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Dalvit C, Vulpetti A. Intermolecular and intramolecular hydrogen bonds involving fluorine atoms: implications for recognition, selectivity, and chemical properties. ChemMedChem 2012; 7:262-72. [PMID: 22262517 DOI: 10.1002/cmdc.201100483] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2011] [Revised: 12/02/2011] [Indexed: 11/06/2022]
Abstract
A correlation between 19F NMR isotropic chemical shift and close intermolecular F⋅⋅⋅H-X contacts (with X=N or O) has been identified upon analysis of the X-ray crystal structures of fluorinated molecules listed in the Cambridge Structural Database (CSD). An optimal F⋅⋅⋅X distance involving primary and shielded secondary fluorine atoms in hydrogen-bond formation along with a correlation between F⋅⋅⋅H distance and F⋅⋅⋅H-X angle were also derived from the analysis. The hydrogen bonds involving fluorine are relevant, not only for the recognition mechanism and stabilization of a preferred conformation, but also for improvement in the permeability of the molecules, as shown with examples taken from a proprietary database. Results of an analysis of the small number of fluorine-containing natural products listed in the Protein Data Bank (PDB) appear to strengthen the derived correlation between 19F NMR isotropic chemical shift and interactions involving fluorine (also known as the "rule of shielding") and provides a hypothesis for the recognition mechanism and catalytic activity of specific enzymes. Novel chemical scaffolds, based on the rule of shielding, have been designed for recognizing distinct structural motifs present in proteins. It is envisaged that this approach could find useful applications in drug design for the efficient optimization of chemical fragments or promising compounds by increasing potency and selectivity against the desired biomolecular target.
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Affiliation(s)
- Claudio Dalvit
- Department of Chemistry, University of Neuchâtel, Avenue de Bellevaux 51, 2000 Neuchâtel, Swizerland.
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Howell RC, Edwards SH, Gajadhar-Plummer AS, Kahwa IA, McPherson GL, Mague JT, White AJP, Williams DJ. Phthalimides: Supramolecular Interactions in Crystals, Hypersensitive Solution 1H-NMR Dynamics and Energy Transfer to Europium(III) and Terbium(III) States. Molecules 2003. [PMCID: PMC6146889 DOI: 10.3390/molecules8070565] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Detailed crystal structures and 1H-NMR characteristics of some alkylamine-phthalimides, including dendritic polyphthalimides, are reported. These investigations were undertaken in order to obtain a better understanding of the relationship between solid-state supramolecular interactions, their persistence in solution and associated dynamics of magnetically hypersensitive phthalimide aromatic AA’BB’-AA’XX’ proton NMR resonances. Some alkylamine phthalimides feature folded molecular geometries, which we attribute to n-π interactions among proximal amine-phthalimide sites; those alkylamine-phthalimides that have no possibility for such interactions feature fully extended phthalimide functionalities. Accordingly, alkylamine phthalimide compounds with folded solid-state geometries feature solvent and temperature dependent hypersensitive AA’BB’-AA’XX’ 1H-NMR line profiles, which we attribute to the n-π interactions. Luminescence of Eu3+(5D0) and Tb3+(5D4) states show well defined metal ion environments in their complexes with dendritic phthalimides, as well as relatively weak phthalimide-lanthanide(III) interactions.
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Affiliation(s)
- Robertha C. Howell
- Department of Chemistry, University of the West Indies, Mona Campus, Kingston 7, Jamaica, West Indies
| | - Selvin H. Edwards
- Department of Chemistry, University of the West Indies, Mona Campus, Kingston 7, Jamaica, West Indies
| | | | - Ishenkumba A. Kahwa
- Department of Chemistry, University of the West Indies, Mona Campus, Kingston 7, Jamaica, West Indies
- Author to whom correspondence should be addressed; Tel +1-(876) 927 1910; Fax +1-(876) 977 1835; E-mail:
| | - Gary L. McPherson
- Department of Chemistry, Tulane University, New Orleans, Louisiana 70118, USA
| | - Joel T. Mague
- Department of Chemistry, Tulane University, New Orleans, Louisiana 70118, USA
| | - Andrew J. P. White
- Chemical Crystallography Laboratory, Department of Chemistry, Imperial College of Science, Technology and Medicine, South Kensington, London SW7 2AY, United Kingdom
| | - David J. Williams
- Chemical Crystallography Laboratory, Department of Chemistry, Imperial College of Science, Technology and Medicine, South Kensington, London SW7 2AY, United Kingdom
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Affiliation(s)
- Allan D. Headley
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409‐1061
| | - Stephen D. Starnes
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409‐1061
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Osipov SN, Golubev AS, Sewald N, Michel T, Kolomiets AF, Fokin AV, Burger K. A New Strategy for the Synthesis of alpha-Difluoromethyl-Substituted alpha-Hydroxy and alpha-Amino Acids. J Org Chem 1996; 61:7521-7528. [PMID: 11667683 DOI: 10.1021/jo9608331] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A new method for the preparation of alpha-chlorodifluoromethyl-, alpha-bromodifluoromethyl-, and alpha-difluoromethyl-substituted alpha-hydroxy and alpha-amino acid esters 11, 19-21 is described. The key step of the synthesis is the regioselective alkylation of ketones 5, 7-9 and imines 16-18 with C-nucleophiles. The ketones 7-9 are readily available from 3,3,3-trifluorolactate 1 by a five-step procedure. Subsequent removal of the protecting groups from 19-21 provides the corresponding free amino acids 25, 26, 28.
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Affiliation(s)
- Sergey N. Osipov
- A. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilov str. 28, GSP-1, V-334, RUS-117813 Moscow, Russia, and Institute of Organic Chemistry, University of Leipzig, Talstrasse 35, D-04103 Leipzig, Germany
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Syntheses of fluorinated amino acids: from the classical to the modern concept. Amino Acids 1996; 11:15-36. [DOI: 10.1007/bf00805718] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/1995] [Accepted: 01/14/1996] [Indexed: 11/27/2022]
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Trimethylsilyl halides: Effective reagents for the synthesis of β-halo amino acid derivatives. Tetrahedron Lett 1995. [DOI: 10.1016/0040-4039(95)01451-m] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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