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Talotta C, Concilio G, De Rosa M, Soriente A, Gaeta C, Rescifina A, Ballester P, Neri P. Expanding Coefficient: A Parameter To Assess the Stability of Induced-Fit Complexes. Org Lett 2021; 23:1804-1808. [PMID: 33591765 PMCID: PMC8028309 DOI: 10.1021/acs.orglett.1c00165] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Indexed: 11/29/2022]
Abstract
Here we propose a new parameter, the Expanding Coefficient (EC), that can be correlated with the thermodynamic stability of supramolecular complexes governed by weak secondary interactions and obeying the induced-fit model. The EC values show a good linear relationship with the log Kapp of the respective pseudorotaxane complexes investigated. According to Cram's Principle of Preorganization, the EC can be considered an approximate mechanical measure of the host's reorganization energy cost upon adopting the final bound geometry.
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Affiliation(s)
- Carmen Talotta
- Dipartimento
di Chimica e Biologia “A. Zambelli”, Università di Salerno, via Giovanni Paolo II, 132, I-84084, Fisciano (Salerno), Italy
| | - Gerardo Concilio
- Dipartimento
di Chimica e Biologia “A. Zambelli”, Università di Salerno, via Giovanni Paolo II, 132, I-84084, Fisciano (Salerno), Italy
| | - Margherita De Rosa
- Dipartimento
di Chimica e Biologia “A. Zambelli”, Università di Salerno, via Giovanni Paolo II, 132, I-84084, Fisciano (Salerno), Italy
| | - Annunziata Soriente
- Dipartimento
di Chimica e Biologia “A. Zambelli”, Università di Salerno, via Giovanni Paolo II, 132, I-84084, Fisciano (Salerno), Italy
| | - Carmine Gaeta
- Dipartimento
di Chimica e Biologia “A. Zambelli”, Università di Salerno, via Giovanni Paolo II, 132, I-84084, Fisciano (Salerno), Italy
| | - Antonio Rescifina
- Dipartimento
di Scienze del Farmaco e della Salute, Università
di Catania, viale Andrea
Doria, 6, I-95125 Catania, Italy
| | - Pablo Ballester
- Institute
of Chemical Research of Catalonia (ICIQ), The Barcelona Institute of Science and Technology (BIST), Av. Països Catalans, 16, 43007 Tarragona, Spain
| | - Placido Neri
- Dipartimento
di Chimica e Biologia “A. Zambelli”, Università di Salerno, via Giovanni Paolo II, 132, I-84084, Fisciano (Salerno), Italy
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2
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Synthesis, characterisation of few N-substituted 1,8-naphthalimide derivatives and their copper(II) complexes. J CHEM SCI 2016. [DOI: 10.1007/bf03356105] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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3
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de Juan Fernández L, Fuentes de Arriba ÁL, Monleón LM, Rubio OH, Alcázar Montero V, Rubio LS, Morán JR. An Enantioselective Benzofuran-Based Receptor for Dinitrobenzoyl-Substituted Amino Acids. European J Org Chem 2016. [DOI: 10.1002/ejoc.201501457] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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4
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Kajiki Y, Sekiya R, Yamasaki Y, Uemura Y, Haino T. Induced-Fit Molecular Recognition of Alkyl Chains in p-tert-Butylcalix[5]arene in the Solid State. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2016. [DOI: 10.1246/bcsj.20150344] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Yasunori Kajiki
- Research Center for the Mathematics on Chromatin Live Dynamics, Hiroshima University
| | - Ryo Sekiya
- Department of Chemistry, Graduate School of Science, Hiroshima University
| | - Yutaro Yamasaki
- Department of Chemistry, Graduate School of Science, Hiroshima University
| | - Yuichiro Uemura
- Department of Chemistry, Graduate School of Science, Hiroshima University
| | - Takeharu Haino
- Research Center for the Mathematics on Chromatin Live Dynamics, Hiroshima University
- Department of Chemistry, Graduate School of Science, Hiroshima University
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5
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Acharyya K, Mukherjee PS. Postsynthetic Exterior Decoration of an Organic Cage by Copper(I)-Catalysed A3-Coupling and Detection of Nitroaromatics. Chemistry 2015; 21:6823-31. [DOI: 10.1002/chem.201406581] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2014] [Indexed: 01/31/2023]
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6
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Dumitrescu D, Legrand YM, Petit E, van der Lee A, Barboiu M. Adaptive binding and selection of compressed 1,ω-diammonium-alkanes via molecular encapsulation in water. Chem Sci 2015; 6:2079-2086. [PMID: 29142675 PMCID: PMC5654369 DOI: 10.1039/c4sc03945a] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Accepted: 01/09/2015] [Indexed: 12/18/2022] Open
Abstract
Guest molecules confined inside hollow molecular assemblies and thus protected from their environment can show unexpected structural behavior or special reactivity compared to their behavior in a bulk, unprotected environment. A special case is the coiling behavior of variable-length alkane chains in rigid hydrogen-bonded molecular cages. It has been found before that coiling may occur in such circumstances, but no experimental evidence concerning the exact conformation of the chains has yet been presented. We reveal in this study the self-assembly of a molecular cage in water and the crystalline state from three distinct components in which linear 1,ω-diammonium-alkanes chains are confined with different degrees of compression. The exact coiling behavior is determined from atomic resolution X-ray diffraction showing crenel-like conformations in the compressed state. Chemical selection can be obtained from mixtures of alkane chains via the encapsulation of kinetically stable conformations observed during the encapsulation of pure components. Moreover, it was found that uncompressed and compressed chains can be competitively trapped inside the capsule. These findings may provide insight in areas to a better understanding of biological processes, such as the fatty acid metabolism.
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Affiliation(s)
- Dan Dumitrescu
- Adaptive Supramolecular Nanosystems Group , Institut Européen des Membranes , ENSCM/UMII/UMR-CNRS 5635 , Pl. Eugène Bataillon , CC 047 , 34095 Montpellier, Cedex 5 , France .
| | - Yves-Marie Legrand
- Adaptive Supramolecular Nanosystems Group , Institut Européen des Membranes , ENSCM/UMII/UMR-CNRS 5635 , Pl. Eugène Bataillon , CC 047 , 34095 Montpellier, Cedex 5 , France .
| | - Eddy Petit
- Adaptive Supramolecular Nanosystems Group , Institut Européen des Membranes , ENSCM/UMII/UMR-CNRS 5635 , Pl. Eugène Bataillon , CC 047 , 34095 Montpellier, Cedex 5 , France .
| | - Arie van der Lee
- Adaptive Supramolecular Nanosystems Group , Institut Européen des Membranes , ENSCM/UMII/UMR-CNRS 5635 , Pl. Eugène Bataillon , CC 047 , 34095 Montpellier, Cedex 5 , France .
| | - Mihail Barboiu
- Adaptive Supramolecular Nanosystems Group , Institut Européen des Membranes , ENSCM/UMII/UMR-CNRS 5635 , Pl. Eugène Bataillon , CC 047 , 34095 Montpellier, Cedex 5 , France .
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7
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Dev D, Palakurthy NB, Thalluri K, Chandra J, Mandal B. Ethyl 2-Cyano-2-(2-nitrobenzenesulfonyloxyimino)acetate (o-NosylOXY): A Recyclable Coupling Reagent for Racemization-Free Synthesis of Peptide, Amide, Hydroxamate, and Ester. J Org Chem 2014; 79:5420-31. [DOI: 10.1021/jo500292m] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Dharm Dev
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati, Assam 781039, India
| | - Nani Babu Palakurthy
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati, Assam 781039, India
| | - Kishore Thalluri
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati, Assam 781039, India
| | - Jyoti Chandra
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati, Assam 781039, India
| | - Bhubaneswar Mandal
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati, Assam 781039, India
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8
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Norrehed S, Polavarapu P, Yang W, Gogoll A, Grennberg H. Conformational restriction of flexible molecules in solution by a semirigid bis-porphyrin molecular tweezer. Tetrahedron 2013. [DOI: 10.1016/j.tet.2013.06.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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9
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Weitman M, Lerman K, Nudelman A, Major DT, Hizi A, Herschhorn A. Structure–activity relationship studies of 1-(4-chloro-2,5-dimethoxyphenyl)-3-(3-propoxypropyl)thiourea, a non-nucleoside reverse transcriptase inhibitor of human immunodeficiency virus type-1. Eur J Med Chem 2011; 46:447-67. [DOI: 10.1016/j.ejmech.2010.11.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2010] [Revised: 11/01/2010] [Accepted: 11/02/2010] [Indexed: 01/17/2023]
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10
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Oelgemöller M, Kramer WH. Synthetic photochemistry of naphthalimides and related compounds. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY C-PHOTOCHEMISTRY REVIEWS 2010. [DOI: 10.1016/j.jphotochemrev.2011.02.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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11
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Ko YH, Kim Y, Kim H, Kim K. U-Shaped Conformation of Alkyl Chains Bound to a Synthetic Receptor Cucurbit[8]uril. Chem Asian J 2010; 6:652-7. [DOI: 10.1002/asia.201000665] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2010] [Indexed: 11/08/2022]
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12
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Liu S, Gan H, Hermann AT, Rick SW, Gibb BC. Kinetic resolution of constitutional isomers controlled by selective protection inside a supramolecular nanocapsule. Nat Chem 2010; 2:847-52. [PMID: 20861900 DOI: 10.1038/nchem.751] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2010] [Accepted: 06/14/2010] [Indexed: 11/09/2022]
Abstract
The concept of self-assembling container molecules as yocto-litre reaction flasks is gaining prominence. However, the idea of using such containers as a means of protection is not well developed. Here, we illustrate this idea in the context of kinetic resolutions. Specifically, we report on the use of a water-soluble, deep-cavity cavitand to bring about kinetic resolutions within pairs of esters that otherwise cannot be resolved because they react at very similar rates. Resolution occurs because the presence of the cavitand leads to a competitive binding equilibrium in which the stronger binder primarily resides inside the host and the weaker binding ester primarily resides in the bulk hydrolytic medium. For the two families of ester examined, the observed kinetic resolutions were highest within the optimally fitting smaller esters.
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Affiliation(s)
- Simin Liu
- Department of Chemistry, University of New Orleans, New Orleans, Louisiana 70148, USA
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13
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Xu KX, Wang YX, Jiao SY, Zhao J, Wang CJ. Enantioselective fluorescent sensors for chiral carboxylates based on BINOL — Synthesis and chiral recognition. CAN J CHEM 2010. [DOI: 10.1139/v10-001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The four novel derivatives of 1,1′-bi-2-naphthol (BINOL) have been prepared, and the structures of these compounds have been characterized by IR, MS, 1H and 13C NMR spectroscopy, and elemental analysis. The enantioselective recognition of these receptors has been studied by fluorescence titration and 1H NMR spectroscopy. The receptors exhibited different chiral-recognition abilities towards some enantiomers of chiral materials and formed 1:1 complexes between host and guest. The receptors exhibit excellent enantioselective fluorescent-recognition ability towards the amino acid derivatives.
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Affiliation(s)
- Kuo-xi Xu
- College of Chemistry and Chemical Engineering, Henan University, Kaifeng 475004, China
- Key Lab of Natural Medicinal and Immunal Engineering, Henan University, Kaifeng 475004, China
| | - Yu-xia Wang
- College of Chemistry and Chemical Engineering, Henan University, Kaifeng 475004, China
- Key Lab of Natural Medicinal and Immunal Engineering, Henan University, Kaifeng 475004, China
| | - Shu-yan Jiao
- College of Chemistry and Chemical Engineering, Henan University, Kaifeng 475004, China
- Key Lab of Natural Medicinal and Immunal Engineering, Henan University, Kaifeng 475004, China
| | - Jin Zhao
- College of Chemistry and Chemical Engineering, Henan University, Kaifeng 475004, China
- Key Lab of Natural Medicinal and Immunal Engineering, Henan University, Kaifeng 475004, China
| | - Chao-jie Wang
- College of Chemistry and Chemical Engineering, Henan University, Kaifeng 475004, China
- Key Lab of Natural Medicinal and Immunal Engineering, Henan University, Kaifeng 475004, China
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14
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Haino T, Fukuta K, Iwamoto H, Iwata S. Noncovalent Isotope Effect for Guest Encapsulation in Self-Assembled Molecular Capsules. Chemistry 2009; 15:13286-90. [DOI: 10.1002/chem.200902526] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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15
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Ajami D, Rebek J. Compressed alkanes in reversible encapsulation complexes. Nat Chem 2009; 1:87-90. [DOI: 10.1038/nchem.111] [Citation(s) in RCA: 137] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2008] [Accepted: 12/22/2008] [Indexed: 11/09/2022]
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16
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Qing G, Sun T, Chen Z, Yang X, Wu X, He Y. ‘Naked-eye’ enantioselective chemosensors for N-protected amino acid anions bearing thiourea units. Chirality 2009; 21:363-73. [DOI: 10.1002/chir.20593] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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17
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Gottschalk T, Jarowski PD, Diederich F. Reversibly controllable guest binding in precisely defined cavities: selectivity, induced fit, and switching in novel resorcin[4]arene-based container molecules. Tetrahedron 2008. [DOI: 10.1016/j.tet.2008.04.102] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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18
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Liu X, Sternberg E, Dolphin D. Cross-Metathesis of the Vinyl Group on Tetrapyrrolic Macrocycles: Reactivity, Selectivity, and Mechanism. J Org Chem 2008; 73:6542-50. [DOI: 10.1021/jo8007989] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Xin Liu
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada
| | - Ethan Sternberg
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada
| | - David Dolphin
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada
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19
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Zürcher M, Diederich F. Structure-Based Drug Design: Exploring the Proper Filling of Apolar Pockets at Enzyme Active Sites. J Org Chem 2008; 73:4345-61. [DOI: 10.1021/jo800527n] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Martina Zürcher
- Department of Chemistry and Applied Biosciences, Laboratorium für Organische Chemie, ETH Zürich, HCI G 313, 8093 Zürich, Switzerland
| | - François Diederich
- Department of Chemistry and Applied Biosciences, Laboratorium für Organische Chemie, ETH Zürich, HCI G 313, 8093 Zürich, Switzerland
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20
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QING GY, CHEN ZH, WANG F, YANG X, MENG LZ, HE YB. Calix[4]arene-Based Enantioselective Fluorescent Sensors for the Recognition of N-Acetyl-aspartate. CHINESE J CHEM 2008. [DOI: 10.1002/cjoc.200890135] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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21
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Zürcher M, Gottschalk T, Meyer S, Bur D, Diederich F. Exploring the Flap Pocket of the Antimalarial Target Plasmepsin II: The “55 % Rule” Applied to Enzymes. ChemMedChem 2008; 3:237-40. [DOI: 10.1002/cmdc.200700236] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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22
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Hirsch AKH, Alphey MS, Lauw S, Seet M, Barandun L, Eisenreich W, Rohdich F, Hunter WN, Bacher A, Diederich F. Inhibitors of the kinase IspE: structure–activity relationships and co-crystal structure analysis. Org Biomol Chem 2008; 6:2719-30. [DOI: 10.1039/b804375b] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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23
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Salvio R, Moisan L, Ajami D, Rebek J. Tertiary Amide Rotation in a Nanoscale Host. European J Org Chem 2007. [DOI: 10.1002/ejoc.200700168] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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24
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Johnston MR, Latter MJ. Capsules, Cages and Three-dimensional Hosts: Self-assembly of Complementary Monomers. Supramol Chem 2007. [DOI: 10.1080/10610270500128400] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Martin R. Johnston
- a Flinders University, School of Chemistry, Physics and Earth Sciences , Adelaide, 5042, Australia
| | - Melissa J. Latter
- a Flinders University, School of Chemistry, Physics and Earth Sciences , Adelaide, 5042, Australia
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25
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Abstract
Rotors are recalled as early molecular devices that transmit information through changes in conformation. Specific cases involve bipyridyls and biphenyls in which the biaryl bond acts as a fulcrum to relay applied stresses from one site to another. New types of molecular stress encountered by encapsulated molecules are identified--including bending, straightening, squeezing, grinding and compression. For flexible molecules in reversibly formed capsules a fluid model of recognition is proposed that is neither lock-and-key nor induced fit. Instead, the guest assumes the shape that best fills the available space, even if contortions to higher energy conformations are required. For encapsulated alkanes, a delicate balance of attraction and repulsion exists when the size of a guest molecule approaches the space available to it. The complexes are analyzed by both NMR and computational methods and detailed maps of the host-guest interfaces in solution are provided. The reversible transition of an encapsulated alkane between a compressed, coiled conformation and a relaxed, extended one is described. The system is a spring-loaded molecular device under the control of acids and bases that offers an alternative to the rotors of current molecular machinery.
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Affiliation(s)
- Julius Rebek
- The Skaggs Institute for Chemical Biology and Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.
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26
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Albunia AR, Gaeta C, Neri P, Grassi A, Milano G. Dynamics of Benzene Guest Inside a Self-Assembled Cylindrical Capsule: A Combined Solid-State 2H NMR and Molecular Dynamics Simulation Study. J Phys Chem B 2006; 110:19207-14. [PMID: 17004770 DOI: 10.1021/jp0617423] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The reorientational dynamics of benzene-d(6) molecules hosted into the cavity of a cavitand-based, self-assembled capsule was investigated by Molecular Dynamics (MD) simulations and temperature-dependent solid-state (2)H NMR spectroscopy. MD simulations were preliminarily performed to assess the motional models of the guest molecules inside the capsules. An in-plane fast reorientation of the benzene guest around the C(6) symmetry axis (B1 motion), characterized by correlation times of the order of picoseconds, was predicted with an activation barrier ( approximately 8 kJ/mol) very similar to that found for neat benzene in the liquid state. An out-of-plane reorientation corresponding to a nutation of the C(6) symmetry axis in a cone angle of 39 degrees (B2 motion, 373 K) with an activation barrier ( approximately 39 kJ/mol) definitely larger than that of liquid benzene was also anticipated. In the temperature range 293-373 K correlation times of the order of a nanosecond have been calculated and a transition from fast to slow regime in the (2)H NMR scale has been predicted between 293 and 173 K. (2)H NMR spectroscopic analysis, carried out in the temperature range 173-373 K on the solid capsules containing the perdeuterated guest (two benzene molecules/capsule), confirmed the occurrence of the B1 and B2 motions found in slow exchange in the (2)H NMR time scale. Line shape simulation of the (2)H NMR spectral lines permitted defining a cone angle value of 39 degrees at 373 K and 35 degrees at 173 K for the nutation axis. The T(1) values measured for the (2)H nuclei of the encapsulated aromatic guest gave correlation times and energetic barrier for the in-plane motion B1 in fine agreement with theoretical calculation. The experimental correlation time for B2 as well as the corresponding energetic barrier are in the same range found for B1. A molecular mechanism for the encapsulated guest accounting for the B1 and B2 motions was also provided.
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Affiliation(s)
- Alexandra R Albunia
- Dipartimento di Chimica, Università di Salerno, Via Ponte don Melillo, I-84084 Fisciano, Salerno, Italy
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27
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Abstract
Alkyl chains can adopt seemingly unusual conformations, such as helices, when bound to natural and synthetic hydrophobic receptors. This plasticity allows the alkanes to assume shapes that are congruent to the receptor's space and fill that space properly. We describe here the use of cavitands and capsules as tools that expose the forces involved in the molecular recognition of hydrocarbons. Studies using NMR spectroscopy reveal how attractive interactions and solvophobic forces are maximized in solution through unprecedented contortions of alkanes and hint at a new generation of nanoscale mechanical devices.
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Affiliation(s)
- Michael P Schramm
- The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 N. Torrey Pines Rd. Mail MB 26, La Jolla, CA 92037, USA
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28
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Purse BW, Rebek J. Self-fulfilling cavitands: packing alkyl chains into small spaces. Proc Natl Acad Sci U S A 2006; 103:2530-4. [PMID: 16477037 PMCID: PMC1413836 DOI: 10.1073/pnas.0511149103] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The present research was undertaken to determine the conformations of alkyl groups that are forced into small spaces. Unbranched alkyl groups assume fully extended conformations in the free space of solutions, because any bends in the structure create steric clashes between hydrogens along the chain. We synthesized a series of alkyl esters of a carboxylic acid attached to the inner surface of a vase-shaped container structure. The shorter esters (ethyl and propyl) can be accommodated in extended conformations, and even small solvent molecules can share the container's space. Longer (butyl-octyl) esters adopt increasingly coiled conformations that writhe rapidly in the limited space of the cavity. Even longer esters (nonyl and decyl) can be synthesized, but their containers become distorted, and their spectra indicate slowed internal motions of the alkyl groups within the space. In general, alkyl groups are readily contorted when their internal strains are compensated by attraction with the inner surfaces and the proper filling of space.
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Affiliation(s)
- Byron W. Purse
- The Skaggs Institute for Chemical Biology and Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037
| | - Julius Rebek
- The Skaggs Institute for Chemical Biology and Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037
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29
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Tomasini C, Luppi G, Monari M. Oxazolidin-2-one-Containing Pseudopeptides That Fold into β-Bend Ribbon Spirals. J Am Chem Soc 2006; 128:2410-20. [PMID: 16478196 DOI: 10.1021/ja056762h] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Three sets of oligomers containing the 4-carboxy-5-methyloxazolidin-2-one (Oxd) moiety have been synthesized with the aim of checking whether these molecules are able to fold in ordered structures: A set [Boc-(L-Ala-L-Oxd)(n)-OR], B set [Boc-(L-Ala-D-Oxd)(n)-OR], and C set [Boc-(Aib-L-Oxd)(n)-OR] preferential conformations have been analyzed with IR absorption, NMR, and CD. We have noticed that in these oligomers three stabilizing effects are active: (i) the rigid Oxd -CO-N(CH<)-CO- moiety, which always tend to assume a trans conformation; (ii) the formation of Oxd C=O...H-(alpha)C intramolecolar H-bonds; (iii) the alternate formation of 1 <-- 4 intramolecular C=O...H-N H-bonds. Through the analysis of the experimental data, we could demonstrate that only the oligomers of the B set are able to meet all three requirements listed above. By a deeper insight into the CD spectra, we gathered that the secondary structure adopted by the B set oligomers is a beta-bend ribbon spiral, which is a subtype of the 3(10)-helix.
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Affiliation(s)
- Claudia Tomasini
- Dipartimento di Chimica G. Ciamician, Alma Mater Studiorum Università di Bologna, Via Selmi 2, 40126 Bologna, Italy.
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30
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Mineno T, Kansui H. High Yielding Methyl Esterification Catalyzed by Indium(III) Chloride. Chem Pharm Bull (Tokyo) 2006; 54:918-9. [PMID: 16755072 DOI: 10.1248/cpb.54.918] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The carboxylic acids are efficiently converted into the methyl esters in methanol using indium(III) chloride as the catalyst. This method is applicable for aromatic and aliphatic carboxyl moieties as well as amino acids in high yields.
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Affiliation(s)
- Tomoko Mineno
- Laboratory of Organic Chemistry, Faculty of Pharmaceutical Sciences, Sojo University, Kumamoto860-0082, Japan.
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31
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Barnhill DK, Sargent AL, Allen WE. Participation of host ‘spacer’ atoms in carboxylic acid binding: implications for amino acid recognition. Tetrahedron 2005. [DOI: 10.1016/j.tet.2005.06.096] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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32
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Schmidt M, Barbayianni E, Fotakopoulou I, Höhne M, Constantinou-Kokotou V, Bornscheuer UT, Kokotos G. Enzymatic Removal of Carboxyl Protecting Groups. 1. Cleavage of thetert-Butyl Moiety. J Org Chem 2005; 70:3737-40. [PMID: 15845019 DOI: 10.1021/jo050114z] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
[reaction: see text] A recent discovery that a certain amino acid motif (GGG(A)X-motif) in lipases and esterases determines their activity toward tertiary alcohols prompted us to investigate the use of these biocatalysts in the mild and selective removal of tert-butyl protecting groups in amino acid derivatives and related compounds. An esterase from Bacillus subtilis (BsubpNBE) and lipase A from Candida antarctica (CAL-A) were identified as the most active enzymes, which hydrolyzed a range of tert-butyl esters of protected amino acids (e.g., Boc-Tyr-O(t)Bu, Z-GABA-O(t)Bu, Fmoc-GABA-O(t)Bu) in good to high yields and left Boc, Z, and Fmoc-protecting groups intact.
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Affiliation(s)
- Marlen Schmidt
- Department of Technical Chemistry and Biotechnology, Institute of Chemistry and Biochemistry, Greifswald University, Soldmannstr. 16, D-17487 Greifswald, Germany
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33
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Purse BW, Rebek J. Encapsulation of oligoethylene glycols and perfluoro-n-alkanes in a cylindrical host molecule. Chem Commun (Camb) 2005:722-4. [PMID: 15685316 DOI: 10.1039/b408878f] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Oligoethylene glycols and perfluoro-n-alkanes are suitable guests for the synthetic cylindrical host molecule 1(2); an investigation of these host-guest systems is reported.
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Affiliation(s)
- Byron W Purse
- The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 N. Torrey Pines Rd., La Jolla, CA 92037, USA
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34
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Gibson SE, Mainolfi N, Kalindjian SB, Wright PT, White AJP. A New Class of Non-Racemic Chiral Macrocycles: A Conformational and Synthetic Study. Chemistry 2005; 11:69-80. [PMID: 15484182 DOI: 10.1002/chem.200400608] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Amino alcohols have been used to introduce non-racemic chirality into macrocycles using a modular approach that relies on a Heck macrocyclisation reaction. A wide variety of macrocycles have been synthesised, and their structures studied using X-ray crystallography and molecular modelling. A fragmentation reaction encountered during the use of (S)-1,1-dimethylvalinol revealed that carboxylic acids generate acylals under reaction conditions often used for Heck reactions.
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Affiliation(s)
- Susan E Gibson
- Department of Chemistry, Imperial College London, South Kensington Campus, London SW7 2AY, UK.
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35
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Abstract
We describe here the behavior of the hydrogen-bonded capsule 1.1 and its complexes in protic solvents. The kinetics and thermodynamics of the encapsulation process were determined through conventional (1)H NMR methods. The enthalpies and entropies of encapsulation are both positive, indicating a process that liberates solvent molecules. The rates of dissociation-association of the capsule were comparable to the rates for the in-out exchange of large guests, which suggests that guest exchange occurs by complete dissociation of the capsule in protic solvents. The stability of the hydrogen-bonded capsule 1.1 toward protic solvents depends strongly on the guests, with the best guest being dimethylstilbene 8. The results establish guidelines for the properties of capsules that could be accessed in water.
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Affiliation(s)
- Toru Amaya
- The Skaggs Institute for Chemical Biology, Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, USA
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36
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Scarso A, Trembleau L, Rebek J. Helical Folding of Alkanes in a Self-Assembled, Cylindrical Capsule. J Am Chem Soc 2004; 126:13512-8. [PMID: 15479107 DOI: 10.1021/ja047952f] [Citation(s) in RCA: 142] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The reversible encapsulation of a series of normal alkane guests in a cylindrical host was studied by NMR methods. For small hydrocarbons such as n-pentane or n-hexane, two guests enter the host, and they move freely within. With n-heptane no encapsulation takes place. For longer alkanes such as n-decane, a single guest enters and the aromatic walls of the host are seen to twist to avoid empty spaces and increase favorable interactions with the hydrocarbon. The best guest (n-undecane) adopts a conformation with minimal gauche interactions. The longest alkane accommodated, n-tetradecane, adopts a helical conformation to fit in the cavity, a shape that maximizes CH/pi interactions with the aromatic walls of the receptor. These reciprocal conformational changes are discussed in terms of optimal host/guest interactions.
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Affiliation(s)
- Alessandro Scarso
- The Skaggs Institute for Chemical Biology and Department of Chemistry, Scripps Research Institute, MB-26, 10550 North Torrey Pines Road, La Jolla, California 92037, USA
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37
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Chou TC, Lin GH. Bicyclo[2.2.2]octene-based molecular spacers. Construction of U-shaped syn-facial etheno-bridged polyhydrononacenyl frameworks. Tetrahedron 2004. [DOI: 10.1016/j.tet.2004.06.046] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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38
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Scarso A, Rebek J. Single Molecule Solvation and Its Effects on Tautomeric Equilibria in a Self-Assembled Capsule. J Am Chem Soc 2004; 126:8956-60. [PMID: 15264826 DOI: 10.1021/ja0396091] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A self-assembled cylindrical capsule provides a nanoscale environment that affects keto-enol equilibria. The equilibrium constants for encapsulated beta-ketoesters show values that differ by an order of magnitude from that of the free tautomers in solution. For complexes with a single, large encapsulated guest, the inner surfaces of the capsule and the seam of the hydrogen bonds influence the equilibrium between the encapsulated keto and enol forms. For complexes of smaller beta-ketoesters, the coencapsulated solvent influences the equilibria. The solvent reduces the space available and affects the positioning of the ester in the capsule.
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Affiliation(s)
- Alessandro Scarso
- Skaggs Institute for Chemical Biology and Department of Chemistry, The Scripps Research Institute, MB-26, 10550 North Torrey Pines Road, La Jolla, California 92037, USA
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Bachmann S, Knudsen KR, Jorgensen KA. Mimicking enzymatic transaminations: attempts to understand and develop a catalytic asymmetric approach to chiral alpha-amino acids. Org Biomol Chem 2004; 2:2044-9. [PMID: 15254632 DOI: 10.1039/b404381b] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Attempts are made to build a bridge between asymmetric catalysis and enzymatic reactions by mechanistic investigations and the development of a catalytic and enantioselective approach to amination of alpha-keto esters by primary amines catalyzed by chiral Lewis acids as a model for transamination enzymes. Different Lewis acids can catalyze the half-transamination of alpha-keto esters using primary amine nitrogen sources such as pyridoxamine and 4-picolylamine. The mechanistic studies of the Lewis-acid catalyzed half-transamination using deuterium-labelled compounds show the incorporation of deuterium atoms in several positions of the alpha-amino acid derivative, indicating that the enol of the alpha-keto ester plays an important role along the reaction path. The catalytic enantioselective reactions are dependent on the pKa-value of the solvent since enantioselectivities were only obtained in solvents with high pKa-values relative to methanol. However, stronger acidic conditions generally gave better yields, but poor enantioselectivities. A series of chiral Lewis acids were screened as catalysts for the enantioselective half-transamination reactions and moderate yields and enantioselectivities of up to 46% ee were obtained.
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Affiliation(s)
- Stephan Bachmann
- Danish National Research Foundation: Center for Catalysis, Department of Chemistry, Aarhus University, DK-8000 Aarhus C, Denmark
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40
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Hernández JV, Oliva AI, Simón L, Muñiz FM, Grande M, Morán JR. Ternary enantioselective complexes from α-amino acids, 18-crown-6 ether and a macrocyclic xanthone-based receptor. Tetrahedron Lett 2004. [DOI: 10.1016/j.tetlet.2004.04.168] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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41
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Oliva AI, Simón L, Muñiz FM, Sanz F, Morán JR. Urea-tetrahydrobenzoxanthene receptors for carboxylic acids. Tetrahedron 2004. [DOI: 10.1016/j.tet.2004.03.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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42
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Abstract
A history of research projects undertaken in the group-ranging from mechanistic investigations to biomimetic chemistry to molecular devices and synthesis-is presented.
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Affiliation(s)
- Julius Rebek
- The Skaggs Institute for Chemical Biology and Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, USA
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43
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Lara KO, Godoy-Alcantar C, Eliseev AV, Yatsimirsky AK. Recognition of α-amino acid derivatives by N,N′-dibenzylated S,S-(+)-tetrandrine. Org Biomol Chem 2004; 2:1712-8. [PMID: 15188038 DOI: 10.1039/b402698e] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Complexation of free and N-acetylated alpha-amino acid anions (Gly, Ala, Phe) and some structurally related guests by a dicationic cyclophane-type N,N'-dibenzylated chiral derivative of a bisisoquinoline macrocyclic alkaloid S,S-(+)-tetrandrine (DBT) has been studied by (1)H-NMR titrations in D(2)O. In contrast to other macrocyclic hosts like cyclodextrins and calixarenes, DBT shows highest affinity and large enantioselectivity (K(S)/K(R) >/=10) toward smaller N-acetylalanine and binds larger phenylalanine derivatives more weakly and non-selectively. With 1,2,3,4-tetrahydroisoquinoline-3-carboxylate, a rigid analog of phenylalanine, binding again becomes enantioselective with K(S)/K(R)= 3.8. The binding specificity of DBT is rationalized on the basis of molecular mechanics calculations.
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Affiliation(s)
- Karen Ochoa Lara
- Departamento de Investigación en Polímeros y Materiales, Universidade de Sonora, México
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Scarso A, Shivanyuk A, Hayashida O, Rebek J. Asymmetric environments in encapsulation complexes. J Am Chem Soc 2003; 125:6239-43. [PMID: 12785856 DOI: 10.1021/ja029574p] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Symmetrical, self-assembled capsules capable of surrounding two guests offer a new approach to enantioselection through coencapsulation: when one guest is chiral, the space remaining is also chiral. This notion is explored within a cylindrical capsule. The dimensions of the capsule select appropriately sized combinations of guests, the shape of the capsule prevents tumbling of rigid molecules, and the chemical surface of the capsule orients polar functions within. Chiral carboxylic acids such as mandelic acid and alpha-Br-butyric acid are identified as promising compounds for this purpose, but diastereoselection is modest (<25% de).
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Affiliation(s)
- Alessandro Scarso
- The Skaggs Institute for Chemical Biology, La Jolla, California 92037, USA
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