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Sukumar G, Rahul, Nayani K, Mainkar PS, Prashanth J, Sridhar B, Sarma AVS, Bharatam J, Chandrasekhar S. 6-Strand to Stable 10/12 Helix Conformational Switch by Incorporating Flexible β-hGly in the Homooligomers of Camphor Derived β-Amino Acid: NMR and X-Ray Crystallographic Evidence. Angew Chem Int Ed Engl 2024; 63:e202403321. [PMID: 38482551 DOI: 10.1002/anie.202403321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2024] [Indexed: 04/07/2024]
Abstract
Rational design of unnatural amino acid building blocks capable of stabilizing predictable secondary structures similar to protein fragments is pivotal for foldamer chemistry/catalysis. Here, we introduce novel β-amino acid building blocks: [1S,2R,4R]exoCDA and [1S,2S,4R]endoCDA, derived from the abundantly available R(+)-camphor, which is traditionally known for its medicinal value. Further, we demonstrate that the homooligomers of exoCDA adopt 6-strand conformation, which switches to a robust 10/12-helix simply by inserting flexible β-hGly spacer at alternate positions (1 : 1 β-hGly/exoCDA heterooligomers), as evident by DFT-calculations, solution-state NMR spectroscopy and X-ray crystallography. To the best of our knowledge, this is the first example of crystalline-state structure of left-handed 10/12-mixed helix, that is free from the conventional approach of employing β-amino acids of either alternate chirality or alternate β2/β3 substitutions, to access the 10/12-helix. The results also show that the homooligomers of heterochiral exoCDA don't adopt helical fold, instead exhibit banana-shaped strands, whereas the homodimers of the other diastereomer endoCDA, nucleate 8-membered turns. Furthermore, the homo-exoCDA and hetero-[β-hGly-exoCDA] oligomers are found to exhibit self-association properties with distinct morphological features. Overall, the results offer new possibilties of constructing discrete stable secondary and tertiary structures based on CDAs, which can accommodate flexible residues with desired side-chain substitutions.
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Affiliation(s)
- Genji Sukumar
- Department of Organic Synthesis and Process Chemistry, CSIR-Indian Institute of Chemical Technology, Hyderabad, 500007, India
- Department of Chemistry, Adikavi Nannaya University, Rajamahendravaram, Andhra Pradesh, 533296, India
| | - Rahul
- Centre for NMR, Department of Analytical & Structural Chemistry, CSIR-Indian Institute of Chemical Technology, Hyderabad, 500007, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
| | - Kiranmai Nayani
- Department of Organic Synthesis and Process Chemistry, CSIR-Indian Institute of Chemical Technology, Hyderabad, 500007, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
| | - Prathama S Mainkar
- Department of Organic Synthesis and Process Chemistry, CSIR-Indian Institute of Chemical Technology, Hyderabad, 500007, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
| | - Jupally Prashanth
- Centre for X-ray Crystallography, Department of Analytical & Structural Chemistry, CSIR-Indian Institute of Chemical Technology, Hyderabad, 500007, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
| | - Balasubramanian Sridhar
- Centre for X-ray Crystallography, Department of Analytical & Structural Chemistry, CSIR-Indian Institute of Chemical Technology, Hyderabad, 500007, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
| | - Akella V S Sarma
- Centre for NMR, Department of Analytical & Structural Chemistry, CSIR-Indian Institute of Chemical Technology, Hyderabad, 500007, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
| | - Jagadeesh Bharatam
- Centre for NMR, Department of Analytical & Structural Chemistry, CSIR-Indian Institute of Chemical Technology, Hyderabad, 500007, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
| | - Srivari Chandrasekhar
- Department of Organic Synthesis and Process Chemistry, CSIR-Indian Institute of Chemical Technology, Hyderabad, 500007, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
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2
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Tilly DP, McColl C, Hu M, Vitórica-Yrezábal IJ, Webb SJ. Enantioselective conjugate addition to nitroolefins catalysed by helical peptides with a single remote stereogenic centre. Org Biomol Chem 2023; 21:9562-9571. [PMID: 38009076 DOI: 10.1039/d3ob01594g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2023]
Abstract
Two short pentapeptides rich in α-aminoisobutyric acid (Aib) residues have been shown to act as enantioselective organocatalysts for the conjugate addition of nucleophiles to nitroolefins. An L-alanine terminated peptide, (Aib)4(L-Ala)NHtBu, which has neither functionalised sidechains nor a highly designed reactive site, used an exposed N-terminal primary amine and the amide bonds of the backbone to mediate catalysis. Folding of this peptide into a 310 helical structure was observed by crystallography. Folding into a helix relays the conformational preference of the chiral alanine residue at the C-terminus to the primary amine at the N-terminus, 0.9 nm distant. The chiral environment and defined shape produced by the 310 helix brings the amine site into proximity to two exposed amide NHs. Reaction scope studies implied that the amine acts as a Brønsted base and the solvent-exposed NH groups of the helix, shown to weakly bind β-nitrostyrene, are needed to obtain an enantiomeric excess. Replacement of L-alanine with D-phenylalanine gave (Aib)4(D-Phe)NHtBu, a peptide that now catalysed the benchmark reaction with the opposite enantioselectivity. These studies show how achiral residues can play a key role in enantioselective catalysis by peptides through the promotion of folding.
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Affiliation(s)
- David P Tilly
- Department of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, UK.
- Manchester Institute of Biotechnology, University of Manchester, 131 Princess Street, Manchester M1 7DN, UK
| | - Catherine McColl
- Department of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, UK.
- Manchester Institute of Biotechnology, University of Manchester, 131 Princess Street, Manchester M1 7DN, UK
| | - Mingda Hu
- Department of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, UK.
- Manchester Institute of Biotechnology, University of Manchester, 131 Princess Street, Manchester M1 7DN, UK
| | | | - Simon J Webb
- Department of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, UK.
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3
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Shah SKH, Modi U, Patel K, James A, N S, De S, Vasita R, Prabhakaran P. Site-selective post-modification of short α/γ hybrid foldamers: a powerful approach for molecular diversification towards biomedical applications. Biomater Sci 2023; 11:6210-6222. [PMID: 37526301 DOI: 10.1039/d3bm00766a] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/02/2023]
Abstract
The extensive research work in the exhilarating area of foldamers (artificial oligomers possessing well-defined conformation in solution) has shown them to be promising candidates in biomedical research and materials science. The post-modification approach is successful in peptides, proteins, and polymers to modulate their functions. To the best of our knowledge, site-selective post-modification of a foldamer affording molecules with different pendant functional groups within a molecular scaffold has not yet been reported. We demonstrate for the first time that late-stage site-selective functionalization of short hybrid oligomers is an efficient approach to afford molecules with diverse functional groups. In this article, we report the design and synthesis of hybrid peptides with repeating units of leucine (Leu) and 5-amino salicylic acid (ASA), regioselective post-modification, conformational analyses (based on solution-state NMR, circular dichroism and computational studies) and morphological studies of the peptide nanostructures. As a proof-of-concept, we demonstrate the applications of differently modified peptides as drug delivery agents, imaging probes, and anticancer agents. The novel feature of the work is that the difference in reactivity of two phenolic OH groups in short biomimetic peptides was utilized to achieve site-selective post-modification. It is challenging to apply the same approach to short α-peptides having a poor folding tendency, and their post-functionalization may considerably affect their conformation.
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Affiliation(s)
| | - Unnati Modi
- School of Life Sciences, Central University of Gujarat, Gandhinagar 382030, India
| | - Karma Patel
- School of Chemical Sciences, Central University of Gujarat, Gandhinagar 382030, India.
| | - Anjima James
- Department of Applied Chemistry, Cochin University of Science and Technology, Kochi 682022, India
| | - Sreerag N
- School of Chemical Sciences, Central University of Gujarat, Gandhinagar 382030, India.
| | - Susmita De
- Department of Chemistry, University of Calicut, Calicut 673635, India
| | - Rajesh Vasita
- School of Life Sciences, Central University of Gujarat, Gandhinagar 382030, India
| | - Panchami Prabhakaran
- School of Chemical Sciences, Central University of Gujarat, Gandhinagar 382030, India.
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Lin Q, Lan H, Ma C, Stendall RT, Shankland K, Musgrave RA, Horton PN, Baldauf C, Hofmann H, Butts CP, Müller MM, Cobb AJA. Crystal Structure and NMR of an α,δ-Peptide Foldamer Helix Shows Side-Chains are Well Placed for Bifunctional Catalysis: Application as a Minimalist Aldolase Mimic. ANGEWANDTE CHEMIE (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023; 135:e202305326. [PMID: 38516402 PMCID: PMC10952562 DOI: 10.1002/ange.202305326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/15/2023] [Indexed: 03/23/2024]
Abstract
We report the first NMR and X-ray diffraction (XRD) structures of an unusual 13/11-helix (alternating i, i+1 {NH-O=C} and i, i+3 {C=O-H-N} H-bonds) formed by a heteromeric 1 : 1 sequence of α- and δ-amino acids, and demonstrate the application of this framework towards catalysis. Whilst intramolecular hydrogen bonds (IMHBs) are the clear driver of helix formation in this system, we also observe an apolar interaction between the ethyl residue of one δ-amino acid and the cyclohexyl group of the next δ-residue in the sequence that seems to stabilize one type of helix over another. To the best of our knowledge this type of additional stabilization leading to a specific helical preference has not been observed before. Critically, the helix type realized places the α-residue functionalities in positions proximal enough to engage in bifunctional catalysis as demonstrated in the application of our system as a minimalist aldolase mimic.
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Affiliation(s)
- Qi Lin
- Department of ChemistryKing's College London7 Trinity StreetLondonSE1 1DBUK
| | - Hao Lan
- School of ChemistryUniversity of BristolCantocks CloseBristolBS8 1TSUK
| | - Chunmiao Ma
- School of Chemistry and Chemical EngineeringHuazhong University of Science and TechnologyWuhan430074P. R. China
| | - Ryan T. Stendall
- Department of ChemistryKing's College London7 Trinity StreetLondonSE1 1DBUK
| | - Kenneth Shankland
- School of ChemistryFood and Pharmacy (SCFP)University of ReadingWhiteknights BerksReadingRG6 6ADUK
| | | | - Peter N. Horton
- EPSRC National Crystallography ServiceSchool of ChemistryUniversity of Southampton HighfieldSouthamptonSO17 1BJUK
| | - Carsten Baldauf
- Fritz-Haber-Institut der Max-Planck-GesellschaftFaradayweg 4–614195BerlinGermany
| | - Hans‐Jörg Hofmann
- Institut für BiochemieUniversität LeipzigBrüderstrasse 3404103LeipzigGermany
| | - Craig P. Butts
- School of ChemistryUniversity of BristolCantocks CloseBristolBS8 1TSUK
| | - Manuel M. Müller
- Department of ChemistryKing's College London7 Trinity StreetLondonSE1 1DBUK
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5
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Lin Q, Lan H, Ma C, Stendall RT, Shankland K, Musgrave RA, Horton PN, Baldauf C, Hofmann H, Butts CP, Müller MM, Cobb AJA. Crystal Structure and NMR of an α,δ-Peptide Foldamer Helix Shows Side-Chains are Well Placed for Bifunctional Catalysis: Application as a Minimalist Aldolase Mimic. Angew Chem Int Ed Engl 2023; 62:e202305326. [PMID: 37218617 PMCID: PMC10952276 DOI: 10.1002/anie.202305326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2023] [Revised: 05/17/2023] [Accepted: 05/22/2023] [Indexed: 05/24/2023]
Abstract
We report the first NMR and X-ray diffraction (XRD) structures of an unusual 13/11-helix (alternating i, i+1 {NH-O=C} and i, i+3 {C=O-H-N} H-bonds) formed by a heteromeric 1 : 1 sequence of α- and δ-amino acids, and demonstrate the application of this framework towards catalysis. Whilst intramolecular hydrogen bonds (IMHBs) are the clear driver of helix formation in this system, we also observe an apolar interaction between the ethyl residue of one δ-amino acid and the cyclohexyl group of the next δ-residue in the sequence that seems to stabilize one type of helix over another. To the best of our knowledge this type of additional stabilization leading to a specific helical preference has not been observed before. Critically, the helix type realized places the α-residue functionalities in positions proximal enough to engage in bifunctional catalysis as demonstrated in the application of our system as a minimalist aldolase mimic.
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Affiliation(s)
- Qi Lin
- Department of ChemistryKing's College London7 Trinity StreetLondonSE1 1DBUK
| | - Hao Lan
- School of ChemistryUniversity of BristolCantocks CloseBristolBS8 1TSUK
| | - Chunmiao Ma
- School of Chemistry and Chemical EngineeringHuazhong University of Science and TechnologyWuhan430074P. R. China
| | - Ryan T. Stendall
- Department of ChemistryKing's College London7 Trinity StreetLondonSE1 1DBUK
| | - Kenneth Shankland
- School of ChemistryFood and Pharmacy (SCFP)University of ReadingWhiteknights BerksReadingRG6 6ADUK
| | | | - Peter N. Horton
- EPSRC National Crystallography ServiceSchool of ChemistryUniversity of Southampton HighfieldSouthamptonSO17 1BJUK
| | - Carsten Baldauf
- Fritz-Haber-Institut der Max-Planck-GesellschaftFaradayweg 4–614195BerlinGermany
| | - Hans‐Jörg Hofmann
- Institut für BiochemieUniversität LeipzigBrüderstrasse 3404103LeipzigGermany
| | - Craig P. Butts
- School of ChemistryUniversity of BristolCantocks CloseBristolBS8 1TSUK
| | - Manuel M. Müller
- Department of ChemistryKing's College London7 Trinity StreetLondonSE1 1DBUK
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6
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Sang P, Cai J. Unnatural helical peptidic foldamers as protein segment mimics. Chem Soc Rev 2023; 52:4843-4877. [PMID: 37401344 PMCID: PMC10389297 DOI: 10.1039/d2cs00395c] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Indexed: 07/05/2023]
Abstract
Unnatural helical peptidic foldamers have attracted considerable attention owing to their unique folding behaviours, diverse artificial protein binding mechanisms, and promising applications in chemical, biological, medical, and material fields. Unlike the conventional α-helix consisting of molecular entities of native α-amino acids, unnatural helical peptidic foldamers are generally comprised of well-defined backbone conformers with unique and unnatural structural parameters. Their folded structures usually arise from unnatural amino acids such as N-substituted glycine, N-substituted-β-alanine, β-amino acid, urea, thiourea, α-aminoxy acid, α-aminoisobutyric acid, aza-amino acid, aromatic amide, γ-amino acid, as well as sulfono-γ-AA amino acid. They can exhibit intriguing and predictable three-dimensional helical structures, generally featuring superior resistance to proteolytic degradation, enhanced bioavailability, and improved chemodiversity, and are promising in mimicking helical segments of various proteins. Although it is impossible to include every piece of research work, we attempt to highlight the research progress in the past 10 years in exploring unnatural peptidic foldamers as protein helical segment mimics, by giving some representative examples and discussing the current challenges and future perspectives. We expect that this review will help elucidate the principles of structural design and applications of existing unnatural helical peptidic foldamers in protein segment mimicry, thereby attracting more researchers to explore and generate novel unnatural peptidic foldamers with unique structural and functional properties, leading to more unprecedented and practical applications.
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Affiliation(s)
- Peng Sang
- Tianjian Laboratory of Advanced Biomedical Sciences, School of Pharmaceutical Sciences, Zhengzhou University, Zhengzhou 450001, China.
| | - Jianfeng Cai
- Department of Chemistry, University of South Florida, Tampa, FL 33620, USA.
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7
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Kim M, Jo H, Jung GY, Oh SS. Molecular Complementarity of Proteomimetic Materials for Target-Specific Recognition and Recognition-Mediated Complex Functions. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2208309. [PMID: 36525617 DOI: 10.1002/adma.202208309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 11/29/2022] [Indexed: 06/02/2023]
Abstract
As biomolecules essential for sustaining life, proteins are generated from long chains of 20 different α-amino acids that are folded into unique 3D structures. In particular, many proteins have molecular recognition functions owing to their binding pockets, which have complementary shapes, charges, and polarities for specific targets, making these biopolymers unique and highly valuable for biomedical and biocatalytic applications. Based on the understanding of protein structures and microenvironments, molecular complementarity can be exhibited by synthesizable and modifiable materials. This has prompted researchers to explore the proteomimetic potentials of a diverse range of materials, including biologically available peptides and oligonucleotides, synthetic supramolecules, inorganic molecules, and related coordination networks. To fully resemble a protein, proteomimetic materials perform the molecular recognition to mediate complex molecular functions, such as allosteric regulation, signal transduction, enzymatic reactions, and stimuli-responsive motions; this can also expand the landscape of their potential bio-applications. This review focuses on the recognitive aspects of proteomimetic designs derived for individual materials and their conformations. Recent progress provides insights to help guide the development of advanced protein mimicry with material heterogeneity, design modularity, and tailored functionality. The perspectives and challenges of current proteomimetic designs and tools are also discussed in relation to future applications.
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Affiliation(s)
- Minsun Kim
- School of Interdisciplinary Bioscience and Bioengineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Hyesung Jo
- Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, South Korea
| | - Gyoo Yeol Jung
- School of Interdisciplinary Bioscience and Bioengineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
- Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, South Korea
| | - Seung Soo Oh
- School of Interdisciplinary Bioscience and Bioengineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
- Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, South Korea
- Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, South Korea
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8
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Tilly DP, Heeb JP, Webb SJ, Clayden J. Switching imidazole reactivity by dynamic control of tautomer state in an allosteric foldamer. Nat Commun 2023; 14:2647. [PMID: 37156760 PMCID: PMC10167260 DOI: 10.1038/s41467-023-38339-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Accepted: 04/26/2023] [Indexed: 05/10/2023] Open
Abstract
Molecular biology achieves control over complex reaction networks by means of molecular systems that translate a chemical input (such as ligand binding) into an orthogonal chemical output (such as acylation or phosphorylation). We present an artificial molecular translation device that converts a chemical input - the presence of chloride ions - into an unrelated chemical output: modulation of the reactivity of an imidazole moiety, both as a Brønsted base and as a nucleophile. The modulation of reactivity operates through the allosteric remote control of imidazole tautomer states. The reversible coordination of chloride to a urea binding site triggers a cascade of conformational changes in a chain of ethylene-bridged hydrogen-bonded ureas, switching the chain's global polarity, that in turn modulates the tautomeric equilibrium of a distal imidazole, and hence its reactivity. Switching reactivities of active sites by dynamically controlling their tautomer states is an untapped strategy for building functional molecular devices with allosteric enzyme-like properties.
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Affiliation(s)
- David P Tilly
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK.
- Department of Chemistry, University of Manchester, Oxford Road, Manchester, M13 9PL, UK.
| | - Jean-Paul Heeb
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK
| | - Simon J Webb
- Department of Chemistry, University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | - Jonathan Clayden
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK.
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9
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Roe WE, Warnock TMC, Knipe PC. A spirocyclic backbone accesses new conformational space in an extended, dipole-stabilized foldamer. Commun Chem 2023; 6:71. [PMID: 37069245 PMCID: PMC10110530 DOI: 10.1038/s42004-023-00868-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Accepted: 03/24/2023] [Indexed: 04/19/2023] Open
Abstract
Most aromatic foldamers adopt uniform secondary structures, offering limited potential for the exploration of conformational space and the formation of tertiary structures. Here we report the incorporation of spiro bis-lactams to allow controlled rotation of the backbone of an iteratively synthesised foldamer. This enables precise control of foldamer shape along two orthogonal directions, likened to the aeronautical yaw and roll axes. XRD, NMR and computational data suggest that homo-oligomers adopt an extended right-handed helix with a pitch of over 30 Å, approximately that of B-DNA. Compatibility with extant foldamers to form hetero-oligomers is demonstrated, allowing greater structural complexity and function in future hybrid foldamer designs.
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Affiliation(s)
- William Edward Roe
- School of Chemistry and Chemical Engineering, Queen's University Belfast, David Keir Building, Belfast, BT9 5AG, UK
| | - Toyah Mary Catherine Warnock
- School of Chemistry and Chemical Engineering, Queen's University Belfast, David Keir Building, Belfast, BT9 5AG, UK
| | - Peter Clarke Knipe
- School of Chemistry and Chemical Engineering, Queen's University Belfast, David Keir Building, Belfast, BT9 5AG, UK.
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10
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Noll N, Groß T, Shoyama K, Beuerle F, Würthner F. Folding-Induced Promotion of Proton-Coupled Electron Transfers via Proximal Base for Light-Driven Water Oxidation. Angew Chem Int Ed Engl 2023; 62:e202217745. [PMID: 36511298 PMCID: PMC10107485 DOI: 10.1002/anie.202217745] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 12/12/2022] [Accepted: 12/13/2022] [Indexed: 12/14/2022]
Abstract
Proton-coupled electron-transfer (PCET) processes play a key role in biocatalytic energy conversion and storage, for example, photosynthesis or nitrogen fixation. Here, we report a series of bipyridine-containing di- to tetranuclear Ru(bda) macrocycles 2 C-4 C (bda: 2,2'-bipyridine-6,6'-dicarboxylate) to promote O-O bond formation. In photocatalytic water oxidation under neutral conditions, all complexes 2 C-4 C prevail in a folded conformation that support the water nucleophilic attack (WNA) pathway with remarkable turnover frequencies of up to 15.5 s-1 per Ru unit respectively. Single-crystal X-ray analysis revealed an increased tendency for intramolecular π-π stacking and preorganization of the proximal bases close to the active centers for the larger macrocycles. H/D kinetic isotope effect studies and electrochemical data demonstrate the key role of the proximal bipyridines as proton acceptors in lowering the activation barrier for the crucial nucleophilic attack of H2 O in the WNA mechanism.
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Affiliation(s)
- Niklas Noll
- Institut für Organische Chemie, Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Tobias Groß
- Institut für Organische Chemie, Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Kazutaka Shoyama
- Institut für Organische Chemie, Universität Würzburg, Am Hubland, 97074, Würzburg, Germany.,Center for Nanosystems Chemistry (CNC), Universität Würzburg, Theodor-Boveri-Weg, 97074, Würzburg, Germany
| | - Florian Beuerle
- Institut für Organische Chemie, Universität Würzburg, Am Hubland, 97074, Würzburg, Germany.,Center for Nanosystems Chemistry (CNC), Universität Würzburg, Theodor-Boveri-Weg, 97074, Würzburg, Germany.,Institut für Organische Chemie, Universität Tübingen, Auf der Morgenstelle 18, 72076, Tübingen, Germany
| | - Frank Würthner
- Institut für Organische Chemie, Universität Würzburg, Am Hubland, 97074, Würzburg, Germany.,Center for Nanosystems Chemistry (CNC), Universität Würzburg, Theodor-Boveri-Weg, 97074, Würzburg, Germany
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11
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Devkota GP, Carson WP, Hartley CS. Conformational Control of ortho-Phenylenes by Terminal Amides. J Org Chem 2023; 88:1331-1338. [PMID: 36650119 DOI: 10.1021/acs.joc.2c01858] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Control over the folding of oligomers, be it broad induction of a preferred helical handedness or subtle changes in the orientations of individual functional groups, is important for applications ranging from molecular recognition to long-range conformational communication. Here, we report a series of ortho-phenylene hexamers functionalized with achiral and chiral amides at their termini. NMR spectroscopy, taking advantage of 19F labeling, allows multiple conformers to be detected for each compound. In combination with CD spectroscopy and DFT calculations, specific geometries corresponding to each conformer have been identified and quantified. General conclusions about the effect of sterics and the amide linker on conformational behavior have been drawn, revealing some similarities to and key differences from previously reported imines. A model for twist sense control has been developed that is supported by computational models.
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Affiliation(s)
- Govinda Prasad Devkota
- Department of Chemistry & Biochemistry, Miami University, Oxford, Ohio 45056, United States
| | - William P Carson
- Department of Chemistry & Biochemistry, Miami University, Oxford, Ohio 45056, United States
| | - C Scott Hartley
- Department of Chemistry & Biochemistry, Miami University, Oxford, Ohio 45056, United States
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12
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Helical Foldamers and Stapled Peptides as New Modalities in Drug Discovery: Modulators of Protein-Protein Interactions. Processes (Basel) 2022. [DOI: 10.3390/pr10050924] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
A “foldamer” is an artificial oligomeric molecule with a regular secondary or tertiary structure consisting of various building blocks. A “stapled peptide” is a peptide with stabilized secondary structures, in particular, helical structures by intramolecular covalent side-chain cross-linking. Helical foldamers and stapled peptides are potential drug candidates that can target protein-protein interactions because they enable multipoint molecular recognition, which is difficult to achieve with low-molecular-weight compounds. This mini-review describes a variety of peptide-based foldamers and stapled peptides with a view to their applications in drug discovery, including our recent progress.
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13
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Andrews MK, Liu X, Gellman SH. Tailoring Reaction Selectivity by Modulating a Catalytic Diad on a Foldamer Scaffold. J Am Chem Soc 2022; 144:2225-2232. [PMID: 35077169 PMCID: PMC9273127 DOI: 10.1021/jacs.1c11542] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Use of a tunable molecular scaffold to align a reactive diad for bifunctional catalysis can reveal relationships between functional group identity and reactivity that might otherwise be impossible to identify. Here we use an α/β-peptide helix to show that an aligned pair of primary amine groups is uniquely competent to catalyze crossed aldol condensations with an aryl aldehyde as the electrophile. Geometrically similar diads in which one amine group is secondary, or both are secondary, are good catalysts for other types of aldol condensations but not those involving an aryl aldehyde. Catalytic efficacy requires β-amino acid residues that are preorganized for helix formation via cyclic constraint. Conventional peptides (exclusively α-amino acid residues) that display the primary amine diad are poor catalysts, which highlights the critical role of the foldamer scaffold.
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Affiliation(s)
- Mary Katherine Andrews
- Department of Chemistry, University of Wisconsin, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Xinyu Liu
- Department of Chemistry, University of Wisconsin, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Samuel H. Gellman
- Department of Chemistry, University of Wisconsin, 1101 University Avenue, Madison, Wisconsin 53706, United States
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14
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Tilly DP, Cullen W, Zhong H, Jamagne R, Vitórica-Yrezábal I, Webb SJ. α-Amino-iso-butyric acid foldamers terminated with rhodium(I) N-heterocyclic carbene catalysts. Chemistry 2021; 28:e202104293. [PMID: 34932229 PMCID: PMC9305545 DOI: 10.1002/chem.202104293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Indexed: 12/01/2022]
Abstract
To investigate how remotely induced changes in ligand folding might affect catalysis by organometallic complexes, dynamic α‐amino‐iso‐butyric acid (Aib) peptide foldamers bearing rhodium(I) N‐heterocyclic carbene (NHC) complexes have been synthesized and studied. X‐ray crystallography of a foldamer with an N‐terminal azide and a C‐terminal Rh(NHC)(Cl)(diene) complex showed a racemate with a chiral axis in the Rh(NHC) complex and a distorted 310 helical body. Replacing the azide with either one or two chiral L‐α‐methylvaline (L‐αMeVal) residues gave diastereoisomeric foldamers that each possessed point, helical and axial chirality. NMR spectroscopy revealed an unequal ratio of diastereoisomers for some foldamers, indicating that the chiral conformational preference of the N‐terminal residue(s) was relayed down the 1 nm helical body to the axially chiral Rh(NHC) complex. Although the remote chiral residue(s) did not affect the stereoselectivity of hydrosilylation reactions catalysed by these foldamers, these studies suggest a potential pathway towards remote conformational control of organometallic catalysts.
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Affiliation(s)
- David P Tilly
- The University of Manchester, Department of Chemistry, UNITED KINGDOM
| | - William Cullen
- The University of Manchester, Department of Chemistry, UNITED KINGDOM
| | - Heng Zhong
- The University of Manchester, Department of Chemistry, UNITED KINGDOM
| | - Romain Jamagne
- The University of Manchester, Department of Chemistry, UNITED KINGDOM
| | | | - Simon John Webb
- University of Manchester, School of Chemistry and MIB, 131 Princess St, M1 7DN, Manchester, UNITED KINGDOM
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15
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Kirinda VC, Vemuri GN, Kress NG, Flynn KM, Kumarage ND, Schrage BR, Tierney DL, Ziegler CJ, Hartley CS. Fluorine Labeling of ortho-Phenylenes to Facilitate Conformational Analysis. J Org Chem 2021; 86:15085-15095. [PMID: 34641678 DOI: 10.1021/acs.joc.1c01770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
1H NMR spectroscopy is a powerful tool for the conformational analysis of ortho-phenylene foldamers in solution. However, as o-phenylenes are integrated into ever more complex systems, we are reaching the limits of what can be analyzed by 1H- and 13C-based NMR techniques. Here, we explore fluorine labeling of o-phenylene oligomers for analysis by 19F NMR spectroscopy. Two series of fluorinated oligomers have been synthesized. Optimization of monomers for Suzuki coupling enables an efficient stepwise oligomer synthesis. The oligomers all adopt well-folded geometries in solution, as determined by 1H NMR spectroscopy and X-ray crystallography. 19F NMR experiments complement these methods well. The resolved singlets of one-dimensional 19F{1H} spectra are very useful for determining relative conformer populations. The additional information from two-dimensional 19F NMR spectra is also clearly valuable when making 1H assignments. The comparison of 19F isotropic shielding predictions to experimental chemical shifts is not, however, currently sufficient by itself to establish o-phenylene geometries.
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Affiliation(s)
- Viraj C Kirinda
- Department of Chemistry & Biochemistry, Miami University, Oxford, Ohio 45056, United States
| | - Gopi Nath Vemuri
- Department of Chemistry & Biochemistry, Miami University, Oxford, Ohio 45056, United States
| | - Nicholas G Kress
- Department of Chemistry & Biochemistry, Miami University, Oxford, Ohio 45056, United States
| | - Kaitlyn M Flynn
- Department of Chemistry & Biochemistry, Miami University, Oxford, Ohio 45056, United States
| | | | - Briana R Schrage
- Department of Chemistry, University of Akron, Akron, Ohio 44325, United States
| | - David L Tierney
- Department of Chemistry & Biochemistry, Miami University, Oxford, Ohio 45056, United States
| | | | - C Scott Hartley
- Department of Chemistry & Biochemistry, Miami University, Oxford, Ohio 45056, United States
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16
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Saito A. Foldamer Catalysts. J SYN ORG CHEM JPN 2021. [DOI: 10.5059/yukigoseikyokaishi.79.871] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Ami Saito
- School of Engineering, Department of Applied Chemistry, The University of Tokyo
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17
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Legrand B, Maillard LT. α,β-Unsaturated γ-Peptide Foldamers. Chempluschem 2021; 86:629-645. [PMID: 33856125 DOI: 10.1002/cplu.202100045] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 03/31/2021] [Indexed: 01/01/2023]
Abstract
Despite their concomitant emergence in the 1990s, γ-peptide foldamers have not developed as fast as β-peptide foldamers and to date, only a few γ-oligomer structures have been reported, and with sparse applications. Among these examples, sequences containing α,β-unsaturated γ-amino acids have recently drawn attention since the Z/E configurations of the double bond provide opposite planar restrictions leading to divergent conformational behaviors, from helix to extended structures. In this Review, we give a comprehensive overview of the developments of γ-peptide foldamers containing α,β-unsaturated γ-amino acids with examples of applications for health and catalysis, as well as materials science.
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Affiliation(s)
- Baptiste Legrand
- Institut des Biomolécules Max Mousseron, IBMM, University of Montpellier, ENSCM, CNRS, Montpellier, France., 15 Av. Charles Flahault BP 14 491, 34093, Montpellier Cedex 5, France
| | - Ludovic T Maillard
- Institut des Biomolécules Max Mousseron, IBMM, University of Montpellier, ENSCM, CNRS, Montpellier, France., 15 Av. Charles Flahault BP 14 491, 34093, Montpellier Cedex 5, France
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18
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Lenartowicz P, Psurski M, Kotynia A, Pieniężna A, Cuprych M, Poniatowska K, Brasuń J, Kafarski P. Dipeptides of S-Substituted Dehydrocysteine as Artzyme Building Blocks: Synthesis, Complexing Abilities and Antiproliferative Properties. Int J Mol Sci 2021; 22:ijms22042168. [PMID: 33671589 PMCID: PMC7927096 DOI: 10.3390/ijms22042168] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Revised: 02/16/2021] [Accepted: 02/18/2021] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND Dehydropeptides are analogs of peptides containing at least one conjugate double bond between α,β-carbon atoms. Its presence provides unique structural properties and reaction centre for chemical modification. In this study, the series of new class of dipeptides containing S-substituted dehydrocysteine with variety of heterocyclic moieties was prepared. The compounds were designed as the building blocks for the construction of artificial metalloenzymes (artzymes). Therefore, the complexing properties of representative compounds were also evaluated. Furthermore, the acknowledged biological activity of natural dehydropeptides was the reason to extend the study for antiproliferative action of against several cancer cell lines. METHODS The synthetic strategy involves glycyl and phenylalanyl-(Z)-β-bromodehydroalanine as a substrate in one pot addition/elimination reaction of thiols. After deprotection of N-terminal amino group the compounds with triazole ring were tested as complexones for copper(II) ions using potentiometric titration and spectroscopic techniques (UV-Vis, CD, EPR). Finally, the antiproliferative activity was evaluated by sulforhodamine B assay. RESULTS AND CONCLUSIONS A simple and efficient procedure for preparation of dipeptides containing S-substituded dehydrocysteine was provided. The peptides containing triazole appeared to be strong complexones of copper(II) ions. Some of the peptides exhibited promising antiproliferative activities against number of cancer cell lines, including cell lines resistant to widely used anticancer agent.
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Affiliation(s)
- Paweł Lenartowicz
- Faculty of Chemistry, University of Opole, ul. Oleska 48, 45-052 Opole, Poland
- Correspondence: (P.L.); (P.K.)
| | - Mateusz Psurski
- Laboratory of Experimental Anticancer Therapy, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, ul. R. Weigla 12, 53-114 Wrocław, Poland; (M.P.); (M.C.); (K.P.)
| | - Aleksandra Kotynia
- Department of Inorganic Chemistry, Wrocław Medical University, ul. Borowska 211 A, 50-556 Wrocław, Poland; (A.K.); (A.P.); (J.B.)
| | - Aleksandra Pieniężna
- Department of Inorganic Chemistry, Wrocław Medical University, ul. Borowska 211 A, 50-556 Wrocław, Poland; (A.K.); (A.P.); (J.B.)
| | - Monika Cuprych
- Laboratory of Experimental Anticancer Therapy, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, ul. R. Weigla 12, 53-114 Wrocław, Poland; (M.P.); (M.C.); (K.P.)
| | - Klaudia Poniatowska
- Laboratory of Experimental Anticancer Therapy, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, ul. R. Weigla 12, 53-114 Wrocław, Poland; (M.P.); (M.C.); (K.P.)
| | - Justyna Brasuń
- Department of Inorganic Chemistry, Wrocław Medical University, ul. Borowska 211 A, 50-556 Wrocław, Poland; (A.K.); (A.P.); (J.B.)
| | - Paweł Kafarski
- Department of Bioorganic Chemistry, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
- Correspondence: (P.L.); (P.K.)
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19
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Milbeo P, Martinez J, Amblard M, Calmès M, Legrand B. 1-Aminobicyclo[2.2.2]octane-2-carboxylic Acid and Derivatives As Chiral Constrained Bridged Scaffolds for Foldamers and Chiral Catalysts. Acc Chem Res 2021; 54:685-696. [PMID: 33464823 DOI: 10.1021/acs.accounts.0c00680] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The improvement of molecular diversity is one of the major concerns of chemists since the continuous development of original synthetic molecules provides unique scaffolds usable in organic and bioorganic chemistry. The challenge is to develop versatile platforms with highly controlled chemical three-dimensional space thanks to controlled chirality and conformational restraints. In this respect, cyclic β-amino acids are of great interest with applications in various fields of chemistry. In addition to their intrinsic biological properties, they are important precursors for the synthesis of new generations of bioactive compounds such as antibiotics, enzyme inhibitors, and antitumor agents. They have also been involved in asymmetric synthesis as efficient organo-catalysts in their free form and as derivatives. Finally, constrained cyclic β-amino acids have been incorporated into oligomers to successfully stabilize original structures in foldamer science with recent successes in health, material science, and catalysis. Over the last ∼10 years, we focused on bicyclic β-amino acids possessing a bicyclo[2.2.2]octane structure. This latter is a structural key element in numerous families of biologically active natural and synthetic products and is an interesting template for asymmetric synthesis. Nonetheless, reported studies on bicyclic carbo-bridged compounds are rather limited compared to those on bicyclic-fused and heterobridged derivatives. In this Account, we particularly focused on the synthesis and applications of the 1-aminobicyclo[2.2.2]octane-2-carboxylic acid, named, ABOC, and its derivatives. This highly constrained bicyclic β-amino acid, with a sterically hindered bridgehead primary amine and an endocyclic chiral center, displays drastically reduced conformational freedom. In addition, its high bulkiness strongly impacts the spatial orientation of the appended functionalities and the conformation of adjacent building blocks. Thus, we have first expanded a fundamental synthetic work by a wide ranging study in the field of foldamers, in the design of various stable peptide/peptidomimetic helical structures incorporating the ABOC residue (11/9-, 18/16-, 12/14/14-, and 12/10-helices). In addition, such bicyclic residue was fully compatible with and stabilized the canonical oligourea helix, whereas very few cyclic β-amino acids have been incorporated into oligoureas. In addition, we have pursued with the synthesis of some ABOC derivatives, in particular the 1,2-diaminobicyclo[2.2.2]octane chiral diamine, named DABO, and its investigation in chiral catalytic systems. Covalent organo-catalysis of the aldol reaction using ABOC-containing tripeptide catalysts provided a range of aldol products with high enantioselectivity. Moreover, the double reductive condensation of DABO with various aldehydes allowed the building of new chiral ligands that proved their efficiency in the copper-catalyzed asymmetric Henry reaction.
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Affiliation(s)
- Pierre Milbeo
- Institut des Biomolécules Max Mousseron, IBMM, University of Montpellier, ENSCM, CNRS, Montpellier, France
| | - Jean Martinez
- Institut des Biomolécules Max Mousseron, IBMM, University of Montpellier, ENSCM, CNRS, Montpellier, France
| | - Muriel Amblard
- Institut des Biomolécules Max Mousseron, IBMM, University of Montpellier, ENSCM, CNRS, Montpellier, France
| | - Monique Calmès
- Institut des Biomolécules Max Mousseron, IBMM, University of Montpellier, ENSCM, CNRS, Montpellier, France
| | - Baptiste Legrand
- Institut des Biomolécules Max Mousseron, IBMM, University of Montpellier, ENSCM, CNRS, Montpellier, France
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20
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Ikai T, Kawabata S, Mamiya F, Taura D, Ousaka N, Yashima E. Helix-Sense-Selective Encapsulation of Helical Poly(lactic acid)s within a Helical Cavity of Syndiotactic Poly(methyl methacrylate) with Helicity Memory. J Am Chem Soc 2020; 142:21913-21925. [PMID: 33315394 DOI: 10.1021/jacs.0c11204] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
We report a highly enantio- and helix-sense-selective encapsulation of helical poly(lactic acid)s (PLAs) through a unique "helix-in-helix" superstructure formation within the helical cavity of syndiotactic poly(methyl methacrylate) (st-PMMA) with a one-handed helicity memory, which enables the separation of the enantiomeric helices of the left (M)- and right (P)-handed-PLAs. The M- and P-helical PLAs with different molar masses and a narrow molar mass distribution were prepared by the ring-opening living polymerization of the optically pure l- and d-lactides, respectively, followed by end-capping of the terminal residues of the PLAs with a 4-halobenzoate and then a C60 unit, giving the C60-free and C60-bound M- and P-PLAs. The C60-free and C60-bound M- and P-PLAs formed crystalline inclusion complexes with achiral st-PMMA accompanied by a preferred-handed helix induction in the st-PMMA backbone, thereby producing helix-in-helix superstructures with the same-handedness to each other. The induced helical st-PMMAs were retained after replacement with the achiral C60, indicating the memory of the induced helicity of the st-PMMAs. Both the C60-free and C60-bound helical PLAs were enantio- and helix-sense selectively encapsulated into the helical hollow space of the optically active M- and P-st-PMMAs with the helicity memory prepared using chiral amines. The M- and P-PLAs are preferentially encapsulated within the M- and P-st-PMMA helical cavity with the same-handedness to each other, respectively, independent of the terminal units. The C60-bound PLAs were more efficiently and enantioselectively trapped in the st-PMMA compared to the C60-free PLAs. The enantioselectivities were highly dependent on the molar mass of the C60-bound and C60-free PLAs and significantly increased as the molar mass of the PLAs increased.
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Affiliation(s)
- Tomoyuki Ikai
- Department of Molecular and Macromolecular Chemistry, Graduate School of Engineering, Nagoya University, Chikusa-ku, Nagoya 464-8603, Japan
| | - Satoshi Kawabata
- Department of Molecular and Macromolecular Chemistry, Graduate School of Engineering, Nagoya University, Chikusa-ku, Nagoya 464-8603, Japan
| | - Fumihiko Mamiya
- Department of Molecular Design and Engineering, Graduate School of Engineering, Nagoya University, Chikusa-ku, Nagoya 464-8603, Japan
| | - Daisuke Taura
- Department of Molecular and Macromolecular Chemistry, Graduate School of Engineering, Nagoya University, Chikusa-ku, Nagoya 464-8603, Japan.,Department of Molecular Design and Engineering, Graduate School of Engineering, Nagoya University, Chikusa-ku, Nagoya 464-8603, Japan
| | - Naoki Ousaka
- Department of Molecular and Macromolecular Chemistry, Graduate School of Engineering, Nagoya University, Chikusa-ku, Nagoya 464-8603, Japan.,Department of Molecular Design and Engineering, Graduate School of Engineering, Nagoya University, Chikusa-ku, Nagoya 464-8603, Japan
| | - Eiji Yashima
- Department of Molecular and Macromolecular Chemistry, Graduate School of Engineering, Nagoya University, Chikusa-ku, Nagoya 464-8603, Japan.,Department of Molecular Design and Engineering, Graduate School of Engineering, Nagoya University, Chikusa-ku, Nagoya 464-8603, Japan
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21
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Song G, Jeong KS. Aromatic Helical Foldamers as Nucleophilic Catalysts for the Regioselective Acetylation of Octyl β-d-Glucopyranoside. Chempluschem 2020; 85:2475-2481. [PMID: 33206472 DOI: 10.1002/cplu.202000685] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 11/03/2020] [Indexed: 12/31/2022]
Abstract
Two indolocarbazole-naphthyridine foldamers 2 and 3 that fold into helical conformations were prepared. The 4-(N,N-dimethylamino)pyridine (DMAP) moiety was introduced at one end of the foldamer strands to develop foldamer-based catalysts for the site-selective acylation of polyols. These foldamers adopt helical conformations containing internal cavities capable of binding octyl β-d-glucopyranoside. The association constants were determined to be 1.9 (±0.1)×105 M-1 for 2 and 2.1 (±0.1)×105 M-1 for 3 in CH2 Cl2 at 25 °C. In the presence of DMAP, 2 or 3 as the catalysts, octyl β-d-glucopyranoside was subjected to acetylation under identical reaction conditions. The DMAP-catalysed reaction afforded the random distribution of the monoacetylates (6-OAc : 4-OAc : 3-OAc : 2-OAc=33 : 24 : 41 : 2). In contrast, foldamers 2 and 3 led to the predominant formation of 6-OAc. The relative distributions were estimated to be 6-OAc : 4-OAc : 3-OAc=88 : 4 : 6 : ∼0 with 2 and 6-OAc : 4-OAc : 3-OAc : 2-OAc=90 : 3 : 6 : 1 with 3.
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Affiliation(s)
- Geunmoo Song
- Department of Chemistry, Yonsei University, Seoul, 03722, Republic of Korea
| | - Kyu-Sung Jeong
- Department of Chemistry, Yonsei University, Seoul, 03722, Republic of Korea
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