DOCSLIB.ORG

Studies in Multicyclic Chemistry

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Studies in Multicyclic Chemistry Studies in Multicyclic Chemistry This thesis is submitted in fulfillment of the requirements for the degree of Doctor of Philosophy by Djamal Sholeh Al Djaidi Supervisor Professor Roger Bishop School of Chemistry The University of New South Wales Sydney, Australia December, 2006 PLEASE TYPE THE UNIVERSITY OF NEW SOUTH WALES Thesis/Dissertation Sheet Surname or Family name: AL DJAIDI First name: DJAMAL Other name/s: SHOLEH Abbreviation for degree as given in the University calendar: PhD School: CHEMISTRY Faculty: SCIENCE Title: STUDIES IN MULTICYCLIC CHEMISTRY Abstract 350 words maximum: (PLEASE TYPE) * A series of investigations has been carried out on multicyclic organic systems. The Ritter Reaction was used to obtain bridged imines containing an azacyclohexene functionality. The crystal structure of the benzene inclusion compound of one of these was determined, and also that of another spontaneously oxidised example. The reactivity of these bridged imines was then investigated using mercaptoacetic acid, and also dimethyl acetylenedicarboxylate (DMAD). The three bridged imines studied were found to react with DMAD in totally different ways and produced most unusual products whose structures were proved using X-ray crystallography. Mechanistic explanations are provided for the formation of these novel and totally unexpected products. * 6-Methylidene-3,3,7,7-tetramethylbicyclo[3.3.1]nonan-2-one was reacted with acetonitrile and sulfuric acid to deliberately combine molecular rearrangement with Ritter Reaction chemistry. Five different products were obtained and the pathway of formation of these products was uncovered. The structures of three of these rearranged substances were confirmed by X-ray methods. * The rare tricyclo[5.3.1.1 3,9]dodecane ring system is known to contain severe skeletal distortions due to the nature of its skeleton. These properties were investigated by means of X-ray determinations at two temperatures. It was found that although the bond lengths were little affected, several of the bond angles were highly anomalous. These had angles far from the ideal tetrahedral value and, in some cases, were close to planar (120 degrees). The molecular motion of the skeleton was also investigated using variable temperature NMR measurements and energy values for the twisting motion involved were determined. * Schroeter and Vossen's Red Salt, first discovered in 1910, was investigated in detail by NMR and X-ray spectroscopy. The detailed structure of this most unusual compound was determined for the first time. * The Red Salt is based on the bicyclo[3.3.0]octane ring system and can be converted into several synthetically useful derivatives, including a tetraester and the 3,7-diketone. The former was shown to exist completely in the enolised tautomeric form (like Meerwein's Ester), and the latter was used as a synthetic entry for making diquinoline substituted analogues of interest in host-guest chemistry. Declaration relating to disposition of project thesis/dissertation I hereby grant to the University of New South Wales or its agents the right to archive and to make available my thesis or dissertation in whole or in part in the University libraries in all forms of media, now or here after known, subject to the provisions of the Copyright Act 1968. I retain all property rights, such as patent rights. I also retain the right to use in future works (such as articles or books) all or part of this thesis or dissertation. I also authorise University Microfilms to use the 350 word abstract of my thesis in Dissertation Abstracts International (this is applicable to doctoral theses only). …………………………………………………………… ……………………………………..……………… ……….……………………...……. Signature Witness … Date The University recognises that there may be exceptional circumstances requiring restrictions on copying or conditions on use. Requests for restriction for a period of up to 2 years must be made in writing. Requests for a longer period of restriction may be considered in exceptional circumstances and require the approval of the Dean of Graduate Research. FOR OFFICE USE ONLY Date of completion of requirements for Award: THIS SHEET IS TO BE GLUED TO THE INSIDE FRONT COVER OF THE THESIS Studies in Multicyclic Chemistry DECLARATION The research presented in this thesis was undertaken in the School of Chemistry at the University of New South Wales, Sydney, Australia under the supervision of Professor Roger Bishop. The work presented in this thesis is, to the best of my knowledge and belief, original. This thesis has not been submitted in part or whole for a degree at any other university. Full acknowledgment has been made where the work of others has been cited or used. Djamal Sholeh Al Djaidi, BSc Pharm, FDA Dip. December, 2006 ii Studies in Multicyclic Chemistry Table of Contents Chapter 1 Introduction 1 1.1 The Ritter Reaction 1 1.1.1 The Classical Ritter Reaction 1 1.1.2 Intramolecular Ritter Reactions 6 1.1.3 Bridged Ritter Reaction Products 9 1.1.4 Inclusion Compounds Formed by Ritter Reaction Products 15 1.2 Addition of DMAD to Bridged Ritter Reaction Products 16 1.3 Ritter Rearrangement Reactions 21 1.4 Tricyclo[5.3.1.13,9]dodecane System Chemistry 30 1.5 Schroeter and Vossen’s Red Salt 35 1.6 Bicyclo[3.3.0]octane-based Diquinolines 38 1.6.1 Inclusion Behaviour of the Dibromo Host 94 43 1.6.2 Inclusion Behaviour of the Dichloro Derivative 97 50 1.6.3 Inclusion Behaviour of the Tetrabromide 95 54 1.6.4 Inclusion Chemistry of the Hexabromide 96 58 1.7 Aims of the Project 64 Chapter 2 Results and Discussion 66 2 Chemistry of Multicyclic Ritter Reactions 66 2.1 The Structure of a Ritter Reaction Product-Benzene Inclusion Compound 66 2.2 The Structure of an Oxidised Ritter Reaction Product 74 Chapter 3 Results and Discussion 80 3 Reaction of Bridged-Ritter Products 80 3.1 Reaction of the Bridged Imines with Mercaptoacetic Acid 80 iii Studies in Multicyclic Chemistry 3.2 Reaction of the Bridged Imines with Dimethyl Acetylenedicarboxylate (DMAD) 83 3.2.1 Reaction of Imine 36a with DMAD 83 3.2.1.1 Mechanism for the Formation of 110 and 112 88 3.2.1.2 Structure of the Inclusion Compound (112).(benzene)0.5 90 3.2.2 Reaction of Imine 100 with DMAD 97 3.2.2.1 Mechanism for Formation of 111 97 3.2.2.2 X-ray Structure of the Orthoester 111 99 3.2.3 Reaction of Imine 101 with DMAD 104 3.2.3.1 Mechanism for Formation of 115 105 3.2.3.2 X-ray Structure of the Lactam 115 106 Chapter 4 Results and Discussion 111 4 A Sequence of Novel Ritter Rearrangement Reactions 111 4.1 Rearrangement of the Unsaturated Ketone 120 111 4.2 3,3,6,6,7-Pentamethylbicyclo[3.3.1]non-7-en-2-one 121 115 4.3 4,4,7,8,8-Pentamethylbicyclo[3.3.1]non-6-en-3-one 122 116 4.4 {7-Anti-hydroxy-3,4,4,8,8-pentamethylbicyclo[3.2.2]non-2-en-1- yl}acetamide monohydrate 123 118 4.5 {3,4,4,8,8-Pentamethyl-2-oxatricyclo[3.3.1.13,7]dec-1- yl}acetamide 124 125 4.6 {4,4,8,8-Tetramethyltricyclo[3.3.1.13,7]decane-1,3- diyl}bis(acetamide) 125 130 Chapter 5 Results and Discussion 137 3,9 5 Tricyclo[5.3.1.1 ]dodecane System Chemistry 137 5.1 Synthetic Studies 137 iv Studies in Multicyclic Chemistry 5.2 X-ray Studies on Tricyclo[5.3.1.13,9]dodecane Derivatives 139 5.2.1 Crystal Structure of the Bis(pyrazolone) 135 139 5.2.2 Crystal structures of compound 83 at 90K and 300K 142 5.3 NMR Studies 149 5.3.1 Tricyclo[5.3.1.13,9]dodecane System Chemistry 149 5.3.2 Dynamic NMR Analysis of Compound 83 161 Chapter 6 Results and Discussion 165 6 The Structure of Schroeter and Vossen’s Red Salt 165 Chapter 7 Results and Discussion 175 7 Further Bicyclo[3.3.0]octane-based Diquinolines 175 7.1 The Stucture of the Tetraester 90 175 7.2 Diquinoline-substituted Bicyclo[3.3.0]octanes 181 Chapter 8 Experimental 185 Chapter 9 References 225 Published Material Related to this Thesis vi v Studies in Multicyclic Chemistry Published Material Related to this Thesis 1. Ritter Reactions. X. Structure of a New Multicyclic Amide—Benzene Inclusion Compound D. Djaidi, R. Bishop, D.C. Craig and M.L. Scudder Journal of Inclusion Phenomena and Molecular Recognition in Chemistry, 1995, 20, 363. (36a).(benzene) ZIPYIG 2. Ritter Reactions. Part 11. The Diverse Reactivity of 5,10-(Azenometheno)-5H- dibenzo[a,d]cyclohepten-11-yl Amides with Dimethyl Acetylenedicarboxylate D. Djaidi, R. Bishop, D.C. Craig and M.L. Scudder Journal of The Chemical Society, Perkin Transactions 1, 1996, 1859. 101 TITKAI (112).(benzene)0.5 TITJIP 111 TITJUB 115 TITJOV 3. Ritter Reactions. XIII. Reactivity of Schiff Bases with Dimethyl Acetylenedicarboxylate and Mercaptoacetic Acid Q. Lin, D. Djaidi, R. Bishop, D.C. Craig and M.L. Scudder Australian Journal of Chemistry, 1998, 51, 799. 4. Ritter Reactions. Part 14. Rearrangement of 3,3,7,7-Tetramethyl-6- methylidenebicyclo[3.3.1]nonan-2-one D. Djaidi, I.S.H. Leung, R. Bishop, D.C. Craig and M.L. Scudder Journal of The Chemical Society, Perkin Transactions 1, 2000, 2037. (123).(H2O) MAYVOX 124 MAYVUD 125 MAYWAK 5. Schroeter and Vossen’s Red Salt Revealed D. Djaidi, R. Bishop, D.C. Craig and M.L. Scudder New Journal of Chemistry, 2002, 26, 614. (89a).(methanol)2 XIZRED Crystallographic data for the X-ray structures listed above were deposited with the Cambridge Crystallographic Data Centre at the time of publication.
Load more

Recommended publications
  • Significance and Implications of Vitamin B-12 Reaction Shema- ETH ZURICH VARIANT: Mechanisms and Insights
    Taylor University Pillars at Taylor University Student Scholarship: Chemistry Chemistry and Biochemistry Fall 2019 Significance and Implications of Vitamin B-12 Reaction Shema- ETH ZURICH VARIANT: Mechanisms and Insights David Joshua Ferguson Follow this and additional works at: https://pillars.taylor.edu/chemistry-student Part of the Analytical Chemistry Commons, Inorganic Chemistry Commons, Organic Chemistry Commons, Other Chemistry Commons, and the Physical Chemistry Commons CHEMISTRY THESIS SIGNIFICANCE AND IMPLICATIONS OF VITAMIN B-12 REACTION SCHEMA- ETH ZURICH VARIANT: MECHANISMS AND INSIGHTS DAVID JOSHUA FERGUSON 2019 2 Table of Contents: Chapter 1 6 Chapter 2 17 Chapter 3 40 Chapter 4 59 Chapter 5 82 Chapter 6 118 Chapter 7 122 Appendix References 3 Chapter 1 A. INTRODUCTION. Vitamin B-12 otherwise known as cyanocobalamin is a compound with synthetic elegance. Considering how it is composed of an aromatic macrocyclic corrin there are key features of this molecule that are observed either in its synthesis of in the biochemical reactions it plays a role in whether they be isomerization reactions or transfer reactions. In this paper the focus for the discussion will be on the history, chemical significance and total synthesis of vitamin B12. Even more so the paper will be concentrated one of the two variants of the vitamin B-12 synthesis, namely the ETH Zurich variant spearheaded by Albert Eschenmoser.Examining the structure as a whole it is observed that a large portion of the vitamin B12 is a corrin structure with a cobalt ion in the center of the macrocyclic part, and that same cobalt ion has cyanide ligands.
    [Show full text]
  • Rare-Earth Metal Methylidene Complexes with Ln3 (Μ3-CH2)(Μ3
    Dalton Transactions View Article Online PAPER View Journal | View Issue Rare-earth metal methylidene complexes with Ln3(μ3-CH2)(μ3-Me)(μ2-Me)3 core structure† Cite this: Dalton Trans., 2015, 44, 18101 Dorothea Schädle,a Melanie Meermann-Zimmermann,b Cäcilia Maichle-Mössmer,a Christoph Schädle,a Karl W. Törnroosc and Reiner Anwander*a Trinuclear rare-earth metal methylidene complexes with a Ln3(µ3-CH2)(µ3-Me)(µ2-Me)3 structural motif were synthesized by applying three protocols. Polymeric [LuMe3]n (1-Lu) reacts with the sterically demand- ing amine H[NSiMe3(Ar)] (Ar = C6H3iPr2-2,6) in tetrahydrofuran via methane elimination to afford isolable monomeric [NSiMe3(Ar)]LuMe2(thf)2 (4-Lu). The formation of trinuclear rare-earth metal tetramethyl methylidene complexes [NSiMe3(Ar)]3Ln3(µ3-CH2)(µ3-Me)(µ2-Me)3(thf)3 (7-Ln; Ln = Y, Ho, Lu) via reaction of [LnMe3]n (1-Ln; Ln = Y, Ho, Lu) with H[NSiMe3(Ar)] is proposed to occur via an “intermediate” species of the type [NSiMe3(Ar)]LnMe2(thf)x and subsequent C−H bond activation. Applying Lappert’s concept of Lewis base-induced methylaluminate cleavage, compounds [NSiMe3(Ar)]Ln(AlMe4)2 (5-Ln; Ln = Y, La, Nd, Creative Commons Attribution-NonCommercial 3.0 Unported Licence. Ho) were converted into methylidene complexes 7-Ln (Ln = Y, Nd, Ho) in the presence of tetrahydrofuran. Similarly, tetramethylgallate complex [NSiMe3(Ar)]Y(GaMe4)2 (6-Y) could be employed as a synthesis pre- cursor for 7-Y. The molecular composition of complexes 4-Ln, 5-Ln, 6-Y and 7-Ln was confirmed by elemental analyses, FTIR spectroscopy, 1H and 13C NMR spectroscopy (except for holmium derivatives) Received 30th July 2015, and single-crystal X-ray diffraction.
    [Show full text]
  • Identification of a Novel Substrate-Derived Spermine
    ЭКСПЕРИМЕНТАЛЬНЫЕ СТАТЬИ UDK 577.152.1 Identification of a Novel Substrate- Derived Spermine Oxidase Inhibitor T. T. Dunston1, M. A. Khomutov2, S. B. Gabelli1,3,4, T. M. Stewart1, J. R. Foley1, S. N. Kochetkov2, A. R. Khomutov2*, R. A. Casero Jr.1* 1Sidney Kimmel Comprehensive Cancer Center, The Johns Hopkins University School of Medicine, Baltimore, MD 21287 USA 2Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, 119991 Russia 3Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA 4Department of Oncology, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA *E-mail: [email protected], [email protected] Received May 08, 2020; in final form, July 07, 2020 DOI: 10.32607/actanaturae.10992 ABSTRACT Homeostasis of the biogenic polyamines spermine (Spm) and spermidine (Spd), present in μM-mM concentrations in all eukaryotic cells, is precisely regulated by coordinated activities of the enzymes of poly- amine synthesis, degradation, and transport, in order to sustain normal cell growth and viability. Spermine oxidase (SMOX) is the key and most recently discovered enzyme of polyamine metabolism that plays an es- sential role in regulating polyamine homeostasis by catalyzing the back-conversion of Spm to Spd. The deve- lopment of many types of epithelial cancer is associated with inflammation, and disease-related inflammatory stimuli induce SMOX. MDL72527 is widely used in vitro and in vivo as an irreversible inhibitor of SMOX, but it is also potent towards N1-acetylpolyamine oxidase. Although SMOX has high substrate specificity, Spm analogues have not been systematically studied as enzyme inhibitors.
    [Show full text]
  • S41467-018-04983-2.Pdf
    ARTICLE DOI: 10.1038/s41467-018-04983-2 OPEN Novofumigatonin biosynthesis involves a non- heme iron-dependent endoperoxide isomerase for orthoester formation Yudai Matsuda 1,2,3, Tongxuan Bai2, Christopher B.W. Phippen1, Christina S. Nødvig1, Inge Kjærbølling1, Tammi C. Vesth1, Mikael R. Andersen 1, Uffe H. Mortensen 1, Charlotte H. Gotfredsen 4, Ikuro Abe 2 & Thomas O. Larsen 1 1234567890():,; Novofumigatonin (1), isolated from the fungus Aspergillus novofumigatus, is a heavily oxy- genated meroterpenoid containing a unique orthoester moiety. Despite the wide distribution of orthoesters in nature and their biological importance, little is known about the biogenesis of orthoesters. Here we show the elucidation of the biosynthetic pathway of 1 and the identification of key enzymes for the orthoester formation by a series of CRISPR-Cas9-based gene-deletion experiments and in vivo and in vitro reconstitutions of the biosynthesis. The novofumigatonin pathway involves endoperoxy compounds as key precursors for the orthoester synthesis, in which the Fe(II)/α-ketoglutarate-dependent enzyme NvfI performs the endoperoxidation. NvfE, the enzyme catalyzing the orthoester synthesis, is an Fe(II)- dependent, but cosubstrate-free, endoperoxide isomerase, despite the fact that NvfE shares sequence homology with the known Fe(II)/α-ketoglutarate-dependent dioxygenases. NvfE thus belongs to a class of enzymes that gained an isomerase activity by losing the α- ketoglutarate-binding ability. 1 Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, 2800 Kgs. Lyngby, Denmark. 2 Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan. 3 Department of Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong SAR, China.
    [Show full text]
  • Publikationsliste Internet
    Professor Dr. Alois Fürstner List of Publications 2020 F. Caló, A. Fürstner A Heteroleptic Dirhodium Catalyst for Asymmetric Cyclopropanation with -Stannyl -Diazoacetate. ‘Stereoretentive’ Stille Coupling with Formation of Chiral Quarternary Carbon Centers Angew. Chem. 2020, 132; 14004-14011, Angew. Chem. Int. Ed. 2020, 59, 13900-13907 H. Jin, A. Fürstner Modular Synthesis of Furans with up to Four Different Substituents by a trans‐Carboboration Strategy Angew. Chem. 2020, 132; 13720-13724, Angew. Chem. Int. Ed. 2020, 29, 1316-13622 Z. Meng, A. Fürstner Total Synthesis Provides Strong Evidence: Xestocyclamine A is the Enantiomer of Ingenamine J. Am. Chem. Soc. 2020, 142, 11703-11708 J. Hillenbrand, M. Leutzsch, E. Yiannakas, C. Gordon, C. Wille, N. Nöthling, C. Copéret, A. Fürstner “Canopy Catalysts” for Alkyne Metathesis: Molybdenum Alkylidyne Complexes with a Tripodal Ligand Framework J. Am. Chem. Soc.2020, 142, 11279-11294 M. Heinrich, J. Murphy, M. Ilg, A. Letort, J. Flasz, P. Philipps, A. Fürstner Chagosensine: A Riddle Wrapped in a Mystery Inside an Enigma J. Am. Chem. Soc. 2020, 142, 6409-6422 M. Buchsteiner, L. Martinez-Rodriguez, P. Jerabek, I. Pozo, M. Patzer, N. Nöthling, C. Lehmann, A. Fürstner Catalytic Asymmetric Fluorination of Copper Carbene Complexes: Preparative Advances and a Mechanistic Rationale Chem.–Eur. J. 2020, 26, 2509-2515 2019 S. Peil, A. Fürstner Mechanistic Divergence in the Hydrogenative Synthesis of Furans and Butenolides: Ruthenium Carbenes Formed by gem-Hydrogenation or via Carbophilic Activation of Alkynes Angew. Chem. 2019, 131; 18647-18652; Angew. Chem. Int. Ed. 2019, 58, 18476-18481 L. Huang, Y. Gu, A. Fürstner Iron Catalyzed Reactions of 2-Pyridone Derivatives: 1,6-Addition and Formal Ring Opening/Cross Coupling Chem.
    [Show full text]
  • Trisubstituted Push-Pull Nitro Alkenes
    The Free Internet Journal Review for Organic Chemistry Archive for Arkivoc 2020, part vii, 401-421 Organic Chemistry Trisubstituted push-pull nitro alkenes Branislav Pavilek* and Viktor Milata Institute of Organic Chemistry, Catalysis, and Petrochemistry, Faculty of Chemical and Food Technology, Slovak University of Technology, Radlinského 9, SK-812 37 Bratislava, Slovakia Email: [email protected] Dedicated to Professor Jan Bergman on the occasion of his 80th birthday. Received 02-18-2021 Accepted 04-19-2021 Published on line 04-30-2021 Abstract Properties, preparations, and utilization in the organic synthesis of the trisubstituted push-pull nitroalkenes are summarized from all the relevant results published until 2020. Preparation of these nitroalkenes is versatile due to numerous of the starting materials. The importance of reviewed nitroalkenes is outlined by their frequent exploitation in the synthesis of biologically active compounds, as well as a vast range of heterocyclic derivatives. Keywords: Push-pull nitroalkenes, nucleophilic vinylic substitution, heterocycles formation, nitroalkenes cycloadditions DOI: https://doi.org/10.24820/ark.5550190.p011.495 Page 401 ©AUTHOR(S) Arkivoc 2020, vii, 401-421 Pavilek, B. et al. Table of Contents 1. Introduction 2. Review 2.1. Isomerism 2.2. Preparation 2.2.1. Formation of nitroenolethers (A) 2.2.2. Formation of mono-N-substituted nitroenamines (B) 2.2.3. Formation of di-N,N-substituted nitroenamines (C) 2.2.4. Other preparations (D) 2.3. Utilization in organic synthesis 2.3.1. Reactions with mono-nucleophiles (E) 2.3.2. Reactions with 1,2-binucleophiles (F) 2.3.3. Reactions with 1,3-binucleophiles (G) 2.3.4.
    [Show full text]
  • Aldehydes Can React with Alcohols to Form Hemiacetals
    340 14 . Nucleophilic substitution at C=O with loss of carbonyl oxygen You have, in fact, already met some reactions in which the carbonyl oxygen atom can be lost, but you probably didn’t notice at the time. The equilibrium between an aldehyde or ketone and its hydrate (p. 000) is one such reaction. O HO OH H2O + R1 R2 R1 R2 When the hydrate reverts to starting materials, either of its two oxygen atoms must leave: one OPh came from the water and one from the carbonyl group, so 50% of the time the oxygen atom that belonged to the carbonyl group will be lost. Usually, this is of no consequence, but it can be useful. O For example, in 1968 some chemists studying the reactions that take place inside mass spectrometers needed to label the carbonyl oxygen atom of this ketone with the isotope 18 O. 16 18 By stirring the ‘normal’ O compound with a large excess of isotopically labelled water, H 2 O, for a few hours in the presence of a drop of acid they were able to make the required labelled com- í In Chapter 13 we saw this way of pound. Without the acid catalyst, the exchange is very slow. Acid catalysis speeds the reaction up by making a reaction go faster by raising making the carbonyl group more electrophilic so that equilibrium is reached more quickly. The the energy of the starting material. We 18 also saw that the position of an equilibrium is controlled by mass action— O is in large excess.
    [Show full text]
  • Orthoester Exchange: a Tripodal Tool for Dynamic Covalent and Systems
    Electronic Supplementary Material (ESI) for Chemical Science. This journal is © The Royal Society of Chemistry 2014 Supporting Information Orthoester Exchange: a Tripodal Tool for Dynamic Covalent and Systems Chemistry René-Chris Brachvogel and Max von Delius* Department of Chemistry and Pharmacy, University of Erlangen-Nürnberg, Henkestr. 42, 91054 Erlangen, Germany. * Fax: +49 9131 85 26864; Tel: +49 9131 85 22946; E-mail: [email protected] Contents General experimental section ....................................................................................................................S2 Reversibility of equilibration .....................................................................................................................S7 Investigation of solvents ...........................................................................................................................S11 Investigation of different orthoesters......................................................................................................S13 Investigation of different alcohols ...........................................................................................................S15 Treatment with bicarbonate solution .....................................................................................................S21 Analysis by GC-FID and HPLC-MS ......................................................................................................S23 Manipulation of equilibrium distribution ..............................................................................................S26
    [Show full text]
  • 1 Protecting Group Strategies in Carbohydrate Chemistry
    1 1 Protecting Group Strategies in Carbohydrate Chemistry Anne G. Volbeda, Gijs A. van der Marel, and Jeroen D. C. Codée Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333 CC, Leiden, The Netherlands Carbohydrates are the most densely functionalized class of biopolymers in nature. Every monosaccharide features multiple contiguous stereocenters and bears multiple hydroxyl functionalities. These can, in turn, be decorated with sulfate groups, acyl esters, lactic acid esters and ethers, or phosphate moieties. Amine and carboxylate functions can also be present. Most often, the amine groups are acetylated, but different amide functions are also found, as well as N‐sulfates and alkylated amines. The discrimination of the functional groups on a carbohydrate ring has been and continues to be one of the great challenges in synthetic carbohydrate chemistry [1–3]. This chapter describes the differences in the reactivity of the various func­ tional groups on a carbohydrate ring and how to exploit these in the design of effective protecting group strategies. The protecting groups on a carbohydrate dictate the reactivity of the (mono)saccharide, and this chapter will describe how protecting group effects can be used to control stereoselective transformations (most importantly, glycosylation reactions) and reactivity‐controlled one‐pot synthesis strategies. Applications and strategies in automated synthesis are also highlighted. 1.1 ­Discriminating Different Functionalities on a Carbohydrate Ring The main challenge in the functionalization of a carbohydrate (mono)saccharide is the discrimination of the different hydroxyl functionalities. The – often subtle – differences in reactivity can be capitalized upon to formulate effective protecting group strategies (see Scheme 1.1A).
    [Show full text]
  • Chapter 3. the Concept of Protecting Functional Groups
    Chapter 3. The Concept of Protecting Functional Groups When a chemical reaction is to be carried out selectively at one reactive site in a multifunctional compound, other reactive sites must be temporarily blocked. A protecting group must fulfill a number of requirements: • The protecting group reagent must react selectively (kinetic chemoselectivity) in good yield to give a protected substrate that is stable to the projected reactions. • The protecting group must be selectively removed in good yield by readily available reagents. • The protecting group should not have additional functionality that might provide additional sites of reaction. 3.1 Protecting of NH groups Primary and secondary amines are prone to oxidation, and N-H bonds undergo metallation on exposure to organolithium and Grignard reagents. Moreover, the amino group possesses a lone pair electrons, which can be protonated or reacted with electrophiles. To render the lone pair electrons less reactive, the amine can be converted into an amide via acylation. N-Benzylamine Useful for exposure to organometallic reagents or metal hydrides Hydrogenolysis Benzylamines are not cleaved by Lewis acid Pearlman’s catalyst Amides Basicity of nitrogen is reduced, making them less susceptible to attack by electrophilic reagent The group is stable to pH 1-14, nucleophiles, organometallics (except organolithium reagents), catalytic hydrogenation, and oxidation. Cleaved by strong acid (6N HCl, HBr) or diisobutylaluminum hydride Carbamates Behave like a amides, hence no longer act as nucleophile Stable to oxidizing agents and aqueous bases but may react with reducing agents. Iodotrimethylsilane is often the reagent for removal of this protecting group Stable to both aqueous acid and base Benzoyloxycarbonyl group for peptide synthesis t-butoxycarbonyl group(Boc) is inert to hydrogenolysis and resistant to bases and nucleophilic reagent.
    [Show full text]
  • Electronic Or Optoelectronic Device Comprising an Anchored Thin Molecular Layer, Process for Its Preparation and Compound Used Therein
    (19) TZZ Z _T (11) EP 2 840 622 A1 (12) EUROPEAN PATENT APPLICATION (43) Date of publication: (51) Int Cl.: 25.02.2015 Bulletin 2015/09 H01L 51/10 (2006.01) H01L 51/50 (2006.01) (21) Application number: 13180827.1 (22) Date of filing: 19.08.2013 (84) Designated Contracting States: • Lüssem, Björn AL AT BE BG CH CY CZ DE DK EE ES FI FR GB 01127 Dresden (DE) GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO •Leo,Karl PL PT RO RS SE SI SK SM TR 01219 Dresden (DE) Designated Extension States: • Fischer, Axel BA ME 01097 Dresden (DE) (71) Applicant: Novaled GmbH (74) Representative: Bittner, Thomas L. 01307 Dresden (DE) Boehmert & Boehmert Anwaltspartnerschaft mbB (72) Inventors: Patentanwälte Rechtsanwälte • Nicht, Sylvia Pettenkoferstrasse 20-22 01187 Dresden (DE) 80336 München (DE) •Blochwitz-Nimoth, Jan 01097 Dresden (DE) (54) Electronic or optoelectronic device comprising an anchored thin molecular layer, process for its preparation and compound used therein (57) The application concerns materials for self as- (EWG) group, such as tetrafluorotetracyanoquin- sembled (SAM) charge injection layers on electrodes of odimethane (F4TCNQ), hexaazatriphenylene (HAT) and organic electronic devices. The materials comprise an hexaazatriphenylene hexacarbonitrile (HATCN). The anchoring group, such as a thiol, a spacer group selected spacer group is connected to the EWG via a single bond from nitrogen aromatic heterocycles and aromatic rings from a nitrogen of the spacer group to a mehtylidenyl substituted with an amine, and an electron withdrawing group of the EWG. EP 2 840 622 A1 Printed by Jouve, 75001 PARIS (FR) EP 2 840 622 A1 Description [0001] The present invention relates to an electronic or optoelectronic device comprising an anchored thin molecular layer.
    [Show full text]
  • Thiazolo[3,2-B][1,2,4]Triazolium Cationic Surfactant
    Article Volume 11, Issue 6, 2021, 13885 - 13892 https://doi.org/10.33263/BRIAC116.1388513892 Synthetic Strategy and Structure Characterization of a New [1,3]Thiazolo[3,2-b][1,2,4]Triazolium Cationic Surfactant Maksym Fizer 1,* , Mikhailo Slivka 2 , Oksana Fizer 3 1 Department of Organic Chemistry, Faculty of Chemistry, Uzhhorod National University, Fedinets', Str. 53/1, 88000, Uzhhorod, Ukraine; [email protected] (M.F.); [email protected] (M.S.); [email protected] (O.F.); * Correspondence: [email protected]; (M.F.); Scopus Author ID 55823743600 Received: 20.01.2021; Revised: 21.02.2021; Accepted: 24.02.2021; Published: 1.03.2021 Abstract: Here, we present a synthetic strategy to access a new [1,3]thiazolo[3,2-b][1,2,4]triazolium- based cationic surfactant via the use of proton-induced heterocyclization method for quaternization of a nitrogen atom. The two-step synthesis of 2-heptyl-6,6-dimethyl-3-phenyl-5,6-dihydro-3H- [1,3]thiazolo[3,2-b][1,2,4]triazol-7-ium perchlorate is described in details. The analysis of NMR spectra unequivocally proved the formation of the 1,3-thiazolinium ring upon cyclization reaction. PM7 semiempirical calculations testify to the similar electronic structure of the newly synthesized surfactant cation and 1-heptylpyridinium cation. Keywords: 1,2,4-triazole; alkylation; cyclization; surfactant; NMR; cation; PM7; semiempirical. © 2021 by the authors. This article is an open-access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
    [Show full text]