DOCSLIB.ORG

Sugar Silanes: Versatile Reagents for Stereocontrolled Glycosylation Via Intramolecular Delivery by Jordan Thomas Walk

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Sugar Silanes: Versatile Reagents for Stereocontrolled Glycosylation Via Intramolecular Delivery by Jordan Thomas Walk Sugar Silanes: Versatile Reagents for Stereocontrolled Glycosylation via Intramolecular Delivery by Jordan Thomas Walk A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy (Chemistry) in the University of Michigan 2015 Doctoral Committee: Professor John Montgomery, Chair Assistant Professor Amanda L. Garner Assistant Professor Pavel Nagorny Professor John P. Wolfe Dedication To my mother and my grandparents. Without their strength, character, and support, I could never have accomplished the things that I have. ii Acknowledgments First and foremost, I am most grateful for my family. I have been surrounded by incredible people my entire life. It was only with your love that I have achieved what I have. My success is your success. John Montgomery has provided wonderful guidance and mentorship as my career has developed. I’d also like to thank John Wolfe, Pavel Nagorny, Amanda Garner, and Jason Gestwicki for their insights into the sugar silane project. I’ve had the great pleasure of working next to wonderful people in the Montgomery Lab. More than coworkers, these friends have enriched my life and helped to create memories that I will always cherish. Last but not least, I love Kelli Sullivan with all of my heart. iii Table of Contents Dedication .......................................................................................................................... ii Acknowledgements ......................................................................................................... iii List of Figures .....................................................................................................................v List of Schemes ................................................................................................................. vi List of Tables .................................................................................................................... ix List of Abbreviations ....................................................................................................... xi Abstract ........................................................................................................................... xiii Chapter 1: Carbohydrate Chemistry ...............................................................................1 1.1) General Overview of Carbohydrates .......................................................1 1.2) Development of Glycosylation Strategies.................................................6 1.3) The Synthesis of 1,2-Cis Glycosides ........................................................10 1.4) Direct Intramolecular Delivery ..............................................................15 1.5) Synthesis of 2-Deoxy-β-Glycosides .........................................................21 Chapter 2: Review of Sugar Silanes ...............................................................................25 2.1) Introduction ..............................................................................................25 2.2) Hydrosilylation of Ketones ......................................................................31 2.3) Aldehyde and Alkyne Coupling ..............................................................35 2.4) Dehydrogenative Silylation of Alcohols .................................................38 Chapter 3: Sugar Silanes and C6 Delivery ....................................................................41 3.1) Glucose and Mannose C2 Sugar Silanes ................................................41 3.2) Background and Strategy Towards 1,2-Trans Glycosides via IAD .....43 3.3) 2-Acetoxy and 2-Benzoyloxy Sugar Silanes ...........................................47 3.4) 2-Benzyloxy and 2-Azido C6 Sugar Silanes ...........................................71 3.5) 2-Deoxy Sugar Silanes .............................................................................85 Chapter 4: Experimental Procedures and Spectral Data ..........................................108 References .......................................................................................................................179 iv List of Figures Figure 1.1 – D-Glucose and D-Mannose ..........................................................................2 Figure 1.2 – The Anomeric Effect ....................................................................................4 Figure 1.3 – Disaccharides and Oligosaccharides ...........................................................5 Figure 2.1 – The Versatility of Sugar Silanes ................................................................28 Figure 3.1 – Potential Intramolecular Anomerization Mechanism ............................98 v List of Schemes Scheme 1.1 – Mutarotation of Glucose ............................................................................3 Scheme 1.2 – First Chemical Glycosylations by Michael and Fischer ..........................7 Scheme 1.3 – Koenigs-Knorr Glycosylation and Proposed Mechanism .......................7 Scheme 1.4 – Different Reactivity Between 1,2-Cis and 1,2-Trans Donors ..................8 Scheme 1.5 – Mechanistic Differences between 1,2-Cis and 1,2-Trans Donors ............9 Scheme 1.6 – Neighboring Group Participation to Give 1,2-Trans Glycosides ..........10 Scheme 1.7 – Lemieux’s in situ Anomerization Strategy .............................................13 Scheme 1.8 – Non-Direct Intramolecular Methods to Obtain 1,2-Cis Glycosides .....15 Scheme 1.9 – Intramolecular Aglycone Delivery to Give 1,2-Cis Glycosides .............16 Scheme 1.10 – Hindsgaul’s Mixed Acetal Strategy .......................................................17 Scheme 1.11 – Use of NIS as Electrophile ......................................................................17 Scheme 1.12 – Enol Ethers as Tethers ...........................................................................18 Scheme 1.13 – PMB Ethers as Tethers...........................................................................18 Scheme 1.14 – Silicon Tethers to Obtain β-Mannosides ...............................................19 Scheme 1.15 – Silicon Tethers to Obtain α-Glucosides ................................................20 Scheme 1.16 – 2-Deoxy-Glucose and 2-Deoxy-Ribose ..................................................21 Scheme 1.17 – Glycosyl Phosphites as Glycosyl Donors ...............................................22 Scheme 1.18 – Anchimeric Assistance from C3 Hydroxyl ...........................................22 Scheme 1.19 – Use of Temporary Directing Groups ....................................................23 Scheme 1.20 – 1,2-Migration of Thioglycosides ............................................................24 Scheme 1.21 – Cycloaddition to Form 2-Deoxy-β-Glycosides......................................24 Scheme 2.1 – Dimethylsilylketals Tethers for Intramolecular Aglycone Delivery ....26 vi Scheme 2.2 – Chlorosilanes for Efficient Heterocoupling ............................................27 Scheme 2.3 – Transition Metal Catalyzed Formation of Oxygen-Silicon Bonds .......29 Scheme 2.4 – Sugar Silane Approach Versus Traditional Approach .........................30 Scheme 2.5 – Synthesis of C2 Sugar Silanes ..................................................................31 Scheme 2.6 – Hydrosilylation of Ketones Using Sugar Silanes ....................................32 Scheme 2.7 – Glycosylation of C2 Sugar Silanes ...........................................................33 Scheme 2.8 – Site Selectivity with Sugar Silanes ...........................................................34 Scheme 2.9 – Chemoselectivity Using Sugar Silanes ....................................................35 Scheme 2.10 – Sugar Silane Approach Versus Traditional Approach .......................36 Scheme 2.11 – Efficient Route to Glycosylated Macrocycle ........................................37 Scheme 2.12 – Aldehyde-Alkyne Coupling to Access Glycosylated Alcohols.............37 Scheme 3.1 – C6 Delivery with Pyrimidine Bases .........................................................44 Scheme 3.2 – Silyl Tethers at Distal Hydroxyl Groups ................................................45 Scheme 3.3 – Intramolecular Glycosylation from the C6 Hydroxyl ...........................46 Scheme 3.4 – Strategy to Overcome 1,6-Anhydro Byproduct Formation ..................46 Scheme 3.5 – Initial Attempt Towards 1,2-Trans Diol Protected Donor ....................47 Scheme 3.6 – Synthesis of 3,4-Trans Diol Protected Thioglucoside .............................48 Scheme 3.7 – Synthesis of 2-Acetoxy Sugar Silanes ......................................................49 Scheme 3.8 – Synthesis of 2-Benzoyloxy Sugar Silanes ................................................50 Scheme 3.9 – Comparison of C2 and C6 Sugar Silanes in Alcohol Silylation ............51 Scheme 3.10 – Formation of Homodimer ......................................................................53 Scheme 3.11 – Formation of Active Catalyst .................................................................55 Scheme 3.12 – Synthesis of Diisopropyl C6 Sugar Silanes ...........................................58 Scheme 3.13 – Comparison of C2 and C6 Sugar Silanes Using B(C6F5)3 ...................60 Scheme 3.14 – Synthesis of Discrete Catalyst ................................................................62 Scheme 3.15 – Control Experiment with Exogenous Alcohol ......................................67 Scheme 3.16 – 2-Acetoxy and 2-Benzoyloxy Crossover
Load more

Recommended publications
  • Identification of Promising Alternative Mono-Alcohol Fuel Blend
    energies Article Identification of Promising Alternative Mono-Alcohol Fuel Blend Components for Spark Ignition Engines Saeid Aghahossein Shirazi 1, Thomas D. Foust 1,2 and Kenneth F. Reardon 1,2,* 1 Department of Chemical and Biological Engineering, Colorado State University, Fort Collins, CO 80523, USA; [email protected] (S.A.S.); [email protected] (T.D.F.) 2 National Renewable Energy Laboratory, Golden, CO 80401, USA * Correspondence: [email protected] Received: 24 March 2020; Accepted: 12 April 2020; Published: 15 April 2020 Abstract: Alcohols are attractive fuel blendstocks for spark ignition engines due to their high octane values and potentially positive influence on performance and emission. Although methanol, ethanol, and butanol have been widely studied, other biomass-derived alcohols may have similar or better properties. However, it is not feasible to experimentally investigate the fuel potential of every molecule. The goals of this study were to develop a methodology for rapid screening of a fuel property database for mono-alcohols and to identify alcohols with the potential of blending to produce advantaged motor gasolines. A database was developed with 13 fuel properties of all saturated C1–C10 mono-alcohols. A decision framework was used to evaluate alcohols suitable for blending in gasoline for spark ignition engines in two scenarios: low-range (up to 15 vol%) blends and high-range (greater than 40 vol%) blends. The low-range blend cases resulted in the identification of 48 alcohols. In the case of high-range blending, only six alcohols were found to be suitable. This is the first study to systematically evaluate all C1–C10 saturated alcohols for blending with gasoline using relevant fuel properties.
    [Show full text]
  • Immunological Approaches to Biomass Characterization and Utilization
    REVIEW published: 28 October 2015 doi: 10.3389/fbioe.2015.00173 Immunological approaches to biomass characterization and utilization Sivakumar Pattathil1,2* , Utku Avci1,2 , Tiantian Zhang1 , Claudia L. Cardenas1† and Michael G. Hahn1,2 1 Complex Carbohydrate Research Center, University of Georgia, Athens, GA, USA, 2 Oak Ridge National Laboratory, BioEnergy Science Center (BESC), Oak Ridge, TN, USA Plant biomass is the major renewable feedstock resource for sustainable generation of alternative transportation fuels to replace fossil carbon-derived fuels. Lignocellulosic cell walls are the principal component of plant biomass. Hence, a detailed understanding of plant cell wall structure and biosynthesis is an important aspect of bioenergy research. Cell walls are dynamic in their composition and structure, varying considerably among Edited by: Jason Lupoi, different organs, cells, and developmental stages of plants. Hence, tools are needed that University of Queensland, USA are highly efficient and broadly applicable at various levels of plant biomass-based bioen- Reviewed by: ergy research. The use of plant cell wall glycan-directed probes has seen increasing use Xu Fang, Shandong University, China over the past decade as an excellent approach for the detailed characterization of cell Arumugam Muthu, walls. Large collections of such probes directed against most major cell wall glycans are Council of Scientific and Industrial currently available worldwide. The largest and most diverse set of such probes consists Research, India of cell wall glycan-directed monoclonal antibodies (McAbs). These McAbs can be used *Correspondence: Sivakumar Pattathil as immunological probes to comprehensively monitor the overall presence, extractability, [email protected] and distribution patterns among cell types of most major cell wall glycan epitopes using †Present address: two mutually complementary immunological approaches, glycome profiling (an in vitro Claudia L.
    [Show full text]
  • Synechococcus Elongatus
    bioRxiv preprint doi: https://doi.org/10.1101/2020.12.30.424818; this version posted December 31, 2020. The copyright holder for this preprint (which was not certified by peer review) is the author/funder. All rights reserved. No reuse allowed without permission. 1 5-Deoxyadenosine Salvage by Promiscuous Enzyme Activity 2 leads to Bioactive Deoxy-Sugar Synthesis in 3 Synechococcus elongatus 4 5 Running title: Unusual 5-deoxyadenosine salvage in S. elongatus 6 7 Johanna Rappa, Pascal Rathb, Joachim Kilianc, Klaus Brilisauera, Stephanie Grondb, Karl 8 Forchhammera# 9 aInterfaculty Institute of Microbiology and Infection Medicine, Microbiology/Organismic Interactions, Eberhard 10 Karls Universität Tübingen, Auf der Morgenstelle 28, 72076 Tübingen, Germany. 11 bInstitute of Organic Chemistry, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, 12 Germany. 13 cCenter for Plant Molecular Biology, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 32, 72076 14 Tübingen, Germany. 15 16 #corresponding author ([email protected], Tel.: +49 (7071) 29- 72096) 17 18 Abbreviations: SAM: S-Adenosylmethionine; MTA: Methylthioadenosine; 5dAdo: 19 5-Deoxyadenosine; MSP: Methionine salvage pathway; 5dR: 5-Deoxyribose; 7dSh: 20 7-Deoxysedoheptulose; 5dR-1P: 5-Deoxyribose 1-phosphate; 5dRu-1P: 5-Deoxyribulose 21 1-phosphate; MTRI: Methylthioribose 1-phosphate isomerase; MTR: Methylthioribose 22 23 Keywords: 5-Deoxyadenosine salvage, 5-deoxyribose, 7-deoxysedoheptulose, 7dSh 24 biosynthesis; enzyme promiscuity, S-adenosylmethionine, radical SAM enzymes, 25 cyanobacteria 1 bioRxiv preprint doi: https://doi.org/10.1101/2020.12.30.424818; this version posted December 31, 2020. The copyright holder for this preprint (which was not certified by peer review) is the author/funder.
    [Show full text]
  • Monosaccharides and Their Derivatives in Carbonaceous Meteorites: a Scenario for Their Synthesis and Onset of Enantiomeric Excesses
    life Review Monosaccharides and Their Derivatives in Carbonaceous Meteorites: A Scenario for Their Synthesis and Onset of Enantiomeric Excesses George Cooper 1,*, Andro C. Rios 1,2,* and Michel Nuevo 1,3 ID 1 NASA-Ames Research Center, Moffett Field, CA 94035, USA; [email protected] 2 Blue Marble Space, 1001 4th Ave, Ste 3201, Seattle, WA 98154, USA 3 Bay Area Environmental Research Institute, NASA Research Park, Moffett Field, CA 94035, USA * Correspondence: [email protected] (G.C.); [email protected] (A.C.R.) Received: 5 June 2018; Accepted: 22 August 2018; Published: 27 August 2018 Abstract: Carbonaceous meteorites provide the best glimpse into the solar system’s earliest physical and chemical processes. These ancient objects, ~4.56 billion years old, contain evidence of phenomena ranging from solar system formation to the synthesis of organic compounds by aqueous and (likely) low-temperature photolytic reactions. Collectively, chemical reactions resulted in an insoluble kerogen-like carbon phase and a complex mixture of discrete soluble compounds including amino acids, nucleobases, and monosaccharide (or “sugar”) derivatives. This review presents the documented search for sugars and their derivatives in carbonaceous meteorites. We examine early papers, published in the early 1960s, and note the analytical methods used for meteorite analysis as well as conclusions on the results. We then present the recent finding of sugar derivatives including sugar alcohols and several sugar acids: The latter compounds were found to possess unusual “D” enantiomeric (mirror-image) excesses. After discussions on the possible roles of interstellar grain chemistry and meteorite parent body aqueous activity in the synthesis of sugar derivatives, we present a scenario that suggests that most of Earth’s extraterrestrial sugar alcohols (e.g., glycerol) were synthesized by interstellar irradiation and/or cold grain chemistry and that the early solar disk was the location of the initial enantiomeric excesses in meteoritic sugar derivatives.
    [Show full text]
  • Chapter 12 Slides
    11/15/17 CHAPTER 12: Carbohydrates: Structure and Function OUTLINE • 12.1 Role of Carbohydrates • 12.2 Monosaccharides • 12.3 Complex Carbohydrates • 12.4 Carbohydrate Catabolism • 12.5 Oligosaccharides as Cell Markers CHAPTER 12: Carbohydrates: Structure and Function WHAT ARE CARBOHYDRATES? • Glucose and its derivatives are carbohydrates: Ø Carbohydrates are simple organic molecules that have a shared basic chemical Formula: Cn(H2O)n Ø The name “carbo + hydrate” represents that Fact that they are made from CO2 and H2O by photosynthesis • About halF oF all earth’s solid carbon is Found in two polymers of glucose found in plants: Ø Starch = major energy storage molecule Ø Cellulose = major structural component oF the plant cell wall (aka. “fiber”) CHAPTER 12: Carbohydrates: Structure and Function THE SIMPLEST CARBOHYDRATES • Monosaccharides are carbohydrates that cannot be hydrolyZed into simpler carbohydrates: Ø These are the Fundamental building blocks For all other carbohydrates (oFten called “simple sugars”) Ø All have Formulas of based on the basic pattern: Cn(H2O)n • Monosaccharides have speciFic Functional groups: 1. An aldehyde OR a ketone (not both!) 2. Several (two or more) alcohol (-OH) groups 1 11/15/17 CHAPTER 12: Carbohydrates: Structure and Function STRUCTURE & NOMENCLATURE OF MONOSACCHARIDES • Monosaccharides are classiFied by two features: 1. Length of their main carbon chain (utilize standard IUPAC naming For # oF carbons) 2. Whether they contain an aldehyde or ketone group • Names always end with –ose • Two common hexoses:
    [Show full text]
  • Catalog Feb 2007 Final.Pmd
    Table of Contents How To Use This Catalog ............................................................................................... 2 Service Information .................................................................................................... 3-4 Placing Orders - Shipping........................................................................................................3 Miscellaneous Information......................................................................................................4 Product Information................................................................................................. 5-17 Definitions .............................................................................................................. 5 Detergent Analysis ............................................................................................. 6-7 Lipid-like Detergents.......................................................................................... 8-9 FOS-CHOLINE® Detergents .............................................................................................8 FOS-MEA® ...........................................................................................................................9 Miscellaneous ....................................................................................................................9 Nonionic Detergents ......................................................................................10-14 Sugar-based Detergents .......................................................................................
    [Show full text]
  • Designing Tools for Studying the Dynamic Glycome John F
    Marshall University Marshall Digital Scholar Chemistry Faculty Research Chemistry Winter 12-2012 Designing Tools for Studying the Dynamic Glycome John F. Rakus Marshall University, [email protected] Follow this and additional works at: http://mds.marshall.edu/chemistry_faculty Part of the Organic Chemistry Commons Recommended Citation Rakus, J. F. (2012, December). Designing tools for studying the dynamic glycome. Invited Lecture at Sonoma State University, Rohnert Park, CA. This Presentation is brought to you for free and open access by the Chemistry at Marshall Digital Scholar. It has been accepted for inclusion in Chemistry Faculty Research by an authorized administrator of Marshall Digital Scholar. For more information, please contact [email protected]. NYU Cover Cells are primarily compose of three types of biomolecules Protein (50% dry weight) HeLa cell Nucleic acid (25% dry weight) Carbohydrate (10% dry weight) Carbohydrates are pervasive and involved in many cellular interactions Holgersson et al, Immuno Cell Biol, 2005 Laughlin et al, Science, 2008 Nucleic acids and proteins are synthesized with a defined template and dedicated polymerases Macromolecule: Nucleic acid Macromolecule: polypeptide Polymerase: DNA Pol or RNA Pol Polymerase: Ribosome Template: DNA strand Template: mRNA strand Glycan biosynthesis lacks a dedicated polymerase and genetic template Formation of Glc3Man9GlcNAc2-DolPP, an intermediate in the N-linked glycosylation pathway, requires 12 separate enzymes Essentially, each linkage in an oligosaccharide is
    [Show full text]
  • Combinatorial Glycomic Analyses to Direct Cazyme Discovery for the Tailored Degradation of Canola Meal Non-Starch Dietary Polysaccharides
    microorganisms Article Combinatorial Glycomic Analyses to Direct CAZyme Discovery for the Tailored Degradation of Canola Meal Non-Starch Dietary Polysaccharides Kristin E. Low 1 , Xiaohui Xing 1,2, Paul E. Moote 1,3, G. Douglas Inglis 1,3,4 , Sivasankari Venketachalam 5,6, Michael G. Hahn 5,6,7 , Marissa L. King 1, Catherine Y. Tétard-Jones 8, Darryl R. Jones 1, William G. T. Willats 8, Bogdan A. Slominski 9 and D. Wade Abbott 1,2,4,* 1 Lethbridge Research and Development Centre, Agriculture and Agri-Food Canada, Lethbridge, AB T1J 4B1, Canada; [email protected] (K.E.L.); [email protected] (X.X.); [email protected] (P.E.M.); [email protected] (G.D.I.); [email protected] (M.L.K.); [email protected] (D.R.J.) 2 Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, AB T1K 3M4, Canada 3 Department of Agricultural, Food & Nutritional Science, University of Alberta, Edmonton, AB T6G 2P5, Canada 4 Department of Biological Sciences, University of Lethbridge, Lethbridge, AB T1K 3M4, Canada 5 Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, USA; [email protected] (S.V.); [email protected] (M.G.H.) 6 Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA 7 Department of Plant Biology, University of Georgia, Athens, GA 30602, USA 8 School of Natural and Environmental Sciences, Newcastle University, Newcastle Upon Tyne NE1 7RU, UK; [email protected] (C.Y.T.-J.); [email protected] (W.G.T.W.) 9 Department of Animal Science, University of Manitoba, Winnipeg, MB R3T 2N2, Canada; [email protected] * Correspondence: [email protected] Received: 30 September 2020; Accepted: 20 November 2020; Published: 29 November 2020 Abstract: Canola meal (CM), the protein-rich by-product of canola oil extraction, has shown promise as an alternative feedstuff and protein supplement in poultry diets, yet its use has been limited due to the abundance of plant cell wall fibre, specifically non-starch polysaccharides (NSP) and lignin.
    [Show full text]
  • USP Excipient Reference Standards Catalog
    Last Updated On: March 15, 2021 USP Excipient Reference Standards Catalog Catalog # Description Current Lot Previous CAS # NDC # Unit Price Special Restriction Lot(Valid Use Date) 1002505 Acesulfame G0H082 F0C136 (30-JUN- 55589-62-3 N/A $410.00 Potassium (200 mg) 2009) 1005706 Glacial Acetic Acid R038A0 I0M342 (31-JUL- 64-19-7 N/A $280.00 (1.5 mL/ampule; 3 2017) ampules) 1006801 Acetone (1.5 R095B0 I0M548 (28-FEB- 67-64-1 N/A $265.00 mL/ampule; 3 2022) ampules) 1009005 Acetylcysteine (200 R10200 K0K294 (30- 616-91-1 N/A $245.00 mg) NOV-2019) 1009901 Acetyltributyl Citrate R053A0 H0I337 (31-AUG- 77-90-7 N/A $275.00 (3 x 200 mg) 2017) 1009923 Acetyltriethyl Citrate R041M0 H0I339 (31-JAN- 77-89-4 N/A $275.00 (500 mg) 2017) 1012190 Adipic Acid (100 mg) F1D318 F0D318 (31- 124-04-9 N/A $265.00 MAR-2018) 1012214 Agar (500 mg) F0K137 N/A N/A $253.00 1012595 rAlbumin Human (6 R04600 G0M268 (31- N/A N/A $314.00 Cold Shipment mg) (Recombinant DEC-2016) Required Human Albumin) (COLD SHIPMENT REQUIRED) 1012688 Alcohol R05900 G0M024 (31- 64-17-5 N/A $265.00 Determination-- OCT-2018) Alcohol (5 Page 1 Last Updated On: March 15, 2021 USP Excipient Reference Standards Catalog Catalog # Description Current Lot Previous CAS # NDC # Unit Price Special Restriction Lot(Valid Use Date) mL/ampule; 5 ampules) 1012768 Alcohol (1.2 R127S0 R087W0 (31- 64-17-5 N/A $245.00 mL/ampule; 5 MAY-2020) ampules) 1012772 Dehydrated Alcohol R119J0 G0M292 (31- 64-17-5 N/A $245.00 (1.2 mL/ampule; 5 MAY-2020) ampules) 1012799 Aleuritic Acid (50 F02300 533-87-9 N/A $278.00 mg)
    [Show full text]
  • Total Synthesis of Zwitterionic Bacterial Polysaccharide (PS A1) Antigen Fragments
    A Dissertation Titled: Total Synthesis of Zwitterionic Bacterial Polysaccharide (PS A1) Antigen Fragments from B. fragilis ATCC 25285/NCTC 9343 with Alternating Charges on Adjacent Monosaccharides by Pradheep Eradi Submitted to the Graduate Faculty as partial fulfillment of the requirements for the Doctor of Philosophy Degree in Chemistry ___________________________________________ Dr. Peter R. Andreana, PhD, Committee Chair ___________________________________________ Dr. Steve Sucheck, PhD, Committee Member ___________________________________________ Dr. Jianglong Zhu, PhD, Committee Member ___________________________________________ Dr. Amanda C. Bryant-Freidrich, PhD, Committee Member ___________________________________________ Dr. Cyndee Gruden, Dean College of Graduate Studies The University of Toledo May 2019 Copyright 2019 Pradheep Eradi This document is copyrighted material. Under copyright law, no parts of this document may be reproduced without the expressed permission of the author. An Abstract of Total Synthesis of Zwitterionic Bacterial Polysaccharide (PS A1) Antigen Fragments from B. fragilis ATCC 25285/NCTC 9343 with Alternating Charges on Adjacent Monosaccharides by Pradheep Eradi Submitted to the Graduate Faculty as partial fulfillment of the requirements for the Doctor of Philosophy Degree in Chemistry The University of Toledo May 2019 Zwitterionic polysaccharides (ZPSs) are a relatively new class of carbohydrate antigens, with a paradigm shifting property; they can activate CD4+ T-cells in the absence of lipids, peptide(s) or protein(s) upon MHC class II presentation. Up until now, various anaerobic bacteria are known to express ZPSs, for example, PS A1, PS A2 and PS B (Bacteroides fragilis), Sp1 (Streptococcus pneumoniae), CP5 and CP8 (Staphylococcus aureus) and O-chain antigen (Morganella morgani). Among all the afore mentioned ZPSs, Sp1 and PS A1 polysaccharides were the prime focus of research for the past few decades and their biological properties are very well-understood.
    [Show full text]
  • A Versatile Glycosylation Strategy Via Au(III) Catalyzed Activation of Thioglycoside Donors† Cite This: Chem
    Chemical Science View Article Online EDGE ARTICLE View Journal | View Issue A versatile glycosylation strategy via Au(III) catalyzed activation of thioglycoside donors† Cite this: Chem. Sci.,2016,7,4259 Amol M. Vibhute, Arun Dhaka, Vignesh Athiyarath and Kana M. Sureshan* Among various methods of chemical glycosylations, glycosylation by activation of thioglycoside donors using a thiophilic promoter is an important strategy. Many promoters have been developed for the activation of thioglycosides. However, incompatibility with substrates having alkenes and the requirement of a stoichiometric amount of promoters, co-promoters and extreme temperatures are some of the limitations. We have developed an efficient methodology for glycosylation via the activation of thioglycoside donors using a catalytic amount of AuCl3 and without any co-promoter. The reaction is Received 10th February 2016 very fast, high-yielding and very facile at room temperature. The versatility of this method is evident from Accepted 4th March 2016 the facile glycosylation with both armed and disarmed donors and sterically demanding substrates DOI: 10.1039/c6sc00633g (acceptors/donors) at ambient conditions, from the stability of the common protecting groups, and from www.rsc.org/chemicalscience the compatibility of alkene-containing substrates during the reaction. Creative Commons Attribution 3.0 Unported Licence. Introduction alkenes;8 and (iv) the requirement of extremely low temperatures for the reaction. Development of novel and milder methods of Various forms of carbohydrates play important biological roles thioglycoside activation that overcome these limitations is an 5 ,6 and hence the chemical synthesis of glycoconjugates and agenda of utmost importance among chemists. g a Pohl et al.
    [Show full text]
  • Development of Sustainable Catalytic Systems for Oxidation Reactions
    DOCTOR OF PHILOSOPHY Development of Sustainable Catalytic Systems For Oxidation Reactions Hughes, Nicola Award date: 2017 Awarding institution: Queen's University Belfast Link to publication Terms of use All those accessing thesis content in Queen’s University Belfast Research Portal are subject to the following terms and conditions of use • Copyright is subject to the Copyright, Designs and Patent Act 1988, or as modified by any successor legislation • Copyright and moral rights for thesis content are retained by the author and/or other copyright owners • A copy of a thesis may be downloaded for personal non-commercial research/study without the need for permission or charge • Distribution or reproduction of thesis content in any format is not permitted without the permission of the copyright holder • When citing this work, full bibliographic details should be supplied, including the author, title, awarding institution and date of thesis Take down policy A thesis can be removed from the Research Portal if there has been a breach of copyright, or a similarly robust reason. If you believe this document breaches copyright, or there is sufficient cause to take down, please contact us, citing details. Email: [email protected] Supplementary materials Where possible, we endeavour to provide supplementary materials to theses. This may include video, audio and other types of files. We endeavour to capture all content and upload as part of the Pure record for each thesis. Note, it may not be possible in all instances to convert analogue formats to usable digital formats for some supplementary materials. We exercise best efforts on our behalf and, in such instances, encourage the individual to consult the physical thesis for further information.
    [Show full text]