One-Pot Formation of Functionalized Indole and Benzofuran Derivatives Using a Single Bifunctional Ruthenium Catalyst
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Retention Indices for Frequently Reported Compounds of Plant Essential Oils
Retention Indices for Frequently Reported Compounds of Plant Essential Oils V. I. Babushok,a) P. J. Linstrom, and I. G. Zenkevichb) National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA (Received 1 August 2011; accepted 27 September 2011; published online 29 November 2011) Gas chromatographic retention indices were evaluated for 505 frequently reported plant essential oil components using a large retention index database. Retention data are presented for three types of commonly used stationary phases: dimethyl silicone (nonpolar), dimethyl sili- cone with 5% phenyl groups (slightly polar), and polyethylene glycol (polar) stationary phases. The evaluations are based on the treatment of multiple measurements with the number of data records ranging from about 5 to 800 per compound. Data analysis was limited to temperature programmed conditions. The data reported include the average and median values of retention index with standard deviations and confidence intervals. VC 2011 by the U.S. Secretary of Commerce on behalf of the United States. All rights reserved. [doi:10.1063/1.3653552] Key words: essential oils; gas chromatography; Kova´ts indices; linear indices; retention indices; identification; flavor; olfaction. CONTENTS 1. Introduction The practical applications of plant essential oils are very 1. Introduction................................ 1 diverse. They are used for the production of food, drugs, per- fumes, aromatherapy, and many other applications.1–4 The 2. Retention Indices ........................... 2 need for identification of essential oil components ranges 3. Retention Data Presentation and Discussion . 2 from product quality control to basic research. The identifi- 4. Summary.................................. 45 cation of unknown compounds remains a complex problem, in spite of great progress made in analytical techniques over 5. -
Electrooxidation Enables Highly Regioselective Dearomative Annulation of Indole and Benzofuran Derivatives
ARTICLE https://doi.org/10.1038/s41467-019-13829-4 OPEN Electrooxidation enables highly regioselective dearomative annulation of indole and benzofuran derivatives Kun Liu1, Wenxu Song1, Yuqi Deng1, Huiyue Yang1, Chunlan Song1, Takfaoui Abdelilah1, Shengchun Wang 1, Hengjiang Cong 1, Shan Tang1 & Aiwen Lei1* 1234567890():,; The dearomatization of arenes represents a powerful synthetic methodology to provide three-dimensional chemicals of high added value. Here we report a general and practical protocol for regioselective dearomative annulation of indole and benzofuran derivatives in an electrochemical way. Under undivided electrolytic conditions, a series of highly functio- nalized five to eight-membered heterocycle-2,3-fused indolines and dihydrobenzofurans, which are typically unattainable under thermal conditions, can be successfully accessed in high yield with excellent regio- and stereo-selectivity. This transformation can also tolerate a wide range of functional groups and achieve good efficiency in large-scale synthesis under oxidant-free conditions. In addition, cyclic voltammetry, electron paramagnetic resonance (EPR) and kinetic studies indicate that the dehydrogenative dearomatization annulations arise from the anodic oxidation of indole into indole radical cation, and this process is the rate- determining step. 1 College of Chemistry and Molecular Sciences, Institute for Advanced Studies (IAS), Wuhan University, Wuhan 430072, P. R. China. *email: aiwenlei@whu. edu.cn NATURE COMMUNICATIONS | (2020) 11:3 | https://doi.org/10.1038/s41467-019-13829-4 | www.nature.com/naturecommunications 1 ARTICLE NATURE COMMUNICATIONS | https://doi.org/10.1038/s41467-019-13829-4 reaking the aromatic systems of electron-rich arenes or fused indolines (Fig. 1a)39–44. Therefore, it is highly appealing to heteroarenes provides three-dimensional chemicals of high develop efficient approaches to allow for their preparation. -
Benzofuran Synthesis Through Iodocyclization Reactions: Recent Advances
MOJ Bioorganic & Organic Chemistry Mini Review Open Access Benzofuran synthesis through iodocyclization reactions: recent advances Abstract Volume 1 Issue 7 - 2017 Recent advancements (2014-17) in the benzofuran synthesis through iodocyclization Saurabh Mehta have been summarized. The successful use of various iodinating agents, bases, additives Department of Applied Chemistry, Delhi Technological etc. make iodocyclization a versatile and efficient methodology. The methodology has University, India been applied for the synthesis of more complex benzofuran derivatives, and may open interesting avenues in the area of heterocyclic chemistry (Figure 1). Correspondence: Saurabh Mehta, Department of Applied O-LG Chemistry, Delhi Technological University, Bawana Road, Delhi, + O R1 I 1 2 110042 India, Tel +9188 0066 5868, R R Email [email protected], [email protected] R2 I Received: December 17, 2017 | Published: December 29, 2017 LG = H, Me or other Protecting group 1 R = H, Me, OMe, I, CO2Me, etc. R2 = H, aryl, alkyl, alkenyl, etc. Figure 1 Keywords: annulations, alkyne, benzofuran, iodocyclization, heterocycle Introduction derivatives were obtained in high yields (84%−100%) under mild conditions. The authors demonstrated that the choice of bis(2,4,6- Benzo[b]furan is a privileged heterocyclic scaffold. Several collidine)iodonium hexafluorophosphate [I(coll)2PF6] as the compounds containing this scaffold have interesting biological iodinating agent was necessary for the success of the reaction. Also, 1 activities, such as anti-cancer, anti-viral, anti-inflammatory, etc. Few the ethoxyethyl ether group acted as a protecting group as well as a 2 derivatives are even used as commercial drugs, such as Amiodarone, good leaving group. -
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. -
Last Decade of Unconventional Methodologies for the Synthesis Of
Review molecules Last Decade of Unconventional Methodologies for theReview Synthesis of Substituted Benzofurans Last Decade of Unconventional Methodologies for the Lucia Chiummiento *, Rosarita D’Orsi, Maria Funicello and Paolo Lupattelli Synthesis of Substituted Benzofurans Department of Science, Via dell’Ateneo Lucano, 10, 85100 Potenza, Italy; [email protected] (R.D.); [email protected] (M.F.); [email protected] (P.L.) Lucia Chiummiento * , Rosarita D’Orsi, Maria Funicello and Paolo Lupattelli * Correspondence: [email protected] Department of Science, Via dell’Ateneo Lucano, 10, 85100 Potenza, Italy; [email protected] (R.D.); Academic Editor: Gianfranco Favi [email protected] (M.F.); [email protected] (P.L.) Received:* Correspondence: 22 April 2020; [email protected] Accepted: 13 May 2020; Published: 16 May 2020 Abstract:Academic This Editor: review Gianfranco describes Favi the progress of the last decade on the synthesis of substituted Received: 22 April 2020; Accepted: 13 May 2020; Published: 16 May 2020 benzofurans, which are useful scaffolds for the synthesis of numerous natural products and pharmaceuticals.Abstract: This In review particular, describes new the intramolecular progress of the and last decadeintermolecular on the synthesis C–C and/or of substituted C–O bond- formingbenzofurans, processes, which with aretransition-metal useful scaffolds catalysi for thes or synthesis metal-free of numerous are summarized. natural products(1) Introduction. and (2) Ringpharmaceuticals. generation via In particular, intramolecular new intramolecular cyclization. and (2.1) intermolecular C7a–O bond C–C formation: and/or C–O (route bond-forming a). (2.2) O– C2 bondprocesses, formation: with transition-metal (route b). -
An Update on Natural Occurrence and Biological Activity of Benzofurans
Acta Scientific MEDICAL SCIENCES (ISSN: 2582-0931) Volume 4 Issue 10 October 2020 Review Article An Update on Natural Occurrence and Biological Activity of Benzofurans Kavita Khatana* and Anjali Gupta Received: June 28, 2020 Department of Chemistry, School of Basic and Applied Sciences, Galgotias Published: September 21, 2020 University, Greater Noida, UP, India © All rights are reserved by Kavita Khatana. *Corresponding Author: Kavita Khatana, Department of Chemistry, School of Basic and Applied Sciences, Galgotias University, Greater Noida, UP, India. Graphical Abstract Figure a Abstract Benzofuran and its derivatives are the major group amongst the natural collection of biologically active heterocyclic compounds. Their wide range of pharmacological activities and imaginable applications in medicinal and pharmaceutical chemistry have at- tracted various research scholars, medicinal chemists and pharmacologists. This review emphasizes the progress and development . ofKeywords: benzofuran Benzofuran; derivatives Antioxidant; in various biological Antiviral; activities Antimicrobial; with an Anticancer update of current research findings during a decade Introduction physiological and industrial world. In reference to pharmaceutical Heterocyclic ring systems have emerged as powerful scaf- industry, over 60% of the top retailing drugs contain at least one folds for many biological evaluations. Heterocyclic compounds heterocyclic motif as a part of overall topography of the compound. Benzofurans and its derivatives are important class of heterocyclic have significant role in medicinal and pharmacological chemistry, Citation: Kavita Khatana and Anjali Gupta. “An Update on Natural Occurrence and Biological Activity of Benzofurans”. Acta Scientific Medical Sciences 4.10 (2020): 114-123. An Update on Natural Occurrence and Biological Activity of Benzofurans 115 compounds, which are known to possess various biological proper- 3-(hydroxymethyl)-7-methoxy-2,3-dihydrobenzo furan-5-yl) ties. -
Synbiotics Alleviate the Gut Indole Load and Dysbiosis in Chronic Kidney Disease
cells Article Synbiotics Alleviate the Gut Indole Load and Dysbiosis in Chronic Kidney Disease Chih-Yu Yang 1,2,3,4 , Ting-Wen Chen 5,6 , Wan-Lun Lu 5, Shih-Shin Liang 7,8 , Hsien-Da Huang 5,†, Ching-Ping Tseng 4,5,* and Der-Cherng Tarng 1,3,4,9,* 1 Institute of Clinical Medicine, School of Medicine, National Yang-Ming University, Taipei 11221, Taiwan; [email protected] 2 Stem Cell Research Center, National Yang-Ming University, Taipei 11221, Taiwan 3 Division of Nephrology, Department of Medicine, Taipei Veterans General Hospital, Taipei 11217, Taiwan 4 Center for Intelligent Drug Systems and Smart Bio-Devices (IDS2B), Hsinchu 30010, Taiwan 5 Department of Biological Science and Technology, National Chiao Tung University, Hsinchu 30010, Taiwan; [email protected] (T.-W.C.); [email protected] (W.-L.L.); [email protected] (H.-D.H.) 6 Institute of Bioinformatics and Systems Biology, National Chiao Tung University, Hsinchu 30010, Taiwan 7 Department of Biotechnology, College of Life Science, Kaohsiung Medical University, Kaohsiung 80708, Taiwan; [email protected] 8 Institute of Biomedical Science, College of Science, National Sun Yat-Sen University, Kaohsiung 80424, Taiwan 9 Department and Institute of Physiology, School of Medicine, National Yang-Ming University, Taipei 11221, Taiwan * Correspondence: [email protected] (C.-P.T.); [email protected] (D.-C.T.) † Current affiliation: Warshel Institute for Computational Biology, School of Life and Health Sciences, The Chinese University of Hong Kong, Longgang District, Shenzhen 518172, China. Abstract: Chronic kidney disease (CKD) has long been known to cause significant digestive tract pathology. -
Organophotocatalytic Dearomatization of Indoles, Pyrroles and Benzo(Thio)Furans Via a Giese-Type Transformation
ARTICLE https://doi.org/10.1038/s42004-021-00460-y OPEN Organophotocatalytic dearomatization of indoles, pyrroles and benzo(thio)furans via a Giese-type transformation Yueteng Zhang1, Peng Ji1, Feng Gao1, Yue Dong1, He Huang2, Changqing Wang1, Ziyuan Zhou3 & ✉ Wei Wang 1 Accessing fascinating organic and biological significant indolines via dearomatization of indoles represents one of the most efficient approaches. However, it has been difficult for the dearomatization of the electron deficient indoles. Here we report the studies leading to 1234567890():,; developing a photoredox mediated Giese-type transformation strategy for the dear- omatization of the indoles. The reaction has been implemented for chemoselectively breaking indolyl C=C bonds embedded in the aromatic system. The synthetic power of this strategy has been demonstrated by using structurally diverse indoles bearing common electron- withdrawing groups including (thio)ester, amide, ketone, nitrile and even aromatics at either C2 or C3 positions and ubiquitous carboxylic acids as radical coupling partner with high trans- stereoselectivity (>20:1 dr). This manifold can also be applied to other aromatic heterocycles including pyrroles, benzofurans and benzothiophenes. Furthermore, enantioselective dear- omatization of indoles has been achieved by a chiral camphorsultam auxiliary with high diastereoselectivity. 1 Departments of Pharmacology and Toxicology and Chemistry and Biochemistry, and BIO5 Institute, University of Arizona, Tucson, AZ, USA. 2 Department of Chemistry and Chemical -
The Relationship Between Growth and Indole-3-Acetic Acid Content of Roots of Pisum Sativum L
The Relationship between Growth and Indole-3-Acetic Acid Content of Roots of Pisum sativum L. Author(s): William L. Pengelly and John G. Torrey Reviewed work(s): Source: Botanical Gazette, Vol. 143, No. 2 (Jun., 1982), pp. 195-200 Published by: The University of Chicago Press Stable URL: http://www.jstor.org/stable/2474706 . Accessed: 03/04/2012 15:52 Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at . http://www.jstor.org/page/info/about/policies/terms.jsp JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact [email protected]. The University of Chicago Press is collaborating with JSTOR to digitize, preserve and extend access to Botanical Gazette. http://www.jstor.org BOT. GAZ. 143(2):195-200. 1982. ? 1982 by The Universityof Chicago. All rightsreserved. 0006-8071/82/4302-0004$02.00 THE RELATIONSHIP BETWEEN GROWTH AND INDOLE-3-ACETIC ACID CONTENT OF ROOTS OF PISUM SATIVUM L. WILLIAM L. PENGELLY1 AND JOHN G. TORREY Cabot Foundation,Harvard University,Petersham, Massachusetts 01366 The indole-3-aceticacid (IAA) contentof roots and shoots of light-grownpea seedlings(Pisizmi sali,zim L. 'Little Marvel') growingat differentrates was studied by radioimmunoassayduring the firstweek of germination.Different growth rates were obtained by daily irrigationwith either deionized water or a dilute Hoagland's mineralnutrient solution. -
Synthesis of Benzo-Fused Heterocycles Using Isomerization and Ring-Closing Metathesis Reactions
I Synthesis of benzo-fused heterocycles using isomerization and ring-closing metathesis reactions Lee Gavin Madeley Supervised by Prof. W.A.L. van Otterlo A dissertation submitted in the School of Chemistry to the Faculty of Science, University of the Witwatersrand, in fulfilment of the requirements for the Degree of Master of Science March 2010 II Declaration I declare that the work presented in this dissertation is my own, unaided work and was carried out under the supervision of Prof. W.A.L. van Otterlo. It is being submitted for the Degree of Master of Science in the University of the Witwatersrand, Johannesburg. It has not been submitted before for any degree or examination in any other University. __________________________ Lee Gavin Madeley March 2010 III Abstract The first part of the dissertation involves the use of ruthenium mediated isomerization (RMI) followed by ring-closing metathesis (RCM) on a selection of phenols and naphthol-1-ol precursors – that had been subjected to allylation; followed by a heat initiated Claisen rearrangement; followed by re-allylation – to form a selection of benzofurans. This procedure, to the best of our knowledge, represents a novel method for the synthesis of benzofurans, with very good average yields of around 90% overall for the RMI/RCM and allylation steps. The lowest yield of the five synthetic steps, were for the Claisen rearrangements with a range of yields between 50% and 86%, indicating the potential to optimise the yields of these reactions, which were carried out using both conventional and microwave heating. The following five-membered oxygen-containing heterocycles were thus obtained: 4,7-dimethoxybenzofuran, 5-bromobenzofuran, 5-tert-butyl-benzofuran, 7- phenyl-1-benzofuran and naphtho[1,2-b]furan. -
One Hundred Years of Benzotropone Chemistry
One hundred years of benzotropone chemistry Arif Dastan*1, Haydar Kilic2,3 and Nurullah Saracoglu*1 Review Open Access Address: Beilstein J. Org. Chem. 2018, 14, 1120–1180. 1Department of Chemistry, Science Faculty, Atatürk University, doi:10.3762/bjoc.14.98 25240, Erzurum, Turkey, 2Oltu Vocational Training School, Atatürk University, 25400, Erzurum, Turkey and 3East Anotolia High Received: 27 December 2017 Technology Application and Research Center, Atatürk University, Accepted: 20 April 2018 25240, Erzurum, Turkey Published: 23 May 2018 Email: Associate Editor: B. Stoltz Arif Dastan* - [email protected]; Nurullah Saracoglu* - [email protected] © 2018 Dastan et al.; licensee Beilstein-Institut. License and terms: see end of document. * Corresponding author Keywords: benzotropolone; benzotropone; dibenzotropone; halobenzotropolone; halobenzotropone; tribenzotropone; tropone Abstract This review focuses on the chemistry of benzo-annulated tropones and tropolones reported since the beginning of the 20th century, which are currently used as tools by the synthetic and biological communities. Review 1. Introduction Tropone (1) and tropolone (2) have fascinated organic chemists have been reported in the literature in a number of natural forms for well over one hundred years. The carbocycles 1 and 2 are a (Figure 1) [1-8]. These compounds have a structural class special variety of organic compounds and represent a nonben- spacing from the simple monocyclic tropones, such as the po- zenoid type of aromatic system (Scheme 1). Their dipolar reso- tent antifungal and antibiotic monoterpene β-thujaplicin (4) nance structures such as tropylium oxide form 1B and 2B have [17-23] (isolated from the heartwood and essential oils of trees been reported to provide a Hückel sextet of electrons that is of the family Cupressaceae), to complex macrocyclic ana- necessary for aromaticity (Scheme 1) [1-9]. -
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