - Matthias Zeller
- Department of Chemistry, Purdue University, West Lafayette, IN 47907-2084, USA
| | - Armando J Roman
- Department of Chemistry & Physics, State University of New York, Old Westbury, 223 Store Hill Road, Old Westbury, NY 11568, USA
| | - Arzu Sevimler
- Department of Chemistry & Physics, State University of New York, Old Westbury, 223 Store Hill Road, Old Westbury, NY 11568, USA
| | - David W Shinn
- Department of Mathematics and Science, United States Merchant Marine Academy, 300 Steamboat Road, Kings Point, NY 11024, USA
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2
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Rodrigues Silva D, de Azevedo Santos L, Hamlin TA, Fonseca Guerra C, Freitas MP, Bickelhaupt FM. The Gauche Effect in XCH 2 CH 2 X Revisited. Chemphyschem 2021; 22:641-648. [PMID: 33555663 PMCID: PMC8048458 DOI: 10.1002/cphc.202100090] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Indexed: 11/22/2022]
Abstract
We have quantum chemically investigated the rotational isomerism of 1,2-dihaloethanes XCH2 CH2 X (X = F, Cl, Br, I) at ZORA-BP86-D3(BJ)/QZ4P. Our Kohn-Sham molecular orbital (KS-MO) analyses reveal that hyperconjugative orbital interactions favor the gauche conformation in all cases (X = F-I), not only for X = F as in the current model of this so-called gauche effect. We show that, instead, it is the interplay of hyperconjugation with Pauli repulsion between lone-pair-type orbitals on the halogen substituents that constitutes the causal mechanism for the gauche effect. Thus, only in the case of the relatively small fluorine atoms, steric Pauli repulsion is too weak to overrule the gauche preference of the hyperconjugative orbital interactions. For the larger halogens, X⋅⋅⋅X steric Pauli repulsion becomes sufficiently destabilizing to shift the energetic preference from gauche to anti, despite the opposite preference of hyperconjugation.
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Affiliation(s)
- Daniela Rodrigues Silva
- Department of Theoretical ChemistryAmsterdam Institute of Molecular and Life Sciences (AIMMS)Amsterdam Center for Multiscale Modeling (ACMM)Vrije Universiteit AmsterdamDe Boelelaan 10831081 HVAmsterdam (TheNetherlands
- Departamento de QuímicaInstituto de Ciências NaturaisUniversidade Federal de Lavras37200-900Lavras-MGBrazil
| | - Lucas de Azevedo Santos
- Department of Theoretical ChemistryAmsterdam Institute of Molecular and Life Sciences (AIMMS)Amsterdam Center for Multiscale Modeling (ACMM)Vrije Universiteit AmsterdamDe Boelelaan 10831081 HVAmsterdam (TheNetherlands
- Departamento de QuímicaInstituto de Ciências NaturaisUniversidade Federal de Lavras37200-900Lavras-MGBrazil
| | - Trevor A. Hamlin
- Department of Theoretical ChemistryAmsterdam Institute of Molecular and Life Sciences (AIMMS)Amsterdam Center for Multiscale Modeling (ACMM)Vrije Universiteit AmsterdamDe Boelelaan 10831081 HVAmsterdam (TheNetherlands
| | - Célia Fonseca Guerra
- Department of Theoretical ChemistryAmsterdam Institute of Molecular and Life Sciences (AIMMS)Amsterdam Center for Multiscale Modeling (ACMM)Vrije Universiteit AmsterdamDe Boelelaan 10831081 HVAmsterdam (TheNetherlands
- Leiden Institute of ChemistryGorlaeus LaboratoriesLeiden UniversityEinsteinweg 552333 CCLeiden (TheNetherlands
| | - Matheus P. Freitas
- Departamento de QuímicaInstituto de Ciências NaturaisUniversidade Federal de Lavras37200-900Lavras-MGBrazil
| | - F. Matthias Bickelhaupt
- Department of Theoretical ChemistryAmsterdam Institute of Molecular and Life Sciences (AIMMS)Amsterdam Center for Multiscale Modeling (ACMM)Vrije Universiteit AmsterdamDe Boelelaan 10831081 HVAmsterdam (TheNetherlands
- Institute for Molecules and Materials (IMM)Radboud UniversityHeyendaalseweg 1356525 AJNijmegen (TheNetherlands
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3
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Silva DR, Daré JK, Freitas MP. Conformational preferences of fluorine-containing agrochemicals and their implications for lipophilicity prediction. Beilstein J Org Chem 2020; 16:2469-2476. [PMID: 33093926 PMCID: PMC7554678 DOI: 10.3762/bjoc.16.200] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Accepted: 09/23/2020] [Indexed: 12/14/2022] Open
Abstract
Molecular polarity governs lipophilicity, which in turn determines important agrochemical and environmental properties, such as soil sorption and bioconcentration of organic compounds. Since the C-F bond is the most polar in organic chemistry, the orientation of fluorine substituents originating from the rotation around C-C(F) bonds should affect the polarity and, consequently, the physicochemical and biological properties of fluorine-containing agrochemicals. Accordingly, this study aims to determine the most likely conformers of some fluorine-containing agrochemicals and to correlate their molecular dipole moments with the respective n-octanol/water partition coefficients (log P), in order to investigate the dependence of the lipophilicity with the molecular conformation.
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Affiliation(s)
| | - Joyce K Daré
- Department of Chemistry, Federal University of Lavras, 37200-900, Lavras-MG, Brazil
| | - Matheus P Freitas
- Department of Chemistry, Federal University of Lavras, 37200-900, Lavras-MG, Brazil
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4
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5
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Tamura Y, Yada R, Kawasaki-Takasuka T, Agou T, Kubota T, Yamazaki T. Clarification of the Reactivity of 1,3,3,3-Tetrafluoropropene Oxides. Org Lett 2020; 22:2044-2048. [DOI: 10.1021/acs.orglett.0c00463] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yuji Tamura
- Department of Applied Chemistry, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Nakamachi, Koganei 184-8588, Japan
| | - Rina Yada
- Department of Applied Chemistry, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Nakamachi, Koganei 184-8588, Japan
| | - Tomoko Kawasaki-Takasuka
- Department of Applied Chemistry, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Nakamachi, Koganei 184-8588, Japan
| | - Tomohiro Agou
- Department of Biomolecular Functional Engineering, Ibaraki University, Nakanarusawa 4-12-1, Hitachi 316-8511, Japan
| | - Toshio Kubota
- Department of Biomolecular Functional Engineering, Ibaraki University, Nakanarusawa 4-12-1, Hitachi 316-8511, Japan
| | - Takashi Yamazaki
- Department of Applied Chemistry, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Nakamachi, Koganei 184-8588, Japan
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6
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Martins FA, Freitas MP. Bioconformational modulation of a thymidine kinase enzyme ligand through F⋯HO intramolecular hydrogen bond. J Mol Graph Model 2020; 97:107545. [PMID: 32062583 DOI: 10.1016/j.jmgm.2020.107545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 01/20/2020] [Accepted: 01/21/2020] [Indexed: 10/25/2022]
Abstract
While the induced-fit of a ligand towards an enzyme is pivotally dictated by intermolecular hydrogen bonds between the small molecule and amino acid residues in the binding site, the role of intramolecular hydrogen bond as contributing interaction for a bioactive conformation is not well understood. This work reports a theoretical conformational analysis of a thymidine kinase enzyme ligand (NMF) that is prone to experience an F⋯HO intramolecular hydrogen bond, inside and outside the biological binding site. This interaction stabilizes the most favorable conformations of NMF in the gas phase and, although it can be disrupted in a biological environment due to intermolecular hydrogen bonds in some cases, these interactions are competitive in other systems. Therefore, an intramolecular hydrogen bond can affect the conformational likeliness most related to the bioactivity. Moreover, isolated conformations governed by this interaction cannot be unequivocally used to generate molecular descriptors in 3D-QSAR (Quantitative Structure-Activity Relationships), since the bioactive conformation may not be determined only by intramolecular interactions.
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Affiliation(s)
- Francisco A Martins
- Department of Chemistry, Federal University of Lavras, 37200-900, Lavras, MG, Brazil
| | - Matheus P Freitas
- Department of Chemistry, Federal University of Lavras, 37200-900, Lavras, MG, Brazil.
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7
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Andrade LAF, Zeoly LA, Cormanich RA, Freitas MP. Conformational signature of Ishikawa´s reagent using NMR information from diastereotopic fluorines. Beilstein J Org Chem 2019; 15:506-512. [PMID: 30873234 PMCID: PMC6404478 DOI: 10.3762/bjoc.15.44] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Accepted: 02/13/2019] [Indexed: 12/25/2022] Open
Abstract
The active species of the Ishikawa´s reagent [N,N-diethyl-(1,1,2,3,3,3-hexafluoropropyl)amine] is a fluorinating hexafluoropropylamine used to convert alcohols into alkyl fluorides. On the other hand, it is also an example of model compound useful to probe conformational preferences using spectroscopic information from diastereotopic fluorines. Moreover, the possibility of experiencing both the generalized anomeric and gauche effects makes the Ishikawa´s reagent an ideal choice to study the governing stereoelectronic interactions of the conformational equilibrium of organofluorine compounds. The conformational equilibrium of the Ishikawa´s reagent was analyzed using NMR 3JH,F coupling constant data in different solvents, since the orientation of the diastereotopic fluorines relative to H-2 and F-2 changes with the medium. In nonpolar cyclohexane solvent, the preferred conformation experiences a weaker steric and electrostatic repulsion. The conformational behavior changes in the more polar pyridine solution, where the double fluorine gauche effect takes place, since F-2 is preferably gauche to both diastereotopic fluorines. An analysis of the rotation around the N–C(F2) bond indicates the manifestation of anomeric interactions (nN → σ*C–F), which can be demonstrated by means of 19F chemical shifts. The results were rationalized with the aid of theoretical calculations and natural bond orbital (NBO) analysis, allowing for the evaluation of competing steric, electrostatic and hyperconjugative interactions.
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Affiliation(s)
- Laize A F Andrade
- Department of Chemistry, Federal University of Lavras, 37200-000, Lavras, MG, Brazil
| | - Lucas A Zeoly
- Institute of Chemistry, University of Campinas, 13083-970, Campinas, SP, Brazil
| | - Rodrigo A Cormanich
- Institute of Chemistry, University of Campinas, 13083-970, Campinas, SP, Brazil
| | - Matheus P Freitas
- Department of Chemistry, Federal University of Lavras, 37200-000, Lavras, MG, Brazil
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8
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Andrade LAF, Freitas MP. Not all third-row elements experience the fluorine gauche effect: β-fluorinated organophosphorus compounds. NEW J CHEM 2017. [DOI: 10.1039/c7nj02463k] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Conformational analyses of β-fluorinated organophosphorus compounds were theoretically carried out to probe the role of a possible fluorine–phosphorus gauche effect in conformer stabilization, specifically using a phosphine, a phosphine oxide, phosphinic and phosphonic acids, and the corresponding anions as model compounds.
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9
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Tormena CF. Conformational analysis of small molecules: NMR and quantum mechanics calculations. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2016; 96:73-88. [PMID: 27573182 DOI: 10.1016/j.pnmrs.2016.04.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Revised: 04/14/2016] [Accepted: 04/14/2016] [Indexed: 06/06/2023]
Abstract
This review deals with conformational analysis in small organic molecules, and describes the stereoelectronic interactions responsible for conformational stability. Conformational analysis is usually performed using NMR spectroscopy through measurement of coupling constants at room or low temperature in different solvents to determine the populations of conformers in solution. Quantum mechanical calculations are used to address the interactions responsible for conformer stability. The conformational analysis of a large number of small molecules is described, using coupling constant measurements in different solvents and at low temperature, as well as recent applications of through-space and through-hydrogen bond coupling constants JFH as tools for the conformational analysis of fluorinated molecules. Besides NMR parameters, stereoelectronic interactions such as conjugative, hyperconjugative, steric and intramolecular hydrogen bond interactions involved in conformational preferences are discussed.
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Affiliation(s)
- Cláudio F Tormena
- Institute of Chemistry, University of Campinas, PO Box 6154, 13083-970 Campinas, Sao Paulo, Brazil.
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10
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The role of nonbonding interactions and the presence of fluoride on the conformational isomerism of 1,2-ethanediol. Chem Phys 2016. [DOI: 10.1016/j.chemphys.2016.04.018] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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11
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Catalytic enantioselective addition of organoboron reagents to fluoroketones controlled by electrostatic interactions. Nat Chem 2016; 8:768-77. [PMID: 27442282 PMCID: PMC4957664 DOI: 10.1038/nchem.2523] [Citation(s) in RCA: 105] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Accepted: 03/30/2016] [Indexed: 12/25/2022]
Abstract
Organofluorine compounds are central to modern chemistry, and broadly applicable transformations that generate them efficiently and enantioselectively are in much demand. Here we introduce efficient catalytic methods for the addition of allyl and allenyl organoboron reagents to fluorine-substituted ketones. These reactions are facilitated by readily and inexpensively available catalysts and deliver versatile and otherwise difficult-to-access tertiary homoallylic alcohols in up to 98% yield and >99:1 enantiomeric ratio. Utility is highlighted by a concise enantioselective approach to the synthesis of the antiparasitic drug fluralaner (Bravecto, presently sold as the racemate). Different forms of ammonium-organofluorine interactions play a key role in the control of enantioselectivity. The greater understanding of various non-bonding interactions afforded by these studies should facilitate the future development of transformations that involve fluoroorganic entities.
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12
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Guimarães MC, Silla JM, da Cunha EFF, Ramalho TC, Freitas MP. Is the bioconformation of 5-deoxy-5-fluoro-d-xylulose affected by intramolecular hydrogen bonds? RSC Adv 2016. [DOI: 10.1039/c6ra23423b] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
5-Deoxy-5-fluoro-d-xylulose (DFX) binds to the xylulokinase enzyme and, as a free ligand, it has preferential conformations governed by intramolecular interactions, such as hydrogen bonds and hyperconjugative interactions.
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Affiliation(s)
| | - Josué M. Silla
- Department of Chemistry
- Federal University of Lavras
- Lavras
- Brazil
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13
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Silla JM, Freitas MP. A halogen bond does not dictate the conformational preferences of cis-1,3-disubstituted cyclohexanes. Org Biomol Chem 2016; 14:8610-8614. [DOI: 10.1039/c6ob01635a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A halogen bond is unlikely to control the conformation of cis-1,3-disubstituted cyclohexanes. In addition, polarization rather than the σ-hole effect describes this weak interaction more appropriately.
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Affiliation(s)
- Josué M. Silla
- Department of Chemistry
- Federal University of Lavras
- Lavras
- Brazil
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14
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Linclau B, Peron F, Bogdan E, Wells N, Wang Z, Compain G, Fontenelle CQ, Galland N, Le Questel JY, Graton J. Intramolecular OH⋅⋅⋅Fluorine Hydrogen Bonding in Saturated, Acyclic Fluorohydrins: The γ-Fluoropropanol Motif. Chemistry 2015; 21:17808-16. [PMID: 26494542 PMCID: PMC4676915 DOI: 10.1002/chem.201503253] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Indexed: 11/23/2022]
Abstract
Fluorination is commonly exercised in compound property optimization. However, the influence of fluorination on hydrogen-bond (HB) properties of adjacent functional groups, as well as the HB-accepting capacity of fluorine itself, is still not completely understood. Although the formation of OH⋅⋅⋅F intramolecular HBs (IMHBs) has been established for conformationally restricted fluorohydrins, such interaction in flexible compounds remained questionable. Herein is demonstrated for the first time-and in contrast to earlier reports-the occurrence of OH⋅⋅⋅F IMHBs in acyclic saturated γ-fluorohydrins, even for the parent 3-fluoropropan-1-ol. The relative stereochemistry is shown to have a crucial influence on the corresponding (h1) JOH⋅⋅⋅F values, as illustrated by syn- and anti-4-fluoropentan-2-ol (6.6 and 1.9 Hz). The magnitude of OH⋅⋅⋅F IMHBs and their strong dependence on the overall molecular conformational profile, fluorination motif, and alkyl substitution level, is rationalized by quantum chemical calculations. For a given alkyl chain, the "rule of shielding" applies to OH⋅⋅⋅F IMHB energies. Surprisingly, the predicted OH⋅⋅⋅F IMHB energies are only moderately weaker than these of the corresponding OH⋅⋅⋅OMe. These results provide new insights of the impact of fluorination of aliphatic alcohols, with attractive perspectives for rational drug design.
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Affiliation(s)
- Bruno Linclau
- Department of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ (UK), Fax: (+44) 23-8059-6805.
| | - Florent Peron
- Department of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ (UK), Fax: (+44) 23-8059-6805
| | - Elena Bogdan
- CEISAM UMR CNRS 6230, Faculté des Sciences et des Techniques, Université de Nantes, 2, rue de la Houssinière - BP 92208, 44322 NANTES Cedex 3 (France), Fax: (+3) 2-51-12-54-02
| | - Neil Wells
- Department of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ (UK), Fax: (+44) 23-8059-6805
| | - Zhong Wang
- Department of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ (UK), Fax: (+44) 23-8059-6805
| | - Guillaume Compain
- Department of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ (UK), Fax: (+44) 23-8059-6805
| | - Clement Q Fontenelle
- Department of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ (UK), Fax: (+44) 23-8059-6805
| | - Nicolas Galland
- CEISAM UMR CNRS 6230, Faculté des Sciences et des Techniques, Université de Nantes, 2, rue de la Houssinière - BP 92208, 44322 NANTES Cedex 3 (France), Fax: (+3) 2-51-12-54-02
| | - Jean-Yves Le Questel
- CEISAM UMR CNRS 6230, Faculté des Sciences et des Techniques, Université de Nantes, 2, rue de la Houssinière - BP 92208, 44322 NANTES Cedex 3 (France), Fax: (+3) 2-51-12-54-02
| | - Jérôme Graton
- CEISAM UMR CNRS 6230, Faculté des Sciences et des Techniques, Université de Nantes, 2, rue de la Houssinière - BP 92208, 44322 NANTES Cedex 3 (France), Fax: (+3) 2-51-12-54-02.
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15
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Intramolecular interactions contributing for the conformational preference of bioactive diphenhydramine: Manifestation of the gauche effect. J Mol Struct 2015. [DOI: 10.1016/j.molstruc.2015.03.033] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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16
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Abstract
The role of fluorine in drug design and development is expanding rapidly as we learn more about the unique properties associated with this unusual element and how to deploy it with greater sophistication. The judicious introduction of fluorine into a molecule can productively influence conformation, pKa, intrinsic potency, membrane permeability, metabolic pathways, and pharmacokinetic properties. In addition, (18)F has been established as a useful positron emitting isotope for use with in vivo imaging technology that potentially has extensive application in drug discovery and development, often limited only by convenient synthetic accessibility to labeled compounds. The wide ranging applications of fluorine in drug design are providing a strong stimulus for the development of new synthetic methodologies that allow more facile access to a wide range of fluorinated compounds. In this review, we provide an update on the effects of the strategic incorporation of fluorine in drug molecules and applications in positron emission tomography.
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Affiliation(s)
- Eric P Gillis
- Department of Discovery Chemistry, Bristol-Myers Squibb Research and Development , 5 Research Parkway, Wallingford, Connecticut 06492, United States
| | - Kyle J Eastman
- Department of Discovery Chemistry, Bristol-Myers Squibb Research and Development , 5 Research Parkway, Wallingford, Connecticut 06492, United States
| | - Matthew D Hill
- Department of Discovery Chemistry, Bristol-Myers Squibb Research and Development , 5 Research Parkway, Wallingford, Connecticut 06492, United States
| | - David J Donnelly
- Discovery Chemistry Platforms, PET Radiochemical Synthesis, Bristol-Myers Squibb Research and Development , P.O. Box 4000, Princeton, New Jersey 08543, United States
| | - Nicholas A Meanwell
- Department of Discovery Chemistry, Bristol-Myers Squibb Research and Development , 5 Research Parkway, Wallingford, Connecticut 06492, United States
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17
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Chan J, Tang A, Bennet AJ. Transition-state structure for the hydronium-ion-promoted hydrolysis of α-d-glucopyranosyl fluoride. CAN J CHEM 2015. [DOI: 10.1139/cjc-2014-0451] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The transition state for the hydronium-ion-promoted hydrolysis of α-d-glucopyranosyl fluoride in water has been characterized by combining multiple kinetic isotope effect measurements with theoretical modelling. The measured kinetic isotope effects for the C1-deuterium, C2-deuterium, C5-deuterium, anomeric carbon-13, and ring oxygen-18 are 1.219 ± 0.021, 1.099 ± 0.024, 0.976 ± 0.014, 1.014 ± 0.005, and 0.991 ± 0.013, respectively. The transition state for the hydronium ion reaction is late with respect to both C–F bond cleavage and proton transfer.
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Affiliation(s)
- Jefferson Chan
- Department of Chemistry, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A 1S6, Canada
- Department of Chemistry, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A 1S6, Canada
| | - Ariel Tang
- Department of Chemistry, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A 1S6, Canada
- Department of Chemistry, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A 1S6, Canada
| | - Andrew J. Bennet
- Department of Chemistry, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A 1S6, Canada
- Department of Chemistry, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A 1S6, Canada
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18
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Baranac-Stojanović M, Aleksić J, Stojanović M. Energy decomposition analysis of gauche preference in 2-haloethanol, 2-haloethylamine (halogen = F, Cl), their protonated forms and anti preference in 1-chloro-2-fluoroethane. RSC Adv 2015. [DOI: 10.1039/c5ra01164g] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Small, electronegative elements contribute more electrostatic and orbital stabilization to the anti → gauche isomerization, and greater steric repulsion. The first and the latter actually oppose our traditional view of conformational equilibria.
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Affiliation(s)
| | - Jovana Aleksić
- Center for Chemistry ICTM
- University of Belgrade
- 11000 Belgrade
- Serbia
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19
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Chan J, Sannikova N, Tang A, Bennet AJ. Transition-State Structure for the Quintessential SN2 Reaction of a Carbohydrate: Reaction of α-Glucopyranosyl Fluoride with Azide Ion in Water. J Am Chem Soc 2014; 136:12225-8. [DOI: 10.1021/ja506092h] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Jefferson Chan
- Chemistry Department, Simon Fraser University, 8888 University Drive, Burnaby, British Columbia V5A 1S6, Canada
| | - Natalia Sannikova
- Chemistry Department, Simon Fraser University, 8888 University Drive, Burnaby, British Columbia V5A 1S6, Canada
| | - Ariel Tang
- Chemistry Department, Simon Fraser University, 8888 University Drive, Burnaby, British Columbia V5A 1S6, Canada
| | - Andrew J. Bennet
- Chemistry Department, Simon Fraser University, 8888 University Drive, Burnaby, British Columbia V5A 1S6, Canada
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20
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Silva TFB, Andrade LAF, Silla JM, Duarte CJ, Rittner R, Freitas MP. Endocyclic oxygen in 3-fluorodihydro-2H-pyran-4(3H)-one that does not induce the gauche effect. J Phys Chem A 2014; 118:6266-71. [PMID: 25059100 DOI: 10.1021/jp505573x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
2-Fluorocyclohexanone undergoes chair inversion, giving rise to axial and equatorial conformers, with the equatorial form being highly preferred in solution, for example, 87% in chloroform and 93% in methylene chloride. Modifications in the conformational preferences can modify macroscopic properties of 2-fluoro ketones. The introduction of an endocyclic oxygen in 2-fluorocyclohexanone to give 3-fluorodihydro-2H-pyran-4(3H)-one would be expected to create a gauche effect in the axial conformer along with the O-C-C-F moiety, inducing an increase of its population. However, small changes were verified in the conformational populations both in the gas phase and solution because the carbonyl group plays an important role for the hyperconjugation in the equatorial conformer, despite experiencing strong dipolar repulsion with the fluorine atom. These data were obtained theoretically and by NMR spectroscopy, while the nature of the interactions governing these conformational shifts were investigated on the basis of natural bond orbital analysis.
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Affiliation(s)
- Thayná F B Silva
- Department of Chemistry, Federal University of Lavras , P.O. Box 3037, 37200-000 Lavras, Minas Gerais, Brazil
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Andrade LA, Silla JM, Freitas MP. The gauche effect is governed by internal hydrogen bond in 2-amino-2-methyl-propanol. J Mol Struct 2014. [DOI: 10.1016/j.molstruc.2014.05.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Silla JM, Cormanich RA, Rittner R, Freitas MP. Does intramolecular hydrogen bond play a key role in the stereochemistry of α- and β-D-glucose? Carbohydr Res 2014; 396:9-13. [PMID: 25079595 DOI: 10.1016/j.carres.2014.06.013] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Revised: 05/19/2014] [Accepted: 06/11/2014] [Indexed: 10/25/2022]
Abstract
Four α- and three β-isomers of the d-glucose were optimized in gas phase using ab initio (MP2) and DFT (ωB97X-D) methods, both using the aug-cc-pVDZ basis set. While earlier works suggest that the orientation of the hydroxyl groups is due to intramolecular hydrogen bonds (H-bonds), the present study reveals that most H-bonds forming five-membered rings are either weak or even do not exist. The quantum theory of atoms in molecules (QTAIM) analysis showed only a few cases of H-bond in d-glucose, particularly for those H-bonds forming six-membered rings, while the non-covalent interactions (NCI) analysis indicated that most intramolecular H-bonds are not strong enough to justify the counter-clockwise arrangement of the OH⋯O chains. Natural bond orbital analysis supported the findings obtained from QTAIM and NCI analyses and indicated that the anomeric effect for d-glucose in the gas phase is governed by a balance of steric, electrostatic, and hyperconjugative interactions.
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Affiliation(s)
- Josué M Silla
- Department of Chemistry, Federal University of Lavras, PO Box 3037, 37200-000 Lavras, MG, Brazil
| | - Rodrigo A Cormanich
- Chemistry Institute, State University of Campinas, PO Box 6154, 13083-970 Campinas, SP, Brazil
| | - Roberto Rittner
- Chemistry Institute, State University of Campinas, PO Box 6154, 13083-970 Campinas, SP, Brazil
| | - Matheus P Freitas
- Department of Chemistry, Federal University of Lavras, PO Box 3037, 37200-000 Lavras, MG, Brazil.
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