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Jeanneret RA, Johnson SE, Galan MC. Conformationally Constrained Glycosyl Donors as Tools to Control Glycosylation Outcomes. J Org Chem 2020; 85:15801-15826. [DOI: 10.1021/acs.joc.0c02045] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Robin A. Jeanneret
- School of Chemistry, University of Bristol, Cantock’s
Close, Bristol BS8 1TS, United Kingdom
| | - Simon E. Johnson
- School of Chemistry, University of Bristol, Cantock’s
Close, Bristol BS8 1TS, United Kingdom
| | - M. Carmen Galan
- School of Chemistry, University of Bristol, Cantock’s
Close, Bristol BS8 1TS, United Kingdom
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2
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Shuto S. [Medicinal Chemical Studies Based on the Theoretical Design of Bioactive Compounds]. YAKUGAKU ZASSHI 2020; 140:329-344. [PMID: 32115550 DOI: 10.1248/yakushi.19-00208] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
I have engaged in medicinal chemical studies based on the theoretical design of bioactive compounds. First, I present a three-dimensional structural diversity-oriented conformational restriction strategy for developing bioactive compounds based on the characteristic steric and stereoelectronic features of cyclopropane. Using this strategy, various biologically active small molecule compounds, such as receptor agonists/antagonists and enzyme inhibitors, were effectively developed. The strategy was also applied to develop versatile peptidomimetics and membrane-permeable cyclic peptides. Next, studies on Ca2+-mobilizing second messengers, cyclic ADP-ribose (cADPR) and myo-inositol trisphosphates (IP3), are described. In these studies, stable equivalents of cADPR were developed, since biological studies of cADPR have been limited due to its instability. Various potent IP3 receptor ligands, which were designed using the d-glucose structure as a bioisostere of the myo-inositol moiety of IP3, have been identified. Organic chemistry studies have also been extensively performed, because excellent organic chemistry is essential for promoting high-level medicinal chemical studies. For examples, new methods for the synthesis of chiral cyclopropanes, new radical reactions with silicon tethers, and kinetic anomeric effect-dependent stereoselective glycosidations have been developed.
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Affiliation(s)
- Satoshi Shuto
- Faculty of Pharmaceutical Sciences, Hokkaido University
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3
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Affiliation(s)
- You Yang
- Shanghai
Key Laboratory of New Drug Design, School of Pharmacy, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China
| | - Biao Yu
- State
Key Laboratory of Bio-organic and Natural Products Chemistry, Shanghai
Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
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4
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Vibhute AM, Pushpanandan P, Varghese M, Koniecnzy V, Taylor CW, Sureshan KM. Synthesis of dimeric analogs of adenophostin A that potently evoke Ca 2+ release through IP 3 receptors. RSC Adv 2016; 6:86346-86351. [PMID: 28066549 PMCID: PMC5171214 DOI: 10.1039/c6ra19413c] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Accepted: 09/05/2016] [Indexed: 11/21/2022] Open
Abstract
Syntheses and Ca2+ release potentials of four dimeric analogs of adenophostin A (AdA) through activation of type 1 IP3R are reported. These analogs are full agonists of IP3R and are equipotent to AdA, the most potent agonist of IP3R.
Inositol 1,4,5-trisphosphate receptors (IP3Rs) are tetrameric intracellular channels through which many extracellular stimuli initiate the Ca2+ signals that regulate diverse cellular responses. There is considerable interest in developing novel ligands of IP3R. Adenophostin A (AdA) is a potent agonist of IP3R and since some dimeric analogs of IP3R ligands are more potent than the corresponding monomer; we considered whether dimeric AdA analogs might provide agonists with increased potency. We previously synthesized traizolophostin, in which a simple triazole replaced the adenine of AdA, and showed it to be equipotent to AdA. Here, we used click chemistry to synthesize four homodimeric analogs of triazolophostin, connected by oligoethylene glycol chains of different lengths. We evaluated the potency of these analogs to release Ca2+ through type 1 IP3R and established that the newly synthesized dimers are equipotent to AdA and triazolophostin.
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Affiliation(s)
- Amol M Vibhute
- School of Chemistry , Indian Institute of Science Education and Research Thiruvananthapuram , Kerala 695016 , India . ; http://kms514.wix.com/kmsgroup
| | - Poornenth Pushpanandan
- School of Chemistry , Indian Institute of Science Education and Research Thiruvananthapuram , Kerala 695016 , India . ; http://kms514.wix.com/kmsgroup
| | - Maria Varghese
- School of Chemistry , Indian Institute of Science Education and Research Thiruvananthapuram , Kerala 695016 , India . ; http://kms514.wix.com/kmsgroup
| | - Vera Koniecnzy
- Department of Pharmacology , University of Cambridge , Tennis Court Road , Cambridge , CB2 1PD , UK
| | - Colin W Taylor
- Department of Pharmacology , University of Cambridge , Tennis Court Road , Cambridge , CB2 1PD , UK
| | - Kana M Sureshan
- School of Chemistry , Indian Institute of Science Education and Research Thiruvananthapuram , Kerala 695016 , India . ; http://kms514.wix.com/kmsgroup
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5
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Vibhute AM, Konieczny V, Taylor CW, Sureshan KM. Triazolophostins: a library of novel and potent agonists of IP3 receptors. Org Biomol Chem 2016; 13:6698-710. [PMID: 25869535 PMCID: PMC4533600 DOI: 10.1039/c5ob00440c] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
IP3R initiate most cellular Ca2+ signaling. AdA is the most potent agonist of IP3R. The structural complexity of AdA makes synthesis of its analogs cumbersome. We report an easy method for generating a library of potent triazole-based analogs of AdA, triazolophostins, which are the most potent AdA analogs devoid of a nucleobase.
IP3 receptors are channels that mediate the release of Ca2+ from the intracellular stores of cells stimulated by hormones or neurotransmitters. Adenophostin A (AdA) is the most potent agonist of IP3 receptors, with the β-anomeric adenine contributing to the increased potency. The potency of AdA and its stability towards the enzymes that degrade IP3 have aroused interest in AdA analogs for biological studies. The complex structure of AdA poses problems that have necessitated optimization of synthetic conditions for each analog. Such lengthy one-at-a-time syntheses limit access to AdA analogs. We have addressed this problem by synthesizing a library of triazole-based AdA analogs, triazolophostins, by employing click chemistry. An advanced intermediate having all the necessary phosphates and a β-azide at the anomeric position was reacted with various alkynes under Cu(i) catalysis to yield triazoles, which upon deprotection gave triazolophostins. All eleven triazolophostins synthesized are more potent than IP3 and some are equipotent with AdA in functional analyses of IP3 receptors. We show that a triazole ring can replace adenine without compromising the potency of AdA and provide facile routes to novel AdA analogs.
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Affiliation(s)
- Amol M Vibhute
- School of Chemistry, Indian Institute of Science Education and Research, Thiruvananthapuram, Kerala-695016, India.
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6
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Nowacki A, Myszka H, Liberek B. Conformational studies of diosgenyl 2-amino-2-deoxy-β-d-glucopyranosides at the PM3 and DFT levels of theory. Carbohydr Res 2013; 377:4-13. [DOI: 10.1016/j.carres.2013.05.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2013] [Revised: 05/17/2013] [Accepted: 05/18/2013] [Indexed: 10/26/2022]
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7
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Kraft MB, Martinez Farias MA, Kiessling LL. Synthesis of lipid-linked arabinofuranose donors for glycosyltransferases. J Org Chem 2013; 78:2128-33. [PMID: 23373821 DOI: 10.1021/jo302507p] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Mycobacteria and corynebacteria use decaprenylphosphoryl-β-D-arabinofuranose (DPA) as a critical cell wall building block. Arabinofuranosyltransferases that process this substrate to mediate cell wall assembly have served as drug targets, but little is known about the substrate specificity of any of these enzymes. To probe substrate recognition of DPA, we developed a general and efficient synthetic route to β-D-arabinofuranosyl phosphodiesters. In this approach, the key glycosyl phosphodiester bond-forming reaction proceeds with high β-selectivity. In addition to its stereoselectivity, our route provides the means to readily access a variety of different lipid analogues, including aliphatic and polyprenyl substrates.
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Affiliation(s)
- Matthew B Kraft
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
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8
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Matsuda A. [Development of highly nuclease-resistant chemically-modified oligonucleotides]. YAKUGAKU ZASSHI 2011; 131:285-98. [PMID: 21297374 DOI: 10.1248/yakushi.131.285] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Chemical modification of therapeutic oligodeoxyribonucleotides (ODNs) is necessary to avoid not only degradation by endo- and exo-nucleases but also recognition by sensors such as an innate immune system. We have been developing modified nucleosides having an aminoalky linker at the pyrimidine nucleobase or sugar moiety. ODNs containing 5-N-(6-aminohexyl)carbamoyl-2'-deoxyuridine (7) were thermally stabilized about 3°C per modification and were about 160 times more stable to hydrolysis by snake venom phosphodiesterase (a 3'-exonuclease) than unmodified ODNs, but not by endonucleases. On the other hand, ODNs containing 4'-C-(aminoethyl)thymidine (14b), which was synthesized by a newly developed radical cyclization-ring-enlargement reaction by us, were 87 times more stable to hydrolysis by DNase I (an endonuclease) and 133 times more stable in 50% human serum than unmodified ODNs. The highly stereoselective synthesis of 4'-thioribonuclesides ((S)Ns) was also developed using a Pummerer reaction. Human thrombin RNA aptamer (CII-1-37) containing 4'-thiouridine and 4'-thiocytidine was obtained by SELEX with a K(d) value of 4.7 nM, while a previously known RNA aptamer (RNA-24) has a K(d) value of 85 nM. Studies of the modification pattern-RNAi activity relationships by using (S)Ns have been carried out against luciferase genes. We found that siRNAs, which have 4 residues of (S)Ns on both ends of the sense strand and 4 residues on the 3'-end of the antisense strand, were the most effective. 4'-ThioRNA is about 1100 times more stable in 50% human plasma than unmodified RNA. However, oligoribonucleotides ((SM)ONs) containing 2'-O-methyl-4'-thioribonucleosides were 9800 times more stable in 50% human plasma than unmodified RNA. Since (SM)ON duplexes were thermally more stable than unmodified ON duplexes, therefore they would be quite suitable to use for oligonucleotide therapeutics.
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Affiliation(s)
- Akira Matsuda
- Faculty of Pharmaceutical Sciences, Hokkaido University.
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10
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Di Bussolo V, Fiasella A, Balzano F, Uccello Barretta G, Crotti P. Stereoselective synthesis of beta-phenylselenoglycosides from glycals and rationalization of the selenoglycosylation processes. J Org Chem 2010; 75:4284-7. [PMID: 20476760 DOI: 10.1021/jo100145s] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Beta-phenylselenoglycosides have been efficiently and stereoselectively synthesized by direct oxidative glycosylation of benzenselenolate (PhSe(-)) with glycals. A rationalization of the presently described beta-selectivity and the opposite alpha-selectivity reported by Danishefsky in the ring-opening of epoxy glycals with benzeneselenol (PhSeH) is proposed.
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Affiliation(s)
- Valeria Di Bussolo
- Dipartimento di Scienze Farmaceutiche, sede Chimica Biorganica e Biofarmacia, Università di Pisa,Via Bonanno 33, 56126 Pisa, Italy.
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11
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Duplessis M, Waltz ME, Bencheqroun M, Cardinal-David B, Guindon Y. Stereoselective Quaternary Center Construction via Atom-Transfer Radical Cyclization Using Silicon Tethers on Acyclic Precursors. Org Lett 2009; 11:3148-51. [DOI: 10.1021/ol901126y] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Martin Duplessis
- Institut de recherches cliniques de Montréal (IRCM), Bio-organic Chemistry Laboratory, 110 avenue des Pins Ouest, Montréal, Québec, Canada H2W 1R7, Department of Chemistry, Université de Montréal, C.P. 6128, succursale Centre-Ville, Montréal, Québec, Canada H3C 3J7, and Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montréal, Québec, Canada H3A 2K6
| | - Marie-Eve Waltz
- Institut de recherches cliniques de Montréal (IRCM), Bio-organic Chemistry Laboratory, 110 avenue des Pins Ouest, Montréal, Québec, Canada H2W 1R7, Department of Chemistry, Université de Montréal, C.P. 6128, succursale Centre-Ville, Montréal, Québec, Canada H3C 3J7, and Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montréal, Québec, Canada H3A 2K6
| | - Mohammed Bencheqroun
- Institut de recherches cliniques de Montréal (IRCM), Bio-organic Chemistry Laboratory, 110 avenue des Pins Ouest, Montréal, Québec, Canada H2W 1R7, Department of Chemistry, Université de Montréal, C.P. 6128, succursale Centre-Ville, Montréal, Québec, Canada H3C 3J7, and Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montréal, Québec, Canada H3A 2K6
| | - Benoit Cardinal-David
- Institut de recherches cliniques de Montréal (IRCM), Bio-organic Chemistry Laboratory, 110 avenue des Pins Ouest, Montréal, Québec, Canada H2W 1R7, Department of Chemistry, Université de Montréal, C.P. 6128, succursale Centre-Ville, Montréal, Québec, Canada H3C 3J7, and Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montréal, Québec, Canada H3A 2K6
| | - Yvan Guindon
- Institut de recherches cliniques de Montréal (IRCM), Bio-organic Chemistry Laboratory, 110 avenue des Pins Ouest, Montréal, Québec, Canada H2W 1R7, Department of Chemistry, Université de Montréal, C.P. 6128, succursale Centre-Ville, Montréal, Québec, Canada H3C 3J7, and Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montréal, Québec, Canada H3A 2K6
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12
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Nowacki A, Liberek B. Methyl 3-Amino-2,3,6,-trideoxy-l-hexopyranosides in DFT Level Theory Conformational Studies. J Phys Chem A 2008; 112:7072-9. [DOI: 10.1021/jp802248d] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Andrzej Nowacki
- Faculty of Chemistry, University of Gdańsk, Sobieskiego 18, PL-80-952 Gdańsk, Poland
| | - Beata Liberek
- Faculty of Chemistry, University of Gdańsk, Sobieskiego 18, PL-80-952 Gdańsk, Poland
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13
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Herrera AJ, Rondón M, Suárez E. Stereocontrolled Photocyclization of 1,2-Diketones: Application of a 1,3-Acetyl Group Transfer Methodology to Carbohydrates. J Org Chem 2008; 73:3384-91. [DOI: 10.1021/jo702663w] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Antonio J. Herrera
- Instituto de Productos Naturales y Agrobiología del C.S.I.C. Carretera de La Esperanza 3, 38206 La Laguna, Tenerife, Spain
| | - María Rondón
- Instituto de Productos Naturales y Agrobiología del C.S.I.C. Carretera de La Esperanza 3, 38206 La Laguna, Tenerife, Spain
| | - Ernesto Suárez
- Instituto de Productos Naturales y Agrobiología del C.S.I.C. Carretera de La Esperanza 3, 38206 La Laguna, Tenerife, Spain
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14
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Angyal SJ, Anderson JE, Craig DC. Inositols: The Effect of Bulky Substituents on Conformations. Aust J Chem 2007. [DOI: 10.1071/ch07092] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Inositols have been converted into their triphenylsilyl derivatives. In all cases only five substituents could be introduced, the remaining free hydroxy group being hindered. The derivative of myo-inositol and one of two of neo-inositol were found to be in the inverted chair conformation, but those of other inositols are in the normal chair form. The structures of two penta-substituted derivatives have been determined by X-ray crystallography.
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15
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Terauchi M, Yahiro Y, Abe H, Ichikawa S, Tovey SC, Dedos SG, Taylor CW, Potter BV, Matsuda A, Shuto S. Synthesis of 4,8-anhydro-d-glycero-d-ido-nonanitol 1,6,7-trisphosphate as a novel IP3 receptor ligand using a stereoselective radical cyclization reaction based on a conformational restriction strategy. Tetrahedron 2005. [DOI: 10.1016/j.tet.2005.02.025] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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16
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Mohal N, Vasella A. Synthesis of Fusion-Isomeric Imidazopyridines and Their Evaluation as Inhibitors ofsyn- andanti-Protonating Glycosidases. Helv Chim Acta 2005. [DOI: 10.1002/hlca.200490287] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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17
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Terauchi M, Abe H, Matsuda A, Shuto S. An Efficient Synthesis of β-C-Glycosides Based on the Conformational Restriction Strategy: Lewis Acid Promoted Silane Reduction of the Anomeric Position with Complete Stereoselectivity. Org Lett 2004; 6:3751-4. [PMID: 15469340 DOI: 10.1021/ol048525+] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
[reaction: see text] The reduction of glyconolactols having an anomeric carbon substituent by Et(3)SiH/TMSOTf proceeded with complete stereoselectivity to produce the corresponding beta-C-glycosides when the substrates were conformationally restricted in the (4)C(1)-chair form by a 3,4-O-cyclic diketal or a 4,6-O-benzylidene protecting group. Thus, the efficient construction of beta-C-glycosides was achieved on the basis of the conformation restriction strategy.
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Affiliation(s)
- Masaru Terauchi
- Graduate School of Pharmaceutical Sciences, Hokkaido University, Kita-12, Nishi-6, Kita-ku, Sapporo 060-0812, Japan
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18
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Diisobutylaluminium hydride (DIBAL-H) as a molecular scalpel: a new mechanistic proposal for a spiroketal rearrangement. Tetrahedron Lett 2004. [DOI: 10.1016/j.tetlet.2004.09.030] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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19
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Beignet J, Tiernan J, Woo CH, Kariuki BM, Cox LR. Stereoselective Synthesis of Allyl-C-mannosyl Compounds: Use of a Temporary Silicon Connection in Intramolecular Allylation Strategies with Allylsilanes. J Org Chem 2004; 69:6341-56. [PMID: 15357594 DOI: 10.1021/jo049061w] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Methyl mannoside 16 containing an allyldimethylsilyl ether at C(2) was synthesized in nine steps from D-mannose. Reaction with TMSOTf in MeCN at room-temperature effected C-glycosylation to provide the alpha-allyl-C-mannosyl product 18 with excellent stereoselectivity. Crossover experiments over a range of reaction concentrations proved that reaction was proceeding via an intermolecular pathway rather than the hoped-for intramolecular delivery route. The exceptionally high stereoselectivity of this allylation in the presence of an acid-scavenger, 2,6-DTBMP, can be attributed to the allylsilyl ether 16 behaving as the allylating agent. Geometrical constraints in the seven-membered ring transition state account for the lack of intramolecular allyl transfer. Attaching a modified allylsilane 29a-c to C(2)OH of methyl mannoside 15 improved matters. Reaction of the tethered mannosides 27a-c with TMSOTf in the presence of 2,6-DTBMP in MeCN at rt provided a range of products, which depended on the size of the alkyl substituents at the silyl ether tether. Diene products were the major compounds irrespective of the size of the alkyl substituents at the silyl ether tether. Their formation can be understood by intramolecular allylation of the allylsilane on to the activated anomeric center, followed by collapse of the intermediate carbocation by preferential attack of an external nucleophile at the silyl ether tether, rather than at the allylic silicon center. A cascade of further reactions rationalizes the formation of the 2-dienyl-substituted tetrahydrofuran 30 and dienes 39 and 40. The desired beta-allyl-C-mannosyl products 42 and 43 were obtained, albeit in low yield, when bulky ethyl and isopropyl groups were employed at the silyl ether tether. Stereospecific oxidative cleavage of the silyl tether in 42 and 43 provided the corresponding stereodefined diols 44 and 45, respectively. Attempts to improve the yield and diastereoselectivity of the desired beta-allyl-C-mannosyls by moving to a sulfoxide mannosyl donor, which could be activated at low temperature, proved unsuccessful.
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Affiliation(s)
- Julien Beignet
- School of Chemistry, The University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
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20
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De Castro M, Marzabadi CH. The preparation of 2-iodoamides from glucals and their further transformations into oxazolines. Tetrahedron Lett 2004. [DOI: 10.1016/j.tetlet.2004.06.082] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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21
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Chinchilla R, Nájera C, Yus M. Metalated Heterocycles and Their Applications in Synthetic Organic Chemistry. Chem Rev 2004; 104:2667-722. [PMID: 15137804 DOI: 10.1021/cr020101a] [Citation(s) in RCA: 272] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Rafael Chinchilla
- Departamento de Química Orgánica and Instituto de Síntesis Orgánica, Facultad de Ciencias, Universidad de Alicante, Apartado 99, 03080 Alicante, Spain.
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22
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Marzabadi CH, Anderson JE, Gonzalez-Outeirino J, Gaffney PRJ, White CGH, Tocher DA, Todaro LJ. Why Are Silyl Ethers Conformationally Different from Alkyl Ethers? Chair−Chair Conformational Equilibria in Silyloxycyclohexanes and Their Dependence on the Substituents on Silicon. The Wider Roles of Eclipsing, of 1,3-Repulsive Steric Interactions, and of Attractive Steric Interactions. J Am Chem Soc 2003; 125:15163-73. [PMID: 14653751 DOI: 10.1021/ja035936x] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
An NMR study of the diaxial/diequatorial chair equilibrium in a range of silylated derivatives of trans-1,4- and trans-1,2-dihydroxycyclohexane is reported and discussed with a view to explaining unusually large populations of chair conformations with axial substituents, noted previously for some monosilyloxycyclohexanes and in some silylated sugars. X-ray diffraction studies of three bis-triphenylsilyloxycyclohexanes are reported and show both axial and equatorial silyloxy groups with the exocyclic bonds eclipsed. Eclipsing is also suggested by molecular mechanics (MM3) calculations on such derivatives. Both axial and equatorial tertiary silyl groups have 1,3-repulsive interactions with whatever substituents or hydrogen atoms are at the two adjacent equatorial positions, and these are relieved by rotation toward the eclipsed conformation of the exocyclic C-O bond. The three substituents on silicon interact attractively with the nine atoms at the 3, 4, and 5-positions of the cyclohexane ring and calculations suggest that these stabilizing interactions are significantly greater in the axial than in the equatorial conformation. An equatorial C-OSiR(3) bond with one or two equatorial neighbors has a restricted potential energy well that becomes much broader when the bond is axial without any equatorial neighbors in the alternative chair. Adjacent silyl groups in the 1,2-disubstituted series interact in a stabilizing way overall in all conformations, this being particularly marked in the diaxial conformation of the more complex ethers. These factors lead to unusually large axial populations.
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Affiliation(s)
- Cecilia H Marzabadi
- Department of Chemistry and Biochemistry, Seton Hall University, 400 South Orange Avenue, South Orange, New Jersey 07079, USA.
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23
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Abe H, Terauchi M, Matsuda A, Shuto S. A study on the conformation-anomeric effect-stereoselectivity relationship in anomeric radical reactions, using conformationally restricted glucose derivatives as substrates. J Org Chem 2003; 68:7439-47. [PMID: 12968898 DOI: 10.1021/jo030128+] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We previously theorized that, since the stereoselectivity of anomeric radical reactions is significantly influenced by the kinetic anomeric effect, which can be controlled by restricting the conformation of the radical intermediate, the proper conformational restriction of the pyranose ring of the substrates would therefore make highly alpha- and beta-stereoselective anomeric radical reactions possible. This theory was based on our previous results of the anomeric radical reactions with d-xylose derivatives as the substrates. We herein report the anomeric radical deuteration reactions with the conformationally restricted 1-phenylseleno-d-glucose derivatives, 2g and 3g, restricted in a (4)C(1)-conformation by an O-cyclic diketal moiety, and 4g, 5g, 6g, 7g, and 8g, restricted in a (1)C(4)-conformation by bulky O-silyl protecting groups. The radical deuterations with Bu(3)SnD, using the (4)C(1)-restricted substrates 2g and 3g, afforded the corresponding alpha-products (alpha/beta = 98:2) highly stereoselectively, whereas the (1)C(4)-restricted substrate 6g, having a trigonal (sp(2)) carbon substituent, i.e., -CHO, at the 5-position, selectively gave the beta-products (alpha/beta = 0:100). Thus, the stereoselectivity was significantly increased by the conformational restriction and was completely inverted by changing the substrate conformation from the (4)C(1)-form to the (1)C(4)-form. On the other hand, the deuterations with the (1)C(4)-restricted substrates 4g and 5g showed that the 1,5-steric effect due to the tetrahedral carbon substituent (-CH(2)OTIPS or -CH(2)OH) at the 5-axial position dominantly prevented the hydride transfer from the beta-face competing with the kinetic anomeric effect. This study suggests that, depending on the restricted conformation of the substrates to the (4)C(1)- or the (1)C(4)-form, the alpha- or beta-products would be obtained highly stereoselectively via anomeric radical reactions of hexopyranoses.
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Affiliation(s)
- Hiroshi Abe
- Graduate School of Pharmaceutical Sciences, Hokkaido University, Kita-12, Nishi-6, Kita-ku, Sapporo 060-0812, Japan
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Abe H, Shuto S, Tamura S, Matsuda A. An efficient method for preparing fully O-silylated pyranoses conformationally restricted in the unusual 1C4-form. Tetrahedron Lett 2001. [DOI: 10.1016/s0040-4039(01)01233-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Kodama T, Shuto S, Nomura M, Matsuda A. An efficient method for the preparation of 1'alpha-branched-chain sugar pyrimidine ribonucleosides from uridine: the first conversion of a natural nucleoside into 1'-substituted ribonucleosides. Chemistry 2001; 7:2332-40. [PMID: 11446636 DOI: 10.1002/1521-3765(20010601)7:11<2332::aid-chem23320>3.0.co;2-w] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The 1'alpha-phenylselenouridine derivative 13 was successfully synthesized by enolization of the 3',5'-O-TIPDS-2'-ketouridine 8, and was subjected to a radical reaction with a vinylsilyl tether--an efficient procedure for preparing 1'alpha-branched-chain sugar pyrimidine nucleosides. Successive treatment of 8 with LiHMDS and PhSeCl in THF at < -70 degrees C gave the desired 1'-phenylseleno products in 85% yield as an anomeric mixture of the 1'alpha-product 11 and the 1'beta-product 12 (11/12= 2.5:1). Highly stereoselective reduction at the 2'-carbonyl of the 1'alpha-product 11 occurred from the beta-face by using NaBH4/CeCl3 in MeOH, and subsequent introduction of a dimethylvinylsilyl tether at the 2'-hydroxyl gave the radical reaction substrate 14. The photochemical radical atom-transfer reaction of 14 by using a high-pressure mercury lamp proceeded effectively in benzene to give the exo-cyclized PhSe-transferred product 18, in which (PhSe)2 proved to be essential as an additive for radical atom-transfer cyclization reactions. Subsequent phenylseleno-group elimination of 18 gave the sugar-protected 1'alpha-vinyluridine. With this procedure, 1'alpha-vinyluridine (22) and -cytidine (25), designed to be potential antitumor agents, were successfully synthesized. This study is the first example of functionalization at the anomeric 1'-position of a nucleoside by starting from a natural nucleoside to produce a ribo-type 1'-modified nucleoside.
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Affiliation(s)
- T Kodama
- Graduate School of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan
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Shuto S, Fukuoka M, Abe H, Matsuda A. Intracellular Ca(2+)-mobilizing adenine nucleotides. Synthesis and biological activity of cyclic ADP-carbocyclic-ribose and C-glycosidic analog of adenophostin A. NUCLEOSIDES, NUCLEOTIDES & NUCLEIC ACIDS 2001; 20:461-70. [PMID: 11563061 DOI: 10.1081/ncn-100002320] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
We designed novel Ca(2+)-mobilizing purine nucleotides, cyclic ADP-carbocyclicribose 4, and its inosine congener 5, and C-glycosidic adenophostin A 6. In the synthesis of cADPR analogs, the intramolecular condensation to form the pyrophosphate linkage should be the key step. We developed an efficient method for forming such an intramolecular pyrophosphate linkage by the activation of the phenylthiophosphate group with I2 or AgNO3. Using this method, we achieved to synthesize the target compounds 4 and 5. The synthesis of C-glycosidic analog 6 of adenophostin A was achieved using a temporary silicon-tethered radical coupling reaction for constructing (3'alpha, 1" alpha)-C-glycosidic structure as the key step.
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Affiliation(s)
- S Shuto
- Graduate School of Pharmaceutical Sciences, Hokkaido University, Kita-12, Nishi-6, Kita-ku, Sapporo 060-0812, Japan.
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Feldman KS, Lawlor MD, Sahasrabudhe K. Ellagitannin chemistry. Evolution of a three-component coupling strategy for the synthesis of the dimeric ellagitannin coriariin A and a dimeric gallotannin analogue. J Org Chem 2000; 65:8011-9. [PMID: 11073611 DOI: 10.1021/jo0010936] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The total synthesis of the dimeric ellagitannin coriariin A is reported. The key reaction to access the dimeric framework was realized early in the synthesis pathway via a bis acylation reaction of a dehydrodigalloyl diacid with 2 equiv of a glucopyranose trichloroacetimidate. The glucose rings were subsequently functionalized, culminating in a double oxidative cyclization to form stereoselectively both (S)-HHDP ester units. This bis acylation strategy was also employed to prepare a gallotannin analogue of coriariin A whose earlier synthesis by orthoquinone dimerization was plagued by yield-limiting side reactions.
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Affiliation(s)
- K S Feldman
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.
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