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Ghosh T, Nokami T. Recent development of stereoselective C-glycosylation via generation of glycosyl radical. Carbohydr Res 2022; 522:108677. [DOI: 10.1016/j.carres.2022.108677] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 08/31/2022] [Accepted: 09/07/2022] [Indexed: 11/27/2022]
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2
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Oka N, Mori A, Suzuki K, Ando K. Stereoselective Synthesis of Ribofuranoid exo-Glycals by One-Pot Julia Olefination Using Ribofuranosyl Sulfones. J Org Chem 2021; 86:657-673. [PMID: 33225690 DOI: 10.1021/acs.joc.0c02297] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
One-pot Julia olefination using ribofuranosyl sulfones is described. The α-anomers of the ribofuranosyl sulfones were synthesized with complete α-selectivity via the glycosylation of heteroarylthiols using ribofuranosyl iodides as glycosyl donors and the subsequent oxidation of the resulting heteroaryl 1-thioribofuranosides with magnesium monoperphthalate (MMPP). The Julia olefination of the α-ribofuranosyl sulfones with aldehydes proceeded smoothly in one pot to afford the thermodynamically less stable (E)-exo-glycals with modest-to-excellent stereoselectivity (up to E/Z = 94:6) under the optimized conditions. The E selectivity was especially high for aromatic aldehydes. In contrast, the (Z)-exo-glycal was obtained as the main product with low stereoselectivity when the corresponding β-ribofuranosyl sulfone was used (E/Z = 41:59). The remarkable impact of the anomeric configuration of the ribofuranosyl sulfones on the stereoselectivity of the Julia olefination has been rationalized using density functional theory (DFT) calculations. The protected ribose moiety of the resulting exo-glycals induced completely α-selective cyclopropanation on the exocyclic carbon-carbon double bond via the Simmons-Smith-Furukawa reaction. The 2-cyanoethyl group was found to be useful for the protection of the exo-glycals, as it could be removed without affecting the exocyclic C═C bond.
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Affiliation(s)
- Natsuhisa Oka
- Institute for Glyco-core Research (iGCORE), Tokai National Higher Education and Research System Furo-cho, Gifu University, Chikusa-ku, Nagoya 464-8601, Japan
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3
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Bege M, Bereczki I, Molnár DJ, Kicsák M, Pénzes-Daku K, Bereczky Z, Ferenc G, Kovács L, Herczegh P, Borbás A. Synthesis and oligomerization of cysteinyl nucleosides. Org Biomol Chem 2020; 18:8161-8178. [PMID: 33020786 DOI: 10.1039/d0ob01890b] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Nucleoside and nucleic acid analogues are known to possess a considerable therapeutic potential. In this work, by coupling cysteine to nucleosides, we successfully synthesized compounds that may not only have interesting biological properties in their monomeric form, but can be used beyond that, for oligomerization, in order to produce new types of synthetic nucleic acids. We elaborated different strategies for the synthesis of cysteinyl nucleosides as monomers of cysteinyl nucleic acids using nucleophilic substitution or thiol-ene coupling as a synthetic tool, and utilised on two complementary nucleosides, uridine and adenosine. Dipeptidyl dinucleosides and pentameric cysteinyl uridine were prepared from the monomeric building blocks, which are the first members of a new class of peptide nucleic acids containing the entire ribofuranosyl nucleoside units bound to the peptide backbone.
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Affiliation(s)
- Miklós Bege
- Department of Pharmaceutical Chemistry, University of Debrecen, Debrecen, H-4032, Hungary. and Doctoral School of Pharmaceutical Sciences, University of Debrecen, Debrecen, H-4032, Hungary and MTA-DE Molecular Recognition and Interaction Research Group, University of Debrecen, Debrecen, H-4032, Hungary
| | - Ilona Bereczki
- Department of Pharmaceutical Chemistry, University of Debrecen, Debrecen, H-4032, Hungary.
| | - Dénes J Molnár
- Department of Pharmaceutical Chemistry, University of Debrecen, Debrecen, H-4032, Hungary.
| | - Máté Kicsák
- Department of Pharmaceutical Chemistry, University of Debrecen, Debrecen, H-4032, Hungary.
| | - Krisztina Pénzes-Daku
- Division of Clinical Laboratory Science, University of Debrecen, Debrecen, H-4032, Hungary
| | - Zsuzsanna Bereczky
- Division of Clinical Laboratory Science, University of Debrecen, Debrecen, H-4032, Hungary
| | - Györgyi Ferenc
- Nucleic Acid Synthesis Laboratory, Biological Research Center, Szeged, H-6726, Hungary
| | - Lajos Kovács
- Nucleic Acids Laboratory, Department of Medicinal Chemistry, University of Szeged, H-6720 Szeged, Hungary
| | - Pál Herczegh
- Department of Pharmaceutical Chemistry, University of Debrecen, Debrecen, H-4032, Hungary.
| | - Anikó Borbás
- Department of Pharmaceutical Chemistry, University of Debrecen, Debrecen, H-4032, Hungary.
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4
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Borbás A. Photoinitiated Thiol-ene Reactions of Enoses: A Powerful Tool for Stereoselective Synthesis of Glycomimetics with Challenging Glycosidic Linkages. Chemistry 2020; 26:6090-6101. [PMID: 31910299 PMCID: PMC7317871 DOI: 10.1002/chem.201905408] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 01/03/2020] [Indexed: 12/21/2022]
Abstract
Thioglycosides and C-glycosides represent pharmacologically useful classes of glycomimetics that possess a high degree of biological stability. One emerging tool for the stereoselective synthesis of thioglycosides is the photoinitiated addition of thiols to unsaturated sugars. Moreover, thiyl radical-mediated reactions of exo-glycals and 1-substituted endo-glycals offer facile routes to β-C-glycosidic structures. This Concept article summarizes the thiol-ene coupling strategies developed recently by our group and Somsák's group for the synthesis of several kinds of glycomimetics which are difficult to synthesize by conventional methods. One unusual characteristic of the thiol-ene reactions of endo-glycals is that heating inhibits, whereas cooling promotes the reaction. This unique temperature dependence as well as the effects of the enose structures and thiol configurations on the efficacy and stereoselectivity of the reactions are also discussed.
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Affiliation(s)
- Anikó Borbás
- Department of Pharmaceutical ChemistryUniversity of DebrecenEgyetem tér 14032DebrecenHungary
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Csávás M, Eszenyi D, Mező E, Lázár L, Debreczeni N, Tóth M, Somsák L, Borbás A. Stereoselective Synthesis of Carbon-Sulfur-Bridged Glycomimetics by Photoinitiated Thiol-Ene Coupling Reactions. Int J Mol Sci 2020; 21:ijms21020573. [PMID: 31963149 PMCID: PMC7013897 DOI: 10.3390/ijms21020573] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 01/13/2020] [Accepted: 01/15/2020] [Indexed: 12/12/2022] Open
Abstract
Oligosaccharides and glycoconjugates are abundant in all living organisms, taking part in a multitude of biological processes. The application of natural O-glycosides in biological studies and drug development is limited by their sensitivity to enzymatic hydrolysis. This issue made it necessary to design hydrolytically stable carbohydrate mimetics, where sulfur, carbon, or longer interglycosidic connections comprising two or three atoms replace the glycosidic oxygen. However, the formation of the interglycosidic linkages between the sugar residues in high diastereoslectivity poses a major challenge. Here, we report on stereoselective synthesis of carbon-sulfur-bridged disaccharide mimetics by the free radical addition of carbohydrate thiols onto the exo-cyclic double bond of unsaturated sugars. A systematic study on UV-light initiated radical mediated hydrothiolation reactions of enoses bearing an exocyclic double bond at C1, C2, C3, C4, C5, and C6 positions of the pyranosyl ring with various sugar thiols was performed. The effect of temperature and structural variations of the alkenes and thiols on the efficacy and stereoselectivity of the reactions was systematically studied and optimized. The reactions proceeded with high efficacy and, in most cases, with complete diastereoselectivity producing a broad array of disaccharide mimetics coupling through an equatorially oriented methylensulfide bridge.
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Affiliation(s)
- Magdolna Csávás
- Department of Pharmaceutical Chemistry University of Debrecen, Egyetem tér 1, H-4032 Debrecen, Hungary; (M.C.); (D.E.); (E.M.); (N.D.)
| | - Dániel Eszenyi
- Department of Pharmaceutical Chemistry University of Debrecen, Egyetem tér 1, H-4032 Debrecen, Hungary; (M.C.); (D.E.); (E.M.); (N.D.)
| | - Erika Mező
- Department of Pharmaceutical Chemistry University of Debrecen, Egyetem tér 1, H-4032 Debrecen, Hungary; (M.C.); (D.E.); (E.M.); (N.D.)
| | - László Lázár
- Department of Organic Chemistry, University of Debrecen, Egyetem tér 1, H-4032 Debrecen, Hungary; (L.L.); (M.T.); (L.S.)
| | - Nóra Debreczeni
- Department of Pharmaceutical Chemistry University of Debrecen, Egyetem tér 1, H-4032 Debrecen, Hungary; (M.C.); (D.E.); (E.M.); (N.D.)
- Doctoral School of Chemistry, University of Debrecen, Egyetem tér 1, H-4032 Debrecen, Hungary
| | - Marietta Tóth
- Department of Organic Chemistry, University of Debrecen, Egyetem tér 1, H-4032 Debrecen, Hungary; (L.L.); (M.T.); (L.S.)
| | - László Somsák
- Department of Organic Chemistry, University of Debrecen, Egyetem tér 1, H-4032 Debrecen, Hungary; (L.L.); (M.T.); (L.S.)
| | - Anikó Borbás
- Department of Pharmaceutical Chemistry University of Debrecen, Egyetem tér 1, H-4032 Debrecen, Hungary; (M.C.); (D.E.); (E.M.); (N.D.)
- Correspondence: ; Tel.: +36-52-512900-22472
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József J, Debreczeni N, Eszenyi D, Borbás A, Juhász L, Somsák L. Synthesis and photoinitiated thiol–ene reactions of exo-mannals – a new route to C-β-d-mannosyl derivatives. RSC Adv 2020; 10:34825-34836. [PMID: 35514420 PMCID: PMC9056834 DOI: 10.1039/d0ra07115c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Accepted: 09/06/2020] [Indexed: 01/19/2023] Open
Abstract
Syntheses of acyl protected exo-mannal derivatives were developed starting from O-peracylated mannopyranoses via the corresponding anhydro-aldose tosylhydrazones under modified Bamford–Stevens conditions. The synthesis of analogous O-peralkylated (benzylated and isopropylenated) derivatives was carried out from pyranoid and furanoid mannonolactones using methylene transfer reagents. Photoinitiated thiol–ene additions of these exo-mannals resulted in the corresponding C-(mannopyranosyl/mannofuranosyl)methyl sulfides in medium to good yields with exclusive regio- and β(d) stereoselectivities. A synthetic procedure was elaborated for O-peracylated exo-mannals. Thiol-ene additions to pyranoid and furanoid exo-mannals gave mannosylmethyl sulfide type adducts with exclusive regio- and β(d)-stereoselectivities including disaccharide mimetics.![]()
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Affiliation(s)
- János József
- Department of Organic Chemistry
- University of Debrecen
- H-4002 Debrecen
- Hungary
- University of Debrecen
| | - Nóra Debreczeni
- Department of Pharmaceutical Chemistry
- University of Debrecen
- H-4002 Debrecen
- Hungary
- University of Debrecen
| | - Dániel Eszenyi
- Department of Pharmaceutical Chemistry
- University of Debrecen
- H-4002 Debrecen
- Hungary
| | - Anikó Borbás
- Department of Pharmaceutical Chemistry
- University of Debrecen
- H-4002 Debrecen
- Hungary
| | - László Juhász
- Department of Organic Chemistry
- University of Debrecen
- H-4002 Debrecen
- Hungary
| | - László Somsák
- Department of Organic Chemistry
- University of Debrecen
- H-4002 Debrecen
- Hungary
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Ho HE, Pagano A, Rossi-Ashton JA, Donald JR, Epton RG, Churchill JC, James MJ, O'Brien P, Taylor RJK, Unsworth WP. Visible-light-induced intramolecular charge transfer in the radical spirocyclisation of indole-tethered ynones. Chem Sci 2019; 11:1353-1360. [PMID: 34123259 PMCID: PMC8148050 DOI: 10.1039/c9sc05311e] [Citation(s) in RCA: 69] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Indole-tethered ynones form an intramolecular electron donor–acceptor complex that can undergo visible-light-induced charge transfer to promote thiyl radical generation from thiols. This initiates a novel radical chain sequence, based on dearomatising spirocyclisation with concomitant C–S bond formation. Sulfur-containing spirocycles are formed in high yields using this simple and mild synthetic protocol, in which neither transition metal catalysts nor photocatalysts are required. The proposed mechanism is supported by various mechanistic studies, and the unusual radical initiation mode represents only the second report of the use of an intramolecular electron donor–acceptor complex in synthesis. Indole-tethered ynones form an intramolecular electron donor–acceptor complex that can undergo visible-light-induced charge transfer to promote thiyl radical generation from thiols.![]()
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Affiliation(s)
- Hon Eong Ho
- Department of Chemistry, University of York York YO10 5DD UK
| | - Angela Pagano
- Department of Chemistry and Industrial Chemistry, University of Genova via Dodecaneso, 31 16146 Genova Italy
| | | | - James R Donald
- Department of Chemistry, University of York York YO10 5DD UK
| | - Ryan G Epton
- Department of Chemistry, University of York York YO10 5DD UK
| | | | - Michael J James
- Department of Chemistry, University of York York YO10 5DD UK
| | - Peter O'Brien
- Department of Chemistry, University of York York YO10 5DD UK
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Kelemen V, Bege M, Eszenyi D, Debreczeni N, Bényei A, Stürzer T, Herczegh P, Borbás A. Stereoselective Thioconjugation by Photoinduced Thiol-ene Coupling Reactions of Hexo- and Pentopyranosyl d- and l-Glycals at Low-Temperature-Reactivity and Stereoselectivity Study. Chemistry 2019; 25:14555-14571. [PMID: 31368604 PMCID: PMC6900028 DOI: 10.1002/chem.201903095] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2019] [Revised: 07/31/2019] [Indexed: 12/17/2022]
Abstract
A comprehensive optimization and mechanistic study on the photoinduced hydrothiolation of different d- and l- hexo- and pentoglycals with various thiols was performed, at the temperature range of RT to -120 °C. Addition of thiols onto 2-substituted hexoglycals proceeded with complete 1,2-cis-α-stereoselectivity in all cases. Hydrothiolation of 2-substituted pentoglycals resulted in mixtures of 1,2-cis-α- and -β-thioglycosides of varying ratio depending on the configuration of the reactants. Hydrothiolation of unsubstituted glycals at -80 °C proceeded with excellent yields and, except for galactal, provided the axially C2-S-linked isomers with high selectivity. Cooling was always beneficial to the efficacy, increased the yields and in most cases significantly raised the stereoselectivity. The suggested mechanism explains the different conformational preferences of the intermediate carbon-centered radicals, which is a crucial factor in the stereoselectivity of the reactions.
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Affiliation(s)
- Viktor Kelemen
- Department of Pharmaceutical ChemistryUniversity of DebrecenEgyetem tér 14032DebrecenHungary
- Doctoral School of Pharmaceutical SciencesUniversity of DebrecenEgyetem tér 14032DebrecenHungary
| | - Miklós Bege
- Department of Pharmaceutical ChemistryUniversity of DebrecenEgyetem tér 14032DebrecenHungary
- MTA-DE Molecular Recognition and Interaction Research GroupUniversity of DebrecenEgyetem tér 14032DebrecenHungary
| | - Dániel Eszenyi
- Department of Pharmaceutical ChemistryUniversity of DebrecenEgyetem tér 14032DebrecenHungary
| | - Nóra Debreczeni
- Department of Pharmaceutical ChemistryUniversity of DebrecenEgyetem tér 14032DebrecenHungary
- Doctoral School of ChemistryUniversity of DebrecenEgyetem tér 14032DebrecenHungary
| | - Attila Bényei
- Department of Physical ChemistryUniversity of DebrecenEgyetem tér 14032DebrecenHungary
| | - Tobias Stürzer
- Bruker AXS GmbHÖstliche Rheinbrückenstraße 4976187KarlsruheGermany
| | - Pál Herczegh
- Department of Pharmaceutical ChemistryUniversity of DebrecenEgyetem tér 14032DebrecenHungary
| | - Anikó Borbás
- Department of Pharmaceutical ChemistryUniversity of DebrecenEgyetem tér 14032DebrecenHungary
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9
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Sánchez-Fernández EM, García-Moreno MI, García-Hernández R, Padrón JM, García Fernández JM, Gamarro F, Ortiz Mellet C. Thiol-ene "Click" Synthesis and Pharmacological Evaluation of C-Glycoside sp 2-Iminosugar Glycolipids. Molecules 2019; 24:E2882. [PMID: 31398901 PMCID: PMC6720825 DOI: 10.3390/molecules24162882] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 08/05/2019] [Accepted: 08/07/2019] [Indexed: 12/30/2022] Open
Abstract
The unique stereoelectronic properties of sp2-iminosugars enable their participation in glycosylation reactions, thereby behaving as true carbohydrate chemical mimics. Among sp2-iminosugar conjugates, the sp2-iminosugar glycolipids (sp2-IGLs) have shown a variety of interesting pharmacological properties ranging from glycosidase inhibition to antiproliferative, antiparasitic, and anti-inflammatory activities. Developing strategies compatible with molecular diversity-oriented strategies for structure-activity relationship studies was therefore highly wanted. Here we show that a reaction sequence consisting in stereoselective C-allylation followed by thiol-ene "click" coupling provides a very convenient access to α-C-glycoside sp2-IGLs. Both the glycone moiety and the aglycone tail can be modified by using sp2-iminosugar precursors with different configurational profiles (d-gluco or d-galacto in this work) and varied thiols, as well as by oxidation of the sulfide adducts (to the corresponding sulfones in this work). A series of derivatives was prepared in this manner and their glycosidase inhibitory, antiproliferative and antileishmanial activities were evaluated in different settings. The results confirm that the inhibition of glycosidases, particularly α-glucosidase, and the antitumor/leishmanicidal activities are unrelated. The data are also consistent with the two later activities arising from the ability of the sp2-IGLs to interfere in the immune system response in a cell line and cell context dependent manner.
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Affiliation(s)
- Elena M Sánchez-Fernández
- Department of Organic Chemistry, Faculty of Chemistry, University of Seville, C/Profesor García González 1, 41012 Seville, Spain.
| | - M Isabel García-Moreno
- Department of Organic Chemistry, Faculty of Chemistry, University of Seville, C/Profesor García González 1, 41012 Seville, Spain
| | - Raquel García-Hernández
- Instituto de Parasitología y Biomedicina "López-Neyra", IPBLN-CSIC, Parque Tecnológico de Ciencias de la Salud, 18016 Granada, Spain
| | - José M Padrón
- BioLab, Instituto Universitario de Bio-Orgánica Antonio González (IUBO AG), Centro de Investigaciones Biomédicas de Canarias (CIBCAN), Universidad de La Laguna, 38206 La Laguna, Spain
| | - José M García Fernández
- Instituto de Investigaciones Químicas (IIQ), CSIC - University of Sevilla, Avda. Américo Vespucio 49, 41092 Sevilla, Spain
| | - Francisco Gamarro
- Instituto de Parasitología y Biomedicina "López-Neyra", IPBLN-CSIC, Parque Tecnológico de Ciencias de la Salud, 18016 Granada, Spain
| | - Carmen Ortiz Mellet
- Department of Organic Chemistry, Faculty of Chemistry, University of Seville, C/Profesor García González 1, 41012 Seville, Spain.
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10
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Abstract
Abstract
Glycomimetics are compounds that resemble carbohydrate molecules in their chemical structure and/or biological effect. A large variety of compounds can be designed and synthesized to get glycomimetics, however, C-glycosyl derivatives represent one of the most frequently studied subgroup. In the present survey syntheses of a range of five- and six membered C-glycopyranosyl heterocycles, anhydro-aldimine type compounds, exo-glycals, C-glycosyl styrenes, carbon-sulfur bonded oligosaccharide mimics are described. Some of the C-glycopyranosyl azoles, namely 1,2,4-triazoles and imidazoles belong to the most efficient glucose analog inhibitors of glycogen phosphorylase known to date. Biological studies revealed the therapeutical potential of such inhibitors. Other synthetic derivatives offer versatile possibilities to get further glycomimetics.
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