DOCSLIB.ORG

Recent Developments on the Carbamation of Amines

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Recent Developments on the Carbamation of Amines View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by IR@NEIST - North East Institute of Science and Technology (CSIR) Current Organic Chemistry, 2011, 15, 1593-1624 1593 Recent Developments on the Carbamation of Amines Devdutt Chaturvedi* Natural Products Chemistry Division, North-East Institute of Science and Technology (CSIR), Jorhat-785006, Assam, India. Abstract: Organic carbamates represent an important class of compounds showing various interesting properties. They find wide utility in various areas as pharmaceuticals, agrochemicals (pesticides, herbicides, insecticides, fungicides etc.), intermediates in organic synthe- sis, protection of amino group in peptide chemistry, and as linker in combinatorial chemistry etc. Classical synthesis of carbamates in- volves use of harmful reagents such as phosgene, its derivatives and carbon monoxide. Recently, various kinds of synthetic methods have been developed for the synthesis of organic carbamates. In the present review, I would like to highlight the recent developments on the synthesis of organic carbamates using variety of reagents. Keywords: Carbamation, amines, carbamates. 1. INTRODUCTION in organic synthesis [7], for the protection of amino groups in pep- tide chemistry [8], as linkers in combinatorial chemistry [9] etc. Organic carbamates are the stable class of compounds derived Functionalization of amines as carbamates offers an attractive from the unstable carbamic acid (H N-COOH) by the substitution 2 method for the generation of derivatives, which may have interest- of amino and acid ends through the various kinds of structurally ing medicinal and biological properties [10]. Organic carbamates diverse alkyl/aryl, aryl-alkyl or substituted alkyl/aryl and aryl-alkyl have been extensively used as useful synthons for the synthesis of groups, and are identified by the presence of the linkage O-CO-NH- structurally diverse synthetic intermediates/molecules of biological [1, 2]. When the carbamate linkage is present in a cyclic system, significance [11]. Therefore, considerable interest has been gener- this class of compounds is referred to as cyclic carbamates [3]. ated in the recent past for the development of efficient and safe When the carbamate group is attached with any inorganic atom methodologies for carbamate esters synthesis. either metal or non metal, such compounds are referred to as inor- ganic carbamates [4]. Organic carbamates have frequently been employed as de- mandable pharmaceuticals in the forms of drugs and prodrugs [12]. The reaction of carbamation of amines has frequently been util- In recent years, several reports have indicated that carbamate link- ized in the synthesis of organic carbamates which holds unique age present in between the active pharmacophores of various struc- applications in the field of pharmaceuticals [5], agrochemicals (pes- turally diverse molecules increases manifold biological activities of ticides, herbicides, insecticides, fungicides etc.) [6], intermediates semisynthetic/synthetic natural/synthetic molecules [13]. Further- O R1 OH O OH H3CHN O R2 O N NH O R3 O N O O Physostigmine: Anti-alzheimer drug OH AcO OH O O O O N N O O Taxol analogues: anticancer drugs F NH Linezolid: Antibacterial drug N O Cl S N O NHCH3 O N O NH2 Cl Carbaryl: Insecticide Capravirine: anti-HIV Fig. (1). Biologically active drug molecules bearing carbamate linkage. *Address correspondence to this author at the Natural Products Chemistry Division, North-East Institute of Science and Technology (CSIR), Jorhat-785006, Assam, India; Tel: ------- ----------; Fax: 91-376-2370011; E-mail: [email protected] 1385-2728/11 $58.00+.00 © 2011 Bentham Science Publishers Ltd. 1594 Current Organic Chemistry, 2011, Vol. 15, No. 10 Devdutt Chaturvedi Carbamates Inorganic Organic Metal Non metal Saturated Unsaturated Symmetrical Unsymmetrical Aliphatic Aliphatic-aromatic Aromatic Others Simple Substituted Simple Activated Cyclic Simple Functional Thio Imido Ortho Pyro Linear Branched Alicyclic Linear-alicyclic Symmetrical Unsymmetrical Symmetrical Unsymmetrical Simple Substituted Fig. (2). Classification of carbamates. more, the role of carbamate linkage have been extensively studied toxic which limits its use. Safer substitutes have been proposed in structurally diverse natural/semisynthetic molecules against vari- such as 1,1,1-Trichloromethylformate (Diphosgene, 2) [17], and ous disease such as anti-cancer, anti-bacterial, anti-fungal, anti- bis-(1,1,1-trichloromethyl) carbonate (Triphosgene 3) [18], which malarial, anti-viral, anti-HIV, anti-estrogenic, anti-progestational, are frequently used in recent years. Depolymerization of 3 into 1 anti-osteoporosis, anti-inflammatory, anti-filarial, anti-tubercular, has widely replaced phosgene by triphosgene, which is relatively anti-diabetic, anti-obesity, anti-convulsant, anti-helminthes, Alz- safer to use [19]. Thus, carbamates 6 synthesis has been achieved heimer disease, CNS and CVS active etc [14, 15, 13, 5]. Some of through the reaction of an amine 4 with an alcohol 5 using either 1, the important biologically active drug molecules bearing carba- or 2 or 3 as source of carbonyl equivalent (Scheme 1). mates have shown in Fig. (1). O O Cl Cl O Cl Cl Cl Cl 2. CLASSIFICATION OF CARBAMATES C C Cl Cl Cl O O O Carbamates can be mainly classified into two groups, namely 1 23Cl Cl Cl inorganic and organic. Depending upon the structural variations on the attached moieties they are further classified as shown in Fig. O O (2). R NH + + R OH 1 2 X X 2 4 NHR1 OR2 3. METHODS OF PREPARATION (either 1 or 2 or 3) 5 6 3.1. Phosgenation Technique Scheme 1. Phosgene (1) is a potentially useful, versatile building block in organic synthesis [16]. It offers the possibility of binding two nu- Chloroformates and isocyanates are intermediates produced cleophilic units to the same carbon atom and such two-component from phosgene, have frequently been employed in the synthesis of system is particularly well suited for the combinatorial synthesis of organic carbamates. Chloroformates [20] 7, can be obtained through carbonate, ureas and carbamate (Scheme 1). Phosgene is extremely the reaction of alcohol/phenol 5 with phosgene 1, reacts with Recent Developments on the Carbamation of Amines Current Organic Chemistry, 2011, Vol. 15, No. 10 1595 amines/substituted amines 4 (i.e. aminolysis) afforded carbamates ketone 11 in the presence of Sn4+ modified Zeolite H (H-SnA) at [21] 6 (Scheme 2). Carbamates synthesis through the chlorofor- room temperature (Scheme 5). mates route has been achieved using different reaction conditions O O such as use of strong bases [22] (NaOH, NaHCO3, Et3N, pyridine 11 and triphenylphosphene), metals [23], ultrasound [24], RNH2 + ClCOOR1 bis(trimethylsilyl)acetamide [21] in combination with azides [23]. 24h, 68-75% 4 7 RNCOOR1 4 12 O O O R1NH2 R2OH + Scheme 5. 5 Cl Cl R O Cl 1 2 7 R2O 6 NHR1 More recently, Kim and Jung have reported [28] a simple and efficient synthesis of carbamates 6, through reacting equimolar Scheme 2. amounts of amines 4, chloroformates 7, and Indium metal (Scheme In recent years, there has been much attention on the synthesis 6). Thus, carbamates of structurally diverse substituted aliphatic, of carbamates using chloroformates as key intermediate. Thus, aromatic, heterocyclic amines were prepared using various kinds of Pandey et al have reported [25] an efficient synthesis of carbamates chloroformates. 6 through the reaction of variety of amines 4 with chloroformates 7 O using catalytic amount of Yttria-Zirconium based Lewis acid cata- O lyst (Scheme 3). In, OR RNH2 + Cl OR RHN 1 Yttria-zirconia based 1 rt, 7-12h, 4 7 6 Lewis acid catalyst 73-91% RNH + ClCOOR1 RNHCOOR 2 1 R = - CH ,-CH=CH , Bn r.t., 5 min-6h, 88-96% 1 3 2 4 7 6 Scheme 6. Scheme 3. Isocyanates [29] 13, obtained through the reaction of phosgene Later on, Mormeneo et al have reported [26] a versatile method 1 and amines 4, react with hydroxy compounds 5 (i.e. alco- for the synthesis of carbamates 6 through an in-situ generated hols/phenols) afforded the corresponding carbamates (Scheme 7) polymer supported chloroformate resin 9. Bis-trichloromethyl car- [30]. Polyurethanes [31], the building blocks of isocyanates have bonate (BTC) has been used as a phosgene equivalent to afford a been used in industry. Synthesis of carbamates starting from isocy- supported chloroformate 9, which on sequential one-pot reaction of anates could be achieved through the use of strong bases [32], and variety of alcohols 5 with amines 4 afforded the corresponding metal halides [33] etc. Carbamates could be converted into isocy- carbamates 6 in high yields (Scheme 4). O O 5 BTC RCH OH OH 2 O Cl O OCH R Pyr 2 Pyr 10 8 9 R1 75-99% NH R2 4 O R1 N OCH2R 6 R2 Scheme 4. O O + R2OH + RNH2 R1-N=C=O 4 - R2OH R O NHR Cl Cl 13 2 1 1 6 Scheme 7. Raje et al have reported [27] an efficient, one-pot synthesis of anates by thermal decomposition at higher temperatures using dif- N-substituted (3-oxobutyl) carbamates 12, via tandem condensation ferent reaction conditions such as use of metal catalysts [34], of primary amines 4, with methyl chloroformate 7 followed by the chlorocatecholborane/boron halides with triethylamine [35], silanes conjugate addition of the resulting carbamates with methyl vinyl [36], chlorosilanes [37], dichlorosilanes [38], Mitsunobu’s reaction 1596 Current Organic Chemistry, 2011, Vol. 15, No. 10 Devdutt Chaturvedi conditions [39], montmorillonite K-10 [40], Bi2O3 [41], and re- NEt4Cl as a cocatalyst that the alcohol participates in the catalytic cently used basic metal oxide nanoparticles [42] etc. cycle, since when it was absent, practically no isocyanate was ob- tained (Scheme 9). 3.2. Reductive Carbonylation of Nitro-aromatics Several reports have been published by Gladfelter and Cenini The reductive carbonylation of aromatic nitro-compounds 14 to giving more insight into the mechanism of the catalytic cycle of the the corresponding carbamates is an interesting approach towards rhodium and ruthenium catalysts.
Load more

Recommended publications
  • Synthesis and Characterization of Toluene Diisocyanate
    SYNTHESIS AND CHARACTERIZATION OF TOLUENE DIISOCYANATE A THESIS SUBMITTED TO THE GRADUATE SCHOOL OF NATURAL AND APPLIED SCIENCES OF MIDDLE EAST TECHNICAL UNIVERSITY BY AYŞEGÜL HİSAR TELLİ IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE IN CHEMISTRY NOVEMBER 2014 Approval of the thesis: SYNTHESIS AND CHARACTERIZATION OF TOLUENE DIISOCYANATE submitted by AYŞEGÜL HİSAR TELLİ in partial fulfillment of the requirements for the degree of Master of Science in Chemistry Department, Middle East Technical University by, Prof. Dr. Gülbin Dural Ünver _____________________ Dean, Graduate School of Natural and Applied Sciences Prof. Dr. İlker Özkan _____________________ Head of Department, Chemistry Prof. Dr. Özdemir Doğan _____________________ Supervisor, Chemistry Dept., METU Examining Committee Members: Prof. Dr. Cihangir Tanyeli _____________________ Chemistry Dept., METU Prof. Dr. Özdemir Doğan _____________________ Chemistry Dept., METU Prof. Dr. Metin Zora _____________________ Chemistry Dept., METU Prof. Dr. Adnan Bulut _____________________ Chemistry Dept., Kırıkkale University Dr. E. Görkem Günbaş _____________________ Chemistry Dept., METU Date: 28.11.2014 I hereby declare that all information in this document has been obtained and presented in accordance with academic rules and ethical conduct. I also declare that, as required by these rules and conduct, I have fully cited and referenced all material and results that are not original to this work. Name, Last name: Ayşegül Hisar Telli Signature: iv ABSTRACT SYNTHESIS AND CHARACTERIZATION OF TOLUENE DIISOCYANATE Hisar Telli, Ayşegül M.S., Department of Chemistry Supervisor: Prof. Dr. Özdemir Doğan November 2014, 52 pages Toluene diisocyanate (TDI) is one of the important components of solid rocket propellants. It is used for the construction of polyurethane network by reacting with hydroxy terminated polybutadiene (HTPB) and functions as a curing agent.
    [Show full text]
  • The Total Synthesis of Securinine and Other Methodology Studies
    University of Windsor Scholarship at UWindsor Electronic Theses and Dissertations Theses, Dissertations, and Major Papers 2010 The total synthesis of securinine and other methodology studies Bhartesh Dhudshia University of Windsor Follow this and additional works at: https://scholar.uwindsor.ca/etd Recommended Citation Dhudshia, Bhartesh, "The total synthesis of securinine and other methodology studies" (2010). Electronic Theses and Dissertations. 8275. https://scholar.uwindsor.ca/etd/8275 This online database contains the full-text of PhD dissertations and Masters’ theses of University of Windsor students from 1954 forward. These documents are made available for personal study and research purposes only, in accordance with the Canadian Copyright Act and the Creative Commons license—CC BY-NC-ND (Attribution, Non-Commercial, No Derivative Works). Under this license, works must always be attributed to the copyright holder (original author), cannot be used for any commercial purposes, and may not be altered. Any other use would require the permission of the copyright holder. Students may inquire about withdrawing their dissertation and/or thesis from this database. For additional inquiries, please contact the repository administrator via email ([email protected]) or by telephone at 519-253-3000ext. 3208. The Total Synthesis of Securinine and Other Methodology Studies by Bhartesh Dhudshia A Dissertation Submitted to the Faculty of Graduate Studies through the Department of Chemistry and Biochemistry in Partial Fulfillment of the Requirements
    [Show full text]
  • Synthesis and Consecutive Reactions of Α-Azido Ketones: a Review
    Molecules 2015, 20, 14699-14745; doi:10.3390/molecules200814699 OPEN ACCESS molecules ISSN 1420-3049 www.mdpi.com/journal/molecules Review Synthesis and Consecutive Reactions of α-Azido Ketones: A Review Sadia Faiz 1,†, Ameer Fawad Zahoor 1,*, Nasir Rasool 1,†, Muhammad Yousaf 1,†, Asim Mansha 1,†, Muhammad Zia-Ul-Haq 2,† and Hawa Z. E. Jaafar 3,* 1 Department of Chemistry, Government College University Faisalabad, Faisalabad-38000, Pakistan, E-Mails: [email protected] (S.F.); [email protected] (N.R.); [email protected] (M.Y.); [email protected] (A.M.) 2 Office of Research, Innovation and Commercialization, Lahore College for Women University, Lahore-54600, Pakistan; E-Mail: [email protected] 3 Department of Crop Science, Faculty of Agriculture, Universiti Putra Malaysia, Serdang-43400, Selangor, Malaysia † These authors contributed equally to this work. * Authors to whom correspondence should be addressed; E-Mails: [email protected] (A.F.Z.); [email protected] (H.Z.E.J.); Tel.: +92-333-6729186 (A.F.Z.); Fax: +92-41-9201032 (A.F.Z.). Academic Editors: Richard A. Bunce, Philippe Belmont and Wim Dehaen Received: 20 April 2015 / Accepted: 3 June 2015 / Published: 13 August 2015 Abstract: This review paper covers the major synthetic approaches attempted towards the synthesis of α-azido ketones, as well as the synthetic applications/consecutive reactions of α-azido ketones. Keywords: α-azido ketones; synthetic applications; heterocycles; click reactions; drugs; azides 1. Introduction α-Azido ketones are very versatile and valuable synthetic intermediates, known for their wide variety of applications, such as in amine, imine, oxazole, pyrazole, triazole, pyrimidine, pyrazine, and amide alkaloid formation, etc.
    [Show full text]
  • Topologically Designed Cylindrical and Spherical Building
    TOPOLOGICALLY DESIGNED CYLINDRICAL AND SPHERICAL BUILDING BLOCKS TO CONSTRUCT MODULAR-ASSEMBLED STRUCTURES IN GIANT SHAPE-AMPHPHILES A Dissertation Presented to The Graduate Faculty of The University of Akron In Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy Jing Jiang May 2018 TOPOLOGICALLY DESIGNED CYLINDRICAL AND SPHERICAL BUILDING BLOCKS TO CONSTRUCT MODULAR-ASSEMBLED STRUCTURES IN GIANT SHAPE-AMPHPHILES Jing Jiang Dissertation Approved: Accepted: Advisor Department Chair Dr. Stephen Z. D. Cheng Dr. Coleen Pugh Committee Chair Dean of the College Dr. Toshikazu Miyoshi Dr. Eric J. Amis Committee Member Dean of the Graduate School Dr. Tianbo Liu Dr. Chand K. Midha Committee Member Date Dr. Yu Zhu Committee Member Dr. Chrys Wesdemiotis ii ABSTRACT Giant shape amphiphiles with isobutyl polyhedral oligomeric silsesquioxane (BPOSS) cages as the periphery at two discotic trisubstituted derivative of benzene cores were specifically designed and synthesized. Depending upon the number of BPOSS cages, these molecules first assembled into either cylindrical or spherical units via π-π interactions among the core unites. The packing of the molecules is mandated by the steric hindrance of the BPOSS cages at the periphery with hydrogen bonding interactions. If the space-packing is allowed, the cylindrical building block can form. Otherwise, the cylindrical building block will be forced to interrupt periodically and to form spherical building blocks. These units can further modular assemble into supramolecular structures. The cylindrical units form columnar structures with both hexagonal and rectangular packing, while the spherical units construct a Frank-Kasper A15 phase, similar to the metal alloy structures. In addition, based on the mechanism proposed by this work, five more giant shape amphiphiles with high steric hindrance on the periphery were synthesized, these giant shape amphiphiles successfully formed A15 phases with precisely size control, iii validating the reliability of this strategy.
    [Show full text]
  • Staudinger Ligation: a Peptide from a Thioester and Azide
    ORGANIC LETTERS 2000 Staudinger Ligation: A Peptide from a Vol. 2, No. 13 Thioester and Azide 1939-1941 Bradley L. Nilsson,† Laura L. Kiessling,†,‡ and Ronald T. Raines*,†,‡ Departments of Chemistry and Biochemistry, UniVersity of Wisconsin-Madison, Madison, Wisconsin 53706 [email protected] Received May 4, 2000 ABSTRACT The technique of native chemical ligation enables the total chemical synthesis of proteins. This method is limited, however, by an absolute requirement for a cysteine residue at the ligation juncture. Here, this restriction is overcome with a new chemical ligation method in which a phosphinobenzenethiol is used to link a thioester and azide. The product is an amide with no residual atoms. New methods are facilitating the total chemical synthesis of residue in one peptide attacks the carbon of a C-terminal proteins.1 In particular, Kent and others have developed an thioester in another peptide to produce, ultimately, an amide elegant means to stitch together two unprotected peptides in bond between the two peptides (Scheme 1). Recently, Muir aqueous solution.2 In this method, which is called “native chemical ligation”, the thiolate of an N-terminal cysteine Scheme 1 † Department of Chemistry. ‡ Department of Biochemistry. (1) For historical references, see: (a) Merrifield, R. B. Science 1984, 232, 341-347. (b) Kent, S. B. Annu. ReV. Biochem. 1988, 57, 957-989. (c) Kaiser, E. T. Acc. Chem. Res. 1989, 22,47-54. (2) Dawson, P. E.; Muir, T. W.; Clark-Lewis, I.; Kent, S. B. Science 1994, 266, 776-779. For important precedents, see: (a) Wieland, T.; Bokelmann, E.; Bauer, L.; Lang, H.
    [Show full text]
  • Benzyl Chloroformate (CHLOROFORMIC ACID, BENZYL ESTER)
    Rev B Benzyl Chloroformate (CHLOROFORMIC ACID, BENZYL ESTER) C8H7O2Cl Molecular Weight = 170.6 CAS# 501‐53‐1 SPECIFICATIONS Assay: 98.% min. Color (APHA): 50 max. Benzyl Alcohol: 0.1% max. Hydrogen Chloride: 0.1% max. Benzyl Chloride: 1.5% max. Phosgene: 0.1% max. Dibenzyl Carbonate: 0.5% max. Iron: 1.5 PPM max. PHYSICAL PROPERTIES Appearance: Clear liquid free of visible contaminants BP: Decomposes at elevated temperature Odor: Pungent Density: 1.195 ‐1.22 MP/Range: ‐30°C Flash Point: 126°C NOTICE: The technical information and suggestions for use made herein are based on VanDeMark’s research and experience and are believed to be reliable, but such information and suggestions do not constitute a warranty, and no patent liability can be assumed. This publication is not to be taken as a license to operate under or infringe on any patents. Since VanDeMark has no control over the conditions under which the product is transported, stored, handled, used or applied, buyer must determine for himself by preliminary tests or otherwise, the suitability of the product for his purposes. VanDeMark’s liability on any basis is limited to the price of the product used. The information in this bulletin supersedes all previously issued bulletins on the subject matter covered. VanDeMark Benzyl Chloroformate APPLICATIONS SPILLS AND DISPOSAL Benzyl Chloroformate is a reactive chemical intermediate Use personal protective equipment (see MSDS). used in the synthesis of pharmaceutical and agrochemical Evacuate personnel to safe areas. Dike far ahead of products. It is used as a reagent in peptide synthesis to liquid spill for later disposal.
    [Show full text]
  • Organic Electrochemistry: Synthesis and Functionalization of Β-Lactams In
    Heterocyclic Communications 2021; 27: 32–44 Review Article Martina Bortolami, Isabella Chiarotto, Leonardo Mattiello, Rita Petrucci, Daniele Rocco, Fabrizio Vetica and Marta Feroci* Organic electrochemistry: Synthesis and functionalization of β-lactams in the twenty-first century https://doi.org/10.1515/hc-2020-0121 Keywords: cathodic reduction, anodic oxidation, azetidin- received December 01, 2020; accepted March 03, 2021 2-ones, electroorganic synthesis, electrogenerated base Abstract: Organic electrochemistry is a technique that allows for the heterogeneous redox reactions avoiding both the use of stoichiometric amounts of redox reagents and the resulting formation of stoichiometric by-pro- 1 Introduction ducts. In fact, the redox reagent in these reactions is β- ( - - ) - the electron, which is naturally eco-friendly and pro- Lactams azetidin 2 ones; Figure 1 are four membered duces no side compounds. It is therefore quite obvious heterocyclic compounds containing an amide moiety. - that electrochemistry can be classified as a “green” tech- This class of molecules is so famous in medicinal chem nology. The use of this methodology in the synthesis of istry that there is no need to describe their importance in fi - β-lactams is not a novelty, but the growing interest in this the antibiotic eld. In fact, since the discovery of peni β- class of biologically active compounds, due to the dis- cillin in 1928 by Fleming, lactam antibiotics have been covery of new fields of application (after a moment of extensively used as antibacterial agents, their use being decrease in interest due to antibiotic resistance) has less frequent in recent years due to the onset of antibiotic [ ] been a stimulus for the search for more efficient electro- resistance 1,2 .
    [Show full text]
  • Switch Peptide Via Staudinger Reaction Vol
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Infoscience - ÉcoleORGANIC polytechnique fédérale de Lausanne LETTERS 2008 Switch Peptide via Staudinger Reaction Vol. 10, No. 22 5243-5246 Natalia Nepomniaschiy,† Valerie Grimminger,‡ Aviv Cohen,† Saviana DiGiovanni,‡ Hilal A. Lashuel,*,‡ and Ashraf Brik*,† Department of Chemistry, Ben-Gurion UniVersity of the NegeV, P.O. Box 653, Beer SheVa 84105, Israel, and Brain Mind Institute, Ecole Polytechnique Federale de Lausanne (EPFL), 1015 Lausanne, Switzerland hilal.lashuel@epfl.ch; [email protected] Received September 29, 2008 ABSTRACT A new transformation based on the Staudinger reaction is described, and its application in the design of a novel switch element to control peptide folding is demonstrated. We found that the azide switch is activated rapidly in water to promote acyl transfer using tris(2-carboxyethyl)phosphine hydrochloride (TCEP) via the Staudinger reaction. Our findings expand the repertoire of uses of the Staudinger reaction in chemical biology and the number of available triggers for use in switch peptides. The Staudinger reaction, discovered nearly a century ago, While the aza-ylide intermediate is known to be stable in occurs between a phosphine and an azide to form an aza- organic solvents, it tends to hydrolyze rapidly in aqueous ylide.1 This transformation has been exploited in several media to furnish the primary amine and the phosphine oxide reactions of high synthetic importance wherein the aza-ylide products. In the traceless Staudinger ligation, however, the intermediate, with its highly nucleophilic nitrogen atom, reduction of the azide to amine is a competing side reaction, serves to trap various electrophiles.2 Staudinger ligation is thus reversing the capture step and leading to two peptide 4 one example of such reactions, in which an ester moiety is fragments.
    [Show full text]
  • Influence of Sulfur for Oxygen Substitution in the Solvolytic Reactions of Chloroformate Esters and Related Compounds
    Int. J. Mol. Sci. 2014, 15, 18310-18332; doi:10.3390/ijms151018310 OPEN ACCESS International Journal of Molecular Sciences ISSN 1422-0067 www.mdpi.com/journal/ijms Review Influence of Sulfur for Oxygen Substitution in the Solvolytic Reactions of Chloroformate Esters and Related Compounds Malcolm J. D’Souza 1,†,* and Dennis N. Kevill 2,†,* 1 Department of Chemistry, Wesley College, 120 N. State Street, Dover, DE 19901-3875, USA 2 Department of Chemistry and Biochemistry, Northern Illinois University, DeKalb, IL 60115-2862, USA † These authors contributed equally to this work. * Authors to whom correspondence should be addressed; E-Mails: [email protected] (M.J.D.); [email protected] (D.N.K.); Tel.: +1-302-736-2528 (M.J.D.); +1-815-753-6882 (D.N.K.); Fax: +1-302-736-2301 (M.J.D.); +1-815-753-4802 (D.N.K.). External Editor: Habil. Mihai V. Putz Received: 10 September 2014; in revised form: 22 September 2014 / Accepted: 29 September 2014 / Published: 10 October 2014 Abstract: The replacement of oxygen within a chloroformate ester (ROCOCl) by sulfur can lead to a chlorothioformate (RSCOCl), a chlorothionoformate (ROCSCl), or a chlorodithioformate (RSCSCl). Phenyl chloroformate (PhOCOCl) reacts over the full range of solvents usually included in Grunwald-Winstein equation studies of solvolysis by an addition-elimination (A-E) pathway. At the other extreme, phenyl chlorodithioformate (PhSCSCl) reacts across the range by an ionization pathway. The phenyl chlorothioformate (PhSCOCl) and phenyl chlorothionoformate (PhOCSCl) react at remarkably similar rates in a given solvent and there is a dichotomy of behavior with the A-E pathway favored in solvents such as ethanol-water and the ionization mechanism favored in aqueous solvents rich in fluoroalcohol.
    [Show full text]
  • Photoremovable Protecting Groups in Chemistry and Biology: Reaction Mechanisms and Efficacy Petr Klan,́*,†,‡ Tomaś̌solomek,̌ †,‡ Christian G
    Review pubs.acs.org/CR Photoremovable Protecting Groups in Chemistry and Biology: Reaction Mechanisms and Efficacy Petr Klan,́*,†,‡ Tomaś̌Solomek,̌ †,‡ Christian G. Bochet,§ Aurelień Blanc,∥ Richard Givens,⊥ Marina Rubina,⊥ Vladimir Popik,# Alexey Kostikov,# and Jakob Wirz∇ † Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic ‡ Research Centre for Toxic Compounds in the Environment, Faculty of Science, Masaryk University, Kamenice 3, 625 00 Brno, Czech Republic § Department of Chemistry, University of Fribourg, Chemin du Museé 9, CH-1700 Fribourg, Switzerland ∥ Institut de Chimie, University of Strasbourg, 4 rue Blaise Pascal, 67000 Strasbourg, France ⊥ Department of Chemistry, University of Kansas, 1251 Wescoe Hall Drive, 5010 Malott Hall, Lawrence, Kansas 66045, United States # Department of Chemistry, University of Georgia, Athens, Georgia 30602, United States ∇ Department of Chemistry, University of Basel, Klingelbergstrasse 80, CH-4056 Basel, Switzerland 7.3. Arylsulfonyl Group 160 7.4. Ketones: 1,5- and 1,6-Hydrogen Abstraction 160 7.5. Carbanion-Mediated Groups 160 7.6. Sisyl and Other Silicon-Based Groups 161 7.7. 2-Hydroxycinnamyl Groups 161 7.8. α-Keto Amides, α,β-Unsaturated Anilides, CONTENTS and Methyl(phenyl)thiocarbamic Acid 162 7.9. Thiochromone S,S-Dioxide 162 1. Introduction 119 7.10. 2-Pyrrolidino-1,4-Benzoquinone Group 162 2. Arylcarbonylmethyl Groups 121 7.11. Triazine and Arylmethyleneimino Groups 162 2.1. Phenacyl and Other Related Arylcarbonyl- 7.12. Xanthene and Pyronin Groups 163 methyl Groups 121 o 7.13. Retro-Cycloaddition Reactions 163 2.2. -Alkylphenacyl Groups 123 8. Sensitized Release 163 2.3. p-Hydroxyphenacyl Groups 125 p 8.1.
    [Show full text]
  • Siteselective Traceless Staudinger Ligation for Glycoprotein Synthesis Reveals Scope and Limitations
    DOI: 10.1002/cbic.201100125 Site-Selective Traceless Staudinger Ligation for Glycoprotein Synthesis Reveals Scope and Limitations GonÅalo J. L. Bernardes, Lars Linderoth, Katie J. Doores, Omar Boutureira, and Benjamin G. Davis*[a] Efficient, chemoselective reactions enable access to well-de- al stability towards hydrolases as previously demonstrated for fined post-translationally modified proteins.[1–4] One approach other natural substrates.[32,33] The construction of glycoproteins involves the positioning of a reactive moiety within a side bearing this unnatural motif may also circumvent problems en- chain that may be chemoselectively addressed (a tag-and- countered in chemoenzymatic syntheses of glycoproteins by modify approach).[5] Among functionalities, the azide group using endoglycosidases[34] and provide a linkage more resistant has received attention since it can be installed in biopolymers to hydrolysis than natural Asn-linked glycoconjugates.[35] Our (e.g., by using auxotrophic or non-natural expression as well as strategy is based on a “tag-and-modify” approach[5] and ex- metabolic and enzymatic processes[6,7]) and has been used in ploits the introduction into proteins of Aha[20] (tag) that may installation of post-translational modifications and mimics[8,9] be chemoselectively addressed (modified) using traceless Stau- and/or protein labelling[2–4, 10] in combination with Huisgen cy- dinger conditions mild enough to retain protein activity cloaddition reactions that are CuI catalysed[11,12] (CCHC) or throughout (Scheme 1). strain promoted.[13–16] The Staudinger reaction[17] is another azide-selective reaction that has been used, for example, to modify cell surface carbo- hydrates,[18,19] and to label proteins that contain azidohomoala- nine (Aha).[20] The reaction proceeds by attack of phosphine on azide to form an aza-ylid intermediate (Scheme S1A in the Supporting Information).
    [Show full text]
  • Advanced Studies on the Synthesis of Organophosphorus Compounds
    ALMA MATER STUDIORUM UNIVERSITÀ DI BOLOGNA DOTTORATO DI RICERCA IN SCIENZE CHIMICHE (XIX° ciclo) Area 03 Scienze Chimiche-CHIM/06 Chimica Organica Dipartimento di Chimica Organica “A. Mangini” Coordinatore: Chiar.mo Prof. Vincenzo Balzani Advanced Studies on the Synthesis of Organophosphorus Compounds Dissertazione Finale Presentata da: Relatore: Dott. ssa Marzia Mazzacurati Prof. Graziano Baccolini Co-relatore: Dott.ssa Carla Boga INDEX Index: Keywords…………………………………………………………….………….VII Chapter 1…………………………………………………………………………..3 GENERAL INTRODUCTION ON PHOSPHORUS CHEMISTRY 1.1 Organophosphorus Chemistry………………………………………………….4 1.1.1 Phosphines………………………………………………………………..5 1.1.2 Phosphonates……………………………………………………………..6 1.1.3 Phosphites………………………………………………………………...7 1.2 Uses of Organophosphorus Compounds………………………………………..7 1.2.1 Agricultural Application………………………………………………….8 1.2.2 Catalysis……………………………………………………………..…....9 1.2.3 Organophosphorus Conpounds in Medicine…………………………….11 1.2.4 Phosphorus in Biological Compounds…………………………………..12 1.3 References……………………………………………………………………..15 Chapter 2…………………………………………………………………………17 THE HYPERCOORDINATE STATES OF PHOSPHORUS 2.1 The 5-Coordinate State of Phosphorus……………………………………….17 2.2 Pentacoordinated structures and their non rigid character…………………….18 2.3 Permutational isomerization…………………………………………………..19 2.3.1 Berry pseudorotation……………………………………………………20 2.3.2 Turnstile rotation………………………………………………………..21 2.4 The 6-Coordinate State of Phosphorus……………………………………….22 2.5 References…………………………………………………………………......24 I Chapter
    [Show full text]