Structure-Reactivity Relations for Thiol-Disulfide Interchange Janette Houk and George M
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Sodium Borohydride (Nabh4) Itself Is a Relatively Mild Reducing Agent
1770 Vol. 35 (1987) Chem. Pharm. Bull. _35( 5 )1770-1776(1987). Reactions of Sodium Borohydride. IV.1) Reduction of Aromatic Sulfonyl Chlorides with Sodium Borohydride ATSUKO NOSE and TADAHIRO KUDO* Daiichi College of Pharmaceutical Sciences, 22-1 Tamagawa-cho, Minami-ku, Fukuoka 815, Japan (Received September 12, 1986) Aromatic sulfonyl chlorides were reduced with sodium borohydride in tetrahydrofuran at 0•Ž to the corresponding sulfinic acids in good yields. Further reduction proceeded when the reaction was carried out under reflux in tetrahydrofuran to give disulfide and thiophenol derivatives via sulfinic acid. Furthermore, sulfonamides were reduced with sodium borohydride by heating directly to give sulfide, disulfide and thiophenol derivatives, and diphenyl sulfone was reduced under similar conditions to give thiophenol and biphenyl. Keywords reduction; sodium borohydride; aromatic sulfonyl chloride; sulfonamide; sulfone; aromatic sulfinic acid; disulfide; sulfide; thiophenol Sodium borohydride (NaBH4) itself is a relatively mild reducing agent which is extensively used for the selective reduction of the carbonyl group of ketone, aldehyde and (carboxylic) acid halide derivatives. In the previous papers, we reported that NaBI-14 can reduce some functional groups, such as carboxylic anhydrides,2) carboxylic acids3) and nitro compounds.1) As a continuation of these studies, in the present paper, we wish to report the reduction of aromatic sulfonyl chlorides, sulfinic acids and sulfonamides with NaBH4. Many methods have been reported for the reduction of sulfonyl chlorides to sulfinic acids, such as the use of sodium sulfite,4a-d) zinc,5) electrolytic reduction,6) catalytic reduction,7) magnesium,8) sodium amalgam,9) sodium hydrogen sulfite,10) stannous chlo- TABLE I. -
Unit One Part 2: Naming and Functional Groups
gjr-–- 1 Unit One Part 2: naming and functional groups • To write and interpret IUPAC names for small, simple molecules • Identify some common functional groups found in organic molecules O CH3 H3C N H N O N N O H3C S N O N H3C viagra™ (trade name) sildenafil (trivial name) 5-(2-ethoxy-5-(4-methylpiperazin-1-ylsulfonyl)phenyl)-1-methyl-3-propyl-1H- pyrazolo[4,3-d] pyrimidin-7(6H)-one dr gareth rowlands; [email protected]; science tower a4.12 http://www.massey.ac.nz/~gjrowlan gjr-–- 2 Systematic (IUPAC) naming PREFIX PARENT SUFFIX substituents / minor number of C principal functional functional groups AND multiple bond group index • Comprises of three main parts • Note: multiple bond index is always incorporated in parent section No. Carbons Root No. Carbons Root Multiple-bond 1 meth 6 hex Bond index 2 eth 7 hept C–C an(e) 3 prop 8 oct C=C en(e) 4 but 9 non C≡C yn(e) 5 pent 10 dec gjr-–- 3 Systematic (IUPAC) naming: functional groups Functional group Structure Suffix Prefix General form O –oic acid acid –carboxylic acid carboxy R-COOH R OH O O –oic anhydride anhydride –carboxylic anhydride R-C(O)OC(O)-R R O R O –oyl chloride acyl chloride -carbonyl chloride chlorocarbonyl R-COCl R Cl O –oate ester –carboxylate alkoxycarbonyl R-COOR R OR O –amide amide –carboxamide carbamoyl R-CONH2 R NH2 nitrile R N –nitrile cyano R-C≡N O –al aldehyde –carbaldehyde oxo R-CHO R H O ketone –one oxo R-CO-R R R alcohol R OH –ol hydroxy R-OH amine R NH2 –amine amino R-NH2 O ether R R –ether alkoxy R-O-R alkyl bromide bromo R-Br (alkyl halide) R Br (halo) (R-X) gjr-–- 4 Nomenclature rules 1. -
Polymeric Reagents with Propane-1,3-Dithiol Functions and Their Precursors for Supported Organic Syntheses
J. Org. Chem. 2000, 65, 4839-4842 4839 Polymeric Reagents with Propane-1,3-dithiol Functions and Their Precursors for Supported Organic Syntheses Vincenzo Bertini,*,† Francesco Lucchesini,† Marco Pocci,† and Angela De Munno‡ Dipartimento di Chimica e Tecnologie Farmaceutiche ed Alimentari, Universita´ di Genova, Via Brigata Salerno, I-16147 Genova, Italy, and Dipartimento di Chimica e Chimica Industriale, Universita´ di Pisa, Via Risorgimento, 35, I-56126 Pisa, Italy [email protected] Received January 19, 2000 Reliable completely odorless syntheses of soluble copolymeric reagents of styrene type containing propane-1,3-dithiol functions able to convert carbonyl compounds into 1,3-dithiane derivatives and to support other useful transformations are reported together with their progenitor copolymers containing benzenesulfonate or thioacetate groups perfectly stable in open air and suitable for unlimited storage. The effectiveness of the prepared reagents as tools for polymer-supported syntheses to produce ketones by aldehyde umpolung and alkylation is tested in the conversion of benzaldehyde to phenyl n-hexyl ketone starting from copolymers with different contents of active units and molecular weights. To facilitate the adaptation of the prepared soluble copolymeric reagents to other possible applications, a table of solvents and nonsolvents is presented. Introduction Scheme 1 Recently we have reported in a preliminary com- munication1 how to harness the great synthetic potenti- alities of thioacetals and thioketals by preparing, with a completely odorless synthesis, polymeric reagents2,3 of styrene type containing propane-1,3-dithiol functions effective in producing ketones by aldehyde umpolung and alkylation after the formation of 1,3-dithiane derivatives. Such polymeric reagents were obtained through a pro- cedure based on the use of the difunctional monomer 1 prepared from commercial 4-vinylbenzyl chloride (Scheme 1), its copolymerization with styrene, and chemical modification of its copolymers. -
Cyclohexane Oxidation Continues to Be a Challenge Ulf Schuchardt A,∗, Dilson Cardoso B, Ricardo Sercheli C, Ricardo Pereira A, Rosenira S
Applied Catalysis A: General 211 (2001) 1–17 Review Cyclohexane oxidation continues to be a challenge Ulf Schuchardt a,∗, Dilson Cardoso b, Ricardo Sercheli c, Ricardo Pereira a, Rosenira S. da Cruz d, Mário C. Guerreiro e, Dalmo Mandelli f , Estevam V. Spinacé g, Emerson L. Pires a a Instituto de Qu´ımica, Universidade Estadual de Campinas, P.O. Box 6154, 13083-970 Campinas, SP, Brazil b Depto de Eng. Qu´ımica, Universidade Federal de São Carlos, 13565-905 São Carlos, SP, Brazil c College of Chemistry, University of California, Berkeley, CA 94720, USA d Depto Ciências Exatas e Tecnológicas, Universidade Estadual de Santa Cruz, 45650-000 Ilhéus, BA, Brazil e Universidade Federal de Lavras, Lavras, MG, Brazil f Instituto de Ciências Biológicas e Qu´ımicas, PUC-Campinas, 13020-904 Campinas, SP, Brazil g Sup. Caracterização Qu´ımica, IPEN, 05508-900 São Paulo, SP, Brazil Received 3 October 2000; received in revised form 21 December 2000; accepted 28 December 2000 Abstract Many efforts have been made to develop new catalysts to oxidize cyclohexane under mild conditions. Herein, we review the most interesting systems for this process with different oxidants such as hydrogen peroxide, tert-butyl hydroperoxide and molecular oxygen. Using H2O2, Na-GeX has been shown to be a most stable and active catalyst. Mesoporous TS-1 and Ti-MCM-41 are also stable, but the use of other metals such as Cr, V, Fe and Mo leads to leaching of the metal. Homogeneous systems based on binuclear manganese(IV) complexes have also been shown to be interesting. When t-BuOOH is used, the active systems are those phthalocyanines based on Ru, Co and Cu and polyoxometalates of dinuclear ruthenium and palladium. -
WIIINIPEG, I{ANI1.Oba October 1971
THE UNTVERSITY OF FJAI,TTTOBA STTIDIES ON TSOTHTÁ.ZOIIU}.I SÂLTS AND REIATED CO},IPOUI{DS by GART ED}¡ARD BACIIERS A T}MSIS SIMÌ,1TTTED TO TI{E FACULTY OF GR]I.DUÀTE STIIDIES ÏN PIIRÎI/iL FULIi'TIJ'&Til'r OF TI# REQUTREI.Tiü{TS TÇR TI.III DEGREE I'IÂSTER 0F SCIEÎIICE DEPARTI'ÎE]VT 0F CI{EI,IISTRY WIIINIPEG, I{ANI1.oBA October 1971 üF fi "*i¡l,''ÉËR$$iY LT BRARY ACIOTOIILEDGH,ÍTÍüTS : The research degcribed in thís thesis has been undertaken at tho suggestion of Dr. D. Id. McKínnon, for v¡hose guidance, advice, æd ass*stance ï exprees r¡\y sincere appreciation" My gratitud.e ie also due the National Research CounciÌ of Canada for the scholarships provid.ed. d.uring the course of this research, and the University of }ianitoba for the provisíon of laboratory facilities. Finally, I should like to thank rny colleaguee, I'fiss Sheena Loosmore, Ivlr. Joe Buchsbriber, Iilr. Pat Ma, a¡rd. Mr. Jack Wong. Their forbearance during several unusually od.or-ous experiments was admirable. 11 TA3I,E 0F.coNTlNTS ABSTRACT.......... o.. ó..... o. ...:. r. o õ i.. o.... o.......iii INTRODUCTION Ggngial.. - - . ô. :.' ..... o. ... .. .. .. .. r. .. o. .. .... 1 fsothiazoles. o r . c o. o . ... .. o. ¡. 2 ' I s o thi azo 1 um s s i al t . c . o . c . , . , . , o . ! 4-rsothiazoline-3-thiones... o... ô........ o.... r........ 13 . 3-Isothiazoline-l-thiones....o.....,r........er........18 Thiothiophthenes and an aza arialogue.. o...... c o. o... .,.19 DISCUSSION Purpose of resgarch...... c.. o...^... r.............. o., o..2J Reaction of isothiazolium salts ç¡ittr sutf:p¡ ¡ o o. -
8.6 Acidity of Alcohols and Thiols 355
08_BRCLoudon_pgs5-1.qxd 12/8/08 11:05 AM Page 355 8.6 ACIDITY OF ALCOHOLS AND THIOLS 355 ural barrier to the passage of ions. However, the hydrocarbon surface of nonactin allows it to enter readily into, and pass through, membranes. Because nonactin binds and thus transports ions, the ion balance crucial to proper cell function is upset, and the cell dies. Ion Channels Ion channels, or “ion gates,” provide passageways for ions into and out of cells. (Recall that ions are not soluble in membrane phospholipids.) The flow of ions is essen- tial for the transmission of nerve impulses and for other biological processes. A typical chan- nel is a large protein molecule imbedded in a cell membrane. Through various mechanisms, ion channels can be opened or closed to regulate the concentration of ions in the interior of the cell. Ions do not diffuse passively through an open channel; rather, an open channel contains regions that bind a specific ion. Such an ion is bound specifically within the channel at one side of the membrane and is somehow expelled from the channel on the other side. Remark- ably, the structures of the ion-binding regions of these channels have much in common with the structures of ionophores such as nonactin. The first X-ray crystal structure of a potassium- ion channel was determined in 1998 by a team of scientists at Rockefeller University led by Prof. Roderick MacKinnon (b. 1956), who shared the 2003 Nobel Prize in Chemistry for this work. The interior of the channel contains binding sites for two potassium ions; these sites are oxygen-rich, much like the interior of nonactin. -
N* Interactions Modulate the Properties of Cysteine Residues
n →π* Interactions Modulate the Properties of Cysteine Residues and Disulfide Bonds in Proteins The MIT Faculty has made this article openly available. Please share how this access benefits you. Your story matters. Citation Kilgore, Henry R. and Ronald T. Raines. “n →π* Interactions Modulate the Properties of Cysteine Residues and Disulfide Bonds in Proteins.” Journal of the American Chemical Society 140 (2018): 17606-17611 © 2018 The Author(s) As Published https://dx.doi.org/10.1021/JACS.8B09701 Publisher American Chemical Society (ACS) Version Author's final manuscript Citable link https://hdl.handle.net/1721.1/125597 Terms of Use Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. HHS Public Access Author manuscript Author ManuscriptAuthor Manuscript Author J Am Chem Manuscript Author Soc. Author Manuscript Author manuscript; available in PMC 2019 May 21. Published in final edited form as: J Am Chem Soc. 2018 December 19; 140(50): 17606–17611. doi:10.1021/jacs.8b09701. n➝π* Interactions Modulate the Properties of Cysteine Residues and Disulfide Bonds in Proteins Henry R. Kilgore and Ronald T. Raines* Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States Abstract Noncovalent interactions are ubiquitous in biology, taking on roles that include stabilizing the conformation of and assembling biomolecules, and providing an optimal environment for enzymatic catalysis. Here, we describe a noncovalent interaction that engages the sulfur atoms of cysteine residues and disulfide bonds in proteins—their donation of electron density into an antibonding orbital of proximal amide carbonyl groups. -
Heats of Formation of Certain Nickel-Pyridine Complex Salts
HEATS OF FORFATION OF CERTAIN NICKEL-PYRIDINE COLPLEX SALTS DAVID CLAIR BUSH A THESIS submitted to OREGON STATE COLLEGE in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE June l9O [4CKNOWLEDGMENT The writer wishes to acknowledge his indebtedness and gratitude to Dr. [4. V. Logan for his help and encour- agement during this investigation. The writer also wishes to express his appreciation to Dr. E. C. Gilbert for helpful suggestions on the con- struction of the calortheter, and to Lee F. Tiller for his excellent drafting and photostating of the figures and graphs. APPROVED: In Charge of ?ajor Head of Department of Chemistry Chairrian of School Graduate Comrittee Dean of Graduate School Date thesis is presented /11 ' Typed by Norma Bush TABLE OF CONTENTS HISTORICAL BACKGROUND i INTRODUCTION 2 EXPERIMENTAL 5 Preparation of the Compounds 5 Analyses of the Compounds 7 The Calorimeter Determination of the Heat Capacity 19 Determination of the Heat of Formation 22 DISCUSSION 39 41 LITERATURE CITED 42 TABLES I Analyses of the Compounds 8 II Heat Capacity of the Calorimeter 23 III Heat of Reaction of Pyridine 26 IV Sample Run and Calculation 27 V Heat of Reaction of Nickel Cyanate 30 VI Heat of Reaction of Nickel Thiocyanate 31 VII Heat of Reaction of Hexapyridinated Nickel Cyanate 32 VIII Heat of Reaction of Tetrapyridinated Nickel Thiocyanate 33 IX Heat of Formation of the Pyridine Complexes 34 FI GURES i The Calorimeter 10 2 Sample Ijector (solids) 14 2A Sample Ejector (liquids) 15 3 Heater Circuit Wiring Diagram 17 4 heat Capacity of the Calorimeter 24 5 Heat of Reaction of Pyridine 28 6 Heat of Reaction of Hexapyridinated Nickel Cyanate 35 7 Heat of Reaction of Tetrapyridinated Nickel Thiocyanate 36 8 Heat of Reaction of Nickel Cyanate 37 9 Heat of Reaction of Nickel Thiocyanate 38 HEATS OF FOW ATION OF CERTAIN NICKEL-PYRIDINE COMPLEX SALTS HISTORICAL BACKGROUND Compounds of pyridine with inorganic salts have been prepared since 1970. -
United States Patent Office Patented Jan
3,071,593 United States Patent Office Patented Jan. 1, 1963 2 3,071,593 O PREPARATION OF AELKENE SULFES Paul F. Warner, Philips, Tex., assignor to Philips Petroleum Company, a corporation of Delaware wherein each R is selected from the group consisting of No Drawing. Filed July 27, 1959, Ser. No. 829,518 5 hydrogen, alkyl, aryl, alkaryl, aralkyl and cycloalkyl 8 Claims. (C. 260-327) groups having 1 to 8 carbon atoms, the combined R groups having up to 12 carbon atoms. Examples of Suit This invention relates to a method of preparing alkene able compounds are ethylene oxide, propylene oxide, iso sulfides. Another aspect relates to a method of convert butylene oxide, a-amylene oxide, styrene oxide, isopropyl ing an alkene oxide to the corresponding sulfide at rela O ethylene oxide, methylethylethylene oxide, 3-phenyl-1, tively high yields without refrigeration. 2-propylene oxide, (3-methylphenyl) ethylene oxide, By the term "alkene sulfide' as used in this specifica cyclohexylethylene oxide, 1-phenyl-3,4-epoxyhexane, and tion and in the claims, I mean to include not only un the like. substituted alkene sulfides such as ethylene sulfide, propyl The salts of thiocyanic acid which I prefer to use are ene sulfide, isobutylene sulfide, and the like, but also 5 the salts of the alkali metals or ammonium. I especially hydrocarbon-substituted alkene sulfides such as styrene prefer ammonium thiocyanate, sodium thiocyanate, and oxide, and in general all compounds conforming to the potassium thiocyanate. These compounds can be reacted formula with ethylene oxide in a cycloparaffin diluent to produce 20 substantial yields of ethylene sulfide and with little or S no polymer formation. -
Validation of a Methodology to Determine Benzene, Toluene
M. L. Gallego-Diez et al.; Revista Facultad de Ingeniería, No. 79, pp. 138-149, 2016 Revista Facultad de Ingeniería, Universidad de Antioquia, No. 79, pp. 138-149, 2016 Validation of a methodology to determine Benzene, Toluene, Ethylbenzene, and Xylenes concentration present in the air and adsorbed in activated charcoal passive samplers by GC/ FID chromatography Validación de una metodología para la determinación de la concentración de Benceno, Tolueno, Etilbenceno y Xilenos, presentes en muestras aire y adsorbidos en captadores pasivos de carbón activado, mediante cromatografía GC/FID Mary Luz Gallego-Díez1*, Mauricio Andrés Correa-Ochoa2, Julio César Saldarriaga-Molina2 1Facultad de Ingeniería, Universidad de Antioquia. Calle 67 # 53- 108. A. A. 1226. Medellín, Colombia. 2Grupo de Ingeniería y Gestión Ambiental (GIGA), Facultad de Ingeniería, Universidad de Antioquia. Calle 67 # 53- 108. A. A. 1226. Medellín, Colombia. ARTICLE INFO ABSTRACT: This article shows the validation of the analytical procedure which allows Received August 28, 2015 determining concentrations of Benzene (B), Toluene (T), Ethylbenzene (E), and Xylenes (X) Accepted April 02, 2016 -compounds known as BTEX- present in the air and adsorbed by over activated charcoal by GC-FID using the (Fluorobenzene) internal standard addition as quantification method. In the process, reference activated charcoal was employed for validation and coconut -base granular charcoal (CGC) for the construction of passive captors used in sample taken in external places or in environmental air. CGC material was selected from its recovering capacity of BTEX, with an average of 89.1% for all analytes. In this research, BTEX presence KEYWORDS in air samples, taken in a road of six lines and characterized for having heavy traffic, in Validation, activated Medellín city (Antioquia, Colombia), was analyzed. -
THIOL OXIDATION a Slippery Slope the Oxidation of Thiols — Molecules RSH Oxidation May Proceed Too Predominates
RESEARCH HIGHLIGHTS Nature Reviews Chemistry | Published online 25 Jan 2017; doi:10.1038/s41570-016-0013 THIOL OXIDATION A slippery slope The oxidation of thiols — molecules RSH oxidation may proceed too predominates. Here, the maximum of the form RSH — can afford quickly for intermediates like RSOH rate constants indicate the order − − − These are many products. From least to most to be spotted and may also afford of reactivity: RSO > RS >> RSO2 . common oxidized, these include disulfides intractable mixtures. Addressing When the reactions are carried out (RSSR), as well as sulfenic (RSOH), the first problem, Chauvin and Pratt in methanol-d , the obtained kinetic reactions, 1 sulfinic (RSO2H) and sulfonic slowed the reactions down by using isotope effect values (kH/kD) are all but have (RSO3H) acids. Such chemistry “very sterically bulky thiols, whose in the range 1.1–1.2, indicating that historically is pervasive in nature, in which corresponding sulfenic acids were no acidic proton is transferred in the been very disulfide bonds between cysteine known to be isolable but were yet rate-determining step. Rather, the residues stabilize protein structures, to be thoroughly explored in terms oxidations involve a specific base- difficult to and where thiols and thiolates often of reactivity”. The second problem catalysed mechanism wherein an study undergo oxidation by H2O2 or O2 in was tackled by modifying the model acid–base equilibrium precedes the order to protect important biological system, 9-mercaptotriptycene, by rate-determining nucleophilic attack − − − structures from damage. Among including a fluorine substituent to of RS , RSO or RSO2 on H2O2. the oxidation products, sulfenic serve as a spectroscopic handle. -
POLYMERISATION of SOME CYCLIC ETHERS and ALLYL COMPOUNDS at Higf PRESSURES
POLYMERISATION OF SOME CYCLIC ETHERS AND ALLYL COMPOUNDS AT HIGf PRESSURES. THESIS SUBMITTED FOR THE DEGREE OF DOCTOR OF PHILOSOPHY IN THE FACULTY OF SCIENCE UNIVERSITY OF LONDON BY MUSTAFIZUR RAHMAN. DEPARTMENT OF CHEMICAL ENGINEERING AND CHEMICAL TECHNOLOGY, IMPERIAL COLLEGE OF SCIENCE AND TECHNOLOGY, LONDON, S.W.7. SEPTEMBER, 1967. ABSTRACT. The polymerizations of seven cyclic ethers and two allyl compounds have been studied at high pressures (up to 12,000 atm.). BF3.(C2H5)20 was usually used as catalyst to polymerize the ethers, except for 1,4-epoxycyclohexane with wilich the co-catalyst epichlorohydrin was employed. Benzoyl peroxide and azo-isobutyronitrile were used to polymerize the allyl compounds. The polymerizations of 1,4-epoxycyclohexane and tetrahydrofuran (THF) have been studied most extensively. From the lag rate vs. pressure graphs, "overall volumes of activation" Air*pol were calculated and compared with those for vinyl compounds. Conductances of solutions of BP3.(C2H5)20 in tetrahydropyran were measured and the results discussed in relation to the kinetic measurements. The variation of the polymerization ceiling temperature of THF with pressure was determined between 1 and 2500 atm. The polymerizations of cyclohexene oxide, styrene cxide, cyclooctene oxide, tetrahydropyran, triallyl phosphate, triallyl phosphite and the co-polymerization of triallyl phosphate and styrene, have been studied briefly. The results, wherever possible, have been explained in terms of existing ideas. 3. Polymers from viscous liquid to insoluble solids were obtained during this investigation and the molecular weights were determined, where possible. 4 ACKNOWLEDGEBENTS. The author wishes to express his gratitude to Dr. K.E.Weale for his kind supervision, valuane guidance and constant encouragement during the course of this study.