Reactions of Benzene & Its Derivatives

Total Page:16

File Type:pdf, Size:1020Kb

Reactions of Benzene & Its Derivatives Organic Lecture Series ReactionsReactions ofof BenzeneBenzene && ItsIts DerivativesDerivatives Chapter 22 1 Organic Lecture Series Reactions of Benzene The most characteristic reaction of aromatic compounds is substitution at a ring carbon: Halogenation: FeCl3 H + Cl2 Cl + HCl Chlorobenzene Nitration: H2 SO4 HNO+ HNO3 2 + H2 O Nitrobenzene 2 Organic Lecture Series Reactions of Benzene Sulfonation: H 2 SO4 HSO+ SO3 3 H Benzenesulfonic acid Alkylation: AlX3 H + RX R + HX An alkylbenzene Acylation: O O AlX H + RCX 3 CR + HX An acylbenzene 3 Organic Lecture Series Carbon-Carbon Bond Formations: R RCl AlCl3 Arenes Alkylbenzenes 4 Organic Lecture Series Electrophilic Aromatic Substitution • Electrophilic aromatic substitution: a reaction in which a hydrogen atom of an aromatic ring is replaced by an electrophile H E + + + E + H • In this section: – several common types of electrophiles – how each is generated – the mechanism by which each replaces hydrogen 5 Organic Lecture Series EAS: General Mechanism • A general mechanism slow, rate + determining H Step 1: H + E+ E El e ctro - Resonance-stabilized phile cation intermediate + H fast Step 2: E + H+ E • Key question: What is the electrophile and how is it generated? 6 Organic Lecture Series + + 7 Organic Lecture Series Chlorination Step 1: formation of a chloronium ion Cl Cl + + - - Cl Cl+ Fe Cl Cl Cl Fe Cl Cl Fe Cl4 Cl Cl Chlorine Ferric chloride A molecular complex An ion pair (a Lewis (a Lewis with a positive charge containing a base) acid) on ch lorine ch loronium ion Step 2: attack of the chloronium ion on the ring slow, rate determining + Cl + H H H + Cl Cl Cl + Resonance-stabilized cation intermediate; the positive charge is delocalized onto three atoms of the ring 8 Organic Lecture Series Chlorination Step 3: proton transfer regenerates the aromatic character of the ring + H - + fast Cl-FeCl3 Cl + HCl + FeCl3 Cl Cation Chlorobenzene intermediate 9 Organic Lecture Series Bromination FeBr 3 + H + Br 2 Br HBr Bromobenzene This is the general method for Substitution of halogen onto a benzene ring (CANNOT be halogenated by Free Radical Mechanism) 10 Organic Lecture Series Bromination-Why not addn of Br2? Regains Aromatic Energy 11 Organic Lecture Series Nitration + • Generation of the nitronium ion, NO2 – Step 1: proton transfer to nitric acid O H O HSO3 OH+ HON HSO4 + ON O H O Sulfuric Nitric Co nju gate acid acid pKa= -3 acid pKa= -1.4 of nitric acid – Step 2: loss of H2O gives the nitronium ion, a very strong electrophile H O H ON O + ONO H H O The nitronium ion 12 Nitration Organic Lecture Series Step 1: attack of the nitronium ion (an electrophile) on the aromatic ring (a nucleophile) HNO 2 H NO2 HNO2 + + + + ONO + Resonance-stabilized cation intermediate Step 2: proton transfer regenerates the aromatic ring HHNO NO2 H 2 H O + + + O H H H 13 Organic Lecture Series Nitration • A particular value of nitration is that the nitro group can be reduced to a 1° amino group COOH COOH Ni + 3H + 2H O 2 (3 atm) 2 NO2 NH2 4-Nitrobenzoic acid 4-Aminobenzoic acid 14 Organic Lecture Series Sulfonation • Carried out using concentrated sulfuric acid containing dissolved sulfur trioxide H SO + 2 4 SO3 SO3 H Benzene B enzenesulfonic acid (SO3 in H2SO4 is sometimes called “fuming” sulfuric acid.) 15 Organic Lecture Series Friedel-Crafts Alkylation • Friedel-Crafts alkylation forms a new C-C bond between an aromatic ring and an alkyl group AlCl3 + Cl + HCl Benzene 2-Chloropropane Cumene (Isopropyl chloride) (Isopropylbenzene) The electrophilic partner is a carbocation; it will arrange to the most stable ion: allylic>3o>2o>1o 16 Friedel-Crafts Alkylation Organic Lecture Series Step 1: formation of an alkyl cation as an ion pair Cl + Cl - + - RCl+ Al Cl RClAl Cl R AlCl4 Cl Cl A molecular An ion pair containing comp lex a carbocation Step 2: attack of the alkyl cation on the aromatic ring + H H H + R+ + R R R + A resonance-stabilized cation Step 3: proton transfer regenerates the aromatic ring H + Cl AlCl3 R ++AlCl3 HCl R 17 Friedel-Crafts Alkylation Organic Lecture Series There are two major limitations on Friedel-Crafts alkylations: 1. carbocation rearrangements are common: AlCl3 + Cl +HCl Benzene Isobutyl tert-Butylbenzene chloride CH CH 3 CH3 + 3 - + - CH3 CHCH2 -Cl + AlCl3 CH 3 C- CH2 -Cl-AlCl3 CH3 C AlCl4 H CH 3 I sobutyl chloride amolecular an ion pair complex 18 Organic Lecture Series Friedel-Crafts Alkylation 2. F-C alkylation fails on benzene rings bearing one or more of these strongly electron- withdrawing groups Y AlCl + RX 3 No reacti on When Y Equals Any of These Groups, the Benzene Ring Does Not Undergo Friedel-Crafts Alkylation O O O O O CH CR COH COR CNH2 + SO3 HNOCN 2 NR3 CF3 CCl3 19 Organic Lecture Series 20 Organic Lecture Series The “De-activation” of Aromatic Systems Note: deactivation refers to the rate of EAS 21 Organic Lecture Series Friedel-Crafts Acylation • Friedel-Crafts acylation forms a new C-C bond between a benzene ring and an acyl group: O O AlCl3 + CH3 CCl + HCl BenzeneAcetyl Acetophenone ch loride O Cl O AlCl 3 + HCl 4-Phenylbutanoyl α-Tetralone chlorid e 22 Organic Lecture Series Friedel-Crafts Acylation • The electrophile is an acylium ion O Cl (1) •• •• R-C Cl + Al-Cl •• Cl An acyl Aluminum chloride chloride O O + Cl (2) •• - R-C Cl Al Cl R-C + AlCl - •• 4 Cl A molecular complex A n ion pair with a positive charge containing an charge on chlorine acylium ion 23 Friedel-Crafts Acylation Organic Lecture Series – an acylium ion is a resonance hybrid of two major contributing structures complete valence shells + + : R-C O: : R-C O The more important contributing structure • F-C acylations are free of a major limitation of F-C alkylations; acylium ions do not rearrange. 24 Organic Lecture Series Friedel-Crafts Acylation A special value of F-C acylations is preparation of unrearranged alkylbenzenes: O AlCl + Cl 3 2-Methylpropanoyl chloride O N 2H 4, KOH diethylene 2-Methyl-1- glycol Isobutylbenzene phenyl-1-propanone 25 Organic Lecture Series Di- and Polysubstitution Only a trace 26 Organic Lecture Series Di- and Polysubstitution Orientation on nitration of monosubstituted benzenes: ortho + Substituent ortho meta para para meta - OCH3 44 55 99 trace CH 3 58 4 38 96 4 Cl 70 - 30 100 trace Br 37 1 62 99 1 COOH 18 80 2 20 80 CN 19 80 1 20 80 NO2 6.4 93.2 0.3 6.7 93.2 27 Organic Lecture Series Di- and Polysubstitution • Orientation: –certain substituents direct preferentially to ortho & para positions; others to meta positions –substituents are classified as either ortho-para directing or meta directing toward further substitution 28 Di- and Polysubstitution Organic Lecture Series • Rate –certain substituents cause the rate of a second substitution to be greater than that for benzene itself; others cause the rate to be lower –substituents are classified as activating or deactivating toward further substitution 29 Organic Lecture Series 30 Di- and Polysubstitution Organic Lecture Series – -OCH3 is ortho-para directing: OCH3 OCH3 OCH3 NO2 + HNO3 + + H2 O CH 3 COOH NO2 Anisole o-Nitroanisole p-Nitroanisole (44%) (55%) –-CO2H is meta directing COOH COOH COOH COOH NO H2 SO4 2 ++HNO3 + 100°C NO2 Benzoic NO2 acid o-Nitro- m-Nitro- p-Nitro- benzoic benzoic benzoic acid acid acid (18%) (80%) (2%) 31 Organic Lecture Series Di- and Polysubstitution : : : Strongly : : NH NHR NR OH OR: activating 2 2 : OOOO: : Moderately : : NHCR NHCAr OCR: OCAr activating : Weakly activating R :: :: :: : Ortho-para Directing Weakly F: : : : deactivating Cl: Br I OOO O CH CR COH COR Moderately deactivating O CNH2 SO3 H CN Strongly + Meta Directing deactivating NO2 NH3 CF3 CCl3 32 Di- and Polysubstitution Organic Lecture Series the order of steps is important: CH3 COOH HNO 3 K2 Cr2O7 H SO 2 4 H2SO4 CH 3 NO2 NO2 p-Nitrobenzoic acid COOH COOH HNO K2 Cr 2 O7 3 H SO H2 SO4 2 4 NO2 m-Nitrobenzoic acid 33 Organic Lecture Series Theory of Directing Effects • The rate of EAS is limited by the slowest step in the reaction • For almost every EAS, the rate- determining step is attack of E+ on the aromatic ring to give a resonance- stabilized cation intermediate •The more stable this cation intermediate, the faster the rate- determining step and the faster the overall reaction 34 Organic Lecture Series Theory of Directing Effects • For ortho-para directors, ortho-para attack forms a more stable cation than meta attack – ortho-para products are formed faster than meta products • For meta directors, meta attack forms a more stable cation than ortho-para attack – meta products are formed faster than ortho-para products 35 Theory of Directing Effects Organic Lecture Series Nitration of anisole -OCH3; examine the meta attack: OCH3 slow + + NO2 OCH3 OCH3 OCH3 OCH3 + + fast H H H -H+ NO2 NO2 NO2 + NO2 (a) (b) (c) 36 Organic Lecture Series Nitration of anisole -OCH3: examine the ortho-para attack: OCH3 OCH3 + slow + NO2 : +: : : NO : 2 OCH3 ::OCH3 OCH3 OCH3 fast + -H+ + + NO H 2 HNO2 H NO2 H NO2 (d) (e) (f) (g) This resonance structure accounts for the selectivity 37 Organic Lecture Series Theory of Directing Effects Nitration of benzoic acid -NO2; examine the meta attack: COOH + slow + NO2 COOH COOH COOH COOH fast H H H -H+ NO2 NO2 NO2 NO2 (a) (b) (c) 38 Organic Lecture Series Nitration of benzoic acid -NO2: assume ortho-para attack: COOH + slow + NO2 COOH COOH COOH COOH fast -H+ H NO 2 H NO2 H NO2 NO2 (d) (e) (f) The most disfavored contributing structure This resonance structure accounts for the selectivity 39 Organic Lecture Series Activating-Deactivating • Any resonance effect,effect such as that of - NH2,
Recommended publications
  • Vapor Phase Nitration of Butane in a Fused Salt Reactor Frank Slates Adams Iowa State University
    Iowa State University Capstones, Theses and Retrospective Theses and Dissertations Dissertations 1961 Vapor phase nitration of butane in a fused salt reactor Frank Slates Adams Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/rtd Part of the Chemical Engineering Commons Recommended Citation Adams, Frank Slates, "Vapor phase nitration of butane in a fused salt reactor " (1961). Retrospective Theses and Dissertations. 2472. https://lib.dr.iastate.edu/rtd/2472 This Dissertation is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Retrospective Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. This dissertation has been 61-6173 microfilmed exactly as received ADAMS, Jr., Frank Slates, 1931— VAPOR PHASE NITRATION OF BUTANE IN A FUSED SALT REACTOR. Iowa State University of Science and Technology Ph.D., 1961 Engineering, chemical University Microfilms, Inc., Ann Arbor, Michigan VAPOR PHASK NITRATION OF BUTANE IN A FUSED SALT REACTOR by Frank Slates Adams, Jr. A Dissertation Submitted to the Graduate Faculty in Partial Fulfillment of The Requirements for the Degree of DOCTOR OF PHIDSOPHÏ Major Subject: Chemical Engineering Approved: Signature was redacted for privacy. In Charge of Major Work Signature was redacted for privacy. Head of Major Department Signature was
    [Show full text]
  • Common Name: P-TOLUENE SULFONIC ACID HAZARD
    Common Name: p-TOLUENE SULFONIC ACID CAS Number: 104-15-4 DOT Number: UN 2583 (solid, with more than 5% free Sulfuric Acid) UN 2585 (solid, with less than 5% free RTK Substance number: 1870 Sulfuric Acid) Date: October 1996 Revision: May 2003 ------------------------------------------------------------------------- ------------------------------------------------------------------------- HAZARD SUMMARY WORKPLACE EXPOSURE LIMITS * p-Toluene Sulfonic Acid can affect you when breathed in. No occupational exposure limits have been established for * p-Toluene Sulfonic Acid is a CORROSIVE CHEMICAL p-Toluene Sulfonic Acid. This does not mean that this and contact can cause severe skin and eye irritation and substance is not harmful. Safe work practices should always burns. be followed. * Exposure to p-Toluene Sulfonic Acid can irritate the nose, throat and lungs causing burning, dryness and WAYS OF REDUCING EXPOSURE coughing. * Where possible, enclose operations and use local exhaust ventilation at the site of chemical release. If local exhaust IDENTIFICATION ventilation or enclosure is not used, respirators should be p-Toluene Sulfonic Acid is a colorless, clear, or dark-colored worn. liquid or a colorless, crystalline (sand-like) material. It is used * Wear protective work clothing. to make dyes, drugs and other chemicals. * Wash thoroughly immediately after exposure to p- Toluene Sulfonic Acid and at the end of the workshift. REASON FOR CITATION * Post hazard and warning information in the work area. In * p-Toluene Sulfonic Acid is on the Hazardous Substance addition, as part of an ongoing education and training List because it is cited by DOT and NFPA. effort, communicate all information on the health and * This chemical is on the Special Health Hazard Substance safety hazards of p-Toluene Sulfonic Acid to potentially List because it is CORROSIVE.
    [Show full text]
  • Products from Reactions of Carbon Nucleophiles and Carbon
    14C synthesis strategies, Chem 315/316 / Beauchamp 1 Products from reactions of carbon nucleophiles and carbon electrophiles used in the 14C Game and our course: Carbon and hydrogen nucleophiles Ph R Ph Al H N R Li R (MgBr) P Li AlH R Cu Li Na CN RCC Na Ph 4 Li Carbon 2 H C R organolithium organolithium cyanide acetylides 2 ylid Na BH4 diisobutylaluminium lithium diisopropy- electrophiles cuprates (LAH) o reagents reagents Wittig reagents hydride (DIBAH) amide (LDA), -78 C H C Br 3 not useful not useful 2 RX coupling nitrilesalkynes not useful alkyls alkyls not useful methyl RX reaction R Br not useful not useful 2 RX coupling nitriles alkynes not useful alkyls alkyls not useful primary RX reaction R 2 RX coupling nitriles alkyls not useful E2 not useful alkyls not useful not useful reaction R Br secondary RX O 1o ROH 1o ROH 1o ROH 1o ROH not useful 1o ROH o not useful not useful 1o ROH 1 ROH ethylene oxide nitriles alkynes O o o o o o o 2 ROH 2 ROH 2 ROH 2 ROH 2o ROH 2 ROH 2 ROH not useful not useful E2, make nitriles alkynes allylic alcohols propylene oxide O o 3 ROH 3o ROH o 3o ROH o not useful o 3o ROH not useful E2, make 3 ROH 3 ROH 3 ROH allylic alcohols nitriles alkynes isobutylene oxide O o o specific methanol methanol C 1 ROH 1 ROH not used cyanohydrin 1o ROH not useful not useful in our course alkenes H H alkynes methanal O specific o enolate o o cyanohydrin o 1 ROH o C 2 ROH 2 ROH not useful 2 ROH alkenes 1 ROH not useful chemistry R H alkynes simple aldehydes O cyanohydrin o unless specific o enolate C 3 ROH 3o ROH o 2o ROH
    [Show full text]
  • Preparation and Purification of Atmospherically Relevant Α
    Atmos. Chem. Phys., 20, 4241–4254, 2020 https://doi.org/10.5194/acp-20-4241-2020 © Author(s) 2020. This work is distributed under the Creative Commons Attribution 4.0 License. Technical note: Preparation and purification of atmospherically relevant α-hydroxynitrate esters of monoterpenes Elena Ali McKnight, Nicole P. Kretekos, Demi Owusu, and Rebecca Lyn LaLonde Chemistry Department, Reed College, Portland, OR 97202, USA Correspondence: Rebecca Lyn LaLonde ([email protected]) Received: 31 July 2019 – Discussion started: 6 August 2019 Revised: 8 December 2019 – Accepted: 20 January 2020 – Published: 9 April 2020 Abstract. Organic nitrate esters are key products of terpene oxidation in the atmosphere. We report here the preparation and purification of nine nitrate esters derived from (C)-3- carene, limonene, α-pinene, β-pinene and perillic alcohol. The availability of these compounds will enable detailed investigations into the structure–reactivity relationships of aerosol formation and processing and will allow individual investigations into aqueous-phase reactions of organic nitrate esters. Figure 1. Two hydroxynitrate esters with available spectral data. Relative stereochemistry is undefined. 1 Introduction derived ON is difficult, particularly due to partitioning into the aerosol phase in which hydrolysis and other reactivity Biogenic volatile organic compound (BVOC) emissions ac- can occur (Bleier and Elrod, 2013; Rindelaub et al., 2014, count for ∼ 88 % of non-methane VOC emissions. Of the to- 2015; Romonosky et al., 2015; Thomas et al., 2016). Hydrol- tal BVOC estimated by the Model of Emission of Gases and ysis reactions of nitrate esters of isoprene have been stud- Aerosols from Nature version 2.1 (MEGAN2.1), isoprene is ied directly (Jacobs et al., 2014) and the hydrolysis of ON estimated to comprise half, and methanol, ethanol, acetalde- has been studied in bulk (Baker and Easty, 1950).
    [Show full text]
  • Chapter 7, Haloalkanes, Properties and Substitution Reactions of Haloalkanes Table of Contents 1
    Chapter 7, Haloalkanes, Properties and Substitution Reactions of Haloalkanes Table of Contents 1. Alkyl Halides (Haloalkane) 2. Nucleophilic Substitution Reactions (SNX, X=1 or 2) 3. Nucleophiles (Acid-Base Chemistry, pka) 4. Leaving Groups (Acid-Base Chemistry, pka) 5. Kinetics of a Nucleophilic Substitution Reaction: An SN2 Reaction 6. A Mechanism for the SN2 Reaction 7. The Stereochemistry of SN2 Reactions 8. A Mechanism for the SN1 Reaction 9. Carbocations, SN1, E1 10. Stereochemistry of SN1 Reactions 11. Factors Affecting the Rates of SN1 and SN2 Reactions 12. --Eliminations, E1 and E2 13. E2 and E1 mechanisms and product predictions In this chapter we will consider: What groups can be replaced (i.e., substituted) or eliminated The various mechanisms by which such processes occur The conditions that can promote such reactions Alkyl Halides (Haloalkane) An alkyl halide has a halogen atom bonded to an sp3-hybridized (tetrahedral) carbon atom The carbon–chlorine and carbon– bromine bonds are polarized because the halogen is more electronegative than carbon The carbon-iodine bond do not have a per- manent dipole, the bond is easily polarizable Iodine is a good leaving group due to its polarizability, i.e. its ability to stabilize a charge due to its large atomic size Generally, a carbon-halogen bond is polar with a partial positive () charge on the carbon and partial negative () charge on the halogen C X X = Cl, Br, I Different Types of Organic Halides Alkyl halides (haloalkanes) sp3-hybridized Attached to Attached to Attached
    [Show full text]
  • Nitroso and Nitro Compounds 11/22/2014 Part 1
    Hai Dao Baran Group Meeting Nitroso and Nitro Compounds 11/22/2014 Part 1. Introduction Nitro Compounds O D(Kcal/mol) d (Å) NO NO+ Ph NO Ph N cellular signaling 2 N O N O OH CH3−NO 40 1.48 molecule in mammals a nitro compound a nitronic acid nitric oxide b.p = 100 oC (8 mm) o CH3−NO2 57 1.47 nitrosonium m.p = 84 C ion (pKa = 2−6) CH3−NH2 79 1.47 IR: υ(N=O): 1621-1539 cm-1 CH3−I 56 Nitro group is an EWG (both −I and −M) Reaction Modes Nitro group is a "sink" of electron Nitroso vs. olefin: e Diels-Alder reaction: as dienophiles Nu O NO − NO Ene reaction 3 2 2 NO + N R h 2 O e Cope rearrangement υ O O Nu R2 N N N R1 N Nitroso vs. carbonyl R1 O O O O O N O O hυ Nucleophilic addition [O] N R2 R O O R3 Other reaction modes nitrite Radical addition high temp low temp nitrolium EWG [H] ion brown color less ion Redox reaction Photochemical reaction Nitroso Compounds (C-Nitroso Compounds) R2 R1 O R3 R1 Synthesis of C-Nitroso Compounds 2 O R1 R 2 N R3 3 R 3 N R N R N 3 + R2 2 R N O With NO sources: NaNO2/HCl, NOBF4, NOCl, NOSbF6, RONO... 1 R O R R1 O Substitution trans-dimer monomer: blue color cis-dimer colorless colorless R R NOBF OH 4 - R = OH, OMe, Me, NR2, NHR N R2 R3 = H or NaNO /HCl - para-selectivity ΔG = 10 Kcal mol-1 Me 2 Me R1 NO oxime R rate determining step Blue color: n π∗ absorption band 630-790 nm IR: υ(N=O): 1621-1539 cm-1, dimer υ(N−O): 1300 (cis), 1200 (trans) cm-1 + 1 Me H NMR (α-C-H) δ = 4 ppm: nitroso is an EWG ON H 3 Kochi et al.
    [Show full text]
  • Nitrobenzene
    This report contains the collective views of an international group of experts and does not necessarily represent the decisions or the stated policy of the United Nations Environment Programme, the International Labour Organization or the World Health Organization. Environmental Health Criteria 230 NITROBENZENE First draft prepared by L. Davies, Office of Chemical Safety, Therapeutic Goods Administration, Australian Department of Health and Ageing, Canberra, Australia Plese note that the pagination and layout of this web verson are not identical to those of the (to be) printed document Published under the joint sponsorship of the United Nations Environment Programme, the International Labour Organization and the World Health Organization, and produced within the framework of the Inter-Organization Programme for the Sound Management of Chemicals. World Health Organization Geneva, 2003 The International Programme on Chemical Safety (IPCS), established in 1980, is a joint venture of the United Nations Environment Programme (UNEP), the International Labour Organization (ILO) and the World Health Organization (WHO). The overall objectives of the IPCS are to establish the scientific basis for assessment of the risk to human health and the environment from exposure to chemicals, through international peer review processes, as a prerequisite for the promotion of chemical safety, and to provide technical assistance in strengthening national capacities for the sound management of chemicals. The Inter-Organization Programme for the Sound Management of Chemicals (IOMC) was established in 1995 by UNEP, ILO, the Food and Agriculture Organization of the United Nations, WHO, the United Nations Industrial Development Organization, the United Nations Institute for Training and Research and the Organisation for Economic Co-operation and Development (Participating Organizations), following recommendations made by the 1992 UN Conference on Environment and Development to strengthen cooperation and increase coordination in the field of chemical safety.
    [Show full text]
  • Structural Determination of Subsidiary Colors in Commercial Food Blue No
    February 1998 7 Original Structural Determination of Subsidiary Colors in Commercial Food Blue No. 1 (Brilliant Blue FCF) Product (Received September 1, 1997) Hirosh1 MATSUFUJI*1, Takashi KUSAKA*1, Masatoshi TSUKUDA*1, Makoto CHINO*1, Yoshiaki KATO*2, Mikio NAKAMURA*2, Yukihiro GODA*3, Masatake TOYODA*3 and Mitsuharu TAKEDA*1 (*1College of Bioresource Sciences, Nihon University: 3-34-1, Shimouma, Setagaya-ku, Tokyo 145-0002, Japan; *2San-Ei Gen F. F. I., Inc.: 1-1-11, Sanwa-cho, Toyonaka, Osaka 561-0828, Japan; *3National Institute of Health Sciences (NIHS): 1-18-1, Kamiyoga, Setagaya-ku, Tokyo 158-8501, Japan) HPLC analysis revealed that five subsidiary colors were present in a commercial Food Blue No. l (Brilliant Blue FCF) product. Among them, major subsidiary colors C, D, and E were isolated. On the bases of spectroscopic analyses, their structures were identified as the disodium salt of 2-[[4-[N-ethyl-N-(3-sulfophenylmethyl)amino]phenyl][4-[N-ethyl-N-(4-sulfo- phenylmethyl)amino]phenyl]methylio]benzenesulfonic acid, the disodium salt of 2-[[4- [N-ethyl-N-(2-sulfophenylmethyl) amino]phenyl][4-[N-ethyl-N-(3-sulfophenylmethyl) amino]- phenyl]methylio]benzenesulfonic acid, and the sodium salt of 2-[[4-(N-ethylamino)phenyl][4- [N-ethyl-N-(3-sulfophenylmethyl)amino]phenyl]methylio]benzenesulfonic acid, respectively. Key words: Food Blue No. 1; Brilliant Blue FCF; FD & C Blue No. 1; subsidiary color; HPLC; coal-tar dye ally, it is the disodium salt of 2-[bis[4-[N-ethyl- Introduction N-(3-sulfophenylmethyl) amino] phenyl] meth- Twelve coal-tar dyes are presently permitted ylio]benzensulfonic acid [OSBA-(m-EBASA)(m- as food colors in Japan.
    [Show full text]
  • Amide, and Paratoluenesulfonamide on the Amide of Silver,On the Imides
    68 CHEMISTRY: E. C. FRANKLIN METALLIC SALTS OF AMMONO ACIDS By Edward C. Franklin DEPARTMENT OF CHEMISTRY, STANFORD UNIVERSITY Presented to the Academy, January 9. 1915 The Action of Liquid-Ammonia Solutions of Ammono Acids on Metallic Amides, Imides, and Nitrides. The acid amides and imides, and the metallic derivatives of the acid amides and imides are the acds, bases, and salts respectively of an ammonia system of acids, bases, and salts.1 Guided by the relationships implied in the above statement Franklin and Stafford were able to prepare potassium derivatives of a considerable number of acid amides by the action of potassium amide on certain acid amides in solution in liquid ammonia. That is to say, an ammono base, potassium amide, was found to react with ammono acids in liquid ammonia to form ammono salts just as the aquo base, potassium hydrox- ide, acts upon aquo acids in water solution to form aquo salts. Choos- ing, for example, benzamide and benzoic acid as representative acids of the two systems, the analogous reactions taking place respectively in liquid ammonia and water are represented by the equations: CH6CONH2+KNH2 = C6H5CONHK + NHs. CseHCONH2 + 2KNH2 = CIHsCONK2 + 2NH3. CH6tCOOH + KOH = CIH6COOK + H2O. The ammono acid, since it is dibasic, reacts with either one or two molecules of potassium amide to form an acid and a neutral salt. Having thus demonstrated the possibility of preparing ammono salts of potassium by the interaction of potassium amide and acid amides in liquid ammonia solution, it was further found that ammono salts of the heavy metals may be prepared by the action of liquid ammonia solutions of ammono acids on insoluble metallic amides, imides, and nitrides-that is, by reactions which are analogous to the formation of aquo salts in water by the action of potassium hydroxide on insoluble metallic hydroxides and oxides.
    [Show full text]
  • Course Material 2.Pdf
    Reactive Intermediates Source: https://www.askiitians.com/iit-jee-chemistry/organic-chemistry/iupac- and-goc/reaction-intermediates/ Table of Content • Carbocations • Carbanions • Free Radicals • Carbenes • Arenium Ions • Benzynes Synthetic intermediate are stable products which are prepared, isolated and purified and subsequently used as starting materials in a synthetic sequence. Reactive intermediate, on the other hand, are short lived and their importance lies in the assignment of reaction mechanisms on the pathway from the starting substrate to stable products. These reactive intermediates are not isolated, but are detected by spectroscopic methods, or trapped chemically or their presence is confirmed by indirect evidence. • Carbocations Carbocations are the key intermediates in several reactions and particularly in nucleophilic substitution reactions. Structure of Carbocations : Generally, in the carbocations the positively charged carbon atom is bonded to three other atoms and has no nonbonding electrons. It is sp 2 hybridized with a planar structure and bond angles of about 120°. There is a + vacant unhybridized p orbital which in the case of CH 3 lies perpendicular to the plane of C—H bonds. Stability of Carbocations: There is an increase in carbocation stability with additional alkyl substitution. Thus one finds that addition of HX to three typical olefins decreases in the order (CH 3)2C=CH 2>CH 3—CH = CH 2 > CH 2 = CH 2. This is due to the relative stabilities of the carbocations formed in the rate determining step which in turn follows from the fact that the stability is increased by the electron releasing methyl group (+I), three such groups being more effective than two, and two more effective than one.
    [Show full text]
  • Amide Activation: an Emerging Tool for Chemoselective Synthesis
    Featuring work from the research group of Professor As featured in: Nuno Maulide, University of Vienna, Vienna, Austria Amide activation: an emerging tool for chemoselective synthesis Let them stand out of the crowd – Amide activation enables the chemoselective modification of a large variety of molecules while leaving many other functional groups untouched, making it attractive for the synthesis of sophisticated targets. This issue features a review on this emerging field and its application in total synthesis. See Nuno Maulide et al., Chem. Soc. Rev., 2018, 47, 7899. rsc.li/chem-soc-rev Registered charity number: 207890 Chem Soc Rev View Article Online REVIEW ARTICLE View Journal | View Issue Amide activation: an emerging tool for chemoselective synthesis Cite this: Chem. Soc. Rev., 2018, 47,7899 Daniel Kaiser, Adriano Bauer, Miran Lemmerer and Nuno Maulide * It is textbook knowledge that carboxamides benefit from increased stabilisation of the electrophilic carbonyl carbon when compared to other carbonyl and carboxyl derivatives. This results in a considerably reduced reactivity towards nucleophiles. Accordingly, a perception has been developed of amides as significantly less useful functional handles than their ester and acid chloride counterparts. Received 27th April 2018 However, a significant body of research on the selective activation of amides to achieve powerful DOI: 10.1039/c8cs00335a transformations under mild conditions has emerged over the past decades. This review article aims at placing electrophilic amide activation in both a historical context and in that of natural product rsc.li/chem-soc-rev synthesis, highlighting the synthetic applications and the potential of this approach. Creative Commons Attribution 3.0 Unported Licence.
    [Show full text]
  • Summary of Gas Cylinder and Permeation Tube Standard Reference Materials Issued by the National Bureau of Standards
    A111D3 TTbS?? o z C/J NBS SPECIAL PUBLICATION 260-108 o ^EAU U.S. DEPARTMENT OF COMMERCE/National Bureau of Standards Standard Reference Materials: Summary of Gas Cylinder and Permeation Tube Standard Reference Materials Issued by the National Bureau of Standards QC 100 U57 R. Mavrodineanu and T. E. Gills 260-108 1987 m he National Bureau of Standards' was established by an act of Congress on March 3, 1901. The Bureau's overall goal i s t0 strengthen and advance the nation's science and technology and facilitate their effective application for public benefit. To this end, the Bureau conducts research to assure international competitiveness and leadership of U.S. industry, science arid technology. NBS work involves development and transfer of measurements, standards and related science and technology, in support of continually improving U.S. productivity, product quality and reliability, innovation and underlying science and engineering. The Bureau's technical work is performed by the National Measurement Laboratory, the National Engineering Laboratory, the Institute for Computer Sciences and Technology, and the Institute for Materials Science and Engineering. The National Measurement Laboratory Provides the national system of physical and chemical measurement; • Basic Standards 2 coordinates the system with measurement systems of other nations and • Radiation Research furnishes essential services leading to accurate and uniform physical and • Chemical Physics chemical measurement throughout the Nation's scientific community, • Analytical Chemistry industry, and commerce; provides advisory and research services to other Government agencies; conducts physical and chemical research; develops, produces, and distributes Standard Reference Materials; provides calibration services; and manages the National Standard Reference Data System.
    [Show full text]