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Chen A, Karanastasis A, Casey KR, Necelis M, Carone BR, Caputo GA, Palermo EF. Cationic Molecular Umbrellas as Antibacterial Agents with Remarkable Cell-Type Selectivity. ACS APPLIED MATERIALS & INTERFACES 2020; 12:21270-21282. [PMID: 31917544 DOI: 10.1021/acsami.9b19076] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
We synthesized a combinatorial library of dendrons that display a cluster of cationic charges juxtaposed with a hydrophobic alkyl chain, using the so-called "molecular umbrella" design approach. Systematically tuning the generation number and alkyl chain length enabled a detailed study of the structure-activity relationships in terms of both hydrophobic content and number of cationic charges. These discrete, unimolecular compounds display rapid and broad-spectrum bactericidal activity comparable to the activity of antibacterial peptides. Micellization was examined by pyrene emission and dynamic light scattering, which revealed that monomeric, individually solvated dendrons are present in aqueous media. The antibacterial mechanism of action is putatively driven by the membrane-disrupting nature of these cationic surfactants, which we confirmed by enzymatic assays on E. coli cells. The hemolytic activity of these dendritic macromolecules is sensitively dependent on the dendron generation and the alkyl chain length. Via structural optimization of these two key design features, we identified a leading candidate with potent broad-spectrum antibacterial activity (4-8 μg/mL) combined with outstanding hemocompatibility (up to 5000 μg/mL). This selected compound is >1000-fold more active against bacteria as compared to red blood cells, which represents one of the highest selectivity index values ever reported for a membrane-disrupting antibacterial agent. Thus, the leading candidate from this initial library screen holds great potential for future applications as a nontoxic, degradable disinfectant.
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Affiliation(s)
- Ao Chen
- Materials Science and Engineering, Rensselaer Polytechnic Institute, Troy, New York 12054, United States
| | - Apostolos Karanastasis
- Materials Science and Engineering, Rensselaer Polytechnic Institute, Troy, New York 12054, United States
| | | | | | | | | | - Edmund F Palermo
- Materials Science and Engineering, Rensselaer Polytechnic Institute, Troy, New York 12054, United States
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2
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Cantú-Reyes M, Alvarado-Beltrán I, Ballinas-Indilí R, Álvarez-Toledano C, Hernández-Rodríguez M. Stereodivergent Mannich reaction of bis(trimethylsilyl)ketene acetals with N-tert-butanesulfinyl imines by Lewis acid or Lewis base activation, a one-pot protocol to obtain chiral β-amino acids. Org Biomol Chem 2017; 15:7705-7709. [PMID: 28875215 DOI: 10.1039/c7ob01853c] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report a one-pot synthesis of chiral β2,2,3-amino acids by the Mannich addition of bistrimethylsilyl ketene acetals to N-tert-butanesulfinyl imines followed by the removal of the chiral auxiliary. The synthesis and isolation of pure β-amino acid hydrochlorides were conducted under mild conditions, without strong bases and this method is operationally simple. The stereoselective reaction was promoted by two different activation methods that lead to different stereoisomers: (1) Lewis Acid (LA) catalysis with boron trifluoride diethyl etherate and (2) Lewis Base (LB) catalysis with tetrabutylammonium difluorotriphenylsilicate. The reaction presented good diastereoselectivity with LB activation and moderate to good dr with LA catalysis. The exceptions in both protocols were imines with electron donating groups in the aromatic ring.
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Affiliation(s)
- Margarita Cantú-Reyes
- Instituto de Química, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, Del. Coyoacán, 04510, Cd. Mx., Mexico.
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3
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Wzorek A, Sato A, Drabowicz J, Soloshonok VA, Klika KD. Remarkable magnitude of the self-disproportionation of enantiomers (SDE) via achiral chromatography: application to the practical-scale enantiopurification of β-amino acid esters. Amino Acids 2015; 48:605-13. [PMID: 26704565 DOI: 10.1007/s00726-015-2152-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Accepted: 12/08/2015] [Indexed: 11/28/2022]
Abstract
We report the best performance yet for the self-disproportionation of enantiomers (SDE) via achiral chromatography as typically used in laboratories for the isolated yield of the excess enantiomer using N-acetyl β-amino acid ethyl esters. The results are the most convincing ever demonstration of the capability of the SDE for practical-scale enantiopurification as comparable, or even superior for some systems, to that of recrystallization. For example, from a sample of 94.4 % ee, a yield of 71 % of enantiopure material was isolated in a single chromatographic run. Moreover, the lack of an esoteric structural entity, e.g. strongly polarizing groups, such as, for instance CF3, highlights the fact that the phenomenon is not dependent on the presence of such and thus the process is relevant to any usual-type structure. In contrast to recrystallization, the procedure is predictable, general, and dependable, boding well for its widespread application in routine laboratory settings.
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Affiliation(s)
- Alicja Wzorek
- Institute of Chemistry, Jan Kochanowski University in Kielce, Świętokrzyska 15G, 25-406, Kielce, Poland. .,Department of Organic Chemistry I, Faculty of Chemistry, University of the Basque Country UPV/EHU, Paseo Manuel Lardizábal 3, 20018, San Sebastián, Spain.
| | - Azusa Sato
- Department of Organic Chemistry I, Faculty of Chemistry, University of the Basque Country UPV/EHU, Paseo Manuel Lardizábal 3, 20018, San Sebastián, Spain.,Department of Chemistry, Tokyo Women's Medical University, 8-1 Kawada-cho, Shinjuku-ku, Tokyo, 162-8666, Japan
| | - Józef Drabowicz
- Department of Heteroorganic Chemistry, Center of Molecular and Macromolecular Studies, Polish Academy of Sciences, Sienkiewicza 112, 90-363, Łódź, Poland.,Institute of Chemistry, Environmental Protection and Biotechnology, Jan Dlugosz University in Czestochowa, Armii Krajowej 13/15, 42-201, Częstochowa, Poland
| | - Vadim A Soloshonok
- Department of Organic Chemistry I, Faculty of Chemistry, University of the Basque Country UPV/EHU, Paseo Manuel Lardizábal 3, 20018, San Sebastián, Spain. .,IKERBASQUE, Basque Foundation for Science, Alameda Urquijo 36-5, Plaza Bizkaia, 48011, Bilbao, Spain.
| | - Karel D Klika
- Molecular Structure Analysis, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69009, Heidelberg, Germany.
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Le Gall E, Léonel E. A Four-Component Reaction Involving In Situ Generated Organometallic Reagents: Straightforward Access to β-Amino Esters. Chemistry 2013; 19:5238-41. [DOI: 10.1002/chem.201300345] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Indexed: 11/05/2022]
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5
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Escudero-Casao M, Juaristi E. Asymmetric Synthesis ofβ2-homo-tert-LeucineviaRadical Addition to EnantiopureN-Fumaroylhexahydrobenzooxazolidin-2-one. Helv Chim Acta 2012. [DOI: 10.1002/hlca.201200448] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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6
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Li W, Song B, Bhadury PS, Li L, Wang Z, Zhang X, Hu D, Chen Z, Zhang Y, Bai S, Wu J, Yang S. Chiral cinchona alkaloid-derived thiourea catalyst for enantioselective synthesis of novel β-amino esters by mannich reaction. Chirality 2012; 24:223-31. [DOI: 10.1002/chir.21986] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2011] [Accepted: 11/02/2011] [Indexed: 11/10/2022]
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7
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Montagnat OD, Lessene G, Hughes AB. Synthesis of Azide-alkyne Fragments for 'Click' Chemical Applications. Formation of Chiral 1,4-Disubstituted-(β-alkyl)-γ-1,2,3-triazole Scaffolds from Orthogonally Protected Chiral β-Alkyl-trialkylsilyl-γ-pentynyl Azides and Chiral β-Alkyl-γ-pentynyl-alcohols. Aust J Chem 2010. [DOI: 10.1071/ch10306] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
A library of chiral γ-pentynyl alcohols and γ-pentynyl azides was made using the SuperQuat auxiliary. Coupling of the free alkynes with the azides by Huisgen 1,3-dipolar cycloaddition provided chiral oligomeric 1,4-disubstituted-1,2,3-triazoles as possible peptidomimetic compounds.
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Reyes-Rangel G, Jiménez-González E, Olivares-Romero JL, Juaristi E. Enantioselective synthesis of beta-amino acids using hexahydrobenzoxazolidinones as chiral auxiliaries. ACTA ACUST UNITED AC 2008. [DOI: 10.1016/j.tetasy.2008.12.023] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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9
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Aminomethylation of chiral silyl enol ethers: access to β2-homotryptophane and β2-homolysine derivatives. Tetrahedron Lett 2008. [DOI: 10.1016/j.tetlet.2008.05.131] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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10
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Tessier A, Lahmar N, Pytkowicz J, Brigaud T. Highly Diastereoselective Synthetic Route to Enantiopure β2-Amino Acids and γ-Amino Alcohols Using a Fluorinated Oxazolidine (Fox) as Chiral Auxiliary. J Org Chem 2008; 73:3970-3. [DOI: 10.1021/jo800562x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Arnaud Tessier
- Laboratoire “Synthèse Organique Sélective et Chimie Organométallique” (SOSCO), UMR CNRS 8123, Université de Cergy-Pontoise, 5, Mail Gay Lussac Neuville sur Oise 95031, Cergy-Pontoise Cedex, France
| | - Nour Lahmar
- Laboratoire “Synthèse Organique Sélective et Chimie Organométallique” (SOSCO), UMR CNRS 8123, Université de Cergy-Pontoise, 5, Mail Gay Lussac Neuville sur Oise 95031, Cergy-Pontoise Cedex, France
| | - Julien Pytkowicz
- Laboratoire “Synthèse Organique Sélective et Chimie Organométallique” (SOSCO), UMR CNRS 8123, Université de Cergy-Pontoise, 5, Mail Gay Lussac Neuville sur Oise 95031, Cergy-Pontoise Cedex, France
| | - Thierry Brigaud
- Laboratoire “Synthèse Organique Sélective et Chimie Organométallique” (SOSCO), UMR CNRS 8123, Université de Cergy-Pontoise, 5, Mail Gay Lussac Neuville sur Oise 95031, Cergy-Pontoise Cedex, France
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11
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Preparation of chiral derivatives of β-Ala containing the α-phenylethyl group: useful starting materials for the asymmetric synthesis of β-amino acids. Nat Protoc 2007; 2:2759-66. [DOI: 10.1038/nprot.2007.375] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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12
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Moumné R, Denise B, Guitot K, Rudler H, Lavielle S, Karoyan P. New Scalable Asymmetric Aminomethylation Reaction for the Synthesis of β2-Amino Acids. European J Org Chem 2007. [DOI: 10.1002/ejoc.200600926] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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13
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Beddow JE, Davies SG, Ling KB, Roberts PM, Russell AJ, Smith AD, Thomson JE. Asymmetric synthesis of β2-amino acids: 2-substituted-3-aminopropanoic acids from N-acryloyl SuperQuat derivatives. Org Biomol Chem 2007; 5:2812-25. [PMID: 17700850 DOI: 10.1039/b707689d] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Conjugate addition of lithium dibenzylamide to (S)-N(3)-acryloyl-4-isopropyl-5,5-dimethyloxazolidin-2-one (derived from l-valine) and alkylation of the resultant lithium beta-amino enolate provides, after deprotection, a range of (S)-2-alkyl-3-aminopropanoic acids in good yield and high ee. Alternatively, via a complementary pathway, conjugate addition of a range of secondary lithium amides to (S)-N(3)-(2'-alkylacryloyl)-4-isopropyl-5,5-dimethyloxazolidin-2-ones, diastereoselective protonation with 2-pyridone, and subsequent deprotection furnishes a range of (R)-2-alkyl- and (R)-2-aryl-3-aminopropanoic acids in good yield and high ee. Additionally, the boron-mediated aldol reaction of beta-amino N-acyl oxazolidinones is a highly diastereoselective method for the synthesis of a range of beta-amino-beta'-hydroxy N-acyl oxazolidinones.
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Affiliation(s)
- James E Beddow
- Department of Organic Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford, UK OX1 3TA
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Moumne R, Lavielle S, Karoyan P. Efficient Synthesis of β2-Amino Acid by Homologation of α-Amino Acids Involving the Reformatsky Reaction and Mannich-Type Imminium Electrophile. J Org Chem 2006; 71:3332-4. [PMID: 16599644 DOI: 10.1021/jo060316a] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Development of new methods for the synthesis of beta-amino acids is important as polymers of these compounds are promising peptidomimetic candidates in medicinal chemistry. We report here our findings on a new and highly efficient general strategy for the synthesis of beta2-amino acids by homologation of alpha-amino acids, involving the Reformatsky reaction and Mannich-type imminium electrophile.
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Affiliation(s)
- Roba Moumne
- Synthèses, Structures et Fonctions des Molécules Bioactives, CNRS/UMR 7613, Université Pierre et Marie Curie, 4, Place Jussieu, 75252, Paris Cedex 05, France
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15
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Lelais G, Micuch P, Josien-Lefebvre D, Rossi F, Seebach D. Preparation of Protected?2- and?3-Homocysteine,?2- and?3-Homohistidine, and?2-Homoserine for Solid-Phase Syntheses. Helv Chim Acta 2004. [DOI: 10.1002/hlca.200490280] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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16
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Shim YH, Yilmaz E, Lavielle S, Haupt K. Chiral recognition and separation of β2-amino acids using non-covalently molecularly imprinted polymers. Analyst 2004; 129:1211-5. [PMID: 15565220 DOI: 10.1039/b409836f] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Non-covalently molecularly imprinted polymers (MIPs) for beta2-amino acids were prepared for the first time. N-(2-chlorobenzyloxycarbonyl)-(R)-beta2-homophenylalanine (N-2-ClZ-(R)-beta2-HPhe) was imprinted with methacrylic acid (MAA) and/or 4-vinylpyridine (4-VPy) as the functional monomers, with ethylene glycol dimethacrylate (EDMA) as the cross-linker. The MIPs made with different ratios of MAA:4-VPy were studied in HPLC mode. The results show that MIPs made with 4-VPy yielded the best chiral separation factor (alpha= 1.86) for the template molecule. The importance for an efficient separation of pi-stacking interactions between the MIPs and the template molecule is demonstrated. Racemates of Z-alpha-amino acids and beta-amino acid analogues of the template were either not or poorly resolved by the MIPs, thus demonstrating the close three-dimensional complementarity of the MIPs' recognition sites with the template.
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Affiliation(s)
- Yong-Ho Shim
- Université P. et M. Curie--Paris VI, UMR 7613 CNRS, Paris, France
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17
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Beddow JE, Davies SG, Smith AD, Russell AJ. Asymmetric synthesis of 2-alkyl- and 2-aryl-3-aminopropionic acids (β2-amino acids) from (S)-N-acryloyl-5,5-dimethyloxazolidin-2-one SuperQuat derivatives. Chem Commun (Camb) 2004:2778-9. [PMID: 15568113 DOI: 10.1039/b410938d] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Conjugate addition of lithium amides to (S)-N-acryloyl- or (S)-N-2'-alkylacryloyloxazolidinones and alkylation or protonation of the resulting enolates with 2-pyridone respectively provides a highly stereoselective and product complementary route to a range of (R)- and (S)-2-alkyl-3-aminopropionic acids in good yield and in high ee.
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Affiliation(s)
- James E Beddow
- Department of Organic Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road, Oxford OX1 3TA, UK
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18
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Lelais G, Seebach D. ?2-amino acids?syntheses, occurrence in natural products, and components of ?-peptides1,2. Biopolymers 2004; 76:206-43. [PMID: 15148683 DOI: 10.1002/bip.20088] [Citation(s) in RCA: 261] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Although they are less abundant than their alpha-analogues, beta-amino acids occur in nature both in free form and bound to peptides. Oligomers composed exclusively of beta-amino acids (so-called beta-peptides) might be the most thoroughly investigated peptidomimetics. Beside the facts that they are stable to metabolism, exhibit slow microbial degradation, and are inherently stable to proteases and peptidases, they fold into well-ordered secondary structures consisting of helices, turns, and sheets. In this respect, the most intriguing effects have been observed when beta2-amino acids are present in the beta-peptide backbone. This review gives an overview of the occurrence and importance of beta2-amino acids in nature, placing emphasis on the metabolic pathways of beta-aminoisobutyric acid (beta-Aib) and the appearance of beta2-amino acids as secondary metabolites or as components of more complex natural products, such as peptides, depsipeptides, lactones, and alkaloids. In addition, a compilation of the syntheses of both achiral and chiral beta2-amino acids is presented. While there are numerous routes to achiral beta2-amino acids, their EPC synthesis is currently the subject of many investigations. These include the diastereoselective alkylation and Mannich-type reactions of cyclic- or acyclic beta-homoglycine derivatives containing chiral auxiliaries, the Curtius degradation, the employment of transition-metal catalyzed reactions such as enantioselective hydrogenations, reductions, C-H insertions, and Michael-type additions, and the resolution of rac. beta2-amino acids, as well as several miscellaneous methods. In the last part of the review, the importance of beta2-amino acids in the formation of beta-peptide secondary structures is discussed.
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Affiliation(s)
- Gérald Lelais
- Laboratorium für Organische Chemie der Eidgenössischen Technischen Hochschule, ETH Hönggerberg, HCl, Wolfgang-Pauli-Strasse 10, CH-8093 Zürich, Switzerland
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Park JS, Lee HS, Lai JR, Kim BM, Gellman SH. Accommodation of alpha-substituted residues in the beta-peptide 12-helix: expanding the range of substitution patterns available to a foldamer scaffold. J Am Chem Soc 2003; 125:8539-45. [PMID: 12848561 DOI: 10.1021/ja034180z] [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
Beta-amino acid oligomers composed exclusively of homochiral trans-2-aminocyclopentanecarboxylic acid (ACPC) residues and/or related pyrrolidine-based residues are known to favor a specific helical secondary structure that is defined by 12-membered ring C=O(i)- -H-N(i+3) hydrogen bonds ("12-helix"). The 12-helix is structurally similar to the familiar alpha-helix and therefore represents a source of potential alpha-helix-mimics. The 12-helix will be most useful in this regard if this conformational scaffold can be employed to arrange specific sets of protein-like side chains in space. Here we examine whether the 12-helix tolerates insertion of acyclic beta-amino acid residues bearing a substituent in the alpha-position ("beta(2)-residues"). Seventeen homologous beta-peptide heptamers have been prepared in which one to four beta(2)-residues reside among ACPC and/or pyrrolidine residues. Circular dichroism comparisons suggest that beta(2)-residues have a lower 12-helical propensity than do residues preorganized by a five-membered ring, as expected, but that beta-peptides containing beta(2)-residues at one or two of the seven positions retain a significant preference for 12-helix formation. These results indicate that a limited number of beta(2)-residues can be used to introduce side chains at specific positions along the surface of a 12-helix.
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Affiliation(s)
- Jin-Seong Park
- School of Chemistry, College of Natural Sciences, Seoul National University, Seoul 151-742, Korea
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Eilitz U, Leßmann F, Seidelmann O, Wendisch V. Stereoselective synthesis of β2-amino acids by Michael addition of diorgano zinc reagents to nitro acrylates. ACTA ACUST UNITED AC 2003. [DOI: 10.1016/s0957-4166(02)00788-7] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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22
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Liu WQ, Olszowy C, Bischoff L, Garbay C. Enantioselective synthesis of (2S)-2-(4-phosphonophenylmethyl)-3-aminopropanoic acid suitably protected for peptide synthesis. Tetrahedron Lett 2002. [DOI: 10.1016/s0040-4039(02)00004-7] [Citation(s) in RCA: 10] [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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Garcı́a Martı́nez A, Teso Vilar E, Garcı́a Fraile A, de la Moya Cerero S, Lora Maroto B. Straightforward synthesis of (1 S )-10-dimethylaminomethylcamphor: an enantiospecific model procedure to C10 C-substituted camphor-derived chiral sources. Tetrahedron Lett 2002. [DOI: 10.1016/s0040-4039(01)02343-7] [Citation(s) in RCA: 7] [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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First efficient preparation of enantiopure 10-bromofenchone: the key intermediate to C10-substituted fenchone-derived chiral sources. Tetrahedron Lett 2001. [DOI: 10.1016/s0040-4039(01)01316-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Gutiérrez-Garcı́a VM, López-Ruiz H, Reyes-Rangel G, Juaristi E. Enantioselective synthesis of β-amino acids. Part 11: Diastereoselective alkylation of chiral derivatives of β-aminopropionic acid containing the α-phenethyl group. Tetrahedron 2001. [DOI: 10.1016/s0040-4020(01)00540-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Garcı́a Martı́nez A, Teso Vilar E, Garcı́a Fraile A, de la Moya Cerero S, Lora Maroto B. A new convenient procedure for the preparation of enantiopure C10-S- and C10-Se-substituted camphor-derived sulfides and selenides. Tetrahedron Lett 2001. [DOI: 10.1016/s0040-4039(01)00924-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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