DOCSLIB.ORG

Investigations on Pyrroles and Related Substances

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Investigations on Pyrroles and Related Substances INVESTIGATIONS ON PYRROLES AND RELATED SUBSTANCES CONTAINING THE NITRILE GROUP DISSERTATION Presented in Partial Fulfillment of the Requirements for The Degree of Doctor of Philosophy in the Graduate School of The Ohio State University by Thomas Harvey Curry, B.S. The Ohio State University 1953 Approved by: Advisor i Acknowledgement The research for this dissertation was conducted at the Charles F. Kettering Foundation at Yellow Springs, Ohio. The author is grateful for the Fellowship which made this dissertation possible. He particularly wishes to thank Dr. P. Rothernund under whose guidance this work was performed. For their kind cooperation the author wishes to express his appreciation to Dr. Edward Mack, Jr., and the other members of the Department of Chemistry of The Ohio State University. A 07193 ii Table of Contents Page Introduction 1 Historical 1 Nomenclature 3 Spectroscopic Properties of Pyrroles, Dipyrryl-compounds, and Porphyrins 3 Synthetic Methods 6 Discussion 12 (3-Aminocrotonic acid ethyl ester 15 2.6-Dimethyl-4-chiorome thyl-1,4-dihydro- 3.5-dicarbethoxy pyridine 15 2.6-Dimethyl-4-cyanomethyl-1,4-dihydro- 5 .5-dicarbethoxy pyridine 18 Ring contraction to 2-methyl-4-cyanomethyl- 5-carbethoxy pyrrole 18 2-Methyl-4-cyanomethyl pyrrole 19 2-Methyl-4-cyanomethyl-5-carboxylic acid pyrrole 22 2-Uethyl-4-cyanomethyl-5-bromo pyrrole 22 2-Methyl-4-cyanomethyl-5-formyl pyrrole 23 Resistance of 2-methyl-4-cyanomethyl-5-formyl pyrrole to oxidation 25 5,5'-Dimethy13,3 1 -dicyanomethyl dipyrryl- methane 26 Efforts to condense 2-methyl-4-cyano-methyl pyrrole with 2,4-dinethyl-3-carbethoxy pyrrole Preparation of new dipyrryl-compounds Oxidation of - Cli substituted pyrroles with lead tetraacetate Sulfuryl chloride reactions 2.4-Dimethyl-o-chioromethyl-5-carbethoxy pyrrole (chloromethylation) 2.4-D imethyl-3-c ya nonethyl-5-c arc e thoxy pyrrole 2.4-Dir.iethyl-o-cyano-5-carbethoxy pyrrole Miscellaneous experiments Experimental General Remarks on Physical Measurements P-Aminocrotonic acid ethyl ester 2.6-Dimethyl-4-chloromethyl-l,4-dihydro- 3.5-dicarbethoxy pyridine 2.6-Dimethyl-4-cyan omethyl-1,4-dihydro- 3.5-dicarbethoxy pyridine 2-Methyl-4-cyanomethyl-5-carbethoxy pyrrole 2-Methyl-4-cyanomethyl pyrrole Eromination of 2-methyl-4-cyanomethyl pyrrole 2-Chloro-3-cyanomethyl-5-carboxylic acid - pyrrole Conversion of 2-methyl-4-cyanonethyl pyrrole into a substance having a three banded spectrum Attempted lead tetraacetate oxidation of 2-me thy1-4-c yan omethy1-5-carbethoxy pyrrole 2 -Me thy 1 - 4- c y an ora e thyl -5 - c ar b o xy 1 i c acid pyrrole 2-M e thyl-4-cyanom ethyl-5-f ormy1 pyr r ole Attempted oxidation of 2-methyl-4-cyano­ me thyl -5 -f ormy 1 pyrrole 5,5’-Dimethy1-3,3’-dicyanomethyl dipyrrylmethane 5,5'-Dimethyl-3,3 ’ -dicyanomethyl dipyrrylrnethene hydrobromide Attempted preparation of 3, 5,5'-trimethyl- 4-carbethoxy-3’-cyahomethyl dipyrryl­ me thene hydrobromide 5.5 1 -Dime thyl-4-cyano-3 1 -cyanome thyl dipyrrylme thane 5.5 f-Dimethyl-4,4’-dicyano dipyrrylmethene Attempted preparation of 3 1,5,5'-Trimethyl- - 4-cyano-4'-carbethoxy dipyrrylmethene hydrobromide 2.4-Dimethyl-3-chloromethyl-5-carbethoxy pyrrole 2,21,4,41-Tetramethyl-5,5’-dicarbethoxy dipyrrylmethane Condensation product of 2,4-dimethy1-3- chioromethyl-5-carbethoxy pyrrole and pyridine 2.4-Dimethyl-3-cyanomethyl-5-carbethoxy pyrrole Attempted oxidation of 2,4-dimethyl-3- cyanomethyl-5-carbethoxy pyrrole to the corresponding 2-hydroxymethyl compound 2-Chloromethyl-4-methyl-3-cyanomethyl-5- carbethoxy pyrrole 4,4' -Dime thyl -3,3* -dicyanome thyl -5,5’- diearbe thoxy dipyrrylme thane 2 .4-Dime thyl-3-cyano-5-carbe thoxy pyrrole Attempted oxidation of 2,4-dimethyl-3- cyano-5-carbethoxy pyrrole with lead tetraacetate (Die'thylacetal of 4-methyl-3-cyano-2- formy1-5-carbethoxy pyrrole) 2-Chioromethyl-4-methyl-3-cyano-5- carbethoxy pyrrole 2.4-Dimethyl-3-propionyl-5-carbethoxy pyrrole 2.4-Dimethyl-3-propyl-5-caroethoxy pyrrole 2 .4-Dimethyl-5-butyl-5-carbethoxy pyrrole 2.4-Dimethyl-3-(y-ketobutyric acid)-5- carbethoxy pyrrole Summary Bibliography Au t ob i o graphy vii List of Illustrations Figure Page I. 3,3’,5,5’-Tetramethyl-4,41-dicarbethoxy dipyrrylmethene hydrobromide 4 II. Porphine 4 III. a,a1-Dipyrrylmethane 8 IV. P,P'-Dipyrrylme thane 8 V. a,p1-Dipyrrylmethane 8 VI. a,a'-Dipyrrylmethene hydrobromide 9 VII. 2,6-Dimethyl-4-chloromethyl-l,4-dihydro- 3.5-dicarbethoxy pyridine 17 VIII. 2,6-Dimethyl-4-cyanomethyl-1,4-dihydro- 3.5-dicarbethoxy pyridine 17 IX. 2-I.Iethyl-4-cyanomethyl-5-carbe thoxy pyrrole 17 X. 2-I.Iethyl-4-cyanomethyl-5-carboxylic acid pyrrole 21 XI. 2-I'ethyl-4-cyanomethyl pyrrole 21 XII. 2-I.?3thyl-4-cyanomethyl-5-bromo pyrrole 21 XIII. 2-Chloro-3-cyanomethyl-5-carboxylic acid pyrrole 24 XIV. 2-Methyl-4-cyanomethyl-5-formyl pyrrole 24 XV. 5,5,-Dimethyl-3,5l-dicyanomethyl dipyrryl­ me thane 24 vill «*£, 5,5 ’-Dime thyl-3, 3 •-dicyanomethyl dipyrrylmethene hydrobromide 29 2.4-Dimethyl-3-carbethoxy pyrrole 29 2 .4-Dimethyl-3-carbethoxy-5-f“ormyl pyrrole 29 2-I.Iethyl-3-cyano pyrrole 30 5,5'-Dimethyl-4-cyano-3'-cyanomethyl dipyrrylmethane 30 2-I.!ethyl-3-cyano-5-formyl pyrrole 30 5,5'-Dimethyl-4,4'-dicyano dipyrrylmethene 31 3 1,5,5•-Trimethyl-4-cyano-4’-carbethoxy dipyrrylmethene hydrobromide 31 2 ,4-Dime thyl-5-carbethoxy pyrrole 31 2 .4-Dimethyl-3-chlorome thyl-5-carbethoxy pyrrole 37 2,2*,4,41-Tetramethyl-5,5’-dicarbethoxy dipyrrylmethane 37 2 ,4-Dimethyl-3-cyanomethyl-5-carbethoxy pyrrole 37 2-Chlcromethyl-4-methyl-3-cyanomethyl-5- carbethoxy pyrrole 40 4,41-Dimethyl-3,3•-dicyanomethyl-5,51- dicarbethoxy dipyrrylmethane 40 2.4-Dimethyl-3-aldoxime-5-carbethoxy pyrrole 40 ix Figure Page XXXI. 2,4-Dimethyl-3-cyano-5-carbethoxy pyrrole 41 XXXII. Diothylacetal of 4-methyl-3-cyano-2- formyl-5-carbethoxy pyrrole 41 XXXIII. 2-Chloromethyl-4-methyl-3-cyano-6- -carbe thoxy pyrrole 41 XXXIV. 2,4-Dimethyl-3-propionyl-5-carbethoxy pyrrole 43 XXXV. 2,4-Dimethyl-3-propyl-6-carbethoxy pyrrole 43 XXXVI. 2,4-Dimethyl-3-butyryl-5-carbethoxy pyrrole 43 XXXVII. 2,4-Dimethyl-3-butyl-5-carbethoxy pyrrole 43 XXXVIII. 2,4-Dimethyl-3-(y-ketobutyric acid)-5- carbethoxy pyrrole 43 / Introduction Historical Several investigators have attempted to prepare porphyrins containing the -CN, or nitrile, group because of its potential transformation into such functional groups as-the carboxyl, formyl or amino. These attempts were successful in two cases: Fischer and M&Ller (1) dehydrated the oxime of the corresponding 6-formyl substituted porphine with acetic anhydride and potassium acetate, and obtained 1,3,5,8,v-pchtamethyl-2,4-diethyl- 6-cyano-7-propionic acid methyl ester porphine. Fischer and Beer (2) used substantially the same procedure for the synthesis of a. l,3,5,8-tetramethyl-2,4-diethyl-6-cyano-7- propionic acid methyl ester porphine, b • 1,3,5,8-tetramethyl-4-cyano-6,7-dipropionic acid dimethyl ester porphine, and c . 1,3,5,8-tetramethyl-2,4-dicyano-6,7-dipropionic acid dimethyl ester porphine. In these cases the nitrile group was introduced after the porphyrin ring system was extant. Porphyrins contain­ ing nitrile groups, have never been synthesized from pyrroles with a nitrile group as substituent, in spite of a number of investigations undertaken by different authors in this field. 2 Substituted pyrroles, dipyrrylmethanes and dipyrryl­ me thenes containing -CN are, however, well known, since the attempts at synthesis of nitrile substituted porphyrins necessarily involved the preparation of these simpler compounds as starting materials. Pisclier and Rothemund (3) attempted to synthesize such a porphyrin from 3,5,3',5*-tetramethyl-4-cyano-4'- propionic acid dipyrrylmethene hydrobromide. The product, however, was 1,4,5,8-tetramethyl-2,3,6,7-tetraethyl porphine, etioporphyrin II. Cleavage of the dipyrryl­ methene occurred, and only the nitrile-free pyrrole rings formed porphyrin. It was assumed that the negative result was related to the inertness of the a-methyl groups; bromination of the dipyrrylmethene failed, and 2,4-dimethyl-3-cyano-5-carbethoxy pyrrole was slow to react whereas 2,4-dimethyl-3,5-dicarbetlaoxy pyrrole brominates very readily. Fischer and Wassenegger (4) condensed 3,5,3',5'- tetra«ethyl-4-ethyl-4 *-(h>-cyano-6)-carboxyl) -vinyl dipyrryl­ methene with bis-(2-bromo-3-methyl-4-ethyl pyrrole)- 5-methene in a succinic anhydride melt and obtained only etioporphyrin. Again cleavage occurred and only the component without nitrile function was involved in porphyrin formation. 3 Nomenclature Fischer (5) reviewed the nomenclature for substituted pyrroles and dipyrryl-compounds • The system for the latter is illustrated in Figure I for 5,3',5,5'-tetra- methyl-4,4*-dicarbethoxy dipyrrylmethene hydrobromide. The nomenclature for porphyrins and other degradation products of chlorophyll was reviewed by Rothemund (6). Porphyrins contain 4 pyrrole nuclei linked by four methine bridges in a-positions. According to Fischer's (7) system of nomenclature the pyrrole rings are assigned Roman numerals I to IV; the methine bridge carbon atoms are designated as a,p,Y and 6 starting between rings I and II, and the p carbon atoms of the pyrrole rings are numbered 1 to 8 beginning with ring I. Porphyrins are substituted porphines and are named as such. Porphine, Figure II, is the simplest porphyrin; the pyrrole nuclei carry only hydrogen atoms. It was first synthesized by Rothemund (8) ih 1935. Spectroscopic Properties of Pyrroles. Dipyrryl-compounds. and Porphyrins. Spectroscopic properties of these compounds, especially of porphyrins, are very characteristic and there­ fore extremely helpful in synthetic work in this field.
Load more

Recommended publications
  • On Conducting Polymer Coated Electrodes: a Versatile Platform for the Modification of Electrode Surfacesa
    Full Paper http://www.paper.edu.cn ‘‘Click’’ on Conducting Polymer Coated Electrodes: A Versatile Platform for the Modification of Electrode Surfacesa Yan Li, Weixia Zhang, Jing Chang, Jinchun Chen, Guangtao Li,* Yong Ju* Two types of N-substituted pyrroles with azide and terminal alkyne groups have been synthesized and electropolymerized. ‘‘Click’’ chemistry, specifically Huisgen 1,3-dipolar cycloaddition, was used as a general method for functionalization of the polypyrrole films. Several model compounds, including redox active (quinone), bioactive (cholic acid) and recognition elements (carbohydrate and thymi- dine) could easily be attached onto the electrode surfaces without loss of functionality or the elec- troactivity of the underlying conducting polymers. The results suggest that the polypyrrole films are clickable and provide a novel biocompatible and versatile platform for efficient modifications on electrode surfaces. Introduction catalysis.[1,2] A key factor in such investigations and applications is the achievement of an efficient interface The immobilization of functional units, such as electro- between the functional groups and the conductive active, bioactive and biological recognition elements, onto surface.[3,4] conductive surfaces is of enormous interest, both in Compared to various protocols developed for confining studies of functional groups themselves and in numerous functional units onto solid surfaces, electrodeposition of applications ranging from disease diagnosis to electro- conducting polymers offers a simple and
    [Show full text]
  • Heterocycles 2 Daniel Palleros
    Heterocycles 2 Daniel Palleros Heterocycles 1. Structures 2. Aromaticity and Basicity 2.1 Pyrrole 2.2 Imidazole 2.3 Pyridine 2.4 Pyrimidine 2.5 Purine 3. Π-excessive and Π-deficient Heterocycles 4. Electrophilic Aromatic Substitution 5. Oxidation-Reduction 6. DNA and RNA Bases 7. Tautomers 8. H-bond Formation 9. Absorption of UV Radiation 10. Reactions and Mutations Heterocycles 3 Daniel Palleros Heterocycles Heterocycles are cyclic compounds in which one or more atoms of the ring are heteroatoms: O, N, S, P, etc. They are present in many biologically important molecules such as amino acids, nucleic acids and hormones. They are also indispensable components of pharmaceuticals and therapeutic drugs. Caffeine, sildenafil (the active ingredient in Viagra), acyclovir (an antiviral agent), clopidogrel (an antiplatelet agent) and nicotine, they all have heterocyclic systems. O CH3 N HN O O N O CH 3 N H3C N N HN N OH O S O H N N N 2 N O N N O CH3 N CH3 caffeine sildenafil acyclovir Cl S N CH3 N N H COOCH3 nicotine (S)-clopidogrel Here we will discuss the chemistry of this important group of compounds beginning with the simplest rings and continuing to more complex systems such as those present in nucleic acids. Heterocycles 4 Daniel Palleros 1. Structures Some of the most important heterocycles are shown below. Note that they have five or six-membered rings such as pyrrole and pyridine or polycyclic ring systems such as quinoline and purine. Imidazole, pyrimidine and purine play a very important role in the chemistry of nucleic acids and are highlighted.
    [Show full text]
  • Combined Experimental and Theoretical Study of Poly(Aniline-Co-Pyrrole) Oligomer
    ORE Open Research Exeter TITLE Combined experimental and theoretical study of poly(aniline-co-pyrrole) oligomer AUTHORS Kamran, Muhammad; Ullah, Habib; Shah, Anwar-ul-Haq A.; et al. JOURNAL Polymer DEPOSITED IN ORE 15 March 2016 This version available at http://hdl.handle.net/10871/20729 COPYRIGHT AND REUSE Open Research Exeter makes this work available in accordance with publisher policies. A NOTE ON VERSIONS The version presented here may differ from the published version. If citing, you are advised to consult the published version for pagination, volume/issue and date of publication Combined Experimental and Theoretical Study of Poly(Aniline-co-Pyrrole) Oligomer Habib Ullah*,a,b, Muhammad Kamranb, Salma Bibic, Anwar-ul-Haq A. Shah*,b, Asif A. Tahira, Khurshid Ayub*,d aEnvironment and Sustainability Institute (ESI), University of Exeter, Penryn Campus, Penryn, Cornwall TR10 9FE, UK bInstitute of Chemical Sciences, University of Peshawar, 25120 Peshawar, Pakistan cNational Centre of Excellence in Physical Chemistry, University of Peshawar, 25120 Peshawar, Pakistan. dDepartment of Chemistry, COMSATS Institute of Information Technology, University Road, Tobe Camp, 22060 Abbottabad, Pakistan * To whom corresponding should be addressed Email: [email protected] Abstract Quantum mechanical calculations are performed to establish the structure of an oligomer of aniline and pyrrole [Poly(Ani-co-Py)], through comparison of experimental and theoretically calculated properties, including conductivity. The copolymer was synthesized through chemical oxidative polymerization and then confirmed from the experimental IR, UV-vis, mass spectra, elemental, XRD, TGA, and SEM analysis. Quantum mechanical calculations are performed at Density Functional Theory (DFT) and Time dependent DFT (TD-DFT) methods for the electronic and spectroscopic properties of the oligomer.
    [Show full text]
  • Reactions of Pyrrole, Imidazole, and Pyrazole with Ozone
    Environmental Science Water Research & Technology View Article Online PAPER View Journal | View Issue Reactions of pyrrole, imidazole, and pyrazole with † Cite this: Environ. Sci.: Water Res. ozone: kinetics and mechanisms Technol., 2020, 6,976 Agnes Tekle-Röttering,‡a Sungeun Lim, ‡bc Erika Reisz,d Holger V. Lutze,efgj Mohammad Sajjad Abdighahroudi, e Sarah Willach,e Winfried Schmidt,af Peter R. Tentscher,h Daniel Rentsch, i Christa S. McArdell, b Torsten C. Schmidt *efg and Urs von Gunten*bc Five-membered nitrogen-containing heterocyclic compounds (azoles) belong to potential moieties in com- plex structures where transformations during ozonation can occur. This study focused on the azole–ozone chemistry of pyrrole, imidazole, and pyrazole as model compounds. Reaction kinetics and ozonation products were determined by kinetic and analytical methods including NMR, LC-HRMS/MS, HPLC-UV, and IC-MS. 1 Analyses of reactive oxygen species ( O2, ˙OH, H2O2), quantum chemical computations (Gibbs energies), and kinetic simulations were used to further support the proposed reaction mechanisms. The species-specific 6 −1 Creative Commons Attribution-NonCommercial 3.0 Unported Licence. second-order rate constants for the reactions of ozone with pyrrole and imidazole were (1.4 ± 1.1) × 10 M −1 5 −1 −1 s and (2.3 ± 0.1) × 10 M s , respectively. Pyrazole reacted more slowly with ozone at pH 7 (kapp =(5.6± 0.9) × 101 M−1 s−1). Maleimide was an identified product of pyrrole with a 34% yield. Together with other prod- ucts,formate,formamide,andglyoxal,CandNmassbalancesof∼50% were achieved. Imidazole reacted with ozone to cyanate, formamide, and formate (∼100% yields per transformed imidazole, respectively) with a closed mass balance.
    [Show full text]
  • CONCISE STUDY NOTES for BG 4Th Semester (UNIT: Amines and Heterocyclic Compounds)
    CONCISE STUDY NOTES FOR BG 4th Semester (UNIT: Amines and Heterocyclic Compounds) Syllabus Amines: Classification and factors affecting basicity of amines. Mechanistic details (wherever applicable) of methods of formation of alkyl and arylamines through reduction of nitro compounds and nitriles. Gabriel-Phthalamide reaction and Hofmann rearrangement. Mechanisms involved in the formation and reactions of arenediazonium salts including Azo coupling. Heterocyclic compounds bearing one nitrogen atom: Stuctural features of pyrrole, pyrrolidine, pyridine and piperidine and comparative account of their basic strength. Aromaticity and electrophilic substitution reactions of pyrrole and their comparison with those of furan and thiophene.Mechanisms involved in the preparations of Indole and quinoline using Fischer-Indole and Bishlier-Napierlaski syntheses. Amines: Their classification Alkyl, aryl and ar-alkyl derivatives of ammonia are known as amines General formula is RNH2, R2NH, R3NH, where R can be any alkyl, aryl or aralkyl group. Amines are classified in to primary, secondary and tertiary amines depending upon the number of Hydrogen atoms in ammonia replaced by alkyl or aryl group. If one of hydrogen atom in NH3 is replaced by alkyl or aryl group, the derivative of ammonia so obtained is known as primary amine, if two hydrogen atoms in ammonia are replaced by alkyl, aryl or ar-alkyl groups, the derivative obtained is known as secondary amine, while as if all H atoms in ammonia are replaced by alkyl aryl or aralkyl groups, a tertiaty amine is obtained as shown below: The R groups can be alkyl, aryl or aralkyl groups. Further a secondary or tertiary amine may contain same or different R groups.
    [Show full text]
  • Heterocyclic Chemistrychemistry
    HeterocyclicHeterocyclic ChemistryChemistry Professor J. Stephen Clark Room C4-04 Email: [email protected] 2011 –2012 1 http://www.chem.gla.ac.uk/staff/stephenc/UndergraduateTeaching.html Recommended Reading • Heterocyclic Chemistry – J. A. Joule, K. Mills and G. F. Smith • Heterocyclic Chemistry (Oxford Primer Series) – T. Gilchrist • Aromatic Heterocyclic Chemistry – D. T. Davies 2 Course Summary Introduction • Definition of terms and classification of heterocycles • Functional group chemistry: imines, enamines, acetals, enols, and sulfur-containing groups Intermediates used for the construction of aromatic heterocycles • Synthesis of aromatic heterocycles • Carbon–heteroatom bond formation and choice of oxidation state • Examples of commonly used strategies for heterocycle synthesis Pyridines • General properties, electronic structure • Synthesis of pyridines • Electrophilic substitution of pyridines • Nucleophilic substitution of pyridines • Metallation of pyridines Pyridine derivatives • Structure and reactivity of oxy-pyridines, alkyl pyridines, pyridinium salts, and pyridine N-oxides Quinolines and isoquinolines • General properties and reactivity compared to pyridine • Electrophilic and nucleophilic substitution quinolines and isoquinolines 3 • General methods used for the synthesis of quinolines and isoquinolines Course Summary (cont) Five-membered aromatic heterocycles • General properties, structure and reactivity of pyrroles, furans and thiophenes • Methods and strategies for the synthesis of five-membered heteroaromatics
    [Show full text]
  • N-Methylprotoporphyrin IX: Chemical Synthesis and Identification
    Proc. Nati. Acad. Sci. USA Vol. 78, No. 3, pp. 1490-1494, March 1981 Biochemistry N-Methylprotoporphyrin IX: Chemical synthesis and identification as the green pigment produced by 3,5-diethoxycarbonyl-1,4- dihydrocollidine treatment (N-alkyl porphyrins/porphyrin synthesis/ferrochelatase inhibitor/NMR) PAUL R. ORTIZ DE MONTELLANO, HAL S. BEILAN, AND KENT L. KUNZE Department of Pharmaceutical Chemistry, School of Pharmacy, and Liver Center, University of California, San Francisco, California 94143 Communicated by Rudi Schmid, November 24, 1980 ABSTRACT The hepatic pigment accumulated in 3,5-di- mitochondrial ferrochelatase (13, 14). The differential physio- ethoxycarbonyl-1,4-dihydrocollidine-treated rats, which has been logical effects of AIA and DDC are thus related, at least in part, reported to inhibit ferrochelatase, has been isolated and purified. to differences in the structures of the accompanying The pigment has been resolved into one major, one minor, and hepatic two trace components, all of which appear to be isomeric por- pigments. In concert with our efforts to define the structure of phyrins. The major fraction has been unambiguously identified the abnormal porphyrins due to AIA and other unsaturated byspectroscopic methods as the isomer of N-methyprotopor- agents (9, 10, 15, 16), we have undertaken a structural inves- phyrin IX (isolated as the dimethyl ester) in which vinyl-substituted tigation of the DDC-induced pigment. We report here un- pyrrole ring A is methylated. The minor product appears to be an ambiguous spectroscopic identification of the DDC pigment isomer of the same porphyrin with the N-methyl group on pro- as N-methylprotoporphyrin IX (dimethyl ester), confirmation pionic acid-substituted ring C, and the trace components have the same high-pressure liquid chromatography retention times as the of this structural assignment by chemical synthesis of the four other two possible isomers of the porphyrin.
    [Show full text]
  • Strecker Degradation Products of Aspartic and Glutamic Acids and Their Amides
    Czech J. Food Sci. Vol. 19, No. 2: 41–45 Strecker Degradation Products of Aspartic and Glutamic Acids and their Amides JAN RÖSSNER, JAN VELÍEK, FRANTIEK PUDIL and JIØÍ DAVÍDEK Institute of Chemical Technology Department of Food Chemistry and Analysis, Prague, Czech Republic Abstract RÖSSNER J., VELÍEK J., PUDIL F., DAVÍDEK J. (2001): Strecker degradation products of aspartic and glutamic acids and their amides. Czech J. Food Sci., 19: 4145. Aspartic and glutamic acids, asparagine and glutamine were oxidised with either potassium peroxodisulphate or glyoxal. Non- volatile products were derivatised and analysed by GC/FID and GC/MS. Volatile reaction products were isolated and analysed by the same methods. It was found that the degradation reactions of amino acids are complex. Amino acids are principally degraded via the corresponding α-keto acids to Strecker aldehydes (aspartic acid to oxalacetic and 3-oxopropionic acids and glutamic acid to α-ketoglutaric and 4-oxobutyric acids), which are unstable and decomposed by decarboxylation to the corresponding alde- hydes. Aspartic acid also eliminates ammonia and yields fumaric acid whereas glutamic acid gives rise to an imine, pyroglutamic acid. A recombination of free radicals leads to dicarboxylic acids (succinic acid from aspartic acid, succinic, glutaric and adipic acids from glutamic acid). The major volatile products (besides the aldehydes) are lower carboxylic acids (acetic acid from aspartic acid and propionic acid acid from glutamic acid) that can at least partly arise by radical reactions. In both quality and quantity terms, a higher amount of degradation products arises by oxidation of amino acids by peroxodisulphate. Keywords: Strecker degradation; Strecker aldehydes; amino acids; glyoxal; sodium peroxodisulphate; aspartic acid; glutamic acid; asparagine; glutamine; radicals The reaction of an α-amino acid with an oxidation re- asparagine (Asn) and glutamine (Gln).
    [Show full text]
  • Indole & Pyrrole Synthesis: Cliffsnotes (Richter, 2004)
    9/1/04 Richter Indole and Pyrrole Synthesis: " " Group Meeting Disclaimer: Indole: This lecture will only cover methodology for the construction of the indole and pyrrole ring systems, rather than functionalionalization of pre-existing heterocycles, Nature: which would be the topic of another series of lectures. – The most abundant heterocycle in nature – Found in tryptophan, indole-3-acetic acid (plant growth hormone), Partial List of Transforms Discussed: serotonin (neurotransmitter), natural products, drugs – Isolated industrially from coal tar 1. Batcho-Leimgruber Indole Synthesis – Biosynthesis of tryptophan 2. Reissert Indole Synthesis CO H 3. Hegedus Indole Synthesis 15 2 3 serine 4. Fukuyama Indole Synthesis glucose Steps NH Steps N 5. Sugasawa Indole Synthesis 2 H 6. Bischler Indole Synthesis anthranilate 7. Gassman Indole Synthesis tryptophan 8. Fischer Indole Synthesis 9. Japp-Klingemann Indole Synthesis Reactivity: 10. Buchwald Indole Synthesis C–4 C–3 11. Bucherer Carbazole Synthesis C–5 C–2 12. Japp-Maitland Carbazole Synthesis C–6 N 13. Larock Indole Synthesis C–7 H 14. Bartoli Indole Synthesis 15. Castro Indole Synthesis – Isoelectronic with naphthalene (slightly lower stabilization energy) 16. Hemetsberger Indole Synthesis – Indole has a higher stabilization energy than benzene 17. Mori-Ban Indole Synthesis – Very weakly basic: pKa of protonated indole: –2.4 18. Graebe-Ullmann Carbazole Synthesis – Protonation occurs at C–3 preferentially 19. Madelung Indole Synthesis – Easily oxidized (atmospheric oxygen) – very electron rich 20. Nenitzescu Indole Synthesis – Less prone to oxidation of EWG's on the ring – less electron rich 21. Piloty Pyrrole Synthesis – Electrophilic attack occurs at C–3 (site of most electron density) 13 22.
    [Show full text]
  • Theoretical Study on the Acidities of Pyrrole, Indole, Carbazole and Their Hydrocarbon Analogues in DMSO
    Canadian Journal of Chemistry Theoretical study on the acidities of pyrrole, indole, carbazole and their hydrocarbon analogues in DMSO Journal: Canadian Journal of Chemistry Manuscript ID cjc-2018-0032.R1 Manuscript Type: Article Date Submitted by the Author: 13-May-2018 Complete List of Authors: Ariche, Berkane; Modelisation and computational Méthods Laboratory, Faculty of Sciences, University of Saida, Chemistry RAHMOUNI,Draft Ali; Universite Dr Tahar Moulay de Saida, Chimie Is the invited manuscript for consideration in a Special Not applicable (regular submission) Issue?: Keyword: pKa calculation, Aromaticity index, Pyrolle, DMSO, DFT https://mc06.manuscriptcentral.com/cjc-pubs Page 1 of 33 Canadian Journal of Chemistry Theoretical study on the acidities of pyrrole, indole, carbazole and their hydrocarbon analogues in DMSO Ariche Berkane, Rahmouni Ali* Modeling and Calculation Methods Laboratory, University of Saida, B.P. 138, 20002 Saida, Algeria *Corresponding author [email protected] Abstract SMD and IEF-PCM continuum solvation models have been used, in combination with three quantum chemistry methods (B3LYP,Draft M062X and CBS-QB3) to study the acidities of pyrrole, indole and carbazole as well as their hydrocarbon analogues in DMSO, following a direct thermodynamic method. Theoretical parameters such as aromaticity indices (HOMA and SA), molecular electrostatic potential (MEP) and atomic charges have been calculated using B3LYP/6-311++G(d,p) level of theory. Calculated pKa values indicate that there is generally good agreement with experimental data, with all deviations being less than the acceptable error for a directly calculated pKa values. The M062X functional combined to SMD solvation model provide the more accurate pKa values.
    [Show full text]
  • Essentials of Heterocyclic Chemistry-I Heterocyclic Chemistry
    Baran, Richter Essentials of Heterocyclic Chemistry-I Heterocyclic Chemistry 5 4 Deprotonation of N–H, Deprotonation of C–H, Deprotonation of Conjugate Acid 3 4 3 4 5 4 3 5 6 6 3 3 4 6 2 2 N 4 4 3 4 3 4 3 3 5 5 2 3 5 4 N HN 5 2 N N 7 2 7 N N 5 2 5 2 7 2 2 1 1 N NH H H 8 1 8 N 6 4 N 5 1 2 6 3 4 N 1 6 3 1 8 N 2-Pyrazoline Pyrazolidine H N 9 1 1 5 N 1 Quinazoline N 7 7 H Cinnoline 1 Pyrrolidine H 2 5 2 5 4 5 4 4 Isoindole 3H-Indole 6 Pyrazole N 3 4 Pyrimidine N pK : 11.3,44 Carbazole N 1 6 6 3 N 3 5 1 a N N 3 5 H 4 7 H pKa: 19.8, 35.9 N N pKa: 1.3 pKa: 19.9 8 3 Pyrrole 1 5 7 2 7 N 2 3 4 3 4 3 4 7 Indole 2 N 6 2 6 2 N N pK : 23.0, 39.5 2 8 1 8 1 N N a 6 pKa: 21.0, 38.1 1 1 2 5 2 5 2 5 6 N N 1 4 Pteridine 4 4 7 Phthalazine 1,2,4-Triazine 1,3,5-Triazine N 1 N 1 N 1 5 3 H N H H 3 5 pK : <0 pK : <0 3 5 Indoline H a a 3-Pyrroline 2H-Pyrrole 2-Pyrroline Indolizine 4 5 4 4 pKa: 4.9 2 6 N N 4 5 6 3 N 6 N 3 5 6 3 N 5 2 N 1 3 7 2 1 4 4 3 4 3 4 3 4 3 3 N 4 4 2 6 5 5 5 Pyrazine 7 2 6 Pyridazine 2 3 5 3 5 N 2 8 N 1 2 2 1 8 N 2 5 O 2 5 pKa: 0.6 H 1 1 N10 9 7 H pKa: 2.3 O 6 6 2 6 2 6 6 S Piperazine 1 O 1 O S 1 1 Quinoxaline 1H-Indazole 7 7 1 1 O1 7 Phenazine Furan Thiophene Benzofuran Isobenzofuran 2H-Pyran 4H-Pyran Benzo[b]thiophene Effects of Substitution on Pyridine Basicity: pKa: 35.6 pKa: 33.0 pKa: 33.2 pKa: 32.4 t 4 Me Bu NH2 NHAc OMe SMe Cl Ph vinyl CN NO2 CH(OH)2 4 8 5 4 9 1 3 2-position 6.0 5.8 6.9 4.1 3.3 3.6 0.7 4.5 4.8 –0.3 –2.6 3.8 6 3 3 5 7 4 8 2 3 5 2 3-position 5.7 5.9 6.1 4.5 4.9 4.4 2.8 4.8 4.8 1.4 0.6 3.8 4 2 6 7 7 3 N2 N 1 4-position
    [Show full text]
  • Combined Experimental and Theoretical Study of Poly(Aniline-Co-Pyrrole) Oligomer
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Open Research Exeter Combined Experimental and Theoretical Study of Poly(Aniline-co-Pyrrole) Oligomer Habib Ullah*,a,b, Muhammad Kamranb, Salma Bibic, Anwar-ul-Haq A. Shah*,b, Asif A. Tahira, Khurshid Ayub*,d aEnvironment and Sustainability Institute (ESI), University of Exeter, Penryn Campus, Penryn, Cornwall TR10 9FE, UK bInstitute of Chemical Sciences, University of Peshawar, 25120 Peshawar, Pakistan cNational Centre of Excellence in Physical Chemistry, University of Peshawar, 25120 Peshawar, Pakistan. dDepartment of Chemistry, COMSATS Institute of Information Technology, University Road, Tobe Camp, 22060 Abbottabad, Pakistan * To whom corresponding should be addressed Email: [email protected] Abstract Quantum mechanical calculations are performed to establish the structure of an oligomer of aniline and pyrrole [Poly(Ani-co-Py)], through comparison of experimental and theoretically calculated properties, including conductivity. The copolymer was synthesized through chemical oxidative polymerization and then confirmed from the experimental IR, UV-vis, mass spectra, elemental, XRD, TGA, and SEM analysis. Quantum mechanical calculations are performed at Density Functional Theory (DFT) and Time dependent DFT (TD-DFT) methods for the electronic and spectroscopic properties of the oligomer. A very nice correlation is found between the theory and experiment which consequences the structure of Poly(Ani-co-Py). Poly(Ani-co-Py) is not explored like other conducting polymers; however, by tuning this molecular structure, the electro-active nature of this material can be enhanced adequately. KEYWORDS: DFT, Poly(Ani-co-Py), PPy, PANI, Band gap, IR, UV-vis, IP, EA, HOMO-LUMO 2 1.
    [Show full text]