Aromatic Heterocycles 1: Structures and Reactions 43 Connections
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[1,2,5]Thiadiazolo[3,4-D]Pyridazine As an Internal Acceptor in the DA-Π-A
Article [1,2,5]Thiadiazolo[3,4-d]Pyridazine as an Internal Acceptor in the D-A-π-A Organic Sensitizers for Dye- Sensitized Solar Cells Timofey N. Chmovzh 1, Ekaterina A. Knyazeva 1,2, Ellie Tanaka 3, Vadim V. Popov 2, Ludmila V. Mikhalchenko 1, Neil Robertson 3,* and Oleg A. Rakitin 1,2,* 1 N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 119991 Moscow, Russia; [email protected] (O.A.R.); [email protected] (T.N.C.); [email protected] (E.A.K.); [email protected] (L.V.M.) 2 Nanotechnology Education and Research Center, South Ural State University, 454080 Chelyabinsk, Russia; [email protected] 3 EaStCHEM School of Chemistry, University of Edinburgh, Edinburgh EH9 3FJ, UK; [email protected] * Correspondence: Correspondence: [email protected] (N.R.); [email protected] (O.A.R.); Tel.: +44-131-650-4755 (N.R.); +7-499-135-5327(O.A.R.) Academic Editor: Panayiotis A. Koutentis Received: 4 April 2019; Accepted: 19 April 2019; Published: 22 April 2019 Abstract: Four new D-A-π-A metal-free organic sensitizers for dye-sensitized solar cells (DSSCs), with [1,2,5]thiadiazolo[3 ,4-d]pyridazine as internal acceptor, thiophene unit as π-spacer and cyanoacrylate as anchoring electron acceptor, have been synthesized. The donor moiety was introduced into [1,2,5]thiadiazolo[3,4-d]pyridazine by nucleophilic aromatic substitution and Suzuki cross-coupling reactions, allowing design of D-A-π-A sensitizers with the donor attached to the internal heterocyclic acceptor not only by the carbon atom, as it is in a majority of DSSCs, but by the nitrogen atom also. -
Pyrylium Salt Chemistry Emerging As a Powerful Approach for the Cite This: Chem
Chemical Science View Article Online PERSPECTIVE View Journal | View Issue Over one century after discovery: pyrylium salt chemistry emerging as a powerful approach for the Cite this: Chem. Sci., 2020, 11, 12249 All publication charges for this article construction of complex macrocycles and metallo- have been paid for by the Royal Society of Chemistry supramolecules Yiming Li, ab Heng Wanga and Xiaopeng Li *a Over one century after its discovery, pyrylium salt chemistry has been extensively applied in preparing light emitters, photocatalysts, and sensitizers. In most of these studies, pyrylium salts acted as versatile precursors for the preparation of small molecules (such as furan, pyridines, phosphines, pyridinium salts, thiopyryliums and betaine dyes) and poly(pyridinium salt)s. In recent decades, pyrylium salt chemistry has emerged as a powerful approach for constructing complex macrocycles and metallo-supramolecules. In this perspective, we attempt to summarize the representative efforts of synthesizing and self-assembling Received 20th August 2020 large, complex architectures using pyrylium salt chemistry. We believe that this perspective not only Creative Commons Attribution-NonCommercial 3.0 Unported Licence. Accepted 13th October 2020 highlights the recent achievements in pyrylium salt chemistry, but also inspires us to revisit this chemistry DOI: 10.1039/d0sc04585c to design and construct macrocycles and metallo-supramolecules with increasing complexity and rsc.li/chemical-science desired function. 1. Introduction pyrylium salt with perchlorate as the counterion was reported in 1911 by Baeyer;7 however, since the discovery of pyrylium salts, Pyrylium salts are a type of six-membered cationic heterocycles such salts have been underappreciated for about a half-century. -
Rhodium-Catalyzed Synthesis of Organosulfur Compounds Involving S-S Bond Cleavage of Disulfides and Sulfur
molecules Review Rhodium-Catalyzed Synthesis of Organosulfur Compounds Involving S-S Bond Cleavage of Disulfides and Sulfur Mieko Arisawa * and Masahiko Yamaguchi Department of Organic Chemistry, Graduate School of Pharmaceutical Sciences, Tohoku University, Aoba, Sendai 980-8578, Japan; [email protected] * Correspondence: [email protected]; Tel.: +81-22-795-6814 Academic Editor: Bartolo Gabriele Received: 17 July 2020; Accepted: 5 August 2020; Published: 7 August 2020 Abstract: Organosulfur compounds are widely used for the manufacture of drugs and materials, and their synthesis in general conventionally employs nucleophilic substitution reactions of thiolate anions formed from thiols and bases. To synthesize advanced functional organosulfur compounds, development of novel synthetic methods is an important task. We have been studying the synthesis of organosulfur compounds by transition-metal catalysis using disulfides and sulfur, which are easier to handle and less odiferous than thiols. In this article, we describe our development that rhodium complexes efficiently catalyze the cleavage of S-S bonds and transfer organothio groups to organic compounds, which provide diverse organosulfur compounds. The synthesis does not require use of bases or organometallic reagents; furthermore, it is reversible, involving chemical equilibria and interconversion reactions. Keywords: rhodium; catalysis; synthesis; organosulfur compounds; S-S bond cleavage; chemical equilibrium; reversible reaction 1. Introduction 1.1. Structure and Reactivity of Organic Disulfides Organosulfur compounds containing C-S bonds are widely used for the manufacture of drugs and materials. Compared with organic compounds containing oxygen, which is another group 16(6A) element, different properties appear owing to the large size and polarizability of sulfur atoms. -
B.Sc. III YEAR ORGANIC CHEMISTRY-III
BSCCH- 302 B.Sc. III YEAR ORGANIC CHEMISTRY-III SCHOOL OF SCIENCES DEPARTMENT OF CHEMISTRY UTTARAKHAND OPEN UNIVERSITY ORGANIC CHEMISTRY-III BSCCH-302 BSCCH-302 ORGANIC CHEMISTRY III SCHOOL OF SCIENCES DEPARTMENT OF CHEMISTRY UTTARAKHAND OPEN UNIVERSITY Phone No. 05946-261122, 261123 Toll free No. 18001804025 Fax No. 05946-264232, E. mail [email protected] htpp://uou.ac.in UTTARAKHAND OPEN UNIVERSITY Page 1 ORGANIC CHEMISTRY-III BSCCH-302 Expert Committee Prof. B.S.Saraswat Prof. A.K. Pant Department of Chemistry Department of Chemistry Indira Gandhi National Open University G.B.Pant Agriculture, University Maidan Garhi, New Delhi Pantnagar Prof. A. B. Melkani Prof. Diwan S Rawat Department of Chemistry Department of Chemistry DSB Campus, Delhi University Kumaun University, Nainital Delhi Dr. Hemant Kandpal Dr. Charu Pant Assistant Professor Academic Consultant School of Health Science Department of Chemistry Uttarakhand Open University, Haldwani Uttarakhand Open University, Board of Studies Prof. A.B. Melkani Prof. G.C. Shah Department of Chemistry Department of Chemistry DSB Campus, Kumaun University SSJ Campus, Kumaun University Nainital Nainital Prof. R.D.Kaushik Prof. P.D.Pant Department of Chemistry Director I/C, School of Sciences Gurukul Kangri Vishwavidyalaya Uttarakhand Open University Haridwar Haldwani Dr. Shalini Singh Dr. Charu Pant Assistant Professor Academic Consultant Department of Chemistry Department of Chemistry School of Sciences School of Science Uttarakhand Open University, Haldwani Uttarakhand Open University, Programme Coordinator Dr. Shalini Singh Assistant Professor Department of Chemistry Uttarakhand Open University Haldwani UTTARAKHAND OPEN UNIVERSITY Page 2 ORGANIC CHEMISTRY-III BSCCH-302 Unit Written By Unit No. Dr. Charu Pant 01, 02 & 03 Department of Chemistry Uttarakhand Open University Haldwani Dr. -
Heterocyclic Chemistry Updated
1 | Page Heterocyclic Chemistry By Dr Vipul Kataria Definition: A heterocyclic compound or ring structure is a cyclic compound that has atoms of at least two different elements (N, O, S, P) as members of its ring. Introduction: Heterocyclic compounds may be defined as cyclic compounds having as ring members atoms of at least two different elements. It means the cyclic compound has one another atom different than carbon. Heterocyclic compounds have much importance in organic chemistry because of abundant presence of heterocyclic compounds in present pharmaceutical drugs. Like other organic compounds, there are several defined rules for naming heterocyclic compounds. IUPAC rules for nomenclature of heterocyclic systems (SPU 2012, 2 Marks) The system for nomenclature for heterocyclic systems was given by Hantzsch and Widman. The Hantzsch-Widman nomenclature is based on the type (Z) of the heteroatom; the ring size (n) and nature of the ring, whether it is saturated or unsaturated. This system of nomenclature applies to monocyclic 3-to-10-membered ring heterocycles. Type of the heteroatom: The type of heteroatom is indicated by a prefix as shown below for common hetreroatoms. Dr Vipul Kataria, Chemistry Department, V. P. & R. P. T. P. Science College, VV Nagar 2 | Pag e When two or more of the same heteroatoms are present, the prrefix di, tri, tetra… are used. e.g. dioxa, triaza, dithia. If the heteroatoms are different their atomic number in that grroup is considered. Thus order of numbering will be O, S, N, P, Si. Ring size: The ring size is indicated by a suffix according to Table I below. -
Synthesis of Densely Substituted Pyridine Derivatives from Nitriles by a Non-Classical [4+2] Cycloaddition/1,5-Hydrogen Shift Strategy
Synthesis of densely substituted pyridine derivatives from nitriles by a non-classical [4+2] cycloaddition/1,5-hydrogen shift strategy Wanqing Wu ( [email protected] ) South China University of Technology https://orcid.org/0000-0001-5151-7788 Dandan He South China University of Technology Kanghui Duan South China University of Technology Yang Zhou South China University of Technology Meng Li South China University of Technology Huanfeng Jiang South China University of Technology Article Keywords: pyridine derivatives, organic synthesis, medicinal chemistry. Posted Date: March 3rd, 2021 DOI: https://doi.org/10.21203/rs.3.rs-258126/v1 License: This work is licensed under a Creative Commons Attribution 4.0 International License. Read Full License Page 1/18 Abstract A novel strategy has been established to assemble an array of densely substituted pyridine derivatives from nitriles and o-substituted aryl alkynes or 1-methyl-1,3-enynes via a non-classical [4 + 2] cycloaddition along with 1,5-hydrogen shift process. The well-balanced anities of two different alkali metal salts enable the C(sp3)-H bond activation as well as the excellent chemo- and regioselectivities. This protocol offers a new guide to construct pyridine frameworks from nitriles with sp3-carbon pronucleophiles, and shows potential applications in organic synthesis and medicinal chemistry. Introduction Compounds containing pyridine core structures, not only widely exist in natural products, pharmaceuticals, and functional materials,1–7 but also serve as useful and valuable building blocks for metal ligands.8,9 For instance, pyridine derivative Actos I10 is a famous drug for the treatment of type 2 diabetes; Bi-(or tri-)pyridines II11–15 are often used as ligands in metal-catalyzed reactions; Kv1.5 antagonist III16 and alkaloid papaverine IV17 are two representative isoquinolines as a promising atrial- selective agent and a smooth muscle relaxant, respectively (Fig. -
From Pyrylium to Pyridinium Salts: Understanding Physicochemical Features
From Pyrylium to Pyridinium Salts: Understanding Physicochemical Features Antonio Franconetti, Lidia Contreras-Bernal and Francisca Cabrera-Escribano Departamento de Química Orgánica, Facultad de Química, Universidad de Sevilla, Apartado de Correos No. 1203, 41071 Sevilla, Spain. Fax: +34954624960; Tel: +34954556868; E-mail: [email protected] Abstract It is known that physical properties of pyridinium salts can be modulated by their chemical characteristics. Owing to their broad range of applications in biology, biotechnology and chemical research, the design and synthesis of a series of 2,4,6-tri- arylpyridinium salts with modified structural backbone have been carried out. The main strands of work have included modifications on pyrylium cation and nature of amines used as precursors. For pyrylium moiety electronic and steric changes in ortho and para positions were performed. The steric influence of the neighbouring groups into the amine reactivity and the changes of the nucleophile strength of this function have also been investigated. Thus, we have analyzed all these aspects to understand the chemical reactivity and seeking further applications. Keywords Pyridinium salts; Pyrylium salts; Amines; Carbohydrates Introduction Pyridinium salts are widely applied as synthetic building blocks to obtain substituted pyridine, dihydropyridine or piperidine. This synthetic strategy has been described for different applications such as total synthesis of Geissoschizine,1 cannabisativine, Lepadin B, among others. Pyridinium salts have been also used to achieve asymmetric and regioselective synthesis by additions of Grignard reagents.2 Furthermore, pyridinium salts have been applied as acylating agents, phase transfer catalyst or ionic liquid and dyes as a result of its intrinsic fluorescence. More recently, bispyridinium moieties have been employed in a tandem cyclization for the synthesis of indolizine derivatives.3 Different methods are available for the synthesis of pyridinium salts depending on the symmetry around of cation. -
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. -
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. -
TR-470: Pyridine (CASRN 110-86-1) in F344/N Rats, Wistar Rats, And
NTP TECHNICAL REPORT ON THE TOXICOLOGY AND CARCINOGENESIS STUDIES OF PYRIDINE (CAS NO. 110-86-1) IN F344/N RATS, WISTAR RATS, AND B6C3F1 MICE (DRINKING WATER STUDIES) NATIONAL TOXICOLOGY PROGRAM P.O. Box 12233 Research Triangle Park, NC 27709 March 2000 NTP TR 470 NIH Publication No. 00-3960 U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES Public Health Service National Institutes of Health FOREWORD The National Toxicology Program (NTP) is made up of four charter agencies of the U.S. Department of Health and Human Services (DHHS): the National Cancer Institute (NCI), National Institutes of Health; the National Institute of Environmental Health Sciences (NIEHS), National Institutes of Health; the National Center for Toxicological Research (NCTR), Food and Drug Administration; and the National Institute for Occupational Safety and Health (NIOSH), Centers for Disease Control and Prevention. In July 1981, the Carcinogenesis Bioassay Testing Program, NCI, was transferred to the NIEHS. The NTP coordinates the relevant programs, staff, and resources from these Public Health Service agencies relating to basic and applied research and to biological assay development and validation. The NTP develops, evaluates, and disseminates scientific information about potentially toxic and hazardous chemicals. This knowledge is used for protecting the health of the American people and for the primary prevention of disease. The studies described in this Technical Report were performed under the direction of the NIEHS and were conducted in compliance with NTP laboratory health and safety requirements and must meet or exceed all applicable federal, state, and local health and safety regulations. Animal care and use were in accordance with the Public Health Service Policy on Humane Care and Use of Animals. -
Recent Applications of Isatin in the Synthesis of Organic Compounds
The Free Internet Journal Review for Organic Chemistry Archive for Arkivoc 2017, part i, 148-201 Organic Chemistry Recent applications of isatin in the synthesis of organic compounds Razieh Moradi,a Ghodsi Mohammadi Ziarani,*a and Negar Lashgari b a Department of Chemistry, Alzahra University, Tehran, Iran b School of Chemistry, College of Science, University of Tehran, Tehran, Iran E-mail: [email protected] [email protected] Received 12-06-2016 Accepted 02-25-2017 Published on line 04-10-2017 Abstract Isatin has been used in design and synthesis of diverse types of heterocyclic and carbocyclic compounds and considered as a valuable building block in organic synthesis. There is a diversity of multicomponent reactions of this useful reagent. This article aims to review the advances in the use of isatin as starting material in the synthesis of various organic compounds and drugs up to June 2016. Keywords: Isatin, organic compounds, heterocyclic compounds, carbocyclic compounds DOI: https://doi.org/10.24820/ark.5550190.p009.980 Page 148 ©ARKAT USA, Inc Arkivoc 2017, i, 148-201 Moradi, R. et al. Table of Contents 1. Introduction 2. Reactions at the C-3 Position of Isatin 3. Synthesis of Isatin-based Spiro-fused Heterocyclic Frameworks 3.1 Synthesis involving two-component reactions of isatins 3.1.1 Three-membered heterocycles 3.1.2 Five-membered heterocycles 3.1.3 Six-membered heterocycles 3.1.4 Seven-membered heterocycles 4. Synthesis Involving Multicomponent Reactions 4.1 Three-membered heterocycles 4.2 Five-membered heterocycles 4.3 Six-membered heterocycles 4.4 Seven-membered heterocycles 5. -
Construction of Unusual Indole-Based Heterocycles from Tetrahydro-1H-Pyridazino[3,4-B]Indoles
molecules Article Construction of Unusual Indole-Based Heterocycles from Tetrahydro-1H-pyridazino[3,4-b]indoles Cecilia Ciccolini, Lucia De Crescentini, Fabio Mantellini, Giacomo Mari, Stefania Santeusanio and Gianfranco Favi * Department of Biomolecular Sciences, Section of Chemistry and Pharmaceutical Technologies, University of Urbino “Carlo Bo”, Via I Maggetti 24, 61029 Urbino, Italy; [email protected] (C.C.); [email protected] (L.D.C.); [email protected] (F.M.); [email protected] (G.M.); [email protected] (S.S.) * Correspondence: [email protected]; Tel.: +39-0722-303444 Academic Editor: Pascale Moreau Received: 27 August 2020; Accepted: 7 September 2020; Published: 9 September 2020 Abstract: Herein, we report the successful syntheses of scarcely represented indole-based heterocycles which have a structural connection with biologically active natural-like molecules. The selective oxidation of indoline nucleus to indole, hydrolysis of ester and carbamoyl residues followed by decarboxylation with concomitant aromatization of the pyridazine ring starting from tetrahydro-1H-pyridazino[3,4-b]indole derivatives lead to fused indole-pyridazine compounds. On the other hand, non-fused indole-pyrazol-5-one scaffolds are easily prepared by subjecting the same C2,C3-fused indoline tetrahydropyridazines to treatment with trifluoroacetic acid (TFA). These methods feature mild conditions, easy operation, high yields in most cases avoiding the chromatographic purification, and broad substrate scope. Interestingly, the formation of indole linked pyrazol-5-one system serves as a good example of the application of the umpolung strategy in the synthesis of C3-alkylated indoles. Keywords: indole-based heterocycles; C2-C3 indole oxidation; aromatization; ring-opening/ring-closing; umpolung 1.