DOCSLIB.ORG

The Journal of Organic Chemistry 1959 Volume 24 No.7

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The Journal of Organic Chemistry 1959 Volume 24 No.7 THE JOURNAL OF Organic Chemistry Volume 24 JULY-DECEMBER 1959 (Pages 897-2108) George H. Coleman, Editor Detroit, Mich. R. Martin Stiles, Assistant Editor Ann Arbor, Mich. BOARD OF EDITORS William J. Bailey Harlan L. Goering W. E. Parham Virgil B oekelheide George S. Hammond C. C. Price F. G. B ordwell H enry B. Hass John D. R oberts Herbert C. Brown R. G. Jones H arold Shechter Marvin Carmack N elson J. Leonard J. C. Sheehan Alsoph H. Corwin Leo Marion Gilbert Stork D. J. Cram Frank C. McGrew R. B. T urner William G. D auben George P. M ueller W. H. Urry Carl D jerassi Milton Orchin Bernhard Witkop Foreign rs: R obert R obinson, P. Karrer EASTON, PENNSYLVANIA MACK PRINTING CO. THE JOURNAL OF Organic Chemistry © Copyright J959 Volume 24, Number 7 by the American Chemical Society July 30, 1959 [Contribution from the P harmaceutical L aboratory, M edical School, K eio U n iversity ] Santonin and Related Compounds. XIX.1 Some Transformation Reactions of 2-Bromo-a-tetrahydrosantonin KOJI YAMAKAWA Received November 25, 1958 The 2-bromo structure (II) for the monobromo derivative of a-tetrahydrosantonin (I) was definitely proved by the reaction sequence (II —*■ IV —► VI —► VIII). The 2-bromoketone (II) on acetolysis afforded the more stable epimer (IX) of the ketol acetate, which was also prepared from I with lead tetraacetate in reflux acetic acid. When the latter reaction was performed at the lower temperature, the other epimer (X) was obtained almost quantitatively. Epimerization of X to IX was effected by refluxing with acetic acid. Both ketol acetates were reduced to the parent ketone (I) or 3-desoxy-<*-tet,ra- hydrosantonin (VII), respectively, with zinc dust-acetic acid or by the Clemmensen method. The dimethylene thioketals (XIV and XV) of the ketol acetates gave the 3-desoxy compound (VII) on reduction with Raney nickel. Compound XV could be easily epimerized to XIV. It has been reported2 that treating a-(I) and nated at the 4-position rather than the 2-position.6’7 y-tetrahydrosantonin3 with bromine gave exclu­ In view of these observations, the slight possibility sively the 2-bromo compounds. The evidence for of 4-bromination in the tetrahydrosantonins can­ the 2-bromo structure of these derivatives was not be completely excluded. It seems to us worth­ principally based on the fact that on collidine treat­ while to unequivocally establish the structure of ment, each of these bromoketones gave a A1- these bromoketones. The present paper reports on dihydrosantonin (III) as the sole product isolated. a study of the derivatives of a-tetrahydrosantonin However, because the yields of the dihydro com­ (I), possessing the trans-decalin system. pounds were small, the allocation of bromine in the The monobromo derivative of I was subjected to bromoketones, though it appears very logical, the same sequence of reactions (II—*-IV-*-VI—► cannot be considered conclusive. Moreover, pre­ VIII) employed earlier for the proof of the position vious work has shown that dehydrobromination of of bromine in the 2-bromo derivative of 9-methyl- the 2-bromo derivative of 9-methyl-3-decalones 3-decalone.4,5b Reduction of the bromoketone with •y-collidine was always accompanied by re­ with sodium borohydride in ethanol at room tem­ arrangement,4 5’6 and that 4,9-dimethyl-3-decalones, perature proceeded stereospecifically, and one of both cis- and trans- fusions, were invariably bromi- two possible bromohydrin isomers was obtained as a crystalline solid in a 74% yield. It is generally accepted that a cfs-bromohydrin is converted by (1) Paper XVIII, M. Yanagita and H. Ogura, J. Org. alkali to a ketone whereas its trans-isomer readily Chem., 23, 1268 (1958). gives an epoxide. Upon treatment with methanolic (2) M. Yanagita and A. Tahara, J. Org. Chem., 20, 959 potassium hydroxide, the present bromohydrin (1955); cf. M. Yanagita and H. Ogura, J. Org. Chem., 22, 1092 (1957). was unaffected at room temperature, but when (3) The prefixes a and y are used in this and following heated to reflux, it was converted to the parent papers in conformity to the original paper in this series ketone (I) in a good yield. This result clearly (ref. 2); cf. ref. lib. favored the ws-structure (IV) for the bromohydrin. (4) M. Yanagita and K. Yamakawa, J. Org. Chem.., 22, 291 (1957). (6) M. Yanagita and R. Futaki, J. Org. Chem., 21, 949 % (5) (a) M. Yanagita and A. Tahara, J. Org. Chem., 18, (1956). 792 (1953); (b) M. Yanagita and K. Yamakawa, J. Org. (7) Cf. M. Yanagita and H. Ogura, J. Org. Chem., 23, Chem., 21,500(1956). 443 (1958). 897 8 9 8 YAM AK A WA v o l . 24 as suggested previously for explanation of the. same stereochemical course of borohydride reduc­ tion of the 2a,4a-dihalo-3-ketosteroids.u This con­ sideration was supported by the previous result1 !a that borohydride reduction of a-tetrahydrosantonin (I), unlike the case of II, reesulted in the pre­ dominant formation of an epimer of the hexahy- drosantonin (V), carrying the equatorial hydroxyl group at the 3-position. Reduction of the bromohydrin (IV) with zinc dust and acetic acid afforded in 67% yield an olefin (VI), which was differentiated from the known A3-isomerllb 14 by comparisons of the melting points and rotational data. It had the infrared absorption bands at 1662 and 678 cm.-1, indicating the presence of a m-disubstituted double bond.4,!>b'u The olefin was quantitatively hydrogenated over platinic oxide to 3-desoxy-a-tetrahydrosantonin (ATI) reported previously15 Permanganate oxida­ tion of the olefin was carried out in pyridine solu­ tion at low temperature with addition of magnesium sulfate in keeping the mixture neutral to litmus paper. There was obtained a diacid in 50% yield. The same acid was also formed in comparable yield directly from I by oxidation with hot concentrated nitric acid. From these modes of the preparation, it may be presumed that the diacid (VIII) pre­ served the original lactone ring, which is consider­ ably stable to acid. The diacid was quantitatively recovered from the hot alkaline solution by acidi­ fication, shoving that the lactone ring in the di­ ketone (II), which was rendered likely from con­ acid possesses the most favorable of the possible formational analysis,8 was established by the shifts isomeric structures.16 Ozonolysis of the olefin of the carbonyl absorption in the ultraviolet (AAma* (VI), which seems to be the most promising method — 5.5 m+ 9 and infrared spectra (Av +23 c m r1)111 for preparing the diacid, was attempted under over the parent ketone (I). It is most likely that the various conditions, but even when methanol17 bromine in the bromohydrin takes up the same was used as a solvent at low temperature, no equatorial position. Consequently, it is deduced crystalline products were obtained.18 that the hydroxyl group in the bromohydrin may be (12) L. F. Fieser and X. A. Dominguez, J. Am. Chein. axially oriented. This deduction was confirmed by Soc., 75, 1704 (1953); E. J. Corey, J. Am. Chem. Soc., 75, 4832 (1953); H. B. Henbest and T. I. Wrigle, J. Chem. Soc., the observation that the bromohydrin was cata- 4596 (1957): Cf. J. J. Beereboom, C. Djerassi, D. Ginsburg, lytically reduced to one isomer of the hexahydro- and L. F. Fieser [(J. Am. Chem. Soc., 75, 3500 (1953)] santonin, in which the axial character of the hy­ reported that borohydride hydrogenation of 2-chlorocholes- droxyl group at the 3-position has been estab­ tan-3-one resulted in an epimeric mixture, consisting of lished.11 It is to be noted that the predominant almost an equal amount of cis- and frau-s-chlorohydrins. (13) J. J. Beereboom and C. Djerassi, J. Org. Chem., 19, formation of the m-bromohydrin from the 2- 1196 (1954). bromoketone (II) with borohydride is in a re­ (14) L. J. Bellamy, The Infra-red Spectra of Complex markable contrast to the result of similar reduction Molecules, John Wiley & Sons, Inc., New York, 1954, p. 31. of 2a-bromocholestan-3-one, which gave chiefly (15) (a) Wedekind and K. Tettweiler, Ber., 64, 387 the imns-bromohydrin with the newly-formed (1931). (b) O. Tvovdos, V. Herout, M. Her5k, and F. Sorm, Collection Czeckoslov. Chem. Commun., 21, 225 (1956). l^droxyl group at the equatorial position.12 This (16) With respect to this point, a more detailed argument may be attributed to an increase in steric hindrance including as-series will be made in the following paper of to the carbonyl group due to the combined effects this series XX. of the two a-oriented, adjacent, bulky substituents, (17) Methanol was reported to be an excellent solvent for ozonolysis; for example see P. S. Bailev, J. Am. Chem. (8) E. J. Corev, J. Am. Chem. Soc., 75, 2301 (1053). Soc-., 78, 3811 (1956). (9) R. C. Cookson, J. Chem. Soc., 282 (1954). (18) A similar instance was found in a recent paper (10) R. N. Jones, D. A. Ramsav, F. Herling, and K. describing ozonolysis of the acetate of A2-anhydroisodi- Dobriner, J. Am. Chem. Soc., 74, 2828 (1952). hvdroresin, which gave only a poor yield of the oily ester (11) (a) B. Riniker, Thesis, E. T. H. Zürich, 1955. (b) of the diacid corresponding to VIII [C. Djerassi, F. W. W. Cocker and T. B. H. McMurrv, J. Chem. Soc., 4549 Donovan, S. Burstein, and R. Mauli, J. Am. Chem. Soc., (1956). 80, 1972 (1958)]. j u l y 1959 SANTONIN AND RELATED COMPOUNDS. XIX 8 99 The reaction sequence mentioned above clearly CH3 showed that the olefin (VI) has the double bond between the 2- and 3-positions, and hence, the previous formula (II) of the bromoketone is beyond doubt.
Load more

Recommended publications
  • Selenium-Epoxy ‘Click’ Reaction and Se-Alkylation—Efficient Access to Organo-Selenium and Selenonium Compounds
    Communication Selenium-Epoxy ‘Click’ Reaction and Se-Alkylation—Efficient Access to Organo-Selenium and Selenonium Compounds Taejun Eom and Anzar Khan * Department of Chemical and Biological Engineering, Korea University, 145 Anam-Ro, Seongbuk-Gu, Seoul 02841, Korea; [email protected] * Correspondence: [email protected]; Tel.: +82-2-3290-4859 Received: 3 September 2020; Accepted: 29 September 2020; Published: 5 October 2020 Abstract: This work establishes the ‘click’ nature of the base-catalyzed oxirane ring opening reaction by the selenolate nucleophile. The ‘click’-generated ß-hydroxy selenide can be alkylated to afford cationic selenium species. Hemolytic studies suggest that selenonium cations do not lyse red blood cells even at high concentrations. Overall, these results indicate the future applicability of the developed organo-selenium chemistry in the preparation of a new class of cationic materials based on the seleno-ether motif. Keywords: ‘click’ chemistry; oxirane ring opening reaction; organo-selenium; organo-selenonium 1. Introduction Selenium was discovered in early 1800 [1,2]. The chemistry of organo-selenium nucleophiles, however, only began in 1973 with Sharpless and Lauers’ report on the preparation of phenylselenolate and its application in converting epoxides into allylic alcohols [3]. Since then a wide range of reactions based on nucleophilic selenium reagents have been developed for use in organic synthesis [1,2]. Inspired by Sharpless’ selenium reagent and the growing interest in organoselenium materials [4], we began to examine the full scope of the ring opening reaction of epoxides by the selenolates in context of ‘click’ chemistry—another area of research pioneered by Sharpless [5]. ‘Click’ chemistry entails modular and wide in scope reactions that can be carried out under simple experimental conditions and produce quantitative yields and inoffensive byproducts [6].
    [Show full text]
  • FULL PAPER Alkyl and Aryl Thiol Addition to [1.1.1]Propellane – Scope and Limitations of a Fast Conjugation Reaction
    FULL PAPER Alkyl and aryl thiol addition to [1.1.1]propellane – scope and limitations of a fast conjugation reaction Robin M. Bär,[a] Stefan Kirschner,[a] Martin Nieger,[b] Stefan Bräse*,[a],[c] Abstract: Herein we report the addition of different thiols to the medicinal chemistry as bioisoster of para-substituted benzene[10] strained carbon-carbon bond of [1.1.1]propellane (1). We investigated and alkyne moieties.[11] With similar length and angle proportions, the reaction pathway, performed the addition with substituted thiols, the rigid group can alter the physicochemical properties such as hydrogen sulfide and protected cysteine and verified further solubility and permeability and increase the three-dimensionality. modifications of the products. The clean reaction proceeds probably Driven by the exploration of novel chemical space for drug through a radical chain process as we confirmed with different development, Bunker et al. developed a facile route to deuterium labelling experiments. It shows great functional group bicyclo[1.1.1]pentylamine, a useful building block, in four steps tolerance as halogen-, hydroxy-, methoxy-, carboxy-, amino- and from 1.[12] The group of Baran reported a method for direct nitro-substituted thiols could be added to 1 with few by-products in “propellerization” of amines by strain-release amination.[13] This 16–90% yield. Oxidation of the products offers a tuning of the polarity click-like reaction[14] enables the late-stage modification of amines and subsequent reactions of the products. The “click”-type reaction via the turbo-amides. proceeds even faster with selenols as we show in a proof-of-concept.
    [Show full text]
  • Selenium Redox Biochemistry of Zinc–Sulfur Coordination Sites in Proteins and Enzymes
    Proc. Natl. Acad. Sci. USA Vol. 96, pp. 1910–1914, March 1999 Biochemistry Selenium redox biochemistry of zinc–sulfur coordination sites in proteins and enzymes CLAUS JACOB,WOLFGANG MARET, AND BERT L. VALLEE* Center for Biochemical and Biophysical Sciences and Medicine, Harvard Medical School, Seeley G. Mudd Building, 250 Longwood Avenue, Boston, MA 02115 Contributed by Bert L. Vallee, December 31, 1998 ABSTRACT Selenium has been increasingly recognized pounds can oxidize thiols under reducing conditions such as as an essential element in biology and medicine. Its biochem- those found in the cytosol. Selenium compounds are redox istry resembles that of sulfur, yet differs from it by virtue of fined-tuned owing to the many different oxidation states of both redox potentials and stabilities of its oxidation states. selenium as well as the protein environment in which the Selenium can substitute for the more ubiquitous sulfur of element resides and in which it is found catalytically active in cysteine and as such plays an important role in more than a peroxidative reactions (6), thiolydisulfide interchange (7), and dozen selenoproteins. We have chosen to examine zinc–sulfur reduction of cytochrome c (8) or molecular oxygen to super- centers as possible targets of selenium redox biochemistry. oxide (9) by thiols. These multiple catalytic potentials may be Selenium compounds release zinc from zincythiolate- among the reasons that selenium compounds are so effective coordination environments, thereby affecting the cellular thiol while acting at concentrations much lower than the corre- redox state and the distribution of zinc and likely of other sponding sulfur analogues. metal ions.
    [Show full text]
  • New Reagents for Fluoroalkylchalcogenations : Applications to Hot Chemistry Ermal Ismalaj
    New Reagents For Fluoroalkylchalcogenations : applications To Hot Chemistry Ermal Ismalaj To cite this version: Ermal Ismalaj. New Reagents For Fluoroalkylchalcogenations : applications To Hot Chemistry. Or- ganic chemistry. Université de Lyon, 2017. English. NNT : 2017LYSE1021. tel-01522960 HAL Id: tel-01522960 https://tel.archives-ouvertes.fr/tel-01522960 Submitted on 15 May 2017 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. N°d’ordre NNT : 2017LYSE1021 THESE de DOCTORAT DE L’UNIVERSITE DE LYON opérée au sein de l’Université Claude Bernard Lyon 1 Ecole Doctorale ED 206 (Ecole Doctorale de Chimie) Spécialité de doctorat : Chimie Discipline : Chimie Organique Soutenue publiquement 10/02/2017, par : (Ermal Ismalaj) New Reagents For Fluoroalkylchalcogenations. Applications To Hot Chemistry Devant le jury composé de : Popowycz Florence Professeur INSA Lyon Présidente Gouverneur Véronique Professeur University of Oxford Rapporteur Magnier Emmanuel, DR CNRS Université de Versailles-Saint-Quentin Rapporteur Zimmer Luc, Professeur, Université Claude Bernard Lyon-1, Examinateur Billard Thierry DR CNRS Université Lyon 1 Directeur de thèse Le Bars Didier, MCU-PH, Universite Lyon 1. Membre invite UNIVERSITE CLAUDE BERNARD - LYON 1 Président de l’Université M. le Professeur Frédéric FLEURY Président du Conseil Académique M.
    [Show full text]
  • Page 1 Note: Within Nine Months from the Publication of the Mention
    Europäisches Patentamt (19) European Patent Office & Office européen des brevets (11) EP 0 954 558 B1 (12) EUROPEAN PATENT SPECIFICATION (45) Date of publication and mention (51) Int Cl.: of the grant of the patent: C10L 1/14 (2006.01) C10L 1/10 (2006.01) 14.06.2006 Bulletin 2006/24 C10L 1/02 (2006.01) (21) Application number: 97954909.4 (86) International application number: PCT/US1997/022046 (22) Date of filing: 08.12.1997 (87) International publication number: WO 1998/026028 (18.06.1998 Gazette 1998/24) (54) FUEL COMPOSITIONS EXHIBITING IMPROVED FUEL STABILITY VERBESSERTE BRENNSTOFFESTABILITÄT AUFWEISENDE BRENNSTOFFEZUSAMMENSETZUNGEN COMPOSITIONS DE CARBURANT CARACTERISEES PAR UNE STABILITE AMELIOREE DUDIT CARBURANT (84) Designated Contracting States: (56) References cited: DE FR GB IT NL WO-A-95/23836 WO-A-95/33022 WO-A-96/40844 DE-C- 508 917 (30) Priority: 09.12.1996 US 763696 US-A- 4 390 344 US-A- 4 397 655 US-A- 4 929 252 (43) Date of publication of application: 10.11.1999 Bulletin 1999/45 • DATABASE WPI Section Ch, Week 7626 Derwent Publications Ltd., London, GB; Class E11, AN (73) Proprietor: ORR, William C. 76-48473X XP002065173 & JP 51 052 403 A Denver, (ADACHI M) , 10 May 1976 Colorado 80210 (US) Remarks: (72) Inventor: ORR, William C. The file contains technical information submitted after Denver, the application was filed and not included in this Colorado 80210 (US) specification (74) Representative: Weydert, Robert Dennemeyer & Associates Sàrl P.O. Box 1502 1015 Luxembourg (LU) Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted.
    [Show full text]
  • Working with Hazardous Chemicals
    A Publication of Reliable Methods for the Preparation of Organic Compounds Working with Hazardous Chemicals The procedures in Organic Syntheses are intended for use only by persons with proper training in experimental organic chemistry. All hazardous materials should be handled using the standard procedures for work with chemicals described in references such as "Prudent Practices in the Laboratory" (The National Academies Press, Washington, D.C., 2011; the full text can be accessed free of charge at http://www.nap.edu/catalog.php?record_id=12654). All chemical waste should be disposed of in accordance with local regulations. For general guidelines for the management of chemical waste, see Chapter 8 of Prudent Practices. In some articles in Organic Syntheses, chemical-specific hazards are highlighted in red “Caution Notes” within a procedure. It is important to recognize that the absence of a caution note does not imply that no significant hazards are associated with the chemicals involved in that procedure. Prior to performing a reaction, a thorough risk assessment should be carried out that includes a review of the potential hazards associated with each chemical and experimental operation on the scale that is planned for the procedure. Guidelines for carrying out a risk assessment and for analyzing the hazards associated with chemicals can be found in Chapter 4 of Prudent Practices. The procedures described in Organic Syntheses are provided as published and are conducted at one's own risk. Organic Syntheses, Inc., its Editors, and its Board of Directors do not warrant or guarantee the safety of individuals using these procedures and hereby disclaim any liability for any injuries or damages claimed to have resulted from or related in any way to the procedures herein.
    [Show full text]
  • Selenium-Epoxy 'Click' Reaction and Se-Alkylation
    Selenium-Epoxy ‘Click’ Reaction and Se-Alkylation: Efficient Access to Organo- Selenium and Selenonium Compounds Taejun Eom and Anzar Khan* *Email: [email protected] General Methods and Materials Glycidol, glycidyl methacrylate, allyl glycidyl ether, glycidyl propargyl ether, epichlorohydrin, aniline, benzoic acid, phenol, thiophenol, benzeneselenol, lithium hydroxide monohydrate (LiOH), 1,8,-diazabicyclo[5.4.0]undec-7-ene (DBU), triethylamine (TEA), acetic anhydride, 3-bromopropane-1,2-diol, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDCI), 4-dimethylaminopyridine (DMAP), acetic acid, iodomethane, silver tetrafluoroborate (AgBF4), red blood cells (sterile defibrinated sheep’s blood, RBC), were purchased from commercial sources. NMR spectra were recorded on a Varian NMR system 500 MHz spectrometer, using CDCl3, DMSO-d6 and D2O as the solvents. HRMS was carried out on a JMS-700 from JEOL in EI and FAB mode. FT-IR spectrometer with ATR (attenuated total reflection) was carried out on Agilent Cary 630 FTIR. Hemolysis assay were performed using a microplate reader (Spectra Max 340, Molecular Devices, Sunnyvale, CA USA). Synthesis of 3 in water: To a solution of freshly obtained benzeneselenol 1 (471 mg, 3.0 mmol) and glycidol 2 (222 mg, 3.0 mmol) in 3 mL water was added TEA, DBU, or LiOH (0.01, 0.03 or 0.05 eq., respectively, per selenol unit) at 0 °C. The cooling was removed and the reaction mixture was stirred at room temperature for time shown in Table 2. After this time, 100 L of the reaction mixture was removed and diluted with 1 mL of CDCl3, dried over sodium sulfate, and studied with the help of NMR spectroscopies.
    [Show full text]
  • CRC Handbook
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oIFBUDBQBDJUZBUDPOTUBOUQSFTTVSF *61"1o BMTP QVCMJTIFE JO 1IZTJDB " o Q # oOUIWJSJBMDPFGGJDJFOU O *40 4UBOEBSET )BOECPPL 6OJUT PG .FBTVSFNFOU 4VCTDSJQUTXIJDIIBWFPUIFSNFBOJOHTTIPVMECFJOSPNBOUZQF *OUFSOBUJPOBM 0SHBOJ[BUJPO PG 4UBOEBSEJ[BUJPO (FOFWB NQoNBTTPGUIFQSPUPO &LoLJOFUJDFOFSHZ (&/&3"-36-&4 5IFGPMMPXJOHUBCMFTHJWFUIFSFDPNNFOEFETZNCPMTGPSUIFNB KPSDMBTTFTPGQIZTJDBMBOEDIFNJDBMRVBOUJUJFT5IFFYQSFTTJPOJO 5IFWBMVFPGBQIZTJDBMRVBOUJUZJTFYQSFTTFEBTUIFQSPEVDUPGB
    [Show full text]
  • Radical Cyclization Approaches to Pyrrolidines
    ! " # $ %& '#() %*+*, ## )-,*!-#- $#.-*)- $$#.# 1 CONTENTS 1. INTRODUCTION. ...........................................................................................................................................2 1.1 PYRROLIDINES. ............................................................................................................................................2 1.1.1 Some recent synthetic pathways to pyrrolidines....................................................................................3 1.2 RADICAL CHAIN REACTIONS AND THE TIN HYDRIDE METHOD.................................................................10 1.2.1 The chain reaction. ..............................................................................................................................12 1.2.2 The tin hydride method. .......................................................................................................................14 1.2.3 The 5-hexenyl radical. .........................................................................................................................15 1.2.4 The Beckwith-Houk model...................................................................................................................17 1.2.4.1 1-substituted hexenyl radicals.........................................................................................................................19 1.2.4.2 2-substituted hexenyl radicals.........................................................................................................................19
    [Show full text]
  • Reaction of Acyl Chlorides with in Situ Formed Zinc Selenolates: Synthesis of Selenoesters Versus Ring-Opening Reaction of Tetrahydrofuran
    Hindawi Publishing Corporation Journal of Chemistry Volume 2016, Article ID 2849140, 8 pages http://dx.doi.org/10.1155/2016/2849140 Research Article Reaction of Acyl Chlorides with In Situ Formed Zinc Selenolates: Synthesis of Selenoesters versus Ring-Opening Reaction of Tetrahydrofuran Gemma Bellino,1 Marialaura Scisciani,1 Jaqueline Pinto Vargas,2 Luca Sancineto,1 Luana Bagnoli,1 Francesca Marini,1 Diogo Seibert Lüdtke,2 Eder Joao Lenardao,3 and Claudio Santi1 1 Group of Catalysis and Organic Green Chemistry, Department of Pharmaceutical Sciences, University of Perugia, Via del Liceo 1, 06100 Perugia, Italy 2Instituto de Qu´ımica, Universidade Federal do Rio Grande do Sul (UFRGS), Avenida Bento Gonc¸alves 9500, 91501-970 Porto Alegre, RS, Brazil 3Laboratorio´ de S´ıntese Organicaˆ Limpa (LASOL), Centro de Cienciasˆ Qu´ımicas, Farmaceuticasˆ e de Alimentos (CCQFA), Universidade Federal de Pelotas (UFPel), P.O. Box 354, 96010-900 Pelotas, RS, Brazil Correspondence should be addressed to Claudio Santi; [email protected] Received 2 March 2016; Accepted 24 May 2016 Academic Editor: Matthias D’hooghe Copyright © 2016 Gemma Bellino et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Attempting to apply the in situ production of PhSeZnSePh to the synthesis of selenoesters, an unexpected reaction involving the solvent (tetrahydrofuran) was observed and studied. We reported here some evidences about the mechanism and the possibility to control the chemoselectivity of this new reaction that afforded the formation of interesting selenoderivatives in which the selenium moiety and the carboxylic one are spaced by four carbon units.
    [Show full text]
  • Water and Aqueous Mixtures As Convenient Alternative Media for Organoselenium Chemistry
    Review Water and Aqueous Mixtures as Convenient Alternative Media for Organoselenium Chemistry Claudio Santi 1,*, Raquel G. Jacob 2, Bonifacio Monti 1, Luana Bagnoli 1, Luca Sancineto 1 and Eder J. Lenardão 2 1 Department of Pharmaceutical Sciences, Group of Catalysis and Organic Green Chemistry, University of Perugia, Via del Liceo 1, Perugia 06100, Italy; [email protected] (B.M.); [email protected] (L.B.) [email protected] (L.S.) 2 Laboratório de Síntese Orgânica Limpa-LASOL-CCQFA-Universidade Federal de Pelotas-UFPel, P.O. Box 354, Pelotas 96010-900, RS, Brazil; [email protected] (R.G.J.) [email protected] (E.J.L.) * Correspondence: [email protected]; Tel.: +39-75-585-5102; +39-75-585-5116: Academic Editors: Joaquín García Álvarez and Jonathan Sperry Received: 20 October 2016; Accepted: 2 November 2016; Published: 6 November 2016 Abstract: Even if water is the natural environment for bioorganic reactions, its use in organic chemistry is often severely limited by the high insolubility of the organic derivatives. In this review, we introduce some examples of the use of water to perform organoselenium chemistry. We mainly discuss the advantages of this medium when the recyclability is demonstrated and when the water can control the selectivity of a reaction or enhance the reaction rate. Keywords: on-water reactions; water; selenium; epoxide; zinc; michael addition; coupling; catalysis; oxidation 1. Introduction During the last two decades, the use of water as an alternative solvent for organic reactions has been debated. Water is the natural medium for all biochemical reactions and is often claimed as an ideal green solvent [1,2] because it is non-toxic and non-flammable, has a high heat capacity in adsorbing the energy produced during a chemical reaction, and has low cost and large availability.
    [Show full text]
  • Naming and Indexing of Chemical Substances for Chemical Abstractstm
    Naming and Indexing of Chemical Substances for Chemical AbstractsTM 2007 Edition A publication of Chemical Abstracts Service Published by the American Chemical Society Naming and Indexing of Chemical Substances for Chemical AbstractsTM A publication of Chemical Abstracts Service Published by the American Chemical Society Copyright © 2008 American Chemical Society All Rights Reserved. Printed in the USA Inquiries concerning editorial content should be sent to: Editorial Office, Chemical Abstracts Service, 2540 Olentangy River Road, P.O. Box 3012, Columbus, Ohio 43210-0012 USA SUBSCRIPTION INFORMATION Questions about CAS products and services should be directed to: United States and Canada: CAS Customer Care Phone: 800-753-4227 (North America) 2540 Olentangy River Road 614-447-3700 (worldwide) P.O. Box 3012 Fax: 614-447-3751 Columbus, Ohio 43210-0012 USA E-mail: [email protected] Japan: JAICI (Japan Association for International Phone: 81-3-5978-3621 Chemical Information) Fax: 81-3-5978-3600 6-25-4 Honkomagome E-mail: [email protected] Bunkyo-ku, Tokyo Japan, 113-0021 Countries not named above: Contact CAS Customer Care, 2540 Olentangy River Road, P.O. Box 3012, Columbus, Ohio 43210-0012 USA; Telephone 614-447-3700; Fax 614-447-3751; E-mail [email protected]. For a list of toll-free numbers from outside North America, visit www.cas.org. 1 Naming and Indexing of Chemical Substances for Chemical Abstracts 2007 ¶ 102 NAMING AND INDEXING OF CHEMICAL SUBSTANCES 101. Foreword. Although the account which follows describes in consid- zwitterions (inner salts, sydnones). The changes for the Fourteenth (1997- erable detail the selection of substance names for Chemical Abstracts (CA) in- 2001) Collective Index period affect coordination nomenclature, stereochemi- dexes, it is not a nomenclature manual.
    [Show full text]