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Sample records for ansamblil stereochemistry ilmus

  1. Prantsusmaal ilmus kolm eesti kirjandusteost

    Index Scriptorium Estoniae

    2002-01-01

    Antoine Chalvini tõlgitud novellikogu "Les hirondelles" ("Pääsukesed") sisaldab 19 eesti kirjaniku novelle. Eva Koffi näidendi "Meie isa" tõlkis Eva Toulouze. Prantsuse keeles ilmus ka Jaan Kaplinski luulekogu "Le désir de la poussière" ("Tolmu igatsus")

  2. Mathematical stereochemistry

    CERN Document Server

    Fujita, Shinsaku

    2015-01-01

    Chirality and stereogenicity are closely related concepts and their differentiation and description is still a challenge in chemoinformatics. A new stereoisogram approach, developed by the author, is introduced in this book, providing a theoretical framework for mathematical aspects of modern stereochemistry. The discussion covers point-groups and permutation symmetry and exemplifies the concepts using organic molecules and inorganic complexes.

  3. SYNTHESIS, STEREOCHEMISTRY AND ANTIMICROBIAL ...

    African Journals Online (AJOL)

    Preferred Customer

    KEY WORDS: 4-Phenylsemicarbazone, Metal complexes, Stereochemistry, Antimicrobial activity. INTRODUCTION ... stereochemistry of semicarbazone metal complexes [8-13], this group of ligands deserve further investigations. ..... The cytotoxicity of tested compounds generally increased with increase concentration and ...

  4. Stereochemistry basic concepts and applications

    CERN Document Server

    Nógrádi, M

    2013-01-01

    Stereochemistry: Basic Concepts and Applications is a three-chapter text that introduces the basic principles and concepts of stereochemistry, as well as its application to organic chemistry application.Chapter 1 describes first the stereochemistry of the ground state, specifically the configuration and conformation of organic compounds, as well as the most important methods for its investigation. This chapter also deals with the kinetics of conformational changes and provides an overview of the so-called ""applied stereochemistry"". Chapter 2 focuses on the analysis of the internal motions of

  5. using stereochemistry models in teaching organic compounds

    African Journals Online (AJOL)

    Preferred Customer

    (Stereochemistry Model); the treatment had significant effect: students taught using. Stereochemistry Models ... ISSN 2227-5835. 93. Apart from the heavy conceptual demand on the memory capacity required of the ..... colors and sizes compared with the sketches on the chart that appear to be mock forms of the compounds.

  6. Ilmus teadusartikkel kaasaegsest tantsupedagoogikast / Anu Sööt ja Ele Viskus

    Index Scriptorium Estoniae

    Sööt, Anu, 1957-

    2014-01-01

    Ajakirjas “European Journal of Social and Behavioural Sciences” ilmus Anu Söödi ja Ele Viskuse artikkel “Contemporary Approaches to Dance Pedagogy - the Challenges of the 21st Century” (“Kaasaegne tantsupedagoogika - 21. sajandi väljakutsed”)

  7. Pasteur-The Harbinger of Stereochemistry-Louis Pasteur, Tartaric ...

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 12; Issue 1. Pasteur - The Harbinger of Stereochemistry - Louis Pasteur, Tartaric Acid and Stereochemistry. Gopalpur Nagendrappa. General Article Volume 12 Issue 1 January 2007 pp 38-48 ...

  8. Stereochemistry and rearrangement reactions of hydroxylignanolactones.

    Science.gov (United States)

    Raffaelli, Barbara; Pohjoispää, Monika; Hase, Tapio; Cardin, Christine J; Gan, Yu; Wähälä, Kristiina

    2008-07-21

    Various conflicting data on the rearrangement and absolute stereochemistry of hydroxylignano-9,7'-lactones are resolved using 18O labeled compounds, also confirmed by an X-ray analysis of a pure lignano-9,7'-lactone enantiomer, obtained for the first time. Under NaH/DMF rearrangement conditions a silyl protected hydroxylignano-9,9'-lactone underwent an unexpected silyl migration.

  9. Inhibition stereochemistry of hydroxamate inhibitors for thermolysin.

    Science.gov (United States)

    Jin, Y; Kim, D H

    1998-12-15

    N-Acyl-N-hydroxy-beta-amino acid derivatives were prepared and tested as inhibitors for thermolysin to find that these inhibitors show the L-stereospecificity in contrast to the corresponding hydroxamates prepared from alpha-amino acid, which exhibit the D-stereochemistry. N-Formyl-N-hydroxy-beta-L-Phe-NHMe is the most potent inhibitor having the Ki value of 1.66 microM.

  10. Vox Clamantis esines Belgias ja Prantsusmaal

    Index Scriptorium Estoniae

    2009-01-01

    Vokaalansambli Vox Clamantise osalemisest 22.-25. maini Watou rahvusvahelisel gregoriaanifestivalil Belgias ja kontserdidt 31. mail Prantsusmaal XII sajandist pärit tsistertslaste kloostris Pontignys. Prantsuse plaadifirmalt Mirare ilmus ansamblil Weekend Guitar Trioga ühisplaat "Stella matutina"

  11. THE STEREOCHEMISTRY AND MECHANISM OF HYDRIDE REDUCTIONS OF CYCLOHEXENE OXIDES.

    Science.gov (United States)

    HYDRIDES, *OXIDATION REDUCTION REACTIONS), (* CYCLOHEXANOLS , SYNTHESIS (CHEMISTRY)), (*STEREOCHEMISTRY, CYCLOHEXANES), (*BOROHYDRIDES, REDUCTION...CHEMISTRY)), DIBORANES, OXYGEN HETEROCYCLIC COMPOUNDS, CYCLOHEXANONES, CYCLOHEXENES , MOLECULAR ISOMERISM, ORGANIC SOLVENTS, GAS CHROMATOGRAPHY

  12. Stereochemistries of monapinones produced by Talaromyces pinophilus FKI-3864

    Directory of Open Access Journals (Sweden)

    Ryuji Uchida

    2013-05-01

    Full Text Available Monapinones A (1 to E (5, half parts of dinapinones, were produced by fermentation of Talaromyces pinophilus FKI-3864 in seawater-containing medium and have a common dihydronaphthopyranone skeleton with a different long alkyl chain. The relative stereochemistries of 3–5 were elucidated by various NMR experiments including analysis of 1H NMR coupling constants, ROESY and the dihedral angles. The absolute stereochemistries of 3–5 at C-3 were determined by the circular dichroism spectra in comparison to the data of (R- and (S-semivioxanthins (6 and 7. Accordingly, total absolute stereochemistries of 3–5 were concluded to be 3S,13R,15R,17R,19R,3S,13R,15R,17R and 3S,13R,15R, respectively.

  13. Stereochemistry of substitution at trico-ordinate phosphorus

    DEFF Research Database (Denmark)

    Nielsen, John; Dahl, Otto

    1984-01-01

    and 31P) from reactant and product diastereoisomers have been assigned, and the stereo-chemistry of the substitution reactions have been determined by 31P n.m.r. monitoring. The outcome varies from complete inversion to complete lack of stereoselectivity. During the initial stages many of the non...

  14. SOS: A Mnemonic for the Stereochemistry of Glucose

    Science.gov (United States)

    Starkey, Ronald

    2000-06-01

    The mnemonic SOS (Same, Opposite, Same) can be helpful to recall the stereochemistry in either D-glucose or L-glucose. It refers to the configurations of C-2, C-3, and C-4 relative to that of C-5 in an aldohexose. Same and Opposite refer to either the R or S configuration or to the relative positions of the OH groups on the Fischer projection structural formula. The SOS mnemonic can help to reinforce that gluco specifies the relative configurations of stereocenters in the molecule.

  15. A Simple and Novel Approach to Delineating Stereochemistry of Electrocyclic Reactions

    Science.gov (United States)

    Mandal, Dipak K.

    2012-01-01

    The dynamic stereochemistry of electrocyclic reactions (a class of pericyclic reactions) stems from the operation of either conrotatory (con) or disrotatory (dis) mode of ring-closing and ring-opening processes. Difficulty is often encountered in depicting product stereochemistry resulting from such movements of substituents. A novel, simple,…

  16. Natural polyprenylated benzophenones: keto-enol tautomerism and stereochemistry

    Energy Technology Data Exchange (ETDEWEB)

    Martins, Felipe T.; Cruz Junior, Jose W.; Doriguetto, Antonio C. [Universidade Federal de Alfenas, MG (Brazil). Dept. de Ciencias Exatas. Lab. de Cristalografia]. E-mail: doriguetto@unifal-mg.edu.br; Derogis, Priscilla B.M.C.; Santos, Marcelo H. dos; Veloso, Marcia P. [Universidade Federal de Alfenas, MG (Brazil). Dept. de Ciencias Exatas. Lab. de Fitoquimica e Quimica Medicinal; Ellena, Javier [Universidade de Sao Paulo, Sao Carlos, SP (Brazil). Inst. de Fisica

    2007-07-01

    The keto-enol tautomerism and stereochemistry study of a HIV-inhibitory natural benzophenone, (1R,5R,7R,8S)-(+)-3-(10-(3,4-dihydroxyphenyl)-10-hydroxymethylene) -8-methyl-1,5,7-tris(3-methyl-2-butenyl)-8-(4-methyl-3-pentenyl)-bicyclo [3.3.1]nonane-2,4,9-trione (a), isolated from Garcinia brasiliensis seeds is presented. The crystal structure of (a), which is also know as guttiferona A, was determined by X-ray diffraction and its intra and inter-molecular geometries discussed and compared with two analogue natural benzophenones: clusianone and epiclusianone. In (a), the hydroxyl H atom from enolizable 2,4,10-trione moiety is linked in the oxygen atom bonded to 10-(3,4-dihydroxyphenyl)methylene group, in opposition to the related natural benzophenones, where this analogue H-atom is placed in different O-atoms from bicyclo[3.3.1]nonane ring system. Such behaviour can be explained by the presence of aromatic OH6 group in (a) that origins a further delocalized resonance path along of 3,4-dihydroxyphenyl- C10-OH2 group. In addition, the (a) stereochemistry around C7 atom is compared with known structures of clusianone and epiclusianone and the influence from configuration in this chiral Catom to structural features found in the enolizable system is proposed. (author)

  17. Relationships between the stereochemistry and biological activity of fungal phytotoxins.

    Science.gov (United States)

    Evidente, Antonio; Andolfi, Anna; Cimmino, Alessio

    2011-10-01

    Toxins produced by phytopathogenic fungi assume great importance because of their involvement in several plant diseases. Although such pathogens are known to have seriously damaged crops, forest, and environmental resources, they represent a very important tool to develop new environmentally friendly herbicides and fungicides. This review deals with the relationships between the biological activity of some phytotoxins produced by pathogenic fungi for major forest plants and for damaging weeds and their stereochemistry. In particular, the methods used to determine their relative and/or absolute configuration will be illustrated. These include the application of Mosher's and Murata's methods, X-ray diffractometric analysis, circular dichroism, and the use of computational methods to determine the theoretical optical rotatory power as well as the CD spectrum. The importance of determining the absolute configuration to achieve the total synthesis of some phytotoxins, interesting for their potential practical application, is also discussed. © 2011 Wiley-Liss, Inc.

  18. Determination of the Absolute Stereochemistry of Secondary Alcohols: An Advanced Organic Chemistry Experiment for Undergraduate Students.

    Science.gov (United States)

    Bandaranayake, Wickramasinghe M.

    1980-01-01

    Describes experiments which can be completed in five four-hour laboratory sessions, including two synthesis (alpha-phenylbutyric and alpha-phenylbutyric acid anhydride) and determining the absolute stereochemistry of secondary alcohols using the synthetic products. (JN)

  19. Accurate stereochemistry for two related 22,26-epiminocholestene derivatives

    Energy Technology Data Exchange (ETDEWEB)

    Vega-Baez, José Luis; Sandoval-Ramírez, Jesús; Meza-Reyes, Socorro; Montiel-Smith, Sara; Gómez-Calvario, Victor [Facultad de Ciencias Químicas, Benemérita Universidad Autónoma de Puebla, Ciudad Universitaria, San Manuel, 72000 Puebla, Pue. (Mexico); Bernès, Sylvain, E-mail: sylvain-bernes@hotmail.com [DEP Facultad de Ciencias Químicas, UANL, Guerrero y Progreso S/N, Col. Treviño, 64570 Monterrey, NL (Mexico); Facultad de Ciencias Químicas, Benemérita Universidad Autónoma de Puebla, Ciudad Universitaria, San Manuel, 72000 Puebla, Pue. (Mexico)

    2008-04-01

    Regioselective opening of ring E of solasodine under various conditions afforded (25R)-22,26-epimino@@cholesta-5,22(N)-di@@ene-3β,16β-diyl diacetate (previously known as 3,16-diacetyl pseudosolasodine B), C{sub 31}H{sub 47}NO{sub 4}, or (22S,25R)-16β-hydr@@oxy-22,26-epimino@@cholesta-5-en-3β-yl acetate (a derivative of the naturally occurring alkaloid oblonginine), C{sub 29}H{sub 47}NO{sub 3}. In both cases, the reactions are carried out with retention of chirality at the C16, C20 and C25 stereogenic centers, which are found to be S, S and R, respectively. Although pseudosolasodine was synthesized 50 years ago, these accurate assignments clarify some controversial points about the actual stereochemistry for these alkaloids. This is of particular importance in the case of oblonginine, since this compound is currently under consideration for the treatment of aphasia arising from apoplexy; the present study defines a diastereoisomerically pure compound for pharmacological studies.

  20. Accurate stereochemistry for two related 22,26-epiminocholestene derivatives

    International Nuclear Information System (INIS)

    Vega-Baez, José Luis; Sandoval-Ramírez, Jesús; Meza-Reyes, Socorro; Montiel-Smith, Sara; Gómez-Calvario, Victor; Bernès, Sylvain

    2008-01-01

    Regioselective opening of ring E of solasodine under various conditions afforded (25R)-22,26-epimino@@cholesta-5,22(N)-di@@ene-3β,16β-diyl diacetate (previously known as 3,16-diacetyl pseudosolasodine B), C 31 H 47 NO 4 , or (22S,25R)-16β-hydr@@oxy-22,26-epimino@@cholesta-5-en-3β-yl acetate (a derivative of the naturally occurring alkaloid oblonginine), C 29 H 47 NO 3 . In both cases, the reactions are carried out with retention of chirality at the C16, C20 and C25 stereogenic centers, which are found to be S, S and R, respectively. Although pseudosolasodine was synthesized 50 years ago, these accurate assignments clarify some controversial points about the actual stereochemistry for these alkaloids. This is of particular importance in the case of oblonginine, since this compound is currently under consideration for the treatment of aphasia arising from apoplexy; the present study defines a diastereoisomerically pure compound for pharmacological studies

  1. The Stereochemistry of Complex Polyketide Biosynthesis by Modular Polyketide Synthases

    Directory of Open Access Journals (Sweden)

    David H. Kwan

    2011-07-01

    Full Text Available Polyketides are a diverse class of medically important natural products whose biosynthesis is catalysed by polyketide synthases (PKSs, in a fashion highly analogous to fatty acid biosynthesis. In modular PKSs, the polyketide chain is assembled by the successive condensation of activated carboxylic acid-derived units, where chain extension occurs with the intermediates remaining covalently bound to the enzyme, with the growing polyketide tethered to an acyl carrier domain (ACP. Carboxylated acyl-CoA precursors serve as activated donors that are selected by the acyltransferase domain (AT providing extender units that are added to the growing chain by condensation catalysed by the ketosynthase domain (KS. The action of ketoreductase (KR, dehydratase (DH, and enoylreductase (ER activities can result in unreduced, partially reduced, or fully reduced centres within the polyketide chain depending on which of these enzymes are present and active. The PKS-catalysed assembly process generates stereochemical diversity, because carbon–carbon double bonds may have either cis- or trans- geometry, and because of the chirality of centres bearing hydroxyl groups (where they are retained and branching methyl groups (the latter arising from use of propionate extender units. This review shall cover the studies that have determined the stereochemistry in many of the reactions involved in polyketide biosynthesis by modular PKSs.

  2. Synthesis, stereochemistry, and photochemical and thermal behaviour of bis-tert-butyl substituted overcrowded alkenes

    NARCIS (Netherlands)

    K. J. Ter Wiel, M.; G. Kwit, M.; Meetsma, A.; Feringa, B.L.

    2007-01-01

    In order to study the structural limits in the design of molecular motors, a tert-butyl substituted analogue was prepared. The unexpected photochemical and thermal isomerisation processes and the stereochemistry of new overcrowded alkene 5 are described. The bis tert-butyl substituted alkenes were

  3. Controlling the stereochemistry and regularity of butanethiol self-assembled monolayers on Au(111)

    DEFF Research Database (Denmark)

    Yan, Jiawei; Ouyang, Runhai; Jensen, Palle Skovhus

    2014-01-01

    The rich stereochemistry of the self-assembled monolayers (SAMs) of four butanethiols on Au(111) is described, the SAMs containing up to 12 individual C, S, or Au chiral centers per surface unit cell. This is facilitated by synthesis of enantiomerically pure 2-butanethiol (the smallest unsubstitu......The rich stereochemistry of the self-assembled monolayers (SAMs) of four butanethiols on Au(111) is described, the SAMs containing up to 12 individual C, S, or Au chiral centers per surface unit cell. This is facilitated by synthesis of enantiomerically pure 2-butanethiol (the smallest...... when R is achiral, while adatom binding leads to rectangular plane groups that suppress long-range expression of chirality. Binding as RS• also inhibits the pitting intrinsically associated with adatom binding, desirably producing more regularly structured SAMs....

  4. Evaluating Ketoreductase Exchanges as a Means of Rationally Altering Polyketide Stereochemistry.

    Science.gov (United States)

    Annaval, Thibault; Paris, Cédric; Leadlay, Peter F; Jacob, Christophe; Weissman, Kira J

    2015-06-15

    Modular polyketide synthases (PKSs) are multidomain multienzymes responsible for the biosynthesis in bacteria of a wide range of polyketide secondary metabolites of clinical value. The stereochemistry of these molecules is an attractive target for genetic engineering in attempts to produce analogues exhibiting novel therapeutic properties. The exchange of ketoreductase (KR) domains in model PKSs has been shown in several cases to predictably alter the configuration of the β-hydroxy functionalities but not of the α-methyl groups. By systematic screening of a broad panel of KR domains, we have identified two donor KRs that afford modification of α-methyl group stereochemistry. To the best of our knowledge, this provides the first direct in vivo evidence of KR-catalyzed epimerization. However, none of the introduced KRs afforded simultaneous alteration of methyl and hydroxy configurations in high yield. Therefore, swapping of whole modules might be necessary to achieve such changes in stereochemistry. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Absolute Configuration of (-)-2-(4-Hydroxyphenyl)propionic acid: Stereochemistry of Soy Isoflavone Metabolism

    International Nuclear Information System (INIS)

    Kim, Mihyang; Han, Jaehong

    2014-01-01

    We have elucidated stereochemistry of (-)-2-HPPA. Determination of (R)-2-HPPA stereochemistry also provided stereochemical information of genistein metabolism. Considering the stereochemistry of 2-HPPA, the precursor of (R)-2-HPPA should be (R)-6'-hydroxy-O-DMA. Besides, it is clear that only (S)-dihydrogenistein is the possible precursor of (R)-6'-hydroxy-O-DMA. Therefore, genistein metabolism is suggested to follow the same stereochemical pathway like daidzein. Biotransformation of natural products by human intestinal bacteria has recently drawn a significant interest, due to the emerging strong correlation between gut microbiota and human health. Microbial metabolism of natural products by intestinal bacteria in small intestine and colon proceeds the phase I and II xenobiotic metabolisms in the liver. The metabolites were found to exhibit different biological activities, and affect human etiology. For example, many beneficial effects of dietary polyphenols in human health are attributed to the microbial metabolites produced by intestinal bacteria and the modulation of gut microbiota composition

  6. Absolute Configuration of (-)-2-(4-Hydroxyphenyl)propionic acid: Stereochemistry of Soy Isoflavone Metabolism

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Mihyang; Han, Jaehong [Chung-Ang Univ., Seoul (Korea, Republic of)

    2014-06-15

    We have elucidated stereochemistry of (-)-2-HPPA. Determination of (R)-2-HPPA stereochemistry also provided stereochemical information of genistein metabolism. Considering the stereochemistry of 2-HPPA, the precursor of (R)-2-HPPA should be (R)-6'-hydroxy-O-DMA. Besides, it is clear that only (S)-dihydrogenistein is the possible precursor of (R)-6'-hydroxy-O-DMA. Therefore, genistein metabolism is suggested to follow the same stereochemical pathway like daidzein. Biotransformation of natural products by human intestinal bacteria has recently drawn a significant interest, due to the emerging strong correlation between gut microbiota and human health. Microbial metabolism of natural products by intestinal bacteria in small intestine and colon proceeds the phase I and II xenobiotic metabolisms in the liver. The metabolites were found to exhibit different biological activities, and affect human etiology. For example, many beneficial effects of dietary polyphenols in human health are attributed to the microbial metabolites produced by intestinal bacteria and the modulation of gut microbiota composition.

  7. The stereochemistry of the condensation product of salicylaldehyde and n-butylbarbituric acid by NMR techniques

    Energy Technology Data Exchange (ETDEWEB)

    Cruz, Elizabete R.; Villar, J. Daniel Figueroa [Instituto Militar de Engenharia (IME), Rio de Janeiro, RJ (Brazil). Dept. de Quimica

    1995-12-31

    Since the discovery of the 5-deazaflavin cofactor (coenzyme F{sub 420}) as a naturally occurring compound, a great attention has been focused on several iso steric flavin analogues. One of the simplest approaches towards the synthesis of oxadeazaflavin, compound which the nitrogen at the N-10 position of 5-deazaflavin is replaced by oxygen, is the direct condensation between barbituric acid and salicylaldehyde. In this paper, the use of some NMR techniques so as to determine the stereochemistry of the preformed isomer has been described and a possible mechanism for this isomerization discussed 12 refs., 2 figs., 1 tab.

  8. Ilmus teadusajakirja Rechtstheorie Eesti erinumber

    Index Scriptorium Estoniae

    2008-01-01

    Tutvustus väljaandele: Multiple Modernität, Globalisierung der Rechtsordnung und Kommunikationsstruktur der Rechtssysteme : Internationales Symposium zur Theorie der Rechtskommunikation an der Universität Tartu im April 2006 / herausgegeben von Werner Krawietz und Raul Narits. Berlin : Duncker & Humblot, 2007

  9. Ilmus 20. sajandi suurim raamat

    Index Scriptorium Estoniae

    1999-01-01

    Kirjastus Taschen andis austraalia fotograafi Helmut Newtoni elutöö kokkuvõttena välja tema 480-leheküljelise luksusalbumi 'Big Nude'. 70 cm kõrgune ja 50 cm laiune raamat kaalub 30 kilo, maksab 24000 kroon, trükiti 10000 eksemplari. Erilise raamatupuldi albumi jaoks kujundas Philippe Starck

  10. Ilmus eesti funktsionalistliku arhitektuuri reisijuht

    Index Scriptorium Estoniae

    1998-01-01

    Tallinnas 1998. a. ilmunud Mart Kalmu eesti 1930. aastate arhitektuuri tutvustav 'Eesti funktsionalism/Functionalism in Estonia. Reisijuht' (DOCOMOMO-Eesti). Kujundaja Andres Tali. Mart Kalm DOCOMOMO Eesti grupi peakoordinaatorina

  11. Ilmus võrukeelne aabits

    Index Scriptorium Estoniae

    1999-01-01

    ABC kiräoppus ja lugõmik algkooli latsilõ / koost. Võro Seltsi VKKF ja Võru Instituudi aabitsatoimkond ; Jüvä Sullõv, Kauksi Ülle, Marju Kõivupuu ... [jt] .Võro, 1998. Ka asjatundjate komisjoni koosseisust, mille vabariigi valitsus moodustas lõunaeesti keele ja kultuuri säilitamise ja arendamise riikliku programmi väljatöötamiseks

  12. Ilmus haridusterminite sõnastik

    Index Scriptorium Estoniae

    2003-01-01

    Eurydice programmi poolt välja antud sõnastik : European glossary on education. Vol. 4 : Management, Monitoring and Support Staff. Sõnastik annab ülevaate 30 Euroopa riigis kasutatavatest haridusterminitest, mis puudutavad kooli juhtkonda, seire- ja abipersonali kõigil haridustasemetel

  13. How stereochemistry influences the taste of wine: Isolation, characterization and sensory evaluation of lyoniresinol stereoisomers.

    Science.gov (United States)

    Cretin, Blandine N; Sallembien, Quentin; Sindt, Lauriane; Daugey, Nicolas; Buffeteau, Thierry; Waffo-Teguo, Pierre; Dubourdieu, Denis; Marchal, Axel

    2015-08-12

    Wine expresses its beauty by sending a sensory message to the taster through molecules coming from grapes, yeast metabolism or oak wood. Among the compounds released during barrel aging, lyoniresinol has been recently reported as a relevant contributor to wine bitterness. As this lignan contains three stereogenic carbons, this work aimed at investigating the influence of stereochemistry on wine taste by combining analytical and sensorial techniques. First, an oak wood extract was screened by Liquid Chromatography-High Resolution Mass Spectrometry to target isomers separable in a symmetric environment and a diastereoisomer called epi-lyoniresinol was isolated for the first time. Then, an original racemic resolution based on natural xylose-derivatives was carried out to obtain lyoniresinol enantiomers. Chiroptical spectroscopic measurements associated with theoretical calculations allowed the unambiguous determination of their absolute configuration. The taste properties of all these stereoisomers revealed that only one lyoniresinol enantiomer is strongly bitter whereas the other one is tasteless and the diastereoisomer is slightly sweet. The presence of these three compounds was established in an oaked Bordeaux wine by chiral and non-chiral chromatography, suggesting the significant influence of stereochemistry on wine taste. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Structure and stereochemistry of electrochemically synthesized poly-(1-naphthylamine from neutral acetonitrile solution

    Directory of Open Access Journals (Sweden)

    VESNA ANTIC

    2002-12-01

    Full Text Available Poly-(1-naphthylamine films were synthesized potentiodinamically and potentiostatically from 1-naphthylamine in neutral acetonitrile medium using a platinum electrode. These polymer films were investigated by infrared spectroscopy. Contrary to earlier published results neglecting the stereochemistry of the poly-(1-naphthylamine, we predict on the basis of quantum stereochemical analysis of the possible structural subunits of the polymer, that the ordinary N–C(4 coupled product is not predominant in the polymer because it is far removed from the expected planarity. Based on the results of IR investigations and semiempirical quantum chemical calculations, it is propose that the polymer products are formed via mixed N–C(4, N-C(5 and N–C(7 coupling routes. The heats of formation of the oxidized 1-naphthylamine dimers and hexamers were calculated.

  15. The effect of stereochemistry on the biological activity of natural phytotoxins, fungicides, insecticides and herbicides.

    Science.gov (United States)

    Evidente, Antonio; Cimmino, Alessio; Andolfi, Anna

    2013-02-01

    Phytotoxins are secondary microbial metabolites that play an essential role in the development of disease symptoms induced by fungi on host plants. Although phytotoxins can cause extensive-and in some cases devastating-damage to agricultural crops, they can also represent an important tool to develop natural herbicides when produced by fungi and plants to inhibit the growth and spread of weeds. An alternative strategy to biologically control parasitic plants is based on the use of plant and fungal metabolites, which stimulate seed germination in the absence of the host plant. Nontoxigenic fungi also produce bioactive metabolites with potential fungicide and insecticide activity, and could be applied for crop protection. All these metabolites represent important tools to develop eco-friendly pesticides. This review deals with the relationships between the biological activity of some phytotoxins, seed germination stimulants, fungicides and insecticides, and their stereochemistry. Copyright © 2012 Wiley Periodicals, Inc.

  16. Stereochemistry of Endogenous Palmitic Acid Ester of 9-Hydroxystearic Acid and Relevance of Absolute Configuration to Regulation.

    Science.gov (United States)

    Nelson, Andrew T; Kolar, Matthew J; Chu, Qian; Syed, Ismail; Kahn, Barbara B; Saghatelian, Alan; Siegel, Dionicio

    2017-04-05

    Lipids have fundamental roles in the structure, energetics, and signaling of cells and organisms. The recent discovery of fatty acid esters of hydroxy fatty acids (FAHFAs), lipids with potent antidiabetic and anti-inflammatory activities, indicates that our understanding of the composition of lipidome and the function of lipids is incomplete. The ability to synthesize and test FAHFAs was critical in elucidating the roles of these lipids, but these studies were performed with racemic mixtures, and the role of stereochemistry remains unexplored. Here, we synthesized the R- and S- palmitic acid ester of 9-hydroxystearic acid (R-9-PAHSA, S-9-PAHSA). Access to highly enantioenriched PAHSAs enabled the development of a liquid chromatography-mass spectrometry (LC-MS) method to separate and quantify R- and S-9-PAHSA, and this approach identified R-9-PAHSA as the predominant stereoisomer that accumulates in adipose tissues from transgenic mice where FAHFAs were first discovered. Furthermore, biochemical analysis of 9-PAHSA biosynthesis and degradation indicate that the enzymes and pathways for PAHSA production are stereospecific, with cell lines favoring the production of R-9-PAHSA and carboxyl ester lipase (CEL), a PAHSA degradative enzyme, selectively hydrolyzing S-9-PAHSA. These studies highlight the role of stereochemistry in the production and degradation of PAHSAs and define the endogenous stereochemistry of 9-PAHSA in adipose tissue. This information will be useful in the identification and characterization of the pathway responsible for PAHSA biosynthesis, and access to enantiopure PAHSAs will elucidate the role of stereochemistry in PAHSA activity and metabolism in vivo.

  17. Methods for the comprehensive structural elucidation of constitution and stereochemistry of lipopeptides.

    Science.gov (United States)

    Gerhardt, Heike; Sievers-Engler, Adrian; Jahanshah, Ghazaleh; Pataj, Zoltán; Ianni, Federica; Gross, Harald; Lindner, Wolfgang; Lämmerhofer, Michael

    2016-01-08

    A panel of methods of general suitability for complete structural elucidation of the stereochemistry of cyclopeptides, depsipeptides and lipopeptides is presented and described in detail. The suitability of the proposed methods was exemplified on the lipopeptide poaeamide from Pseudomonas poae. Amino acid configurations have been assigned by direct LC enantiomer separation with Chiralpak ZWIX(+) and were confirmed by GC enantiomer separation on Chirasil L-Val. 3-Hydroxydecanoic acid absolute configuration was analyzed on Chiralpak ZWIX(+) and confirmed by injection on ZWIX(-) which showed opposite elution order. Plenty of d-amino acids have been found in this lipopeptide. It contained in total 5 Leu residues of which one had d-configuration. The position of the d-Leu in the peptide sequence was determined by pepsin and chemical digestions in combination with isolation of diagnostic peptide-fragments and subsequent identification of absolute configurations of the Leu residues. This allowed pinpointing the position of the d-amino acid. The complementarity of the peptide retention profiles on Chiralpak ZWIX column as compared to both RPLC and HILIC suggests its great utility as an alternative peptide separation tool. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. Structure and stereochemistry in f-block complexes of high co-ordination number

    International Nuclear Information System (INIS)

    Kepert, D.L.; Patrick, J.M.; White, A.H.

    1983-01-01

    The crystal structure of [Usup(IV)(PhCOCHCOPh)4- has been determined at 295 K from X-ray diffraction data refined by least squares to a residual of 0.042 for 2 257 'observed' reflections. Crystals are orthorhombic, space group Pccn, with unit-cell dimensions a = 10.323(8), b = 20.172(15), c = 23.65(2) A, and Z = 4; they are isostructural with the previously studied cerium analogue, the eight-co-ordinate uranium atom lying on a crystallographic two-fold axis, with U - O ranging from 2.323(7) to 2.370(6) A. For the cerium analogue, a = 10.29(1), b = 20.07(3), and c = 23.42(4) A; R = 0.043 for 1 817 'observed' reflections. The corresponding Ce - O distances lie between 2.291(7) and 2.348(6) A. The stereochemistries of these complexes are close to square antiprismatic with the bidentate ligands spanning opposite square faces, as predicted by electron-pair repulsion theory. (author)

  19. Influence of Linkage Stereochemistry and Protecting Groups on Glycosidic Bond Stability of Sodium Cationized Glycosyl Phosphates

    Science.gov (United States)

    Zhu, Y.; Yang, Zhihua; Rodgers, M. T.

    2017-12-01

    Energy-resolved collision-induced dissociation (ER-CID) experiments of sodium cationized glycosyl phosphate complexes, [GP x +Na]+, are performed to elucidate the effects of linkage stereochemistry (α versus β), the geometry of the leaving groups (1,2- cis versus 1,2- trans), and protecting groups (cyclic versus non-cyclic) on the stability of the glycosyl phosphate linkage via survival yield analyses. A four parameter logistic dynamic fitting model is used to determine CID50% values, which correspond to the level of rf excitation required to produce 50% dissociation of the precursor ion complexes. Present results suggest that dissociation of 1,2- trans [GP x +Na]+ occurs via a McLafferty-type rearrangement that is facilitated by a syn orientation of the leaving groups, whereas dissociation of 1,2- cis [GPx+Na]+ is more energetic as it involves the formation of an oxocarbenium ion intermediate. Thus, the C1-C2 configuration plays a major role in determining the stability/reactivity of glycosyl phosphate stereoisomers. For 1,2- cis anomers, the cyclic protecting groups at the C4 and C6 positions stabilize the glycosidic bond, whereas for 1,2- trans anomers, the cyclic protecting groups at the C4 and C6 positions tend to activate the glycosidic bond. The C3 O-benzyl (3 BnO) substituent is key to determining whether the sugar or phosphate moiety retains the sodium cation upon CID. For 1,2- cis anomers, the 3 BnO substituent weakens the glycosidic bond, whereas for 1,2- trans anomers, the 3 BnO substituent stabilizes the glycosidic bond. The C2 O-benzyl substituent does not significantly impact the glycosidic bond stability regardless of its orientation. [Figure not available: see fulltext.

  20. Biochemical aromatization of 2-methyleneandrostenedione: stereochemistry of hydrogen removal at the C-1 position.

    Science.gov (United States)

    Numazawa, Mitsuteru; Handa, Wakako; Matsuzaki, Hisao

    2006-11-01

    To explore a stereochemistry of hydrogen removal at C-1 of the powerful aromatase inhibitor 2-methyleneandrostenedione (1), of which the A-ring conformation is markedly different from that of the natural substrate androstenedione (AD), in the course of the aromatase-catalyzed A-ring aromatization producing 2-methylestrone (2), we synthesized [1alpha-2H]labeled steroid 1 and its [1beta-2H]stereoisomer, and the metabolic fate of the C-1 deuterium in aromatization was analyzed by gas chromatography-mass spectrometry (GC-MS) in each. Parallel experiments with the natural substrates [1alpha-2H] and [1beta-2H]ADs were also carried out. The GC-MS analysis indicated that 2-methyl estrogen 2 produced from [1alpha-2H]labeled substrate 1 retained completely the 1alpha-deuterium (1beta-H elimination), while product 2 obtained from [1beta-2H]isomer 1 lost completely the 1beta-deuterium. Stereospecific 1beta-hydrogen elimination was also observed in the parallel experiments with the labeled ADs as established previously. The results indicate that biochemical aromatization of the 2-methylene steroid 1 proceeds through the 1beta-hydrogen removal concomitant with cleavage of the C(10)-C(19) bond, yielding 1(10),4-dienone 9, in a similar manner to that involved in AD aromatization. This would give additional evidence for the stereomechanisms for the last step of aromatization of AD, requiring the stereospecific 1beta-hydrogen abstraction and cleavage of the C(10)-C(19) bond, and for the enolization of a carbonyl group at C-3 in the A-ring aromatization.

  1. Stereochemistry and molecular pharmacology of (S)-thio-ATPA, a new potent and selective GluR5 agonist

    DEFF Research Database (Denmark)

    Stensbøl, T B; Jensen, H S; Nielsen, B

    2001-01-01

    )-Glu) receptors (EC(50)=14 microM), comparable in potency with ATPA (EC(50)=34 microM). Recent findings, that (S)-ATPA is a potent (EC(50)=0.48 microM) and selective agonist at homomerically expressed ionotropic GluR5, prompted us to resolve thio-ATPA using chiral chromatography and pharmacologically characterize...... the two enantiomers at native as well as cloned ionotropic glutamate receptors. The enantiomers, (S)- and (R)-thio-ATPA, were obtained in high enantiomeric excess, and their absolute stereochemistry established by an X-ray crystallographic analysis. Electrophysiologically, the two enantiomers were...

  2. [Stereochemistry, syntheses and biological activity of lupine alkaloids--from studies on the leguminous plants growing mainly in Japan].

    Science.gov (United States)

    Ohmiya, Shigeru

    2007-10-01

    Lupine alkaloids have been studied from the viewpoints of biosynthesis, biotechnology, chemotaxonomy, and biological activity, on the basis of the chemical investigation of the leguminous plants of the 28 species belonging to the 9 genera, which mainly grow in Japan. The results obtained have been comprehensively reviewed by authors. This review describes the stereochemistry of lupine alkaloids and focuses on the conformational flexibility of nitrogen-fused systems such as quinolizidine and indolizidine, syntheses of new unusual types of alkaloids from known lupine alkaloids, and pharmacological activity of lupine alkaloids, especially kappa-opioid receptor-mediated antinociceptive effects of matrine-type lupine alkaloids.

  3. Design and Implementation of a Self-Directed Stereochemistry Lesson Using Embedded Virtual Three-Dimensional Images in a Portable Document Format

    Science.gov (United States)

    Cody, Jeremy A.; Craig, Paul A.; Loudermilk, Adam D.; Yacci, Paul M.; Frisco, Sarah L.; Milillo, Jennifer R.

    2012-01-01

    A novel stereochemistry lesson was prepared that incorporated both handheld molecular models and embedded virtual three-dimensional (3D) images. The images are fully interactive and eye-catching for the students; methods for preparing 3D molecular images in Adobe Acrobat are included. The lesson was designed and implemented to showcase the 3D…

  4. Using Empirical Rules from 13C NMR Analysis to Determine the Stereochemistry of the Epoxide Located at the 5,6-position of Decalinic Systems

    Directory of Open Access Journals (Sweden)

    Raquel M. Cravero

    2000-03-01

    Full Text Available An empiric rule derived from the analysis of the 13C NMR spectral data, allowed us to determine 5,6-epoxide stereochemistry on decalinic systems and a discussion of the scope and limitations of this rule and its extension to other carbon squeletons, is presented.

  5. Stereochemistry of 16a-Hydroxyfriedelin and 3-Oxo-16-methylfriedel-16-ene Established by 2D NMR Spectroscopy

    Directory of Open Access Journals (Sweden)

    Vagner Fernandes Knupp

    2009-02-01

    Full Text Available Friedelin (1, 3b-friedelinol (2, 28-hydroxyfriedelin (3, 16a-hydroxyfriedelin (4, 30-hydroxyfriedelin (5 and 16a,28-dihydroxyfriedelin (6 were isolated through fractionation of the hexane extract obtained from branches of Salacia elliptica. After a week in CDCl3 solution, 16a-hydroxyfriedelin (4 reacted turning into 3-oxo-16-methylfriedel-16-ene (7. This is the first report of a dehydration followed by a Nametkin rearrangement of a pentacyclic triterpene in CDCl3 solution occurring in the NMR tube. These seven pentacyclic triterpenes was identified through NMR spectroscopy and the stereochemistry of compound 4 and 7 was established by 2D NMR (NOESY spectroscopy and mass spectrometry (GC-MS. It is also the first time that all the 13C-NMR and 2D NMR spectral data are reported for compounds 4 and 7.

  6. Stereoselective Synthesis of 8,12-Furanoeudesmanes from Santonin. Absolute Stereochemistry of Natural Furanoeudesma-1,3-diene and Tubipofurane.

    Science.gov (United States)

    Blay, Gonzalo; Cardona, Luz; García, Begoña; Pedro, José R.; Sánchez, Juan J.

    1996-05-31

    Ketobutenolide 3, easily obtained from santonin (1), has been transformed into two natural furanoeudesmanes 4 and 5, isolated from Commiphora molmol and Tubipora musica, respectively. trans- And cis-decalin systems were obtained by stereoselective reduction of the C(4)-C(5) double bond in 3 in the following way: hydrogenation of 3 over Pd/C followed by acidic treatment gave the cis isomer 10 as the major product; selective hydrogenation of the C(1)-C(2) double bond with the Wilkinson's catalyst followed by reduction with NaTeH yielded mainly the trans isomer 9. Compounds 9 and 10 were transformed into 4 and 5 in parallel sequences. Optical rotation and CD measurements of the synthetic products revealed that the stereochemistry of both natural products should be revised to their enantiomeric form.

  7. Ilmus kogumik eesti naiste elulugusid inglise keeles

    Index Scriptorium Estoniae

    2006-01-01

    Carrying Linda's stones : an anthology of Estonian women's life stories / editors: Suzanne Stiver Lie, Lynda Malik, Ilvi Jõe-Cannon, Rutt Hinrikus ; foreword by H.E. Aldona Wos. Tallinn : Tallinn University Press, 2006. Sisaldab Elin Toona jt. elulugusid. Vt. ka SL Õhtuleht, 30. sept., lk. 27

  8. Ilmus Rein Neggo "Vastutuuli. I" / Hannes Oja

    Index Scriptorium Estoniae

    Oja, Hannes

    1999-01-01

    rets. rmt.: Vastutuuli. I : valimik EELK Los Angelese koguduse ajakirjas "Vastutuuli" (1950-1965) avaldatud kirjasõna / koostanud ja toimetanud Rein Neggo. Los Angeles : Eesti Evangeelse Luterliku Kiriku Los Angelese kogudus, 1999. 199 lk. : ill.

  9. Ilmus artiklikogumik "Eesti teadlased paguluses" / Anne Valmas

    Index Scriptorium Estoniae

    Valmas, Anne, 1941-2017

    2009-01-01

    TLÜ AR väliseesti kirjanduse keskuse ja TTÜ Raamatukogu koostöös 24.03.2009 toimunud konverentsist "Eesti teadlased paguluses", mis tutvustas väliseesti teadlaste osa maailmateaduses. Ettekannete põhjal valminud artiklikogumikust "Eesti teadlased paguluses", koostajad Vahur Mägi ja Anne Valmas. Tallinn : Tallinna Ülikooli Kirjastus, 2009

  10. Ilmus kogumik oreleist ja oreli kultuurist

    Index Scriptorium Estoniae

    2007-01-01

    XXI rahvusvahelise orelifestivali eel esitleti Niguliste kirikus Eesti Orelisõprade Ühingu väljaandel ilmunud kogumikku "XXI pilku orelile. Eesti orelikultuurist" (koostanud Ene Pilliroog ja Ivalo Randalu)

  11. TLÜ andragoogide eestvedamisel ilmus rahvusvaheline teadusajakiri

    Index Scriptorium Estoniae

    2009-01-01

    Tallinna Ülikooli Kasvatusteaduste Instituudi andragoogika osakonna teadlaste eestvedamisel valmis rahvusvaheline eelretsenseeritav teadusajakiri "Studies for the Learning Society". See on Balti regiooni täiskasvanuhariduse uuringuid tegevaid ülikoole ühendava assotsiatsiooni Baltic Sea Region Association for Research in Adult Education ametlik teadusajakiri

  12. Alteration of Polyketide Stereochemistry from anti to syn by a Ketoreductase Domain Exchange in a Type I Modular Polyketide Synthase Subunit

    Energy Technology Data Exchange (ETDEWEB)

    Eng, Clara H.; Yuzawa, Satoshi; Wang, George; Baidoo, Edward E. K.; Katz, Leonard; Keasling, Jay D.

    2016-03-29

    Polyketide natural products have broad applications in medicine. Exploiting the modular nature of polyketide synthases to alter stereospecificity is an attractive strategy for obtaining natural product analogues with altered pharmaceutical properties. The purpose of research is to demonstrate that by retaining a dimerization element present in LipPks1+TE, we are able to use a ketoreductase domain exchange to alter α-methyl group stereochemistry with unprecedented retention of activity and simultaneously achieve a novel alteration of polyketide product stereochemistry from anti to syn. The substrate promiscuity of LipPks1+TE further provided a unique opportunity to investigate the substrate dependence of ketoreductase activity in a polyketide synthase module context.

  13. The stereochemistry of the Nozaki-Hiyama-Kishi reaction and the construction of 10-membered lactones. The enantioselective total synthesis of (--decarestrictine D

    Directory of Open Access Journals (Sweden)

    Pilli Ronaldo A.

    2001-01-01

    Full Text Available The use of the intramolecular Nozaki-Hiyama-Kishi reaction to construct 10-membered lactones is described. The influence of the nature of the protecting groups at C4 and C5 on the stereochemistry of the newly formed stereogenic center at C7 was investigated. The utility of this methodology has been demonstrated in the stereoselective total synthesis of (--decarestrictine D from 1,3-propanediol and polyhydroxybutyrate (PHB in 13 steps and 6.3% overall yield.

  14. On the stereochemistry of C3'-O-P-CH2-O-C4'' phosphonate internucleotide bond, a phosphate isostere

    Czech Academy of Sciences Publication Activity Database

    Točík, Zdeněk; Buděšínský, Miloš; Barvík Jr., I.; Rosenberg, Ivan

    -, č. 52 (2008), s. 427-428 ISSN 0261-3166. [Joint Symposium of the International Roundtable on Nucleosides, Nucleotides and Nucleic Acids /18./ and the International Symposium on Nucleic Acid Chemistry /35./. Kyoto, 08.09.2008-12.09.2008] R&D Projects: GA MŠk(CZ) LC06061 Institutional research plan: CEZ:AV0Z40550506 Keywords : phosphonate oligonucleotide stereochemistry Subject RIV: CC - Organic Chemistry

  15. Single Stage Tandem Mass Spectrometry Assignment of the C-5 Uronic Acid Stereochemistry in Heparan Sulfate Tetrasaccharides using Electron Detachment Dissociation

    Science.gov (United States)

    Agyekum, Isaac; Zong, Chengli; Boons, Geert-Jan; Amster, I. Jonathan

    2017-09-01

    The analysis of heparan sulfate (HS) glycosaminoglycans presents many challenges, due to the high degree of structural heterogeneity arising from their non-template biosynthesis. Complete structural elucidation of glycosaminoglycans necessitates the unambiguous assignments of sulfo modifications and the C-5 uronic acid stereochemistry. Efforts to develop tandem mass spectrometric-based methods for the structural analysis of glycosaminoglycans have focused on the assignment of sulfo positions. The present work focuses on the assignment of the C-5 stereochemistry of the uronic acid that lies closest to the reducing end. Prior work with electron-based tandem mass spectrometry methods, specifically electron detachment dissociation (EDD), have shown great promise in providing stereo-specific product ions, such as the B3 ´ -CO2, which has been found to distinguish glucuronic acid (GlcA) from iduronic acid (IdoA) in some HS tetrasaccharides. The previously observed diagnostic ions are generally not observed with 2- O-sulfo uronic acids or for more highly sulfated heparan sulfate tetrasaccharides. A recent study using electron detachment dissociation and principal component analysis revealed a series of ions that correlate with GlcA versus IdoA for a set of 2- O-sulfo HS tetrasaccharide standards. The present work comprehensively investigates the efficacy of these ions for assigning the C-5 stereochemistry of the reducing end uronic acid in 33 HS tetrasaccharides. A diagnostic ratio can be computed from the sum of the ions that correlate to GlcA to those that correlate to IdoA. [Figure not available: see fulltext.

  16. Vladimir Prelog e a estereoquímica das moléculas orgânicas: um centenário de nascimento Vladimir Prelog and the stereochemistry of organic molecules: a centenary of birt

    Directory of Open Access Journals (Sweden)

    Claudia M. Rezende

    2007-08-01

    Full Text Available The Croatian chemist Vladimir Prelog shared in 1975 the Nobel Prize in chemistry with J. W. Cornforth for his research into the stereochemistry of organic molecules and reactions. His studies gave new horizons to the comprehension of steric effects on the reactivity of medium-sized rings, to conformational analysis and to the stereospecificity associated to asymmetric syntheses. Prelog made important contributions to enzyme chemistry and to the structure elucidation of alkaloids and of antibiotics from microorganisms, but probably his most famous work is the CIP system for assigning the stereochemistry of chiral centers.

  17. Cork suberin molecular structure: stereochemistry of the C18 epoxy and vic-diol ω-hydroxyacids and α,ω-diacids analyzed by NMR.

    Science.gov (United States)

    Santos, Sara; Cabral, Vanessa; Graça, José

    2013-07-24

    Suberin is the biopolyester that protects the secondary tissues of plants against environmental variability and aggressions. Cork suberin is composed mostly of C18 ω-hydroxyacids and α,ω-diacids, 9,10-substituted with an unsaturation, an epoxide ring, or a vic-diol group. Although determinant for suberin macromolecular structure, the stereochemistry of these monomers is poorly studied, sometimes with contradictory results. An NMR technique was used here to assign the configuration of the 9,10-epoxy and 9,10-diol groups in C18 suberin acids, comparing the chemical shifts of diagnostic (1)H and (13)C signals with the ones of model compounds, before and after conversion of the vic-diol group into benzylidene acetal derivatives. The relative configuration was proved to be cis in the C18 9,10-epoxy and threo in the C18 9,10-diol suberin acids. These monomers were present in suberin probably as racemic mixtures, as shown by polarimetry. The revealed stereochemistry allows the suberin macromolecule to be built as an ordered array of midchain kinked C18 acids, reinforced by intramolecular hydrogen bonding.

  18. Stereochemistry Structure of Odonicin

    Energy Technology Data Exchange (ETDEWEB)

    Li, Bao Lin; Li, Jin; Tong, Ling [Shaanxi Normal University, Xian (China); Pan, Yuan Jiang [Zhejiang University, Hangzhou (China); Yu, Kai Bei [Academia Sinica, Chengdu (China)

    2004-02-15

    Ent-kaurene diterpenoids have various biological activities, such as antitumor, antibacterial, anti-HIV activities etc. The plant of the genus Isodon used in Chinese traditional medicine is a major source of compounds of this structural class. Our investigations on the bitter diterpenoids constituents of the genus Isodon led to the first isolation of odonicin (1) from the leaves and tender branches of Isodon henryi obtained from Taibai Mountain, Shaanxi Province, P. R. China

  19. Excitatory amino acid receptor ligands: resolution, absolute stereochemistry, and enantiopharmacology of 2-amino-3-(4-butyl-3-hydroxyisoxazol-5-yl)propionic acid

    DEFF Research Database (Denmark)

    Johansen, T N; Ebert, B; Bräuner-Osborne, Hans

    1998-01-01

    -3519). To elucidate the pharmacological significance of this latter binding affinity, which is also shown by quisqualic acid (3) but not by AMPA, we have now resolved Bu-HIBO via diastereomeric salt formation using the diprotected Bu-HIBO derivative 11 and the enantiomers of 1-phenylethylamine (PEA). The absolute...... stereochemistry of (S)-Bu-HIBO (7) (ee = 99.0%) and (R)-Bu-HIBO (8) (ee > 99.6%) were established by an X-ray crystallographic analysis of compound 15, a salt of (R)-PEA, and diprotected 8. Circular dichroism spectra of 7 and 8 were recorded. Whereas 7 (IC50 = 0.64 microM) and 8 (IC50 = 0.57 microM) were...

  20. Investigation of the effect of sugar stereochemistry on biologically relevant lyotropic phases from branched-chain synthetic glycolipids by small-angle X-ray scattering.

    Science.gov (United States)

    Zahid, N Idayu; Conn, Charlotte E; Brooks, Nicholas J; Ahmad, Noraini; Seddon, John M; Hashim, Rauzah

    2013-12-23

    Synthetic branched-chain glycolipids are suitable as model systems in understanding biological cell membranes, particularly because certain natural lipids possess chain branching. Herein, four branched-chain glycopyranosides, namely, 2-hexyl-decyl-α-D-glucopyranoside (α-Glc-OC10C6), 2-hexyl-decyl-β-D-glucopyranoside (β-Glc-OC10C6), 2-hexyl-decyl-α-D-galactopyranoside (α-Gal-OC10C6), and 2-hexyl-decyl-β-D-galactopyranoside (β-Gal-OC10C6), with a total alkyl chain length of 16 carbon atoms have been synthesized, and their phase behavior has been studied. The partial binary phase diagrams of these nonionic surfactants in water were investigated by optical polarizing microscopy (OPM) and small-angle X-ray scattering (SAXS). The introduction of chain branching in the hydrocarbon chain region is shown to result in the formation of inverse structures such as inverse hexagonal and inverse bicontinuous cubic phases. A comparison of the four compounds showed that they exhibited different polymorphism, especially in the thermotropic state, as a result of contributions from anomeric and epimeric effects according to their stereochemistry. The neat α-Glc-OC10C6 compound exhibited a lamellar (Lα) phase whereas dry α-Gal-OC10C6 formed an inverse bicontinuous cubic Ia3d (QII(G)) phase. Both β-anomers of glucoside and galactoside adopted the inverse hexagonal phase (HII) in the dry state. Generally, in the presence of water, all four glycolipids formed inverse bicontinuous cubic Ia3d (QII(G)) and Pn3m (QII(D)) phases over wide temperature and concentration ranges. The formation of inverse nonlamellar phases by these Guerbet branched-chain glycosides confirms their potential as materials for novel biotechnological applications such as drug delivery and crystallization of membrane proteins.

  1. Synthetic cathinones and stereochemistry: S enantiomer of mephedrone reduces anxiety- and depressant-like effects in cocaine- or MDPV-abstinent rats.

    Science.gov (United States)

    Philogene-Khalid, Helene L; Hicks, Callum; Reitz, Allen B; Liu-Chen, Lee-Yuan; Rawls, Scott M

    2017-09-01

    The neuropharmacological profile of the synthetic cathinone mephedrone (MEPH) is influenced by stereochemistry. Both MEPH enantiomers are monoamine transporter substrates, but R-MEPH is primarily responsible for rewarding effects of MEPH as it produces greater locomotor activation and intracranial self-stimulation than S-MEPH. S-MEPH is a 50-fold more potent 5-HT releaser than R-MEPH and does not place preference in rats. MEPH is also structurally similar to the cathinone derivative bupropion, an antidepressant and smoking cessation medication, suggesting MEPH has therapeutic and addictive properties. We tested the hypothesis that S-MEPH reduces anxiety- and depression-like behaviors in rats withdrawn from chronic cocaine or methylenedioxypyrovalerone (MDPV) using the elevated plus maze (EPM) and forced swim test (FST), respectively. Rats were tested 48-h after a binge-like paradigm (3×/day for 10days in 1-h intervals) of cocaine (10mg/kg), MDPV (1mg/kg) or saline. In vitro studies assessed the receptor binding and activity of S-MEPH. Rats withdrawn from chronic cocaine or MDPV displayed an increase in anxiety- and depression-like behaviors that was antagonized by treatment with S-MEPH (10, 30mg/kg). S-MEPH displayed affinity, but not agonist activity, for 5-HT 2 receptors (2A-2C) and showed negligible affinity for dopaminergic, adrenergic and nicotinic receptors. S-MEPH attenuated withdrawal behaviors following chronic cocaine or MDPV, perhaps through 5-HT release and/or 5-HT 2 receptor interactions. The present data suggest S-MEPH may be a possible structural and pharmacological template to develop maintenance therapy for acute anxiety and depression during early withdrawal from psychostimulant abuse. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Mass spectrometric analysis of oxygenations in aromatization of androst-4-ene-3,6,17-trione, a suicide substrate of aromatase, by placental microsomes. Isotope effect and stereochemistry.

    Science.gov (United States)

    Numazawa, Mitsuteru; Takahashi, Madoka; Nagaoka, Masao; Handa, Wakako; Yamashita, Kouwa

    2007-01-01

    Aromatase catalyzes the conversion of androstenedione (AD) to estrone through three sequential oxygenations of the 19-methyl group. 6-OxoAD (1) is one of the typical suicide substrates of aromatase, which is converted by aromatase to 6-oxoestrone through 19-alcohol (19-ol) and 19-aldehyde (19-al) intermediates 2 and 3. To study the deuterium isotope effect on the conversion of 19-ol 2 to 19-al 3 as well as the stereochemistry of the 19-hydrogen removal in this conversion, we initially synthesized [19,19-(2)H(2)] and [19S- or 19R-(2)H] 19-ols 2, starting from the corresponding deuterium-labeled 19-hydroxyAD derivatives. In incubation of non-labeled and [19,19-(2)H(2)]-labeled 19-ol 2 or that of their 1:1 mixture with human placental microsomes in the presence of NADPH under air, there was no significant deuterium-isotope effect on the production of the aromatized product 6-oxoestrone or on the conversion of 19-ol 2 to 19-al 3, based on gas chromatography-mass spectrometric analysis of the estrogen product or liquid chromatography-mass spectrometric (LC-MS) analysis of the deuterium contents of the product 19-al 3 and the recovered 19-ol 2. Moreover, in the incubations of [19S-(2)H] 19-ol 2 and its 19R isomer, LC-MS analysis of the product 3 demonstrated that the 19-pro-R hydrogen atom was stereospecifically removed in the conversion of 19-ol 2 to 19-al 3. These findings indicate that the 19-oxygenation of 19-ol 2 would proceed in the same mechanism as that involved in the AD aromatization.

  3. Stereochemistry of C18 monounsaturated cork suberin acids determined by spectroscopic techniques including (1) H-NMR multiplet analysis of olefinic protons.

    Science.gov (United States)

    Santos, Sara; Graça, José

    2014-01-01

    Suberin is a biopolyester responsible for the protection of secondary plant tissues, and yet its molecular structure remains unknown. The C18:1 ω-hydroxyacid and the C18:1 α,ω-diacid are major monomers in the suberin structure, but the configuration of the double bond remains to be elucidated. To unequivocally define the configuration of the C18:1 suberin acids. Pure C18:1 ω-hydroxyacid and C18:1 α,ω-diacid, isolated from cork suberin, and two structurally very close C18:1 model compounds of known stereochemistry, methyl oleate and methyl elaidate, were analysed by NMR spectroscopy, Fourier transform infrared (FTIR) and Raman spectroscopy, and GC-MS. The GC-MS analysis showed that both acids were present in cork suberin as only one geometric isomer. The analysis of dimethyloxazoline (DMOX) and picolinyl derivatives proved the double bond position to be at C-9. The FTIR spectra were concordant with a cis-configuration for both suberin acids, but their unambiguous stereochemical assignment came from the NMR analysis: (i) the chemical shifts of the allylic (13) C carbons were shielded comparatively to the trans model compound, and (ii) the complex multiplets of the olefinic protons could be simulated only with (3) JHH and long-range (4) JHH coupling constants typical of a cis geometry. The two C18:1 suberin acids in cork are (Z)-18-hydroxyoctadec-9-enoic acid and (Z)-octadec-9-enedoic acid. Copyright © 2013 John Wiley & Sons, Ltd.

  4. Läänemerel ilmus Kinobussile kolleeg / J. R.

    Index Scriptorium Estoniae

    J. R.

    2008-01-01

    9. augustil algab Narva-Jõesuus filmi- ja keskkonnateemaline festival Moving Baltic Sea, mille eestvedajaks on Saksa rändfilmifestivali Moviemiento korraldajad. Festival sai 4. juulil alguse Rostockist ja liigub 100-aastasel purjekal Lovis. Eestis osaleb ka meie Kinobuss

  5. Ilmus väärt artiklikogumik / Arvo Tering

    Index Scriptorium Estoniae

    Tering, Arvo, 1949-

    2008-01-01

    Arvustus: Ajalookirjutaja aeg = Aetas historicum / Eesti Rahvusraamatukogu ; koost. Piret Lotman. - Tallinn, 2008. - 247 lk. - (Eesti Rahvusraamatukogu toimetised. A, Raamat ja aeg, 1736-6984 ; nr. 1) ; (Eesti Rahvusraamatukogu toimetised ; 11)

  6. Ilmus esimene mahukam eestikeelne teatriajaloo ülevaade / Andres Laasik

    Index Scriptorium Estoniae

    Laasik, Andres, 1960-2016

    2007-01-01

    25. jaan. esitleti Eesti Teatriliidus "Oxfordi illustreeritud teatriajaloo" eestikeelset versiooni. Tõlkeraamatu aluseks on 1995. aastal kirjastuses Oxford University Press ilmunud samanimeline raamat, mille koostajaks on John Russell Brown. Teose on tõlkinud Anne Lange, Ilona Kolberg, Piret Kruuspere, Kristjan Jaak Kangur

  7. Ilmus uus CD Arvo Pärdi muusikaga, esitajaks eestlased

    Index Scriptorium Estoniae

    2004-01-01

    heliplaadi "Pro & contra" andis välja Virgin Classics, Eesti Riiklik Sümfooniaorkester Paavo Järvi dirigeerimisel esitab seal järgmised A. Pärdi teosed - "Meie aed", 1. ja 2. sümfoonia, "Pro & contra", "Kollaaž teemal B-A-C-H" ja "Perpetum mobile"

  8. Ilmus uus võõrkeelte õpetamise uuring

    Index Scriptorium Estoniae

    2001-01-01

    Üleeuroopaline hariduse infovõrgustik Eurydice European Network on oma järjekordse uuringu pühendanud võõrkeelte õpetamisele. Võrdlev uuring viidi läbi 29 "Socratese" programmiga liitunud Euroopa riigis. Uuringust on ilmunud kokkuvõte, mis sisaldab infot selle kohta, kuidas mingis riigis võõrkeelt õpetatakse, milline on õppekava sisu, kuidas leitakse õpetajaid ning organiseeritakse õpetajakoolitust. Kokkuvõte uuringust on ilmunud raamatuna "Foreign Language Teaching in Schools in Europe".

  9. Inversion of the stereochemistry around the sulfur atom of the axial methionine side chain through alteration of amino acid side chain packing in Hydrogenobacter thermophilus cytochrome C552 and its functional consequences.

    Science.gov (United States)

    Tai, Hulin; Tonegawa, Ken; Shibata, Tomokazu; Hemmi, Hikaru; Kobayashi, Nagao; Yamamoto, Yasuhiko

    2013-07-16

    In cytochrome c, the coordination of the axial Met Sδ atom to the heme Fe atom occurs in one of two distinctly different stereochemical manners, i.e., R and S configurations, depending upon which of the two lone pairs of the Sδ atom is involved in the bond; hence, the Fe-coordinated Sδ atom becomes a chiral center. In this study, we demonstrated that an alteration of amino acid side chain packing induced by the mutation of a single amino acid residue, i.e., the A73V mutation, in Hydrogenobacter thermophilus cytochrome c552 (HT) forces the inversion of the stereochemistry around the Sδ atom from the R configuration [Travaglini-Allocatelli, C., et al. (2005) J. Biol. Chem. 280, 25729-25734] to the S configuration. Functional comparison between the wild-type HT and the A73V mutant possessing the R and S configurations as to the stereochemistry around the Sδ atom, respectively, demonstrated that the redox potential (Em) of the mutant at pH 6.00 and 25 °C exhibited a positive shift of ∼20 mV relative to that of the wild-type HT, i.e., 245 mV, in an entropic manner. Because these two proteins have similar enthalpically stabilizing interactions, the difference in the entropic contribution to the Em value between them is likely to be due to the effect of the conformational alteration of the axial Met side chain associated with the inversion of the stereochemistry around the Sδ atom due to the effect of mutation on the internal mobility of the loop bearing the axial Met. Thus, the present study demonstrated that the internal mobility of the loop bearing the axial Met, relevant to entropic control of the redox function of the protein, is affected quite sensitively by the contextual stereochemical packing of amino acid side chains in the proximity of the axial Met.

  10. Comparative analysis of the heme iron electronic structure and stereochemistry in tetrameric rabbit hemoglobin and monomeric soybean leghemoglobin a using Mössbauer spectroscopy with a high velocity resolution

    Science.gov (United States)

    Alenkina, I. V.; Kumar, A.; Berkovsky, A. L.; Oshtrakh, M. I.

    2018-02-01

    A comparative study of tetrameric rabbit hemoglobin and monomeric soybean leghemoglobin a in the oxy- and deoxy-forms was carried out using 57Fe Mössbauer spectroscopy with a high velocity resolution in order to analyze the heme iron electronic structure and stereochemistry in relation to the Mössbauer hyperfine parameters. The Mössbauer spectra of tetrameric rabbit hemoglobin in both forms were fitted using two quadrupole doublets related to the 57Fe in ɑ- and β-subunits. In contrast, the Mössbauer spectra of monomeric soybean leghemoglobin a were fitted using: (i) two quadrupole doublets for the oxy-form related to two conformational states of the distal His E7 imidazole ring and different hydrogen bonding of oxygen molecule in the oxy-form and (ii) using three quadrupole doublets for deoxy-form related to three conformational states of the proximal His F8 imidazole ring. Small variations of Mössbauer hyperfine parameters related to small differences in the heme iron electronic structure and stereochemistry in tetrameric rabbit hemoglobin and monomeric soybean leghemoglobin a are discussed.

  11. Synthesis, characterisation, stereochemistry and antimicrobial ...

    Indian Academy of Sciences (India)

    convulsant, anti-anxiety, anti- fungal, anti-bacterial, anti-feedant, analgesic, sedative, anti-depressive and hypnotic agents.2–5 Certain deriva- tives viz., lofendazam, clobazam and triflubazam are used for the treatment of anxiety and neuroses including.

  12. Synthesis, characterisation, stereochemistry and antimicrobial ...

    Indian Academy of Sciences (India)

    benzodiazepine also supports boat conformation in the solid state. The antimicrobial activity for -acetyltetrahydro-1,5-benzodiazepines have been carried out. -morpholinoacetyl-2,2,4-trimethyl-1H-1,5-benzodiazepine demonstrated better antibacterial and ...

  13. Stereochemistry of NaBH4 reduction of a 19-carbonyl group of 3-deoxy androgens. Synthesis of [19S-3H]- and [19R-3H]-labeled aromatase inhibitors having a 19-hydroxy group.

    Science.gov (United States)

    Numazawa, Mitsuteru; Sohtome, Norishige; Nagaoka, Masao

    2004-06-01

    To study the stereochemical aspects of the aromatase reaction of androst-4-en-17-one (1) and its 5-ene isomer 4, competitive inhibitors of aromatase, the [19S-(3)H]- and [19R-(3)H]-labeled 19-hydroxy derivatives 2 and 5, were synthesized through NaB(3)H(4) reduction of the corresponding 19-aldehydes 3 and 6 as a key reaction. The hitherto unknown stereochemistry of the NaB(3)H(4) reduction was established based on the deuterium-labeling experiments with NaB(2)H(4). A comparison of (1)H-NMR spectra of the NaB(2)H(4) reduction products of 19-als 3 and 6 with those of the respective authentic steroids revealed that the ratios of 19S-(2)H to 19R-(2)H were 90 : 10 for the 4-ene steroid 2 and 70 : 30 for the 5-ene isomer 5, respectively. Jones oxidation of the [19S-(2)H]19-ols, followed by the non-labeled NaBH(4) reduction, gave the corresponding [19R-(2)H]19-ols 2 and 5 (R-(2)H : S-(2)H=90 : 10 for steroid 2 and 70 : 30 for steroid 5). The stereoselectively (3)H-labeled compounds 2 and 5 were similarly obtained in these sequences.

  14. Stereochemistry of organometallic and inorganic compounds

    CERN Document Server

    2012-01-01

    The authors of this fourth volume in the series have reviewed the making and breaking of chemical bonds in a sophisticated manner. In particular, new pressures brought about by environmental concerns, larger demands for the medical and pharmaceutical sectors and economics of the market place are forcing us into demanding greater stereochemical control and better product yields for chemical reactions capable of producing useful products. The chapters are written by leading experts in this area and give excellent overviews of the strengths and weaknesses of the various methodologies.In C

  15. Determination of the stereochemistry of 4-chromenecarbaldehydes ...

    African Journals Online (AJOL)

    The paper reports studies on the use of 4-chromenecarbaldehydes as suitable substrates for the assessment of the accuracy of interpretations of Nuclear Overhauser Enhancements (NOE) data for chromenecarbaldehydes and related compounds, such as the 3,4-dibromochromanones. The investigative protocol that has ...

  16. Ilmus folkloristide ja etnoloogide ühisväljaanne / Varje Sootak

    Index Scriptorium Estoniae

    Sootak, Varje, 1946-

    2004-01-01

    Rmt.: Papers delivered at the symposium "Sacred and profane in the dialogue of cultures" : [Aprill, 2002, Tartu] / Department of Estonian and Comparative Folklore, Department of Ethnology, University of Tartu ; [editors Art Leete, Ülo Valk]. - (Studies in Folk Culture. Vol. 1). Tartu, 2003

  17. Aino Tamjärvelt ilmus uus luulekogu / Ülo Ignats

    Index Scriptorium Estoniae

    Ignats, Ülo, 1951-2011

    2008-01-01

    rets. rmt.: Tamjärv, Aino. Man blir aldrig immun mot havet/toimetaja Inger Klingberg. Stockholm, 2004; Meretuulte meelevallas : [luuletused]/toimetaja Katrin Hallas; kujundaja Ivi Piibeleht; fotod Merike Lepp. [Tallinn : Pilgrim ; Stockholm] : Vision Book, 2007

  18. Ilmus lihtne ja asjalik poliitilise mõtte ABC / Rein Veidemann

    Index Scriptorium Estoniae

    Veidemann, Rein, 1946-

    2005-01-01

    Tartu Ülikooli eetikakeskus esitles inglise professori Jonathan Wolffi raamatut "Sissejuhatus poliitikafilosoofiasse". Esitlusel Tartus viibis ka raamatu autor, kes on Londoni ülikooli kolledzhi professor ja filosoofiaosakonna juhataja ning Briti filosoofiaühingu sekretär. Lisa: Raamat

  19. Jäneda viimane mõisaproua ilmus eestlase ette / Andres Laasik

    Index Scriptorium Estoniae

    Laasik, Andres, 1960-2016

    2011-01-01

    Jänedal Pulli tallis 1. juulil esietendunud Hendrik Toompere noorema lavastusest "Pärast surma Jendalis" (MTÜ R.A.A.A.M). Autor: Urmas Lennuk, osades: Merle Palmiste, Rain Simmul, Sulev Teppart, Marta Laan, Hendrik Toompere noorim

  20. Ilmus esimene eestikeelne raamat helilooja Arvo Pärdist / Raul Pettai

    Index Scriptorium Estoniae

    Pettai, Raul, 1928-

    2005-01-01

    rets. rmt.: Arvo Pärt peeglis : vestlused, esseed ja artiklid : [helilooja/koostanud Enzo Restagno; vastutav tõlkija ja toimetaja Toomas Siitan]. Tallinn: Eesti Entsüklopeediakirjastus, 2005. 310 lk. : ill, portr, noot

  1. Ilmus põhjalik raamat intellektuaalsest omandist / Pirjo Ant, Kairi Kurisoo ; intervjueerinud Mari Sarv

    Index Scriptorium Estoniae

    Ant, Pirjo

    2009-01-01

    Autorid räägivad intellektuaalsest omandist ja oma raamatust: Kurisoo, Kairi ; Kaur, Viive ; Ant, Pirjo. Intellektuaalne omand. Tallinn : Äripäeva Kirjastus, 2009. (Juht ja seadus. Äripäeva raamat)

  2. Uudised : Ooperietendus Eesti saatkonnas Moskvas. Klassika-Eurovisiooni finaal Bergenis. Ilmus raamat "Eesti Teatri- ja Muusikamuuseum" / Kristel Kase

    Index Scriptorium Estoniae

    Kase, Kristel

    2000-01-01

    2. juunil mängis Moskva Eesti saatkonnas Tallinna muusikateater "Väike Ooper" lavastust "Printsess Alicia". Lühidalt muusikateatrist ja lavastusest. 8.-15. juunini Bergenis toimuvast X Klassika-Eurovisiooni finaalist. 6. juunil esitleti E. Loidi koostatud raamatut "Eesti Teatri- ja Muusikamuuseum"

  3. Stereochemistry of lead(II) complexes with oxygen donor ligands.

    Energy Technology Data Exchange (ETDEWEB)

    Stavilla, Vitalie; Davidovich, Ruven L.; Whitmire, Kenton Herbert (Rice University); Voit, Elena I.; Marinin, Dmitry V.

    2008-10-01

    This review discusses the coordination number (CN) and the coordination geometry of the first coordination sphere of Pb(II) atoms in crystal structures of 98 lead(II) complexes with O-donor ligands and the stereochemically active lone pair of electrons (LP, E) in the terms of the valence shell electron-pair repulsion (VSEPR) model. The CN of Pb(II) atoms of the first coordination sphere has values falling into the range (3 + E) to (6 + E). The following coordination polyhedra-{psi}-tetrahedron (I), {psi}-trigonal bipyramid (II), {psi}-octahedron (III), {psi}-pentagonal bipyramid with an axial (IV) or equatorial (V) vacant position are formed. For the investigated structures of the Pb(II) complexes, the formula of each compound, the overall CN of the Pb(II) atom considered as the sum of the CN in the first coordination sphere and the number of secondary bonds, the polyhedron shape, the Pb-O bond lengths, and O-Pb-O bond angles in the first coordination sphere, secondary bond lengths, references and REFCODEs are presented in the comprehensive Tables. The quantum chemical investigations performed using density functional theory (DFT) method have confirmed the stereochemical activity of the LP of Pb(II) atoms in the studied structures of lead(II) complexes with O-donor ligands.

  4. The effect of stereochemistry on carbohydrate hydration in aqueous solutions

    NARCIS (Netherlands)

    Galema, Saskia Alexandra

    1992-01-01

    Although-carbohydrates are widely used, not much is known about the stereochemical aspects of hydration of carbohydrates. For D-aldohexoses, for example, there are eight different stereoisomers. Just how the hydroxy topology of a carbohydrate molecule influences the hydration behaviour in water is

  5. Amino acid biogeo- and stereochemistry in coastal Chilean sediments

    DEFF Research Database (Denmark)

    Lomstein, Bente Aagaard; Jørgensen, Bo Barker; Schubert, Carsten J.

    2006-01-01

    The spatial distribution of total hydrolysable amino acids (THAA) and amino acid enantiomers (D- and L-forms) was investigated in sediments underlying two contrasting Chilean upwelling regions,: at ~23°S off Antofagasta and at ~36°S off Concepcion. The contribution of amino acids to total organic...... carbon (%TAAC: 7-14%) and total nitrogen (%TAAN: 23-38%) in surface sediments decreased with increasing water depth (from 126 to 1350 m) indicating that organic matter becomes increasingly decomposed in surface sediments at greater water depth. Changes in the ratio between the protein amino acid...... aspartate and its non-protein degradation product β-alanine confirmed this observation. Furthermore, estimates of THAA mineralization showed that sedimentary amino acid reactivity decreased with both increasing water depth as well as progressive degradation status of the organic matter that was incorporated...

  6. Synthesis, stereochemistry and antimicrobial activity of copper(II ...

    African Journals Online (AJOL)

    On the basis of the analytical data, magnetic moments and spectral data, a square-planar geometry has been proposed for the nickel(II) and copper(II) complexes with these ligands. Some representative complexes of copper(II) and nickel(II) were found to have remarkable antifungal and antibacterial activity. KEY WORDS: ...

  7. Buried chloride stereochemistry in the Protein Data Bank.

    Science.gov (United States)

    Carugo, Oliviero

    2014-09-23

    Despite the chloride anion is involved in fundamental biological processes, its interactions with proteins are little known. In particular, we lack a systematic survey of its coordination spheres. The analysis of a non-redundant set (pairwise sequence identity proteins. The results of these analyses are useful in interpreting, describing, and validating new protein crystal structures that contain chloride anions.

  8. C-11 Acid and the Stereochemistry of Abietic Acid

    Indian Academy of Sciences (India)

    IAS Admin

    developed by Barton (1969 Chemistry Nobel Prize) to the solution of an important configurational problem, as we shall see. The presently accepted structure of abietic acid is the result of intensive chemical researches extending over a period of more than a century. The subject is an important part of authoritative treatises.

  9. Bottom-up elucidation of glycosidic bond stereochemistry

    DEFF Research Database (Denmark)

    Gray, Christopher J.; Schindler, Baptiste; Migas, Lukasz G.

    2017-01-01

    The lack of robust, high-throughput, and sensitive analytical strategies that can conclusively map the structure of glycans has significantly hampered progress in fundamental and applied aspects of glycoscience. Resolution of the anomeric α/β glycan linkage within oligosaccharides remains...

  10. The Metolachlor Herbicide: An Exercise in Today's Stereochemistry

    Science.gov (United States)

    Mannschreck, Albrecht; von Angerer, Erwin

    2009-01-01

    Metolachlor is one of the most widely used agents registered for the protection of many cultivated plants against weeds. Because of axial and central chirality, this molecule forms four stereoisomers, the investigation of which by [superscript 1]H NMR and chromatography is described. It is shown that the isomers do not interconvert at room…

  11. Turinese stereochemistry: Eligio Perucca's enantioselectivity and Primo Levi's asymmetry.

    Science.gov (United States)

    Kahr, Bart; Bing, Yonghong; Kaminsky, Werner; Viterbo, Davide

    2009-01-01

    A reputation restored: Eligio Perucca (see photo) first observed the enantioselective adsorption of a racemic mixture to a chiral crystal (NaClO(3)) in Turin in 1919. However, this milestone in enantioselective chemistry and chiroptics went unnoticed. Identified previously as a coward who refused in 1941 to supervise the research of the budding stereochemist Primo Levi because of the race laws, Perucca was opposed to the fascist regime.

  12. C-11 Acid and the Stereochemistry of Abietic Acid

    Indian Academy of Sciences (India)

    IAS Admin

    organic chemistry' and of the theoretical treatment of the chemical bond, essential to an understanding of how natural products are formed through biosynthetic processes (enzyme mediated synthe- sis of complex structures from substrates of primary structure). C-11 and C-12 Acids. Oxidation of abietic acid or its methyl ...

  13. Estonian contemporary poetry in Galician : [intervjuu] / Arturo Casas Vales ; interv. by Rein Veidemann

    Index Scriptorium Estoniae

    Casas Vales, Arturo

    2002-01-01

    Santiago de Compostelas ilmus galeegi keeles eesti luule antoloogia "Vello ceo n̤rdico" (2002), kogu ilmus kirjandusajakirja Boletin Galego de Literatura erinumbrina. Intervjuu ilmus eesti k.: Postimees, 2002, 28. märts

  14. University Students’ Reflections on Representations in Genetics and Stereochemistry Revealed by a Focus Group Approach

    Directory of Open Access Journals (Sweden)

    Inger Edfors

    2015-05-01

    Full Text Available Genetics and organic chemistry are areas of science that students regard as difficult to learn. Part of this difficulty is derived from the disciplines having representations as part of their discourses. In order to optimally support students’ meaning-making, teachers need to use representations to structure the meaning-making experience in thoughtful ways that consider the variation in students’ prior knowledge. Using a focus group setting, we explored 43 university students’ reasoning on representations in introductory chemistry and genetics courses. Our analysis of eight focus group discussions revealed how students can construct somewhat bewildered relations with disciplinary-specific representations. The students stated that they preferred familiar representations, but without asserting the meaning-making affordances of those representations. Also, the students were highly aware of the affordances of certain representations, but nonetheless chose not to use those representations in their problem solving. We suggest that an effective representation is one that, to some degree, is familiar to the students, but at the same time is challenging and not too closely related to “the usual one”. The focus group discussions led the students to become more aware of their own and others ways of interpreting different representations. Furthermore, feedback from the students’ focus group discussions enhanced the teachers’ awareness of the students’ prior knowledge and limitations in students’ representational literacy. Consequently, we posit that a focus group setting can be used in a university context to promote both student meaning-making and teacher professional development in a fruitful way.

  15. Metabolism of styrene-7,8-oxide in human liver in vitro: interindividual variation and stereochemistry

    NARCIS (Netherlands)

    Wenker, M. A.; Kezić, S.; Monster, A. C.; de Wolff, F. A.

    2000-01-01

    Styrene is an industrial solvent which is mainly oxidized by cytochrome P450 to an electrophilic, chiral epoxide metabolite: styrene-7,8-oxide (SO). SO has cytotoxic and genotoxic properties; the (R)-enantiomer is more mutagenic to Salmonella typhimurium TA 100 in the Ames test than the

  16. Synthesis, stereochemistry, and pharmacology of some new (3-quinuclidyl) diheteroaryl-and aryl heteroaryl carbinols

    Energy Technology Data Exchange (ETDEWEB)

    Arbuzova, O.R.; Mikhlina, E.E.; Tupikina, S.M.; Turchin, K.F.; Zhirnikova, M.L.

    1986-11-01

    The investigation of the antisecretory and antiulcer activity was performed on hybrid male rats. The influence of the compounds on the gastric secretory function was determined by the method of Shai in the modification of Meyer. Gastric ulcers were induced in the rats by the single ip application of 30 mg of histamine. The data obtained indicate that compound (Ic.HCI) shows antisecretory action. Analysis relating to the chemical shifts of protons induced by Eu (DPM)/sub 3/ in the difuryl and dithienyl derivatives indicates that the other two substituents at c/sub 9/ can be determined correspondingly from the concurrence of difference of the signs of the shifts induced for the rotons of the given substituent.

  17. Structural Stereochemistry of Androstene Hormones Determines Interactions with Human Androgen, Estrogen, and Glucocorticoid Receptors

    Directory of Open Access Journals (Sweden)

    Thomas L. Shaak

    2013-01-01

    Full Text Available DHEA, 17α-AED, 17β-AED, and 17β-AET exhibit strong biological activity that has been attributed to androgenic, estrogenic, or antiglucocorticoid activity in vivo and in vitro. This study compared DHEA, 17α-AED, 17β-AED, and 17β-AET for their ability to activate the human AR, ER, and GR and determine the relative androgenicity, estrogenicity, and glucocorticoid activity. The results show that, at the receptor level, these androstene hormones are weak AR and even weaker ER activators. Direct androstene hormone activation of the human AR, ERα, and ERβ may not be essential for their biological function. Similarly, these hormones indirectly activated the human GR, only in the presence of high dexamethasone concentrations. These results underscore the major difference between androstene hormone interactions with these nuclear receptors and their biological effects.

  18. Stereochemistry-Dependent Proton Conduction in Proton Exchange Membrane Fuel Cells.

    Science.gov (United States)

    Thimmappa, Ravikumar; Devendrachari, Mruthyunjayachari Chattanahalli; Kottaichamy, Alagar Raja; Tiwari, Omshanker; Gaikwad, Pramod; Paswan, Bhuneshwar; Thotiyl, Musthafa Ottakam

    2016-01-12

    Graphene oxide (GO) is impermeable to H2 and O2 fuels while permitting H(+) shuttling, making it a potential candidate for proton exchange membrane fuel cells (PEMFC), albeit with a large anisotropy in their proton transport having a dominant in plane (σIP) contribution over the through plane (σTP). If GO-based membranes are ever to succeed in PEMFC, it inevitably should have a dominant through-plane proton shuttling capability (σTP), as it is the direction in which proton gets transported in a real fuel-cell configuration. Here we show that anisotropy in proton conduction in GO-based fuel cell membranes can be brought down by selectively tuning the geometric arrangement of functional groups around the dopant molecules. The results show that cis isomer causes a selective amplification of through-plane proton transport, σTP, pointing to a very strong geometry angle in ionic conduction. Intercalation of cis isomer causes significant expansion of GO (001) planes involved in σTP transport due to their mutual H-bonding interaction and efficient bridging of individual GO planes, bringing down the activation energy required for σTP, suggesting the dominance of a Grotthuss-type mechanism. This isomer-governed amplification of through-plane proton shuttling resulted in the overall boosting of fuel-cell performance, and it underlines that geometrical factors should be given prime consideration while selecting dopant molecules for bringing down the anisotropy in proton conduction and enhancing the fuel-cell performance in GO-based PEMFC.

  19. INFORMATIVE THERMODYNAMIC PROPERTIES OF THE EFFECT OF STEREOCHEMISTRY ON CARBOHYDRATE HYDRATION

    NARCIS (Netherlands)

    GALEMA, SA; ENGBERTS, JBFN; HOILAND, H; FORLAND, GM

    1993-01-01

    Partial molar heat capacities of aqueous solutions of pentoses, hexoses, methyl aldoglycopyranosides, and some disaccharides as well as partial molar expansibilities and isothermal compressibilities of methyl aldoglycopyranosides in aqueous solution are reported. A comparison is made with partial

  20. Stereochemistry of olefinic bond formation in defensive steroids of Acilius sulcatus (Dytiscidae).

    Science.gov (United States)

    Chapman, J C; Lockley, W J; Rees, H H; Goodwin, T W

    1977-12-01

    The defensive secretion of Acilius sulcatus contains a number of pregnane derivates: cortexone, 20alpha-hydroxy-4-pregnen-3-one, together with the unusual delta4,6 dienes, 6,7-dehydrocortexone, 20alpha-hydroxy-4,6-pregnadien-3-one and 4,6-pregnadien-3,20-dione. The synthesis of all these steroids except cortexone is described. Complete separation of the steroids of Acilius can be achieved by high-performance liquid chromatography on the reversed-phase column system. During biosynthesis of the Acilius steroids from cholesterol, introduction of the delta4 and delta6 bonds involves elimination of the 4beta and 7beta hydrogens, respectively. Possible mechanisms of formation of the delta4,6 steroids are discussed.

  1. Frozen Accident Pushing 50: Stereochemistry, Expansion, and Chance in the Evolution of the Genetic Code.

    Science.gov (United States)

    Koonin, Eugene V

    2017-05-23

    Nearly 50 years ago, Francis Crick propounded the frozen accident scenario for the evolution of the genetic code along with the hypothesis that the early translation system consisted primarily of RNA. Under the frozen accident perspective, the code is universal among modern life forms because any change in codon assignment would be highly deleterious. The frozen accident can be considered the default theory of code evolution because it does not imply any specific interactions between amino acids and the cognate codons or anticodons, or any particular properties of the code. The subsequent 49 years of code studies have elucidated notable features of the standard code, such as high robustness to errors, but failed to develop a compelling explanation for codon assignments. In particular, stereochemical affinity between amino acids and the cognate codons or anticodons does not seem to account for the origin and evolution of the code. Here, I expand Crick's hypothesis on RNA-only translation system by presenting evidence that this early translation already attained high fidelity that allowed protein evolution. I outline an experimentally testable scenario for the evolution of the code that combines a distinct version of the stereochemical hypothesis, in which amino acids are recognized via unique sites in the tertiary structure of proto-tRNAs, rather than by anticodons, expansion of the code via proto-tRNA duplication, and the frozen accident.

  2. Polyketide intermediate mimics as probes for revealing cryptic stereochemistry of ketoreductase domains.

    Science.gov (United States)

    Li, Yang; Fiers, William D; Bernard, Steffen M; Smith, Janet L; Aldrich, Courtney C; Fecik, Robert A

    2014-12-19

    Among natural product families, polyketides have shown the most promise for combinatorial biosynthesis of natural product-like libraries. Though recent research in the area has provided many mechanistic revelations, a basic-level understanding of kinetic and substrate tolerability is still needed before the full potential of combinatorial biosynthesis can be realized. We have developed a novel set of chemical probes for the study of ketoreductase domains of polyketide synthases. This chemical tool-based approach was validated using the ketoreductase of pikromycin module 2 (PikKR2) as a model system. Triketide substrate mimics 12 and 13 were designed to increase stability (incorporating a nonhydrolyzable thioether linkage) and minimize nonessential functionality (truncating the phosphopantetheinyl arm). PikKR2 reduction product identities as well as steady-state kinetic parameters were determined by a combination of LC-MS/MS analysis of synthetic standards and a NADPH consumption assay. The d-hydroxyl product is consistent with bioinformatic analysis and results from a complementary biochemical and molecular biological approach. When compared to widely employed substrates in previous studies, diketide 63 and trans-decalone 64, substrates 12 and 13 showed 2-10 fold lower K(M) values (2.4 ± 0.8 and 7.8 ± 2.7 mM, respectively), indicating molecular recognition of intermediate-like substrates. Due to an abundance of the nonreducable enol-tautomer, the k(cat) values were attenuated by as much as 15-336 fold relative to known substrates. This study reveals the high stereoselectivity of PikKR2 in the face of gross substrate permutation, highlighting the utility of a chemical probe-based approach in the study of polyketide ketoreductases.

  3. Amorpha-4,11-diene synthase: mechanism and stereochemistry of the enzymatic cyclization of farnesyl diphosphate.

    Science.gov (United States)

    Picaud, Sarah; Mercke, Per; He, Xiaofei; Sterner, Olov; Brodelius, Maria; Cane, David E; Brodelius, Peter E

    2006-04-15

    Recombinant amorpha-4,11-diene synthase from Artemisia annua, expressed in Escherichia coli, was incubated with the deuterium-labeled farnesyl diphosphates, (1R)-[1-(2)H]FPP, (1S)-[1-(2)H]FPP, and [1,1-(2)H2]FPP. GC-MS analysis of amorpha-4,11-diene formed from the deuterated FPPs shows that the deuterium atoms are retained in the product. Furthermore, analysis of the MS-spectra obtained with the differently labeled substrate indicates that the H-1si-proton of FPP is transferred during the cyclization reaction to carbon 10 of amorphadiene while the H-1re-proton of FPP is retained on C-6 of the product. Proton NMR and COSY experiments proved that the original H-1si-proton of FPP is located at C-10 of amorpha-4,11-diene as a result of a 1,3-hydride shift following initial 1,6-ring closure. The results obtained support the previously suggested mechanism for the cyclization of farnesyl diphosphate by amorph-4,11-diene synthase involving isomerization of FPP to (R)-nerolidyl diphosphate (NPP), ionization of NPP, and C-1,C-6-ring closure to generate a bisabolyl cation, followed by a 1,3-hydride shift, 1,10-ring closure to generate the amorphane skeleton, and deprotonation at either C-12 or C-13 to afford the final product (1S,6R,7R,10R)-amorpha-4,11-diene.

  4. Stereochemistry of some high coordination compounds of dioxouranium(VI) With thiosemicarbazones

    OpenAIRE

    Agarwal, Ram K. [رام اجراول; Agarwal, Himanshu; Chakraborti, Indranil

    1994-01-01

    The UO2 ion is peculiar in its coordination behaviour, because of its inherent capacity of forming compounds with higher coordination number. In the present work we describe the synthesis of a series of eight, nine and ten coordinated compounds of dioxouranium(VI) with 4[N-(2'-nitrobenzalidene)- amino] antipyrinethiosemicarbazone (2'-NO2BAAPT) and 4[N-(3'-nitrobenzalidene) amino] antipyrinethiosemicarbazone (3'-NO2BAAPT) with the general composition UO2X2.nL (X = Br, I, NCS or CIO4, n=2; X = ...

  5. Olefin cross-metathesis as a tool in natural product degradation. The stereochemistry of (+)-falcarindiol.

    Science.gov (United States)

    Ratnayake, Anokha S; Hemscheidt, Thomas

    2002-12-26

    [reaction: see text] There are conflicting reports in the literature concerning the absolute sterochemistry at C-3 of the common plant polyacetylene oxylipin (+)-falcarindiol. We have employed olefin cross-metathesis using Grubbs' second generation catalyst and ethylene gas to degrade falcarindiol to the symmetrical 1,9-decadiene-4,6-diyne-3,8-diol. The reaction is completely selective for net removal of the aliphatic side chain. Degradation of (+)-falcarindiol from Tetraplasandra hawaiiensis yields a meso product as shown by chiral HPLC. Hence, (+)-falcarindiol from this source has a (3R,8S)-configuration.

  6. Role of ligand basicity and stereochemistry in the extraction of plutonium(IV) isoxazolonates

    International Nuclear Information System (INIS)

    Mohapatra, P.K.; Manchanda, V.K.

    2003-01-01

    The extraction behaviour of plutonium (IV) was investigated from nitric acid and perchloric acid using 3-phenyl-4-benzoyl-5-isoxazolone (HPBI) as well as a mixture of HPBI and tri-n-octyl phosphine oxide (TOPO) in xylene. Studies on the binary extraction system Pu(IV)-HPBI indicated extraction of species of the type Pu(PBI) 4 . In the presence of TOPO, while species of the type Pu(PBI) 3 (ClO 4 ).(TOPO) and Pu(PBI) 4 .TOPO were co-extracted from perchloric acid medium, a mixture of Pu(PBI) 2 (NO 3 ) 2 .2TOPO, Pu(PBI) 3 (NO 3 ).(TOPO) and Pu(PBI) 4 .TOPO were co-extracted from nitric acid medium. In addition to the electronic factors, steric factors were found to play a significant role during the formation of binary/ternary/quaternary complexes. The steric hindrance due to the unusual conformation of the isoxazolone led to lowering of the equilibrium constants for both the binary and ternary extraction systems. Possible steric factor influences are explained with the help of molecular modelling. (orig.)

  7. Synthesis, stereochemistry and cytotoxic activity of novel steroidal 16-spiro-1,3,2-dioxaphosphorinanes

    Science.gov (United States)

    Wölfling, János; Kovács-Pénzes, Piroska; Zupkó, István; Schneider, Gyula; Frank, Éva

    2012-04-01

    The epimeric pairs a and b of novel steroidal 16-spiro-dioxaphosphorinanes 4-8 were synthetized via the phosphorylation of 16,16-bis(hydroxymethyl)androst-4-ene-3,17-dione (2) and their stereostructures were investigated by NMR methods. The dioxaphosphorinane moiety exists mainly as one of the possible chair conformers or as a chair-twist equilibrium in solution as a consequence of the rigidity of the sterane framework. The contributions of the conformers depend strongly on the configuration of the P atom and the stereoelectronic properties of the substituents on it. The antiproliferative activities of the structurally related products were determined in vitro with the MTT assay on three malignant human cell lines (HeLa, MCF7 and A431).

  8. Plakortolide stereochemistry revisited: the checkered history of plakortolides e and I.

    Science.gov (United States)

    Yong, Ken W L; Barnych, Bogdan; De Voss, James J; Vatèle, Jean-Michel; Garson, Mary J

    2012-10-26

    The relative configuration of the plakortolide metabolite (4) isolated from a Madagascan Plakortis sp. and named (+)-plakortolide I is revised following reassignment of the ¹³C signals for C-7 and C-16, thereby establishing that the metabolite isolated was likely (+)-plakortolide E (3). We propose that the name "plakortolide I" should be retained for the plakortolide metabolite 5 first isolated by the Faulkner group; its enantiomer 4 can then be named ent-plakortolide I in line with the description of Barnych and Vatèle. The spectroscopic data for MPA esters prepared from synthetic samples of seco derivatives of plakortolide E (3) and ent-plakortolide I (4) were compared with those of MPA esters of seco derivatives from naturally isolated plakortolides L (1) and K (2) and of seco-plakortolide E (6a). Likewise, the spectroscopic data for MTPA esters derived from 3 and 4 were compared with data for the MTPA esters derived from 5. These various comparisons established that the sign of the specific rotation associated with the natural isolates is an unreliable indicator of absolute configuration and verify that the absolute configurations of plakortolides L (1), K (2), E (3), and I (5) are (3S, 4S, 6S), (3R, 4R, 6S), (3R, 4R, 6R), and (3S, 4S, 6R), respectively.

  9. Synthesis and stereochemistry of 8.0.4' type neolignanes with a problable antileukemia activity

    International Nuclear Information System (INIS)

    Braga, A.C.H.; Barata, L.E.S.; Ruveda, E.A.

    The hexane extract from Virola surinameris leaves leads to isolate several compounds such as 8.0.4' type neolignanes surinamensine and viroline. Physical methods such as UV, IV, MS, etc are usec. (A.R.H.) [pt

  10. Stereochemistry of charged nitrogen-aromatic interactions and its involvement in ligand-receptor binding

    Science.gov (United States)

    Verdonk, Marcel L.; Boks, Gertjan J.; Kooijman, Huub; Kanters, Jan A.; Kroon, Jan

    1993-04-01

    Recently, new evidence was found for the involvement of charged nitrogen-aromatic interactions in ligand-receptor binding. In this study we report two favourable orientations of a phenyl ring with respect to a R-N+(CH3)3 group, based on crystal structure statistics from the Cambridge Structural Database. In the first orientation, the phenyl ring is situated in between the substituents at about 4.5 Å from the nitrogen atom, and the ring is approximately oriented on the sphere around the nitrogen atom. In the second orientation, the phenyl ring is situated in the same direction as one of the N-C bonds at about 6.0 Å from the nitrogen atom, and the ring is tilted with respect to the sphere around the nitrogen atom. The same two orientations were also found in the crystal structures of three ligand-receptor complexes, which implies that these orientations probably play a major role in molecular recognition mechanisms.

  11. Non-classical structures of organic compounds: unusual stereochemistry and hypercoordination

    International Nuclear Information System (INIS)

    Minkin, Vladimir I; Minyaev, Ruslan M; Hoffmann, Roald

    2002-01-01

    Non-classical structures of organic compounds are defined as molecules containing non-tetrahedral tetracoordinate and/or hypercoordinate carbon atoms. The evolution of the views on this subject is considered and the accumulated theoretical and experimental data on the structures and dynamic transformations of non-classical organic compounds are systematised. It is shown that computational analysis using the methods and the software potential of modern quantum chemistry has now acquired high predictive capacity and is the most important source of data on the structures of non-classical compounds. The bibliography includes 227 references.

  12. Stereoselective sodium borohydride reductions of cyclopentanones: influence of ceric chloride on the stereochemistry of reaction

    Directory of Open Access Journals (Sweden)

    Constantino Mauricio Gomes

    1998-01-01

    Full Text Available In this paper we describe the reduction by NaBH4 of some cyclopentanones containing an oxygenated function at the side chain position beta to the carbonyl group, both in the presence and in the absence of CeCl3. Some suggestions for the rationalization of the results are discussed, considering the stereochemical course of the reactions.

  13. "Kompromissitu naine. Kui õudne võiks see olla." / Jaanus Kulli

    Index Scriptorium Estoniae

    Kulli, Jaanus, 1955-

    2008-01-01

    Eesti tuntuima bluusiansambli Compromise Blue kahekümnest tegevusaastast räägib ansambli juht ja laulja Emil Rutiku. Vt. samas: President Ilves on Compromise Blue suur fänn. Emil Rutiku sõnul on ansamblil olnud au musitseerida kolm korda laval ka koos Toomas Hendrik Ilvesega

  14. Dosje festivalei : "Raduga". 4-10 maja 2006 g. Tjuz im. A. Brjantseva / Jelena Gorfunkel

    Index Scriptorium Estoniae

    Gorfunkel, Jelena

    2006-01-01

    4.-10. maini Peterburis toimunud VII rahvusvahelisest noorsooteatrite festivalist "Vikerkaar". Arvustatakse ka VAT Teatri lavastust "Pál-tänava poisid" (autor Ferenc Molnár, lavastaja Aare Toikka). Pälvis ühe peapreemiatest : auhinna parimale näitlejate ansamblile

  15. Pal-tänava poisid" võitis Peterburis kõrge auhinna

    Index Scriptorium Estoniae

    2006-01-01

    VAT Teater osales 4.-10. maini Peterburis VII rahvusvahelisel noorsooteatrite festivalil "Vikerkaar" lavastusega "Pál-tänava poisid" (autor Ferenc Molnár, lavastaja Aare Toikka) ja pälvis ühe peapreemiatest : auhinna parimale näitlejate ansamblile

  16. Control of Azomethine Cycloaddition Stereochemistry by CF3 Group: Structural Diversity of Fluorinated β-Proline Dimers.

    Science.gov (United States)

    Kudryavtsev, Konstantin V; Mantsyzov, Alexey B; Ivantcova, Polina M; Sokolov, Mikhail N; Churakov, Andrei V; Bräse, Stefan; Zefirov, Nikolay S; Polshakov, Vladimir I

    2016-09-16

    β-Proline-functionalized dimers consisting of homochiral monomeric units were synthesized by a non-peptidic coupling method for the first time. The applied synthetic methodology is based on 1,3-dipolar cycloaddition chemistry of azomethine ylides and provides absolute control over the β-proline backbone stereogenic centers. An o-(trifluoromethyl)phenyl substituent contributes to appropriate stabilization of the definite acrylamide chiral cis conformation and to achieve the dipole reactivity that is not observed for aryl groups lacking strong electronegative character.

  17. Stereochemistry and synthetic applications of products of fermentation of alpha,beta-unsaturated aromatic aldehydes by baker's yeast.

    Science.gov (United States)

    Fuganti, C; Grasselli, P

    1985-01-01

    Baker's yeast fermenting on D-glucose converts 2-substituted C6-C3 alpha,beta-unsaturated aromatic aldehydes into the corresponding 3-phenylprop-2-en-1-ols and 3-phenylpropan-1-ols, and into the 4-substituted (2S,3R)-5-phenylpent-4-en-2,3-ols. The formation of the C6-C3 alcohols from the aldehydes by baker's yeast was already known, but the production of the methyl diols is new. The conversion of C6-C3 alpha,beta-unsaturated aldehydes into the C6-C5 methyl diols can be viewed as the overall consequence of two distinct chemical operations: (1) addition of a C2 unit equivalent to acetaldehyde onto the Si-face of the carbonyl carbon of the unsaturated aldehyde forms the (R)-alpha-hydroxy ketone in an acyloin-type condensation, and (2) reduction of this intermediate on the Re-face of the carbonyl gives the diol actually isolated. There is some tolerance by the enzymic system(s) involved in the reaction(s) leading from the C6-C3 alpha,beta-unsaturated aromatic aldehydes to the 4-substituted (2S,3R)-5-phenylpent-4-en-2,3-ols as far as the structure of the aromatic aldehydes and the substitutents in the alpha position are concerned, but acetaldehyde is the only aldehyde accepted as second terminus of the reaction. However, synthetic alpha-hydroxy ketones, prepared from aldehydes that cannot be directly converted by yeast into the corresponding methyl diols, are reduced by yeast. This indicates that the reason direct conversion of the aldehydes does not occur is that these materials probably cannot be accepted as substrates by the condensing enzyme(s). The (2S,3R)-diols can be used instead of natural carbohydrates as starting materials for the synthesis of optically active forms of natural products belonging to different structural classes. Applications of these diols in the synthesis of L-daunosamine, the natural form of vitamin E and other products are discussed.

  18. Biosynthesis of sex pheromones in moths: stereochemistry of fatty alcohol oxidation in .I.Manduca sexta./I..

    Czech Academy of Sciences Publication Activity Database

    Hoskovec, Michal; Luxová, Anna; Svatoš, Aleš; Boland, W.

    2002-01-01

    Roč. 96, č. 11 (2002), s. 929 ISSN 0009-2770. [Konference Pokroky v organic ké, bioorganické a farmaceutické chemii /37./. 22.11.2002-24.11.2002, Liblice] Institutional research plan: CEZ:AV0Z4055905 Keywords : sex pheromones Subject RIV: CE - Biochemistry

  19. Impact of fermentation, drying, roasting and Dutch processing on flavan-3-ol stereochemistry in cacao beans and cocoa ingredients

    Science.gov (United States)

    2011-01-01

    This paper reports a systematic study of the level of flavan-3-ol monomers during typical processing steps as cacao beans are dried, fermented and roasted and the results of Dutch-processing. Methods have been used that resolve the stereoisomers of epicatechin and catechin. In beans harvested from unripe and ripe cacao pods, we find only (-)-epicatechin and (+)-catechin with (-)-epicatechin being by far the predominant isomer. When beans are fermented there is a large loss of both (-)-epicatechin and (+)-catechin, but also the formation of (-)-catechin. We hypothesize that the heat of fermentation may, in part, be responsible for the formation of this enantiomer. When beans are progressively roasted at conditions described as low, medium and high roast conditions, there is a progressive loss of (-)-epicatechin and (+)-catechin and an increase in (-)-catechin with the higher roast levels. When natural and Dutch-processed cacao powders are analyzed, there is progressive loss of both (-)-epicatechin and (+)-catechin with lesser losses of (-)-catechin. We thus observe that in even lightly Dutch-processed powder, the level of (-)-catechin exceeds the level of (-)-epicatechin. The results indicate that much of the increase in the level of (-)-catechin observed during various processing steps may be the result of heat-related epimerization from (-)-epicatechin. These results are discussed with reference to the reported preferred order of absorption of (-)-epicatechin > (+)-catechin > (-)-catechin. These results are also discussed with respect to the balance that must be struck between the beneficial impact of fermentation and roasting on chocolate flavor and the healthful benefits of chocolate and cocoa powder that result in part from the flavan-3-ol monomers. PMID:21917164

  20. Impact of Stereochemistry on Ligand Binding: X-ray Crystallographic Analysis of an Epoxide-Based HIV Protease Inhibitor.

    Science.gov (United States)

    Benedetti, Fabio; Berti, Federico; Campaner, Pietro; Fanfoni, Lidia; Demitri, Nicola; Olajuyigbe, Folasade M; De March, Matteo; Geremia, Silvano

    2014-09-11

    A new pseudopeptide epoxide inhibitor, designed for irreversible binding to HIV protease (HIV-PR), has been synthesized and characterized in solution and in the solid state. However, the crystal structure of the complex obtained by inhibitor-enzyme cocrystallization revealed that a minor isomer, with inverted configuration of the epoxide carbons, has been selected by HIV-PR during crystallization. The structural characterization of the well-ordered pseudopeptide, inserted in the catalytic channel with its epoxide group intact, provides deeper insights into inhibitor binding and HIV-PR stereoselectivity, which aids development of future epoxide-based HIV inhibitors.

  1. Mechanism and stereochemistry of the germacradienol/germacrene D synthase of Streptomyces coelicolor A3(2).

    Science.gov (United States)

    He, Xiaofei; Cane, David E

    2004-03-10

    Incubation of farnesyl diphosphate (1, FPP) with recombinant germacradienol synthase from Streptomyces coelicolor A3(2) gave, in addition to (4S,7R)-germacra-1(10)E,5E-diene-11-ol (2), 15% of (-)-germacrene D (5). Incubations of [1,1-2H2]FPP (1a), (1R)-[1-2H]FPP (1b), and (1S)-[1-2H]FPP (1c) with germacradienol/germacrene D synthase and analysis of the resulting samples of germacradienol (2) and germacrene D (5) by a combination of 1H, 2H, and 13C NMR and mass spectrometry established that it is H-1si of FPP that is lost in the formation of germacradienol (2) and that undergoes 1,3-hydride transfer in the formation of (-)-germacrene D (5). The proportion of the two products was also sensitive to isotopic labeling, with cyclization of (1S)-[1-2H]FPP (1c) giving an increased proportion (35%) of 5. These results could be explained by a mechanism involving partitioning of a common helminthogermacradienyl cation intermediate 7.

  2. Impact of fermentation, drying, roasting and Dutch processing on flavan-3-ol stereochemistry in cacao beans and cocoa ingredients

    Directory of Open Access Journals (Sweden)

    Miller Kenneth B

    2011-09-01

    Full Text Available Abstract This paper reports a systematic study of the level of flavan-3-ol monomers during typical processing steps as cacao beans are dried, fermented and roasted and the results of Dutch-processing. Methods have been used that resolve the stereoisomers of epicatechin and catechin. In beans harvested from unripe and ripe cacao pods, we find only (--epicatechin and (+-catechin with (--epicatechin being by far the predominant isomer. When beans are fermented there is a large loss of both (--epicatechin and (+-catechin, but also the formation of (--catechin. We hypothesize that the heat of fermentation may, in part, be responsible for the formation of this enantiomer. When beans are progressively roasted at conditions described as low, medium and high roast conditions, there is a progressive loss of (--epicatechin and (+-catechin and an increase in (--catechin with the higher roast levels. When natural and Dutch-processed cacao powders are analyzed, there is progressive loss of both (--epicatechin and (+-catechin with lesser losses of (--catechin. We thus observe that in even lightly Dutch-processed powder, the level of (--catechin exceeds the level of (--epicatechin. The results indicate that much of the increase in the level of (--catechin observed during various processing steps may be the result of heat-related epimerization from (--epicatechin. These results are discussed with reference to the reported preferred order of absorption of (--epicatechin > (+-catechin > (--catechin. These results are also discussed with respect to the balance that must be struck between the beneficial impact of fermentation and roasting on chocolate flavor and the healthful benefits of chocolate and cocoa powder that result in part from the flavan-3-ol monomers.

  3. Impact of fermentation, drying, roasting and Dutch processing on flavan-3-ol stereochemistry in cacao beans and cocoa ingredients.

    Science.gov (United States)

    Hurst, W Jeffrey; Krake, Susann H; Bergmeier, Stephen C; Payne, Mark J; Miller, Kenneth B; Stuart, David A

    2011-09-14

    This paper reports a systematic study of the level of flavan-3-ol monomers during typical processing steps as cacao beans are dried, fermented and roasted and the results of Dutch-processing. Methods have been used that resolve the stereoisomers of epicatechin and catechin. In beans harvested from unripe and ripe cacao pods, we find only (-)-epicatechin and (+)-catechin with (-)-epicatechin being by far the predominant isomer. When beans are fermented there is a large loss of both (-)-epicatechin and (+)-catechin, but also the formation of (-)-catechin. We hypothesize that the heat of fermentation may, in part, be responsible for the formation of this enantiomer. When beans are progressively roasted at conditions described as low, medium and high roast conditions, there is a progressive loss of (-)-epicatechin and (+)-catechin and an increase in (-)-catechin with the higher roast levels. When natural and Dutch-processed cacao powders are analyzed, there is progressive loss of both (-)-epicatechin and (+)-catechin with lesser losses of (-)-catechin. We thus observe that in even lightly Dutch-processed powder, the level of (-)-catechin exceeds the level of (-)-epicatechin. The results indicate that much of the increase in the level of (-)-catechin observed during various processing steps may be the result of heat-related epimerization from (-)-epicatechin. These results are discussed with reference to the reported preferred order of absorption of (-)-epicatechin > (+)-catechin > (-)-catechin. These results are also discussed with respect to the balance that must be struck between the beneficial impact of fermentation and roasting on chocolate flavor and the healthful benefits of chocolate and cocoa powder that result in part from the flavan-3-ol monomers.

  4. Total Syntheses of (-)-Spirooliganones A and B and Their Diastereoisomers: Absolute Stereochemistry and Inhibitory Activity against Coxsackie Virus B3.

    Science.gov (United States)

    Zhao, Nan; Ren, Xiaodong; Ren, Jinhong; Lü, Haining; Ma, Shuanggang; Gao, Rongmei; Li, Yuhuan; Xu, Song; Li, Li; Yu, Shishan

    2015-06-19

    To investigate the effects of configuration on bioactivity, spirooliganones A and B and their six diastereoisomers (1-8) were synthesized in 11 steps. The key benzopyran core was assembled by intermolecular [4 + 2] hetero-Diels-Alder cycloaddition between (-)-sabinene and o-quinone methide, which was generated from the corresponding o-hydroxybenzyl alcohol. After establishing the absolute configuration, the inhibitory activities of spirooliganones 1-8 against Coxsackie virus B3 were evaluated, and the primary structure-activity relationships were analyzed. Compound 3 was the most potent compound, with an IC50 of 0.41 μM.

  5. Eesti uus autorikoomiks / Mari Laaniste

    Index Scriptorium Estoniae

    Laaniste, Mari, 1977-

    2007-01-01

    Eesti Kunstiakadeemia kirjastuselt ilmus 2007. aastal Andreas Trosseki toimetatud raamat "Narratiivsus piltides. Eesti '00 aastate autorikoomiks = Narration in pictures. Estonian alternative comics from the '00s"

  6. Johann Christoph Brotze ja ajalugu akvarellides / Teet Veispak

    Index Scriptorium Estoniae

    Veispak, Teet, 1955-

    2006-01-01

    Kirjastuselt Estopol ilmus 2006. a. raamat "Estonica" Riias tegutsenud baltisaksa kultuuriloolase Eestit puudutavatest akvarellidest ja joonistustest. Koostajad Ants Hein, Ivar Leimus, Raimo Pullat ja Ants Viires

  7. Täna ilmub Brotze suurteos Liivimaa õitsenguajast / Kätlin Kaldmaa

    Index Scriptorium Estoniae

    Kaldmaa, Kätlin, 1970-

    2006-01-01

    Eestis ilmus Riias tegutsenud baltisaksa kultuuriloolase Johann Christoph Brotze (1742-1823) Liivimaa arhitektuuriobjekte, ajaloomuistisi, linnavaateid ja elu-olu kajastav raamat pealkirjaga "Estonica". Toimetaja ajaloolane Raimo Pullat

  8. Head ja halvad uudised Rootsist / Anu Saluäär

    Index Scriptorium Estoniae

    Saluäär, Anu, 1948-

    2004-01-01

    2003. a. lõpus lõpetas ilmumise Rootsi kirjandusajakiri "Allt om Böcker". Selle eelviimases numbris (2003, nr. 3) ilmus Håkan Lindquisti kirjutis Tõnu Õnnepalust ning katkend Nigovi/Õnnepalu "Harjutustest". Rootsi kultuuriajakirjas "Artes" (2003, nr. 4) ilmus Marcel Beyeri essee "Nõukogude korter", mis hõlmab ka reisimuljeid Tallinnast 2000. a. novembris

  9. Stereochemistry for engineering spin crossover: structures and magnetic properties of a homochiral vs. racemic [Fe(N3O2)(CN)2] complex.

    Science.gov (United States)

    Wang, Qiang; Venneri, Shari; Zarrabi, Niloofar; Wang, Hongfeng; Desplanches, Cédric; Létard, Jean-François; Seda, Takele; Pilkington, Melanie

    2015-04-21

    The Schiff-base condensation of the R,R-(+)-diamine () with 2,6-diacetyl pyridine in the presence of Fe(II) affords the macrocyclic complex [Fe(dpN3O2)(CN)2] () (dp = diphenyl) with ligand centred chirality comprising of a 1 : 1 mixture of LS 6- and HS 7-coordinate Fe(II) centres. Variable temperature magnetic susceptibility and Mössbauer studies reveal that () undergoes an incomplete thermal SCO transition with a T1/2 = 250 K as well as a LIESST effect. In contrast its racemic counterpart () comprises of mostly LS Fe(II) and exhibits no LIESST properties.

  10. Kinetic Isotope Effect Determination Probes the Spin of the Transition State, Its Stereochemistry, and Its Ligand Sphere in Hydrogen Abstraction Reactions of Oxoiron(IV) Complexes.

    Science.gov (United States)

    Mandal, Debasish; Mallick, Dibyendu; Shaik, Sason

    2018-01-16

    This Account outlines interplay of theory and experiment in the quest to identify the reactive-spin-state in chemical reactions that possess a few spin-dependent routes. Metalloenzymes and synthetic models have forged in recent decades an area of increasing appeal, in which oxometal species bring about functionalization of hydrocarbons under mild conditions and via intriguing mechanisms that provide a glimpse of Nature's designs to harness these reactions. Prominent among these are oxoiron(IV) complexes, which are potent H-abstractors. One of the key properties of oxoirons is the presence of close-lying spin-states, which can mediate H-abstractions. As such, these complexes form a fascinating chapter of spin-state chemistry, in which chemical reactivity involves spin-state interchange, so-called two-state reactivity (TSR) and multistate reactivity (MSR). TSR and MSR pose mechanistic challenges. How can one determine the structure of the reactive transition state (TS) and its spin state for these mechanisms? Calculations can do it for us, but the challenge is to find experimental probes. There are, however, no clear kinetic signatures for the reactive-spin-state in such reactions. This is the paucity that our group has been trying to fill for sometime. Hence, it is timely to demonstrate how theory joins experiment in realizing this quest. This Account uses a set of the H-abstraction reactions of 24 synthetic oxoiron(IV) complexes and 11 hydrocarbons, together undergoing H-abstraction reactions with TSR/MSR options, which provide experimentally determined kinetic isotope effect (KIE exp ) data. For this set, we demonstrate that comparing KIE exp results with calculated tunneling-augmented KIE (KIE TC ) data leads to a clear identification of the reactive spin-state during H-abstraction reactions. In addition, generating KIE exp data for a reaction of interest, and comparing these to KIE TC values, provides the mechanistic chemist with a powerful capability to identify the reactive-TS in terms of not only its spin state but also its geometry and ligand-sphere constitution. Since tunneling "cuts through" barriers, it serves as a chemical selectivity factor. Thus, we show that in a family of oxoirons reacting with one hydrocarbon, the tunneling efficiency increases as the ligands become better electron donors. This generates counterintuitive-reactivity patterns, like antielectrophilic reactivity, and induces spin-state reactivity reversals because of differing steric demands of the corresponding 2S+1 TS species, etc. Finally, for the same series, the Account reaches intuitive understanding of tunneling trends. It is shown that the increase of ligand's donicity results in electrostatic narrowing of the barrier, while the decrease of donicity and increase of bond-order asymmetry in the TS (inter alia due to Bell-Evans-Polanyi effects) broadens the barrier. Predictions are made that usage of powerful electron-donating ligands may train H-abstractors to activate the strongest C-H bond in a molecule. The concepts developed here are likely to be applicable to other oxometals in the d- and f-blocks.

  11. Synthesis of a new 1,2,3,4,5-pentasubstituted cyclohexanol and determining its stereochemistry by NMR spectroscopy and quantum-chemical calculations.

    Science.gov (United States)

    Mamedov, Ibrahim; Abbasoglu, Rza; Bayramov, Musa; Maharramov, Abel

    2016-04-01

    The presence of substituents in cyclohexane can influence to the ratio of conformers; for some cases, the boat form is preferable. The new six-membered cyclohexanol derivative 2 has been obtained by the synthesis of (E)-1-(bromophenyl)-3-phenylpropen-2-one (1). The NMR and quantum-chemical conformational analysis for the 2 have carried out, and its possible mechanism of formation was given. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

  12. Triple helices containing arabinonucleotides in the third (Hoogsteen) strand: effects of inverted stereochemistry at the 2'-position of the sugar moiety.

    Science.gov (United States)

    Noronha, A; Damha, M J

    1998-06-01

    Arabinonucleic acid, the 2'-stereoisomer of RNA, was tested for its ability to recognize double-helical DNA, double-helical RNA and RNA-DNA hybrids. A pyrimidine oligoarabinonucleotide (ANA) was shown to form triple-helical complexes only with duplex DNA and hybrid DNA (Pu):RNA (Py) with an affinity that was slightly lower relative to the corresponding pyrimidine oligodeoxynucleotide (DNA) third strand. Neither the ANA nor DNA third strands were able to bind to duplex RNA or hybrid RNA (Pu):DNA (Py). In contrast, an RNA third strand recognized all four possible duplexes (DD, DR, RD and RR), as previously demonstrated. Such an understanding can be applied to the design of sequence-selective oligonucleotides which interact with double-stranded nucleic acids and emphasizes the role of the 2'-OH group as a general recognition and binding determinant of RNA.

  13. Stereochemistry and mechanism of the reduction of some bicyclo (2-2-1-) heptane-2-ones by metals dissolved in liquid ammonia

    International Nuclear Information System (INIS)

    Coulombeau, A.

    1969-01-01

    A systematic experimental study of the reduction of four bicyclo(2-2-1)hepta n-2-ones by dissolved alkaline and alkaline-earth metals in liquid ammonia is reported. Chapter one: models of metal-ammonia solutions and mechanisms of the reduction of ketones by these solutions are rapidly recalled. Chapter two: results obtained in the thermodynamic equilibration of three pairs of epimeric alcohols which formally derive from three of the starting ketones are presented. Chapter three: deals with the results obtained in the reduction of the ketones in the absence or the presence of a proton source. A new interpretation of these results is given and is based upon two different effects: - the torsional interaction created by the bridgehead substituent on the C-O bond which favours the formation of the endo alcohol; - the difference of steric hindrance between the two sides (exo and endo) defined by the plane of the carbonyl group of the starting molecule, which favours the attack of the metal cation from one side or the other, and therefore the formation of the exo or the endo epimer. This mechanism is generalised in a model which is tested by means of some examples published in the literature. It then appears able to construe correctly the obtained results. (author) [fr

  14. Excitatory amino acid receptor ligands: resolution, absolute stereochemistry, and enantiopharmacology of 2-amino-3-(4-butyl-3-hydroxyisoxazol-5-yl)propionic acid

    DEFF Research Database (Denmark)

    Johansen, T N; Ebert, B; Bräuner-Osborne, Hans

    1998-01-01

    (RS)-2-Amino-3-(4-butyl-3-hydroxyisoxazol-5-yl)propionic acid (Bu-HIBO, 6) has previously been shown to be an agonist at (RS)-2-amino-3-(3-hydroxy-5-methylisoxazol-4-yl)propionic acid (AMPA) receptors and an inhibitor of CaCl2-dependent [3H]-(S)-glutamic acid binding (J. Med. Chem. 1992, 35, 3512......-3519). To elucidate the pharmacological significance of this latter binding affinity, which is also shown by quisqualic acid (3) but not by AMPA, we have now resolved Bu-HIBO via diastereomeric salt formation using the diprotected Bu-HIBO derivative 11 and the enantiomers of 1-phenylethylamine (PEA). The absolute...... equipotent as inhibitors of CaCl2-dependent [3H]-(S)-glutamic acid binding, neither enantiomer showed significant affinity for the synaptosomal (S)-glutamic acid uptake system(s). AMPA receptor affinity (IC50 = 0.48 microM) and agonism (EC50 = 17 microM) were shown to reside exclusively in the S...

  15. Insight into stereochemistry of a new IMP allelic variant (IMP-55) metallo-β-lactamase identified in a clinical strain of Acinetobacter baumannii.

    Science.gov (United States)

    Shakibaie, Mohammad Reza; Azizi, Omid; Shahcheraghi, Fereshteh

    2017-07-01

    Metallo-β-lactamases (MBLs) such as IMPs are broad-spectrum β-lactamases that inactivate virtually all β-lactam antibiotics including carbapenems. In this study, we investigated the hydrolytic activity, phylogenetic relationship, three dimensional (3D) structure including zinc binding motif of a new IMP variant (IMP-55) identified in a clinical strain of Acinetobacter baumannii (AB). AB strain 56 was isolated from an adult ICU of a teaching hospital in Kerman, Iran. It exhibited MIC 32μg/ml to imipenem and showed MBL activity. Hydrolytic property of the MBL enzyme was measured phenotypically. Presence of bla IMP gene encoded by class 1 integrons was detected by PCR-sequencing. Phylogenetic tree of IMP protein was constructed using the Unweighted Pair Group Method with Arithmetic Mean (UPGMA) and 3D model including zinc binding motif was predicted by bioinformatics softwares. Analysis of IMP sequence led to the identification of a novel IMP-type designated as IMP-55 (GenBank: KU299753.1; UniprotKB: A0A0S2MTX2). Impact in term of hydrolytic activity compared to the closest variants suggested efficient imipenem hydrolysis by this enzyme. Evolutionary distance matrix assessment indicated that IMP-55 protein is not closely related to other A. baumannii IMPs, however, shared 98% homology with Escherichia coli IMP-30 (UniprotKB: A0A0C5PJR0) and Pseudomonas aeruginosa IMP-1 (UniprotKB: Q19KT1). It consisted of five α-helices, ten β-sheets and six loops. A monovalent zinc ion attached to core of enzyme via His95, His97, His157 and Cys176. Multiple amino acid sequence alignments and mutational trajectory with reported IMPs showed 4 amino acid substitutions at positions 12(Phe→Ile), 31(Asp→Glu), 172(Leu→Phe) and 185(Asn→Lys). We suggest that the pleiotropic effect of mutations due to frequent administration of imipenem is responsible for emergence of new IMP variant in our hospitals. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. α 'agostic' assistance in Ziegler-Natta polymerization of olefins. Deuterium isotopic perturbation of stereochemistry indicating coordination of an α C-H bond in chain propagation

    International Nuclear Information System (INIS)

    Piers, W.E.; Bercaw, J.E.

    1990-01-01

    The well-defined, homogeneous Ziegler-Natta olefin polymerization systems that have been reported recently provide an unprecedented opportunity to investigate the mechanism of this important process. While a consensus appears to be developing that in all these systems the active catalysts are the 14-electron, d 0 (or d 0 f n ) metallocene alkyls, Cp 2 MR (M = lanthanide or group 3 transition metal) or [Cp 2 MR] + (M = group 4 transition metal), the mechanism for chain propagation and the geometry of the transition state for olefin insertion into the metal-carbon bond have not yet been unequivocally established. In a cleverly conceived experiment, Grubbs et al. probed for an α agostic interaction in the transition state for olefin insertion. Racemic 1-d 1 -5-hexenylchlorotitanocene was prepared and found to undergo AlCl 2 (CH 2 CH 3 )-induced cyclization to a mixture of cis- and trans-2-d 1 -cyclopentylmethyl stereoisomers. Any α agostic assistance in the insertion step is expected to favor the trans product (vide infra). Hydrolysis and 2 H NMR analysis of the resultant mixture of deuteriomethylcyclopentanes revealed a 1.00 ± 0.05 ratio of trans:cis products, arguing against an α agostic assisted insertion in their system, however. The scandium hydride, {(η 5 -C 5 Me 4 ) 2 SiMe 2 }Sc(PMe 3 )H ('OpSc(PMe 3 )H'), cleanly catalyzes the hydrocyclization of 1,5-hexadiene to methylcyclopentane. The authors have adapted this catalytic hydrocyclization reaction along the lines of the Grubbs experiment to probe for α agostic assistance with the scandium system

  17. The Precise Structures and Stereochemistry of Trihydroxy-linoleates Esterified in Human and Porcine Epidermis and Their Significance in Skin Barrier Function

    Science.gov (United States)

    Chiba, Takahito; Thomas, Christopher P.; Calcutt, M. Wade; Boeglin, William E.; O'Donnell, Valerie B.; Brash, Alan R.

    2016-01-01

    Creation of an intact skin water barrier, a prerequisite for life on dry land, requires the lipoxygenase-catalyzed oxidation of the essential fatty acid linoleate, which is esterified to the ω-hydroxyl of an epidermis-specific ceramide. Oxidation of the linoleate moiety by lipoxygenases is proposed to facilitate enzymatic cleavage of the ester bond, releasing free ω-hydroxyceramide for covalent binding to protein, thus forming the corneocyte lipid envelope, a key component of the epidermal barrier. Herein, we report the transformations of esterified linoleate proceed beyond the initial steps of oxidation and epoxyalcohol synthesis catalyzed by the consecutive actions of 12R-LOX and epidermal LOX3. The major end product in human and porcine epidermis is a trihydroxy derivative, formed with a specificity that implicates participation of an epoxide hydrolase in converting epoxyalcohol to triol. Of the 16 possible triols arising from hydrolysis of 9,10-epoxy-13-hydroxy-octadecenoates, using LC-MS and chiral analyses, we identify and quantify specifically 9R,10S,13R-trihydroxy-11E-octadecenoate as the single major triol esterified in porcine epidermis and the same isomer with lesser amounts of its 10R diastereomer in human epidermis. The 9R,10S,13R-triol is formed by SN2 hydrolysis of the 9R,10R-epoxy-13R-hydroxy-octadecenoate product of the LOX enzymes, a reaction specificity characteristic of epoxide hydrolase. The high polarity of triol over the primary linoleate products enhances the concept that the oxidations disrupt corneocyte membrane lipids, promoting release of free ω-hydroxyceramide for covalent binding to protein and sealing of the waterproof barrier. PMID:27151221

  18. One-azabicyclic compounds. 22. Stereochemistry and /sup 13/C NMR spectra of salts of pyrrolizidine and its homologs with protonic acids

    Energy Technology Data Exchange (ETDEWEB)

    Subbotin, O.A.; Skvortsov, I.M.

    1986-06-01

    /sup 13/C NMR spectra were obtained for pyrrolizidinium salts and their homologs and their signals were assigned. With the exception of highly strained cis-3,8-H-cis-5,8-H-3,5-dimethylpyrrolizidine (VI), all the bases studied upon their direct mixing with CF/sub 3/CO/sub 2/H form salts only with cis-fused rings in the cation. Mixtures of salts with cis- and trans-fused pyrrolizidinium fragments are formed upon the reaction of cis-3,8-H-methyl- (III) and cis-3,8-H-cis-5,8-H-3,5-dimethylpyrrolizidine (VI) under conditions close to those for kinetically-controlled amine protonation. The /sup 13/C NMR spectra of the isomeric pyrrolizidinium salts obtained as a result of the absorption of base VI by sulfuric acid were used to evaluate the conformational equilibrium in the starting compound VI. The /sup 13/C NMR chemical shifts of unsubstituted trans-fused pyrrolizidinium salts were predicted.

  19. Stereochemistry of the peroxisomal branched-chain fatty acid alpha- and beta-oxidation systems in patients suffering from different peroxisomal disorders

    NARCIS (Netherlands)

    Ferdinandusse, S.; Rusch, H.; van Lint, A. E. M.; Dacremont, G.; Wanders, R. J. A.; Vreken, P.

    2002-01-01

    Phytanic acid (3,7,11,15-tetramethylhexadecanoic acid) is a branched-chain fatty acid derived from dietary sources and broken down in the peroxisome to pristanic acid (2,6,10,14-tetramethylpentadecanoic acid) via alpha-oxidation. Pristanic acid then undergoes beta-oxidation in peroxisomes. Phytanic

  20. Stereochemistry of the epoxidation of bicyclo[2.2.1]hept-2-ene and its 7-syn-substituted derivatives. A DFT study

    Directory of Open Access Journals (Sweden)

    Sergiy I. Okovytyy

    2014-12-01

    Full Text Available The stereochemical aspects of epoxidation of norbornene and its 7-syn-substituted derivatives by performic acid were investigated. Geometry and thermodynamic parameters of transition states and prereactive complexes were computed at the UBHandHLYP/6-31G(d level of theory. It is shown that the transition states have a pronounced biradical character and a nearly coplanar orientation of the C=C bond and the molecule of performic acid. Transition state analysis revealed that, in the case of the syn-7-hydroxy derivative, the preference for the exo-approach of the oxidant can be explained by the stabilization of transition state with hydrogen bonding. In contrast, a chlorine atom or a methyl group at the 7-syn position facilitated the formation of endo-epoxides due to steric repulsion between the substituent and the oxidant.

  1. Käärideta Financial Timesi kallal / Madis Võõras

    Index Scriptorium Estoniae

    Võõras, Madis

    2010-01-01

    24.-25. aprillil 2010 ilmus ajalehe Financial Times nädalalõpulisas artikkel riskikapitali investeerijast Saul Kleinist. Viimane on investeerinud ka edukasse tarkvarafirmasse Erply, mida juhib Kristjan Hiiemaa

  2. Igal mõisal on oma lugu / Mari-Ann Remmel

    Index Scriptorium Estoniae

    Remmel, Mari-Ann

    2008-01-01

    Kirjastuselt "Tänapäev" ilmus raamat "Mõisalegendid. Harjumaa", koostaja Mari-Ann Remmel, kujundaja Angelika Schneider. Kogumik sisaldab ka ajaloolist ning genealoogilist teavet mõisahoonete ning -omanike kohta

  3. Sõnajalgade reportaaž jõudis kooliteatri lavale

    Index Scriptorium Estoniae

    2006-01-01

    1. aprillil Varstu keskkoolis peetud kooliteatrite "Lõunafestivalil" esitas Kolga keskkooli teatritrupp etenduse "Kui tal aru peas, oleks see midagi vahelduvvoolu taolist", mis inspireeritud perekond Sõnajalgade ansambliproovi tekstist (ilmus EE. 22. dets. 2005)

  4. Solzhenitsõni teekond Putini Venemaale / Udo Uibo

    Index Scriptorium Estoniae

    Uibo, Udo, 1956-

    2007-01-01

    Ajalehes The Times Litterary Supplement ilmunud Zinovi Ziniku artiklist Aleksandr Solzhenitsõni loomingust, mis ilmus aasta tagasi kogumikus The Solzhenitsyn Reader. New and essential writings 1947-2005

  5. Esimene nooreestlane / Rein Veidemann

    Index Scriptorium Estoniae

    Veidemann, Rein, 1946-

    2016-01-01

    Aluse panemine eesti noorgeeniusest Kristjan Jaak Petersoni legendile tuli Noor-Eesti koguteoses "Võitluse päevil" 1905. a. Gustav Suits nimetas seal avaldatud artiklis Petersoni meie esimeseks luuletajaks. Luuletus "Laulja" ilmus Noor-Eesti II albumis 1907. a.

  6. Eesti lülitumine modernsusesse : "Noor-Eesti" roll poliitilise ja sotsiaalse mõtte mitmekesistamisel / Toivo Raun ; tõlkinud Anne Lange

    Index Scriptorium Estoniae

    Raun, Toivo, 1943-

    2009-01-01

    Eestis juhatas modernse poliitika sisse 1905. a. revolutsioon. Revolutsiooniga ühel aastal ilmus "Noor-Eesti" esimene album. Rühmituse juhtivate teoreetikute seisukohti rahvusküsimuse, välispoliitika jt. küsimustes

  7. Kruusvall nagu haiku / Margus Mikomägi

    Index Scriptorium Estoniae

    Mikomägi, Margus, 1956-

    2007-01-01

    Saueaugu teatritalus Margus Kasterpalu lavastatud Jaan Kruusvalli kaht lühinäidendit koondpealkirjaga "Kustutage kuuvalgus". Teatrivinjett ilmus esimest korda 2005.a. septembris Maalehes. Artikkel ilmub Teatrikülgedel rubriigis "Teater & küljed" 8/20

  8. Siim Nestor soovitab : Mehhiko tigedikud Tallinnas / Siim Nestor

    Index Scriptorium Estoniae

    Nestor, Siim, 1974-

    2002-01-01

    4. aprillil esineb Von Krahli baaris Euroopa turnee Signos de Aberracion raames mehhiko industrialbänd Hocico, kellelt ilmus samanimeline album. Mehhiklaste kontserti soojendab saksa futuristlik electro-pop ansambel Accessory

  9. Sherlock Holmesi salapärane päritolu / Aare Ermel

    Index Scriptorium Estoniae

    Ermel, Aare, 1957-2013

    2004-01-01

    Sir Arthur Conan Doyle'i detektiivilugudest BBC poolt aastail 2000-2001 toodetud 6-osalisest telesarjast "Mõrvatoad" ilmus Eestis kaht filmi sisaldav DVD "Sherlock Holmesi salapärane päritolu" ja "Sherlock Holmes : Patsiendi silmad"

  10. Eesti kinnas Ameerikas

    Index Scriptorium Estoniae

    2007-01-01

    Eestit külastanud Salt Lake City kudumisringi juhendaja Nancy Bush on agar eesti soki- ja kindakudumistehnika tutvustaja Ameerikas. Ta on avaldanud selleteemalise raamatu, ajakirjas "Piecework" ilmus artikkel Aino Praaklist, juures tema kinnaste mustreid ja skeeme

  11. Intellektuaalse plära mehaanika / Dan Steinbock ; tlk. Aivo Lõhmus

    Index Scriptorium Estoniae

    Steinbock, Dan

    1997-01-01

    Refereeritakse New Yorki ülikooli füüsikaprofessori Alan Sokali paroodiat kaasaegsete kultuuriteooriate, eriti postmodernistliku kirjandusteaduse kohta 'Piiride transgessioon: kvantgravitatsiooni transformatiivse hermeneutika poole' (ilmus ajakirjas Social Text)

  12. Eesti kunst poola silmade kaudu / Heie Treier

    Index Scriptorium Estoniae

    Treier, Heie, 1963-

    2002-01-01

    Poolas Gdanski Laznia keskuses avatud eesti kunsti suurnäitusest, mille koostas Malgorzata Lisiewizc, kes võttis näituse komplekteerimise keskseks märksõnaks "keha". Osaleb 30 kunstnikku, ilmus kataloog. Eksponaatide saatetekstidest

  13. Juutide uurimine tõi tunnustuse : eesti teadlaste artikkel jõudis maailma tippajakirja / Marju Himma

    Index Scriptorium Estoniae

    Himma, Marju

    2010-01-01

    Juutide erinevate kogukondade genotüübilistele erinevuste uurimisrühma juhtideks olid Tartu Ülikooli ja Eesti Biokeskuse teadlased Doron M. Behar, Bayazit Yunusbayev, Mait Metspalu ja Richard Villems. Artikkel ilmus teadusajakirjas Nature

  14. Euroopa laienemise magusad ja hapud viljad / Marco L Sorgetti

    Index Scriptorium Estoniae

    Sorgetti, Marco L

    2005-01-01

    Lühikokkuvõte Euroopa ekspedeerijate assotsiatsioonide ühenduse CLECAT peadirektori artiklist, mis ilmus väljaande FIATA Review detsembrikuu numbris. Muudatustest ekspedeerimise valdkonnas pärast 1. mail 2004 toimunud Euroopa Liidu laienemist. Lisa: Kommentaar

  15. Viis raamatutäit poola näidendeid / Riina Mägi

    Index Scriptorium Estoniae

    Mägi, Riina, 1957-

    2006-01-01

    Tõlkija Hendrik Lindepuult ilmus viies tõlkekogumik poola dramaturgia tippteoseid tutvustavast sarjast. Seekord said kaante vahele Tadeusz Rozewiczi näidendid "Valge abielu", "Lõks" ja "Vana naine haub"

  16. "Eesti pargid"

    Index Scriptorium Estoniae

    2007-01-01

    Kirjastuselt "Varrak" ilmus esimene osa kaheosalisest parkide entsüklopeediast. Tutvustatakse Tallinna, Harjumaa, Hiiumaa, Ida-Virumaa, Jõgevamaa ja Järvamaa parke. Eesti parkide ajaloost annab ülevaate Ants Heina artikkel

  17. Hammasterannast Uusleitudmaani : killuke eestlaste maailma avastamise loost / Peeter Päll

    Index Scriptorium Estoniae

    Päll, Peeter, 1961-

    2009-01-01

    150 aastat tagasi ilmus esimene eestikeelne maailmaatlas: Maa kaardi-ramat kus sees 16 Maa Kaarti / [E. W. W. Schultz]. Pernos : R. Jakobi et Komp., 1859. Ülevaade kohanimede kujudest ja kirjutusviisist atlases

  18. Eesti aastal 1979 Priit Vesilinnu silmade läbi / Priit Vesilind ; interv. Märten Kross

    Index Scriptorium Estoniae

    Vesilind, Priit J., 1943-

    2007-01-01

    Autori elust ajakirjaniku ja fotograafina, esimesest külaskäigust Eestisse 1979. aastal, mille tulemusel ilmus fotoraamat "Eesti aastal 1979", tööst ajakirjas "National Geographic" ja lähematest plaanidest

  19. On dumal naiti "Tretii put" / Boris Tuch

    Index Scriptorium Estoniae

    Tuch, Boris, 1946-

    2007-01-01

    Venemaa Kodusõja legendaarse tegelase Mahno elust ilmus Mihhail Velleril raamat "Mahno" ja Venemaal sai valmis 12-jaoline draamasari "Nestor Mahno üheksa elu" ("Devjat zhiznei Nestora Mahno"), režissöör Nikolai Kaptan

  20. Geenid kontrollivad söögiisu : eesti teadlased haukasid tüki olümpiamedalist / Marju Himma

    Index Scriptorium Estoniae

    Himma, Marju

    2010-01-01

    Võrreldi inimese geeniproove Euroopast, Põhja-Ameerikast ja Austraaliast. Leiti 18 uut geeni, mis mõjutavad kehamassi indeksit. Artikkel uuringute tulemustega ilmus 10. okt. teadlaste tippajakirjas Nature Genetics

  1. Hanna-Liina Võsa ja Ivo Linna laulavad armastatud filmilaule / Romi Erlach

    Index Scriptorium Estoniae

    Erlach, Romi, 1977-

    2000-01-01

    Ilmus eesti filmimuusika plaat "Siin me oleme", millel laulavad Ivo Linna ja Hanna-Liina Võsa Politseiorkestri ja Kuningliku kvinteti saatel. Vestlevad Hanna-Liina Võsa, Ivo Linna ja koostaja Tõnis Kõrvits

  2. Suurim kirjanduslik ja sotsialistlik võistlus / Aarne Ruben

    Index Scriptorium Estoniae

    Ruben, Aarne, 1971-

    2004-01-01

    Eesti kirjanikud Nõukogude Liidus 1920.-1930ndatel, kirjandusajakirjast "Leegid" (ilmus Leningradis a-tel 1926-1936). Ka Jaak Urmeti artiklist "Formalism marksistlikus kirjandusteaduses", Sirp, 2004, 23. apr

  3. Vabaduse Risti vennad : surnud, kuid mitte unustatud / Jaak Pihlak

    Index Scriptorium Estoniae

    Pihlak, Jaak

    2008-01-01

    Detsembris 2005 ilmus ajakirjanduses üleskutse "Vabaduse Risti vennad - Eesti Wabariigi eliit", millele olid lisatud 361 teadmata saatusega Vabaduse Risti kavaleri nimed. Selle üleskutse tulemusena selgus 176 mehe saatus

  4. "Rohkem naisest kui näitlejast..." / Meelis Kapstas

    Index Scriptorium Estoniae

    Kapstas, Meelis, 1963-

    2006-01-01

    Ilmus Ita Everi elulooraamat "Ita Ever. Elu suuruses". Näitlejannad Viire Valdma, Mari-Liis Lill, Ülle Kaljuste, Britta Vahur, Elina Reinold, Kersti Kreismann, Merle Palmiste ja Ülle Ulla avaldavad oma esmamulje raamatust

  5. Carlo Ginzburg: anomaalia viitab normile / intervjueerinud Marek Tamm

    Index Scriptorium Estoniae

    Ginzburg, Carlo, 1939-

    2014-01-01

    Intervjuu itaalia ajaloolase Carlo Ginzburgiga tema raamatu "Ükski saar pole saar : neli pilguheitu inglise kirjandusele globaalsest vaatenurgast" eesti keeles ilmumise puhul. Teos ilmus Tallinna Ülikooli Kirjastuses

  6. Elamu Kuldtiiva tänaval Pirital on üks maailma "21. sajandi majadest" / Triin Ojari

    Index Scriptorium Estoniae

    Ojari, Triin, 1974-

    2006-01-01

    Briti kirjastuselt Laurence King ilmus 2006. a. Jonathan Belli raamat "21st Century House", kus 50 maailma silmapaistva elamu hulgas on ära nimetatud Arhitektuuribüroo 3+1 projekteeritud eramu Tallinnas Pirital

  7. Eesti kirjandus läks üle piiri

    Index Scriptorium Estoniae

    2015-01-01

    Ingliskeelse kirjandusliku veebiajakirja "Words Without Borders" (http://www.wordswithoutborders.org/) oktoobrinumber oli pühendatud eesti kirjandusele. USA kirjastuselt "Dalkey Archive Press" ilmus Mihkel Muti romaani "Kooparahvas läheb ajalukku" tõlge

  8. Kuidas ehitada ilma plaanita / Raivo Palmaru ; intervjueerinud Raivo Juurak

    Index Scriptorium Estoniae

    Palmaru, Raivo, 1951-

    2009-01-01

    Intervjuu Akadeemia Nord professori Raivo Palmaruga, kellel ilmus tänavu raamat "Kujutluste ühiskond" (Tallinn : Akadeemia Nord, 2009), kus autor keskendub postmodernistliku ühiskonna tunnetuslikele alustele

  9. Eestikeelseid filosoofiaraamatuid oodates / Leo Luks, Margus Ott

    Index Scriptorium Estoniae

    Luks, Leo, 1976-

    2016-01-01

    Möödunud aastal ilmus kaks algupärast eestikeelset filosoofiamonograafiat - Margus Oti "Vägi" ja Leo Luksi "Nihilism ja kirjandus". Nende autorid arutlevad vestluses, miks on filosoofiaraamatuid nii vähe

  10. Piilupart Donald sai tähe Hollywoodi kuulsuste alleel

    Index Scriptorium Estoniae

    2004-01-01

    Walt Disney joonistatud Piilupart ilmus ekraanile esmakordselt 1934. aastal joonisfilmis "Tark tibu". Nüüd sai ka tema Hollywoodi tähtede alleel oma staaritähe Miki-Hiire, Pluuto ja Daisy kõrvale

  11. Donalda Daka udostoili zvezdõ

    Index Scriptorium Estoniae

    2004-01-01

    Walt Disney joonistatud Piilupart ilmus ekraanile esmakordselt 1934. aastal joonisfilmis "Tark tibu". Nüüd sai ka tema Hollywoodi tähtede alleel oma staaritähe Miki-Hiire, Pluuto ja Daisy kõrvale

  12. Meediaekspert: vene inimesed väsivad infosõjast / Valeri Solovei ; intervjueerinud Taavi Minnik

    Index Scriptorium Estoniae

    Solovei, Valeri

    2015-01-01

    Intervjuu Venemaa Välisministeeriumi Moskva Riikliku Rahvusvaheliste Suhete Instituudi avalike suhete kateedri juhataja professor Valeri Soloveiga, kellelt ilmus raamat "Fake - absoluutne relv", mis keskendub meediamanipulatsioonidele ja propagandale. Nendel teemadel räägib ta ka intervjuus

  13. Большинство людей не имеет мнения / Валерий Соловей ; интервьюировал Таави Минник

    Index Scriptorium Estoniae

    Соловей, Валерий

    2015-01-01

    Intervjuu Venemaa Välisministeeriumi Moskva Riikliku Rahvusvaheliste Suhete Instituudi avalike suhete kateedri juhataja professor Valeri Soloveiga, kellelt ilmus raamat "Fake - absoluutne relv", mis keskendub meediamanipulatsioonidele ja propagandale. Nendel teemadel räägib ta ka intervjuus

  14. Vene juudid Ameerikas ehk Nõukogude Liidu Jurassic Park / Boris Fishman ; intervjueerinud Priit Hõbemägi

    Index Scriptorium Estoniae

    Fishman, Boris

    2016-01-01

    Intervjuu Tallinna külastanud ameerika kirjaniku Boris Fishmaniga, kes pidas Tallinna ülikoolis loengu ja vestles ameerika vene-juudi kultuuri teemal. Eesti keeles ilmus tema teos "Asenduselu" 2015. aastal

  15. Eesti vanausulised jõudsid Moskva huviorbiiti

    Index Scriptorium Estoniae

    2011-01-01

    Ajakirjas "Ogonjok" ilmus Birgit Püve fotoseeria Eestis elavatest vanausulistest. Sama seeria jõudis ka Ameerika fotoajakirja Photo District News (PDN) Magazine'i korraldatud fotokonkursi Photo Annual 2011 võitjate sekka

  16. Jubilei majaka-"grafina" / Juri Revalshtein

    Index Scriptorium Estoniae

    Revalshtein, Juri

    2003-01-01

    Ilmus Keri tuletorni ehitamise (arhitekt Charles Cameron) 145-aastapäevale pühendatud mark seeriast "Eesti tuletornid". Kunstnik Roman Matkiewicz. Pikem ülevaade tuletorni ehituse ajaloost alates 1718. a

  17. 14 sajandit lukus keel / Kätlin Hommik-Mrabte ; intervjueerinud Raivo Kaer

    Index Scriptorium Estoniae

    Hommik-Mrabte, Kätlin

    2016-01-01

    Hiljuti ilmus "Arabia keele vestmik-sõnastik", mis on koostatud nii eestlastele kui ka araabia keelt kõnelevatele inimestele, kes soovivad õppida eesti keelt. Intervjuu vestmiku autori Kätlin Hommik-Mrabtega

  18. Ilmar Külveti mälestusteose esitlus Tartus / Riina Kindlam

    Index Scriptorium Estoniae

    Kindlam, Riina, 1969-

    2005-01-01

    7. novembril 2005 Eesti Kirjandusmuuseumis. Kogumik pealkirjaga "Vana arm ei roosteta" ilmus ajakirjaniku 85. sünnipäevaks. Raamatuesitlusel esinesid Anne Valmas, Janika Kronberg, Vaike Külvet, Piret Noorhani

  19. Õpilasteaduse rajal

    Index Scriptorium Estoniae

    2005-01-01

    Tartu Hugo Treffneri Gümnaasiumi 10. klassi õpilane Rudolf Bichele kirjutas oma esimese teadusliku artikli "Lisateavet sinepiliblikatest Leptidea reali ja L. sinapis (Lepidoptera, Pieridae)", mis ilmus ajakirjas Lepinfo

  20. Hiiu murdekeel Jean Baptiste Holzmayeri "Osilianas" / Helmi Neetar

    Index Scriptorium Estoniae

    Neetar, Helmi

    1997-01-01

    Saaremaa muinasusundi ja rahvaluule koguja ning uurija Jean Baptiste Holzmayeri teosest "Osiliana" (II osa ilmus 1873) ja Pühalepa pastori von Segenbuschi kaastööst sellele ning uurimuses sisalduvatest hiiumurdelistest keelenditest

  1. Algas tulbikollektsioonide täiendamise hooaeg / Kristina Amor

    Index Scriptorium Estoniae

    Amor, Kristina

    2008-01-01

    Näitlejate Guido Kanguri ja Jaanus Orgulase tulbihuvist. Näitlejate ühisloominguna ilmus 2007. a. ka raamat "Dialoog tulpidega". Tegemist on tulbiteatmikuga, mis heidab pilgu ka näitlejate koduaeda ning lapsepõlve

  2. Peipsi järve uurijate töö mahtus nelja raamatusse / Raimu Hanson

    Index Scriptorium Estoniae

    Hanson, Raimu, 1957-

    2002-01-01

    Trükist ilmunud ingliskeelsest monograafiatriloogiast "Lake Peipsi. Geology", "Lake Peipsi. Fauna and flora", "Lake Peipsi. Meteorology. Hydrochemistry". Eesti keeles ilmus raamatust "Peipsi" saab Peipsi kohta põhjaliku ülevaate ka laiem lugejaskond

  3. Ristipoja mälestusi / Reino Sepp

    Index Scriptorium Estoniae

    Sepp, Reino

    2005-01-01

    Reino Sepa mälestusi Johannes Aavikust. Katkendid on võetud tema varem ilmunud artiklist "Mälestusi ja mõteid Johannes Aavikust", mis ilmus 1991. aastal ajalehe Meie Maa väljaandes "Minu Saaremaa"

  4. Telepoisi kolmas tulemine / Jaanus Kulli

    Index Scriptorium Estoniae

    Kulli, Jaanus, 1955-

    2008-01-01

    ETV lastesaadete esimese telepoisi looja oli 1960. aastatel Jaak Palmse, 2000. aastatel "taastas" telepoisi Meelis Arulepp ja 2008.a. ilmus telepoiss ekraanile Daniel Müntineni ja animatsioonistuudio Birds of Paradise loominguna

  5. Linlane arhitektuuri ja kunsti tellijana. Tallinna näide / Krista Kodres

    Index Scriptorium Estoniae

    Kodres, Krista, 1957-

    2005-01-01

    Tallinna elanikkond ja selle sotsiaalne koosseis 16.-18. sajandil. Jõukas tallinlane kui kultuuri tarbija. Muusika- ja teatriharrastused. 1710 ilmus esimene Tallinna ajaleht "Revalsche Postzeitung". Informatsioon arhitektuuri ja kunsti kohta. Bibliograafia lk. 443

  6. Homefucking is Killing Prostitution / Taavi Eelmaa

    Index Scriptorium Estoniae

    Eelmaa, Taavi, 1971-

    2008-01-01

    Mis jääb vaatajale teatrietendusest meelde? Ilmus Kris Moori raamat "Homefucking is Killing Prostitution". Raamat sisaldab tekste ja Erki Lauri fotosid Von Krahli Teatri samanimelisest etendusest, mida kordagi ei mängitud

  7. Eesti koomiks rajab teed tuntusele / Mari Laaniste

    Index Scriptorium Estoniae

    Laaniste, Mari, 1977-

    2001-01-01

    Ljubljanas ilmus Ida-Euroopa alternatiivkoomiksi antoloogia "Stripburek 2. Comics from the Other Europe", mille üheks autoriks on Veiko Tammjärv. Lisasse on paigutatud Zildre, Endorfin, Ilmar Kruusamäe ja loominguline kollektiiv Badblock

  8. Fuugad tühjale tusale / Kärt Hellerma

    Index Scriptorium Estoniae

    Hellerma, Kärt, 1956-

    2006-01-01

    Mängufilm "Tunnid" ("The Hours") Michael Cunninghami romaani põhjal: režissöör Stephen Daldry : Ameerika Ühendriigid - Suurbritannia, 2002. Artikkel ilmus esmakordselt ajakirjas Teater. Muusika. Kino, 2004, nr. 8-9

  9. Komendandi Kahni-raamat prantsuse keeles

    Index Scriptorium Estoniae

    2006-01-01

    Väliseesti inseneri August Komendandi raamat koostööst arhitekti Louis Kahniga ilmus prantsuse keeles pealkirjaga "Dixhuit annees avec Louis I. Kahn". Tiitellehel on avaldatud tänu Mart Kalmule teabe andmise eest

  10. Ainsa eestlasena Pulitzeri võitnud Edmund Valtman pandi raamatusse / Riho Laurisaar

    Index Scriptorium Estoniae

    Laurisaar, Riho

    2006-01-01

    Tallinnas ilmus 2006. a. kirjastuselt Ilo Heiki Raudla raamat "Edmund Valtman, eestlane, kes võitis Pulitzeri". USA-sse emigreerunud Edmund Valtman (1914-2005) sai 1962. a. Kuuba-ainelise karikatuuri eest Pulitzeri auhinna

  11. Solistatinol, a novel phenolic compactin analogue from Penicillium solitum

    DEFF Research Database (Denmark)

    Larsen, Thomas Ostenfeld; Lange, Lene; Schnorr, Kirk

    2007-01-01

    Solistatinol, a novel phenolic compactin analogue, has been isolated from Penicillium solitum using a UV-guided strategy. The structure and relative stereochemistry were determined by NMR spectroscopy and mass spectrometry. The absolute stereochemistry was determined by chemical degradation...

  12. Selective agonists at group II metabotropic glutamate receptors: synthesis, stereochemistry, and molecular pharmacology of (S)- and (R)-2-amino-4-(4-hydroxy[1,2,5]thiadiazol-3-yl)butyric acid

    DEFF Research Database (Denmark)

    Clausen, Rasmus P; Bräuner-Osborne, Hans; Greenwood, Jeremy R

    2002-01-01

    Homologation of analogues of the central excitatory neurotransmitter glutamic acid (Glu), in which the distal carboxy group has been bioisosterically replaced by acidic heterocyclic units, has previously provided subtype selective ligands for metabotropic Glu receptors (mGluRs). The (S)-form of t...

  13. 5-OXYGENATED N-ALKYL-2-AMINO-1-METHYLTETRALINS AND N,N-DIALKYL-2-AMINO-1-METHYLTETRALINS - EFFECTS OF STRUCTURE AND STEREOCHEMISTRY ON DOPAMINE-D2-RECEPTOR AFFINITY

    NARCIS (Netherlands)

    GROL, CJ; NORDVALL, G; JOHANSSON, AM; HACKSELL, U

    The ability of a series of stereochemically well-defined 5-oxygenated 2-aminotetralins, consisting of dopamine-receptor agonists and antagonists, to displace [H-3]spiperone and [H-3]N-propylnorapomorphine (NPA) from calf-caudate dopamine receptor sites has been evaluated in-vitro. In addition, the

  14. Stereochemistry and kinetic deuterium isotope effects in the thermal 1,3-sigmatropic rearrangement of (-)-(R,R)-trans-2-methyl-1-(1-tert-butylvinyl)cyclopropane: evidence for a biradical intermediate

    International Nuclear Information System (INIS)

    Gajewski, J.J.; Warner, J.M.

    1984-01-01

    The mechanism of the thermally induced, first order 1,3-chemical shift in cyclopropanes has not been clearly defined. In an effort to resolve the mechanism of the 1,3-shift, (-)-(R,R)-trans-2-methyl-1-(1-tert-butylvinyl) cyclopropane and its 1-(2,2-dideuterio-1-tert-butylvinyl) derivative (80% deuterated) were prepared and heated in the gas phase in a static well-conditioned reactor at 280 0 C. The observed normal isotope effect on the 1,3-shift is in the opposite direction from that usually associated with secondary α deuterium isotope effects resulting from changes in bonding, and this inverse isotope effect is thought to arise by induction from the rotational effect on the 1,3-shift. However, the explanation is not consistent with the relatively large rate constant for enantiomerization unless the enantiomerization is a separate process

  15. Nuclear magnetic resonance studies of an N2-guanine adduct derived from the tumorigen dibenzo[a,l]pyrene in DNA: impact of adduct stereochemistry, size, and local DNA sequence on solution conformations.

    Science.gov (United States)

    Rodríguez, Fabián A; Liu, Zhi; Lin, Chin H; Ding, Shuang; Cai, Yuqin; Kolbanovskiy, Alexander; Kolbanovskiy, Marina; Amin, Shantu; Broyde, Suse; Geacintov, Nicholas E

    2014-03-25

    The dimensions and arrangements of aromatic rings (topology) in adducts derived from the reactions of polycyclic aromatic hydrocarbon (PAH) diol epoxide metabolites with DNA influence the distortions and stabilities of double-stranded DNA, and hence their recognition and processing by the human nucleotide excision repair (NER) system. Dibenzo[a,l]pyrene (DB[a,l]P) is a highly tumorigenic six-ring PAH, which contains a nonplanar and aromatic fjord region that is absent in the structurally related bay region five-ring PAH benzo[a]pyrene (B[a]P). The PAH diol epoxide-DNA adducts formed include the stereoisomeric 14S and 14R trans-anti-DB[a,l]P-N(2)-dG and the stereochemically analogous 10S- and 10R-B[a]P-N(2)-dG (B[a]P-dG) guanine adducts. However, nuclear magnetic resonance (NMR) solution studies of the 14S-DB[a,l]P-N(2)-dG adduct in DNA have not yet been presented. Here we have investigated the 14S-DB[a,l]P-N(2)-dG adduct in two different sequence contexts using NMR methods with distance-restrained molecular dynamics simulations. In duplexes with dC opposite the adduct deleted, a well-resolved base-displaced intercalative adduct conformation can be observed. In full duplexes, in contrast to the intercalated 14R stereoisomeric adduct, the bulky DB[a,l]P residue in the 14S adduct is positioned in a greatly widened and distorted minor groove, with significant disruptions and distortions of base pairing at the lesion site and two 5'-side adjacent base pairs. These unique structural features are significantly different from those of the stereochemically analogous but smaller B[a]P-dG adduct. The greater size and different topology of the DB[a,l]P aromatic ring system lead to greater structurally destabilizing DNA distortions that are partially compensated by stabilizing DB[a,l]P-DNA van der Waals interactions, whose combined effects impact the NER response to the adduct. These structural results broaden our understanding of the structure-function relationship in NER.

  16. Selective agonists at group II metabotropic glutamate receptors: synthesis, stereochemistry, and molecular pharmacology of (S)- and (R)-2-amino-4-(4-hydroxy[1,2,5]thiadiazol-3-yl)butyric acid

    DEFF Research Database (Denmark)

    Clausen, Rasmus P; Bräuner-Osborne, Hans; Greenwood, Jeremy R

    2002-01-01

    )-form of the 1,2,5-thiadiazol-3-ol Glu analogue, 2-amino-3-(4-hydroxy[1,2,5]thiadiazol-3-yl)propionic acid (TDPA, 6), is an 2-amino-3-(3-hydroxy-5-methyl-4-isoxazolyl)propionic acid (AMPA) receptor agonist, which in addition stereospecifically activates group I mGluRs. We have now synthesized the (S)- and (R......Homologation of analogues of the central excitatory neurotransmitter glutamic acid (Glu), in which the distal carboxy group has been bioisosterically replaced by acidic heterocyclic units, has previously provided subtype selective ligands for metabotropic Glu receptors (mGluRs). The (S......)-forms of 2-amino-4-(4-hydroxy[1,2,5]thiadiazol-3-yl)butyric acid (homo-TDPA, 7) and shown that whereas neither enantiomer interacts with AMPA receptors, (S)- and (R)-7 appear to be selective and equipotent agonists at group II mGluRs as represented by the mGluR2 subtype. The activities of (S)- and (R)-7...

  17. The Precise Structures and Stereochemistry of Trihydroxy-linoleates Esterified in Human and Porcine Epidermis and Their Significance in Skin Barrier Function: IMPLICATION OF AN EPOXIDE HYDROLASE IN THE TRANSFORMATIONS OF LINOLEATE.

    Science.gov (United States)

    Chiba, Takahito; Thomas, Christopher P; Calcutt, M Wade; Boeglin, William E; O'Donnell, Valerie B; Brash, Alan R

    2016-07-08

    Creation of an intact skin water barrier, a prerequisite for life on dry land, requires the lipoxygenase-catalyzed oxidation of the essential fatty acid linoleate, which is esterified to the ω-hydroxyl of an epidermis-specific ceramide. Oxidation of the linoleate moiety by lipoxygenases is proposed to facilitate enzymatic cleavage of the ester bond, releasing free ω-hydroxyceramide for covalent binding to protein, thus forming the corneocyte lipid envelope, a key component of the epidermal barrier. Herein, we report the transformations of esterified linoleate proceed beyond the initial steps of oxidation and epoxyalcohol synthesis catalyzed by the consecutive actions of 12R-LOX and epidermal LOX3. The major end product in human and porcine epidermis is a trihydroxy derivative, formed with a specificity that implicates participation of an epoxide hydrolase in converting epoxyalcohol to triol. Of the 16 possible triols arising from hydrolysis of 9,10-epoxy-13-hydroxy-octadecenoates, using LC-MS and chiral analyses, we identify and quantify specifically 9R,10S,13R-trihydroxy-11E-octadecenoate as the single major triol esterified in porcine epidermis and the same isomer with lesser amounts of its 10R diastereomer in human epidermis. The 9R,10S,13R-triol is formed by SN2 hydrolysis of the 9R,10R-epoxy-13R-hydroxy-octadecenoate product of the LOX enzymes, a reaction specificity characteristic of epoxide hydrolase. The high polarity of triol over the primary linoleate products enhances the concept that the oxidations disrupt corneocyte membrane lipids, promoting release of free ω-hydroxyceramide for covalent binding to protein and sealing of the waterproof barrier. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  18. Muusikamaailm : Ateena konkurss tuleb esinduslik. Kaks raamatut juubilar-lauljatest. David Robertson lahkub Pariisist. Jean-Pierre Rampal surnud / Priit Kuusk

    Index Scriptorium Estoniae

    Kuusk, Priit, 1938-

    2000-01-01

    Septembris Ateenas toimuvast D. Mitropoulose nim. rahvusvahelisest noorte dirigentide konkursist. Saksamaal ilmus kaks raamatut nimekatelt lauljatelt ئ D. Fischer-Dieskau "Zeit eines Lebens. Auf Fährtensuche" ja J. King'i "Nun sollt Ihr mich befragen". D. Robertson lahkub Ensemble InterContemporaini kunstilise juhi kohalt, dirigendi edasisest tegevuskavast. J.-P. Rampal'i muusikuteest

  19. Meie avangardismi löögirühm / Jüri Hain

    Index Scriptorium Estoniae

    Hain, Jüri, 1941-

    2005-01-01

    Näitus "Eesti Kunstnikkude Ryhm" Tartu Kunstimuuseumis 21. I-20. III. 1923. a. lõpul asutatud rühmitusest, EKRi näitusetegevusest, 1928. a. ilmunud almanahhist "Uue Kunsti Raamat" (kujundaja Märt Laarman), mille kohta ajakirjas "Die Form" ilmus Theo van Doesburgi artikkel "Raamat ja selle kujundus"

  20. Martin Guerre ei tulnud tagasi üksi / Jürgen Beyer ; saksa keelest tõlkinud Tiina Lias

    Index Scriptorium Estoniae

    Beyer, Jürgen, 1965-

    2002-01-01

    Rets. rmt.: Davis, Natalie Zemon. Martin Guerre'i tagasitulek / inglise keelest tõlkinud Ainiki Väljataga. Tallinn : Varrak, 2002. Arvustus ilmus ka ajakirjas Vikerkaar, 2002, nr. 8-9 lk. 189-191, kuna käesolevast numbrist oli välja jäänud üks lõik

  1. George Sandi "Consuelo" / Ott Ojamaa

    Index Scriptorium Estoniae

    Ojamaa, Ott, 1926-1996

    2010-01-01

    Arvustus: Sand, George, pseud. Consuelo. 1-2. : romaan / [prantsuse keelest tõlkinud Leili-Maria Kask järelsõna ja märkused: Ott Ojamaa]. Tallinn : Eesti Riiklik Kirjastus, 1961. (Suuri sõnameistreid). 2. tr. ilmus 1988. a.

  2. "Tõde ja õigus" ilmutab end prantslastele : [vestlusring A. H. Tammsaare peateose tõlkijatega] / Jean Pascal Ollivry, Eva Toulouze, Jean-Pierre Minaudier ; vestlust juhtinud Tiina Väljaste

    Index Scriptorium Estoniae

    Ollivry, Jean Pascal

    2010-01-01

    2009. a. ilmus kirjastus Gaïa väljaandel "Tõde ja õigus" kolm esimest köidet: "La colline-du-voleur", "Indrek" (mõlemad tõlkis J. P. Ollivry) ja "Jours d'emeutes" (tlk. J.-P. Minaudier). E. Toulouze tõlgib romaani 4. osa ("Indrek et Karin") ning J. P. Ollivry 5. osa

  3. Eesti luule 1937. aastal / Aleksander Aspel

    Index Scriptorium Estoniae

    Aspel, Aleksander

    2000-01-01

    Ka Gustav Suitsu tõlgitud "Hollandi värsipõimikust" (Tartu : Eesti Kirjanikkude Liit, 1937) ja Ants Orase tõlgitud William Shakespeare'i sonettidest (ilmus raamatus Shaksepeare, W. Sonette ; Suveöö unenägu ; Othello. Tartu : Eesti Kirjanduse Selts, 1937). Varem ilmunud: "Eesti Kirjandus" 1938, nr. 3, lk. 141-159

  4. Shavian / Pent Nurmekund

    Index Scriptorium Estoniae

    Nurmekund, Pent, 1906-1996

    1997-01-01

    G. B. Shaw' näidendi "Androkles ja lõvi" ilmus erilises foneetilises tähestikus, mille lõid Kingsley Read ja Peter MacCarthy, täites G. B. Shaw' testamendi ühte punkti. Varem ilm. ajal. Edasi, 1962, 18. dets.

  5. Блюм как "шестидесятник" / Леонид Столович

    Index Scriptorium Estoniae

    Столович, Леонид, 1929-

    2005-01-01

    Rem Blum'ist, kui marksistist ja revolutsionäärist, tõelisest 1960ndate põlvkonna esindajast, kes ühena esimestest käsitles võõrandumise probleemi nõukogude filosoofias. Ilmus ka ajakirjas "Tallinn", 2000, nr. 19-20, lk. 105-112

  6. Genealogentag 2006 / Nils Saje

    Index Scriptorium Estoniae

    Saje, Nils

    2006-01-01

    18.-19. märtsini 2006 toimunud Baltisaksa Genealoogia Seltsi (Deutsch-Baltischen Genealogischen Gesellschaft) genealoogiapäevast Darmstadtis. Baltisaksa Genealoogia Selts on organisatsioon, mille liikmeskond kasvab. 2006. aasta jaanuaris ilmus esimest korda "DBGG-Genealogen-Echo". Uue valitud juhatuse koosseis, ettekannete loetelu

  7. Münchenis esitletakse Eesti juveelikunsti

    Index Scriptorium Estoniae

    2009-01-01

    Münchenis toimuval üritusel Schmuckzene esitletakse raamatut "Just Must", mis ilmus 2008. aastal Tallinnas samanimelise ehtekunstinäituse raames. Koostaja Kadri Mälk, kujundaja Aadam Kaarma, fotod Tanel Veenre. Kirjastus Arnoldsche Art Publishers arvas raamatu aasta viie parema ehtekunstiraamatu hulka

  8. Kohalejõudmise kõrvaltee : graafikatriennaal / Lucy Harrison ; interv. Anneli Porri

    Index Scriptorium Estoniae

    Harrison, Lucy

    2004-01-01

    Intervjuu Lucy Harrisoniga, kes esineb Tallinna XIII graafikatriennaalil tekstikogumikuga "Fantastilised linnad" ja kellel ilmus koostöös Christiane Baumgartneriga raamat "Detour", kus kunstnikud püüavad kahe turistidele mõeldud nõukogudeaegse linnagiidi abil ühitada seal antud kirjeldust Tallinna tegelikkusega

  9. Kodutunne kogu maailmas!

    Index Scriptorium Estoniae

    2002-01-01

    2001. a. alanud rahvusvahelises lastekunsti projektis "Feeling at Home" ("Kodutunne") osales Eestist Sally Stuudio, kelle õpilaste popkunsti võtmes akrüülmaalid kodusest elust pälvisid kiidusõnu. Projekti kokkuvõttena ilmus Belgias raamat

  10. Ines Karu tantsis end raamatusse / Kais Allkivi

    Index Scriptorium Estoniae

    Allkivi, Kais

    2008-01-01

    USAs ilmus raamat kõhutantsust "Kõhutants tähistamas püha naiselikkust" ("Belly Dance Celebrating the Sacred Feminine"). Raamatu autor on Martha Elena Burns. Eestlannadest on raamatus Ines Karu ja tema trupikaaslane Janne Mõistus. Lisaks fakte Ines Karust "Pühendunud tantsule"

  11. Kuninglik kingitus Sofiero / Meeli Müüripeal

    Index Scriptorium Estoniae

    Müüripeal, Meeli, 1963-

    2005-01-01

    Sofiero pargist, mille tulevane Rootsi kuningas Gustav VI Adolf ja kroonprintsess Margareta said 1905. a. pulmakingiks, mille nad tegid kauniks ja kuulsaks ning pärandasid Helsingborgi linnale. Margareta avaldatud aiaraamatutest. Juubelisuveks ilmus rootsi ja inglise keeles kogumik "Sofiero. Royal Residence and Glorius Garden". 18 ill

  12. Nii hea, kui keegi mõtleb absoluudi peale

    Index Scriptorium Estoniae

    2008-01-01

    11. I avatakse Tallinna Kunstihoones Arne Maasiku fotode näitus. Kuraator Karin Paulus, kujundaja Urmas Luure. Detsembris 2007 ilmus Urmas Luure monograafia, fotod 1994-2007, kujundaja Martin Pedanik. Lõigud Eero Epneri, Jan Kausi ja Peeter Lauritsa sissejuhatavatest kirjutistest

  13. Kohtumine tõlkijaga

    Index Scriptorium Estoniae

    2000-01-01

    Charles Baudelaire'i luulekogu "Kurja õied" tõlkija Tõnu Õnnepalu kohtus lugejatega Tartu Ülikooli ajaloomuuseumis 12. dets. Ka kirjastuses Tänapäev ilmus Indrek Hirve koostatud Ch. Baudelaire'i luuleraamat "Väikesed kurja lilled"

  14. "Гарри Поттер" уступил Толкиену

    Index Scriptorium Estoniae

    2007-01-01

    Aprillis 2007 ilmus J.R.R. Tolkieni lõpetamata jäänud "Children of Hurin" ("Hurini lapsed"), millele kirjutas lõpu kirjaniku poeg Christopher Tolkien. Raamatu müügiedu edestab J. K. Rowlingi "Harry Potteri" 7. raamatut "Harry Potter and the deathly hallows" ("Harry Potter ja surmapühakud")

  15. Raimo Pullati XX "Vana Tallinn" / Tõnis Liibek

    Index Scriptorium Estoniae

    Liibek, Tõnis

    2009-01-01

    Ilmus professor Raimo Pullati poolt välja antava linnaajalugu ja -kultuuri tutvustava sarja "Vana Tallinn" XX köide. Tšehhi Teaduste Akadeemia raamatukogus toimus Raimo Pullati poolt välja antud entsüklopeedilise suurteose "Johann Christoph Brotze. Estonica" esitlus

  16. Ameerika keskkool probleemidega silmitsi / Edgar Krull

    Index Scriptorium Estoniae

    Krull, Edgar, 1948-

    2001-01-01

    USA-s on hakatud tegema etteheiteid keskkooli (high school) lõpuklassi õppesisule ja töökorraldusele. Ajalehes "The Atlanta Journal-Constitution" ilmus 18. jaan. Andrew Mollisoni artikkel "Liiga palju keskkooli viimase klassi õpilasi tegeleb aja raiskamisega". Kirjutis seab kahtluse alla nii 12. klassi otstarbekuse kui ka keskkooli kui haridusinstitutsiooni üldised põhimõtted

  17. Памяти духовного отца / Яак Аллик

    Index Scriptorium Estoniae

    Аллик, Яак, 1946-

    2005-01-01

    Rem Blum'ist kui Ida-Euroopa silmapaistvaimast revolutsiooniteoreetikust. Rem Blum'i kõnest Hendrik Alliku matustel. Mõtisklus teemal "millest ma räägiksin täna Rem Blum'iga" ja hinnang tänasele eesti ühiskonnale. Artikkel ilmus ajakirjas "Tallinn", 2000, nr. 19-20, lk. 145-148

  18. Elamisväärse linna elukvaliteet ei ole seotud riigi või linna suurusega / Jan Gehl ; intervjueerinud Yoko Alender

    Index Scriptorium Estoniae

    Gehl, Jan, 1936-

    2015-01-01

    Yoko Alenderi (Yoko Oma OÜ) algatusel ja koostöös Eesti Kunstiakadeemiaga ilmus Taani urbanisti Jan Gehli raamat "Linnad inimestele" eesti keels. Yoko Alender selgitab projekti tagamaid ning uurib ka vanameistrilt endalt, mis teda elus ja töös tõdedeni on viinud ning kui helgena näeb ta linnade tulevikku

  19. Segadus : naiste seksuaaldüsfunktsioon / Juhan Kaldre

    Index Scriptorium Estoniae

    Kaldre, Juhan

    2003-01-01

    Ajakirjas "British Medical Journal" ilmus uuring, kus Washingtonis töötav Austraalia ajakirjanik Ray Moynihan süüdistab ravimifirmasid, et nad on sisuliselt leiutanud naiste seksuaaldüsfunktsiooni, et müüa paremini uusi ravimeid

  20. Edmund Valtmann - mees, kes joonistas Ameerika presidente / Heiki Raudla

    Index Scriptorium Estoniae

    Raudla, Heiki, 1949-

    2004-01-01

    2004.a. Eesti Ekspressis ilmus nimekiri sajast eestlasest, kes on kõige rohkem muutnud maailma. Nende seas ainus Pulitzeri preemia (1962) saanud eestlane karikaturist Edmund Valtman, kes tähistas tänavu 31. mail USA-s Duncasteris oma 90. sünnipäeva

  1. Tuglas ja Ristikivi avavad prantslaste tõlkesarja

    Index Scriptorium Estoniae

    2010-01-01

    Prantsuse kirjastuselt "Editions Ameline" ilmus Friedebert Tuglase prantsuskeelne novellikogu L'Ombre d'un Homme ("Inimese vari"). Sarja nimi Le chemin du lézard tähendab tõlkes "Sisaliku tee", see Ristikivi luuletus on prantsuse kui eesti keeles ära toodud

  2. Piret Raua raamatud Saksamaal ja iPhone´is

    Index Scriptorium Estoniae

    2010-01-01

    Piret Raua lasteraamat "Härra Linnu lugu" ilmus saksa keeles ; Piret Raua digitaalset pildiraamatut lastele "Emma roosad asjad" on võimalik kasutada Apple´i elektroonikatoodetes iPad, iPhone ja iPod (eesti, inglise ja jaapani keeles). Esitlus toimus 24. mail Lastekirjanduse Teabekeskuses

  3. Ahmed Zakajev: Litvinenko tapeti, sest ta abistas omakasupüüdmatult tšetšeene / Tõnis Erilaid

    Index Scriptorium Estoniae

    Erilaid, Tõnis, 1943-

    2007-01-01

    Vene ajalehes Kommersant ilmus intervjuu endise Itškeeria ministri Ahmed Zakajeviga, kes ei kahtle, et Aleksandr Litvinenko tapmisega on seotud Andrei Lugovoi. Suurbritannia politsei tegutseb täie tõsidusega, et sundida Venemaad Andrei Lugovoid välja andma

  4. Gabriel Osmonde'i mõistatus / Triinu Tamm

    Index Scriptorium Estoniae

    Tamm, Triinu

    2011-01-01

    Ühest müstifikatsioonist viimase aja prantsuse kirjanduses. Prantsuse kirjastuselt "Pygmalion" ilmus Gabriel Osmonde'i romaan "Alternatiivne sündimine" (Alternaissance). Tegu on nimelt Venemaalt emigreerunud Andrei Makine pseudonüümiga. Räägitakse ka teistest taolistest müstifikatsioonidest kirjanduses

  5. Свобода по-русски / Анатолий Королев

    Index Scriptorium Estoniae

    Королев, Анатолий

    2007-01-01

    Tom Stoppardi triloogia vene ajaloost "The Coast of Utopia" ilmus vene keeles "Берег утопии" ja lavastatakse Moskvas Venemaa Akadeemilises Noorsooteatris. Teater korraldas esseevõistluse üliõpilastele "Vabadus vene keeles..."

  6. Juubelikogumik Laabani auks

    Index Scriptorium Estoniae

    1998-01-01

    Stockholmis ilmus trükist Ilmar Laabani 75. juubelile pühendatud rootsikeelne artiklikogumik, mille andis välja Liljevalchsi Kunstihall ja mis sisaldab 7.XII 1996 Liljevalchsis toimunud Laabani austamisõhtul peetud sõnavõtte, ettekandeid, luuletusi. Olev Mikiveri kujundatud kaanega kogumikku illustreerivad reproduktsioonid rootsi ja eesti kunstnike, kellest Laaban on kirjutanud, töödest

  7. "Tehisintellekti" pikk tee ekraanile

    Index Scriptorium Estoniae

    2001-01-01

    Mängufilmi "A.I. - Tehisintellekt" ("A.I. : Artificial Intelligence") ekraanile seadmise mõte sündis režissöör Stanley Kubrick'il 1969. aastal, kui ilmus Brian Aldissi ulmejutt "Supertoys Last All Summer Long". Ekraanile jõudis see 2001. a. Steven Spielbergi käe all

  8. Seksuaalsus ja eksitus / Kärt Hellerma

    Index Scriptorium Estoniae

    Hellerma, Kärt, 1956-

    2006-01-01

    Kahe 1992.a. mängufilmi võrdlev analüüs - Jean-Jacques Annaud' "Armuke" ("L'Amant") ja Paul Verhoeveni "Ürginstinkt" ("Basic Instinct"). Artikkel ilmus esmakordselt ajakirjas Teater. Muusika. Kino, 1994, nr. 8-9

  9. Linnamaastike kaitse on osa arengust / Jukka Jokilehto, Mehr Azar Soheil ; intervjueerinud Liisa Pakosta

    Index Scriptorium Estoniae

    Jokilehto, Jukka

    2010-01-01

    Vestlus soome arhitekti, Nova Gorica ülikooli professori, UNESCO ja ICOMOSi konsultandi Jukka Jokilehto ja tema abikaasa, pärslannast arhitekti Mehr Azar Soheiliga. Ka Tallinna vanalinnast maailmapärandi komitees valmivate linnamaastike kaitseks mõeldud soovituste valguses, linna arengust sadama suunas. Eestikeelsena ilmus J. Jokilehto raamat "Arhitektuuri konserveerimise ajalugu" (Tallinn : Eesti Kunstiakadeemia, 2010)

  10. Anomaalne juhtum Rajangu näitusel / Lemming Nagel

    Index Scriptorium Estoniae

    Nagel, Lemming, 1948-2016

    2000-01-01

    Galeriis "Vaal" Raul Rajangu näitusel olevast perepildist "Kashmiir I" (1996), millel on L. Nagel, tema vend ja vanemad, kujutatu on tõepärase värviga. 1959. a. tehtud foto ilmus albumis "Tartu", kuid must-valgena.

  11. Tartu kui märk / Jüri Talvet

    Index Scriptorium Estoniae

    Talvet, Jüri, 1945-

    1996-01-01

    Ilmus algkujul hispaania keeles Sevillas Andaluusia Semiootikaassotsiatsiooni ajakirja Discurso Tartu semiootikakoolkonnale pühendatud erinumbris (nr. 8, 1993). Ilmunud ka kogumikus: Talvet, Jüri. Ameerika märkmeid, ehk, Kaemusi Eestist. Tartu : Ilmamaa, 2000, lk. 62-71, pealk.: Tartu vaim

  12. Notes on customary law and worldview / Collin Hakkinen, Art Leete

    Index Scriptorium Estoniae

    Hakkinen, Collin

    2004-01-01

    Autorite kirjavahetus Art Leete artikli "The role of customary law in the Kazym war : women and sacred rules" kohta, mis ilmus kogumikus Papers delivered at the symposium "Sacred and profane in the dialogue of cultures" : [Aprill, 2002, Tartu]. - Tartu, 2003. - (Studies in folk culture ; Vol. 1)

  13. Hilja Rüütli - Aili Helm : poliittinen vanki, sairaanhoitaja, kirjailija, ystävä / Anu Marttila

    Index Scriptorium Estoniae

    Marttila, Anu

    2009-01-01

    Isiklikke mälestusi. Ka Aili Helmi nime all ilmunud tetraloogiast, mille 3 osa kordustrükk ilmus ühiste kaante vahel 2009. a. Eesti Päevalehe ja ajakirja Akadeemia sarjas "Eesti lugu": Kuradil ei ole varju ; Vägivallamaa ; Režiim - see kõlab uhkelt

  14. ZIM – Kajakate eelkäija / Tõnu Ojala

    Index Scriptorium Estoniae

    Ojala, Tõnu, 1969-

    2010-01-01

    Oktoober ajaloos. 60 aastat tagasi tulid Gorki autotehase tootmisliinilt esimesed seeriaautod GAZ-12 ZIM. Lühidalt: 28. oktoobril 1925. a ilmus Tallinna tänavatele elektritramm. 24. oktoobril 1960 leidis Baikonuri kosmodroomil aset kosmonautika ajaloo ohvriterohkeim õnnetus. 10 aastat tagasi lõpetati klassikalise Mini tootmine

  15. Bagatellid : maailm / Nele-Eva Steinfeld, Harry Liivrand, Ivo Heinloo

    Index Scriptorium Estoniae

    Steinfeld, Nele-Eva

    2010-01-01

    Uudiseid maailmast: Helilooja Jennifer Higdon pälvis Pulitzeri preemia. Fabio Luisist sai Metropolitan Opera esimene külalisdirigent. "Operalia" võitjad Sonya Yoncheva ja Stefan Pop. Lahkus metsosopran Giulietta Simionato. Kaija Saariaho uus ooper "Emilie" Amsterdamis. Hollandi maineka jazziauhinna noppis Anton Goudsmit. Herbie Hancock tähisats juubelit. Jagati reggae- ja maailmamuusika auhindu. Ilmus Stevie Wonderi biograafia

  16. Eksperdid: video Liibanonis röövitud eestlastest on hea märk / Kärt Anvelt, Kadri Ibrus, Erik Rand

    Index Scriptorium Estoniae

    Anvelt, Kärt, 1973-

    2011-01-01

    Youtube'i videokeskkonda ilmus Liibanonis röövitud eestlastest video, milles nad paluvad Liibanoni, Saudi Araabia, Jordaania ja Prantsusmaa juhtide abi enda vabastamiseks. Saudi Araabia, Araabia Ühendemiraadid ja Jordaania on lubanud igakülgset abi. President Toomas Hendrik Ilvese avaldusest seoses videopöördumisega

  17. Kust sai USA president oma välispoliitika? / Vello Saarme

    Index Scriptorium Estoniae

    Saarme, Vello

    2003-01-01

    Autor tutvustab Morton Abramowitzi art., mis ilmus 11. sept. 2001 Washington Postis. Artikkel osutus kokkuvõtteks USA presidendi George W. Bushi senisest välispoliitikast ja lõi aluse praeguse välispoliitika analüüsiks

  18. Led Zeppelin reklaamib Narvat / Anti Ronk

    Index Scriptorium Estoniae

    Ronk, Anti

    2007-01-01

    Ilmus Narva-teemaline kahest CD-st koosnev album, kus ühel plaadil on 60 minutit videot linna vaatamisväärsuste ja informatsiooniga, teisel - briti rockansambli Led Zeppelini teosed Narva sümfooniaorkestri ja rockansambli Led R esituses

  19. Teekond Kirjasõna Vabariigis / Märt Väljataga ; intervjueerinud Marek Tamm

    Index Scriptorium Estoniae

    Väljataga, Märt, 1965-

    2015-01-01

    Märt Väljataga tõlgitud R. Rorty artiklist "Pragmatism ja filosoofia", mis ilmus Akadeemia 1992, nr. 2, lk. 281-282, 285, tema filosoofiast ja Märt Väljataga tööst ajakirja "Vikerkaar" toimetajana ning tõlkijana

  20. Olof Palme mõrvar võib olla hoopis tshiillane / Allan Espenberg

    Index Scriptorium Estoniae

    Espenberg, Allan

    2008-01-01

    Rootsi ajakirjanikul Anders Leopoldil ilmus käesoleval aastal teos, mis võtab taas luubi alla Olof Palme mõrva ja tõstatab sellega seoses uusi versioone. Raamatus "Rootsi puu tuleb langetada" seostatakse peaministri mõrva Tšiili tolleaegse kõrgema juhtkonnaga

  1. "Гарри Поттера" сочинили члены Малтийского ордена? / Петр Образцов ; интервьюировал Андрей Моисеенко

    Index Scriptorium Estoniae

    Образцов, Петр

    2005-01-01

    Venemaal ilmus raamat "АнтиГарриПоттер", mille autorid Saša Batenev ja Pjotr Obraztsov väidavad, et J. K. Rowlingi asemel kirjutab "Harry Potteri" lugusid rühm autoreid Malta ordu tellimusel

  2. Kuidas kasvavad juhid? / Koit Luus

    Index Scriptorium Estoniae

    Luus, Koit, 1967-

    2005-01-01

    Autor tõdeb, et Eesti ei saa riigi juhtimiseks valida paremaid juhte kui ühiskond ise suudab kasvatada. Ettevõtte allüksuse tegevuse sidumise olulisusest kogu organisatsiooni eesmärkidega tuginedes juhtimiskonsultandi Douglas A. Ready artiklile, mis ilmus ajakirja Harvard Business Review selle aasta avanumbris

  3. Peaaegu valmis : ehk kuidas liidrid liiguvad / Dan Ciampa

    Index Scriptorium Estoniae

    Ciampa, Dan

    2007-01-01

    Omadustest, mis on vajalikud tippjuhiks saamiseks ning näiteid tippjuhikandidaatide poolt tehtud vigadest. Tabel: Mis vahe on heal ja parimal kandidaadil. Artikkel ilmus Directori ja Harvard Business Review koostöös, originaalpealkiri "Almost Ready: How Leaders Move Up", HBR 2005 jaanuar

  4. Kujundades ja tootes / Mart Kalm

    Index Scriptorium Estoniae

    Kalm, Mart, 1961-

    2010-01-01

    Uurimata disain. Tsaariaegse tööstuse eripära. Lutheri vabrik. Teised mööblivalmistajad. Ilmus sisearhitekt. Kujundatud ühiskauplus. Uued tootmisharud. Kunsttööstuskooli panus. Nahkehistöö. Langebrauni kirjatud nõud. Lorupi klaas ja kristall. Kopfi ja Tavasti metallitööd. Naiste näputööd

  5. Millest kõneleb Noam Chomsky? / Tiit Hennoste

    Index Scriptorium Estoniae

    Hennoste, Tiit, 1953-

    2006-01-01

    Eesti keeles ilmus Noam Chomsky raamat "Meedia ja võim". Anarhismitraditsioonide mõju, Chomsky meediamudel, võrdlus Eestis toimuvaga. Artikli autori arvates on Eesti pisike ühiskond just samasugune korporatiivne totalitaarne demokraatia nagu USA-s, kuigi nüanssidega

  6. Kirjad Paduasse / Marijke Vallanzasca ; tõlkinud Mart Rummo

    Index Scriptorium Estoniae

    Vallanzasca, Marijke

    2010-01-01

    Eesti ehtekunstinäitus Marijke Studios Paduas 23. 04.-30. 06. 2010. 17 osalejat loetletud. Eksponeeritud oli 69 ehteobjekti, ilmus kataloog. Kadri Mälgu, Piret Hirve, Tanel Veenre, Villu Plingi, Eve Margus-Villemsi, Kristiina Kibe ja Kertu Tubergi töödest

  7. Jüri Talvet võeti ida-lääne akadeemia liikmeks

    Index Scriptorium Estoniae

    2011-01-01

    Rumeenias ilmus Jüri Talveti luulekogu "De din somn, de din zapada" ("Unest lumest"), mida autor Curtea de Argese luulefestivalil esitlemas käis. Lisaks pühitseti ta rahvusvahelise ida-lääne akadeemia tegevliikmeks

  8. Provintsialnõje strasti... provintsialnõi terror... / Boris Tuch

    Index Scriptorium Estoniae

    Tuch, Boris, 1946-

    2007-01-01

    H. Toompere jun. lavastusest "Sortsid" F. Dostojevski romaani järgi, esietendus 14. veebr. Eesti Draamateatris ja M. Tsumatshenko "Onu unenägu" F. Dostojevski jutustuse järgi, esietendus 15. veebr. Vene Teatris. Artikli teine osa ilmus 9. märts, lk. 25 : ill

  9. Akadeemilised üksused : muusikateaduse osakond / Urve Lippus

    Index Scriptorium Estoniae

    Lippus, Urve, 1950-2015

    2013-01-01

    Korraldati rahvusvaheline konverents "New music in history and new methods of music history writing". Eesti Kultuurkapitali Helikunsti Sihtkapitali aastapremia sai professor Kristel Pappel. Professor Jaan Rossi osalusel ilmus kogumik " Encapsulated voices : Estonian sound recordings from the German Prisoner-of-War camps in 1916-1918"

  10. Scully : võin ka lolli mängida / Gillian Anderson ; tõlk. Triin Tael

    Index Scriptorium Estoniae

    Anderson, Gillian

    2008-01-01

    USA sarjale "The X-Files" põhinev teine järjefilm "Salatoimikud: Ma tahan uskuda" ("The X-Files: I Want to Believe") : režissöör Chris Carter : peaosades David Duchovny, Gillian Anderson : Ameerika Ühendriigid - Kanada 2008. Intervjuu ilmus juulis portaalis USA Weekend

  11. R. Taagepera ja M. S. Shugart valimissüsteemidest / Peet Kask

    Index Scriptorium Estoniae

    Kask, Peet, 1948-

    1989-01-01

    Rein Taagepera ja Matthew Soberg Shugarti raamatust "Häältest mandaatideni: valimissüsteemide mõjud ja mõjutajad", mis ilmus inglise keeles 1989. a. Londonis (Seats and votes: the effects and determinants of electoral systems) ning annab ülevaate parlamendivalimistel kasutatavate süsteemide tüüpidest, komponentidest, nende uurimise ajaloost ja hetkeseisust

  12. Keskastmejuhi salatarkus : kuidas juhtida oma ülemust / John Gabarro, John Kotter ; tõlk. Kadi Tarand

    Index Scriptorium Estoniae

    Gabarro, John

    2006-01-01

    Ülemuse juhtimisest ehk keskastmejuhtide teadlikust tööst ülemusega keskastme- ja tippjuhtide suhete parandamiseks. Lisa: Kuidas juhtida oma ülemust - kontroll-leht. Artikkel ilmus Directori ja Harvard Business Review koostöös, originaalpealkiri "Managing your Boss", HBR 2005 jaanuar

  13. Iga aastaga uus mälestuste tuba / Lii Sammler

    Index Scriptorium Estoniae

    Sammler, Lii, 1963-

    2008-01-01

    Sargvere Mõisa Ajalootoad registreeriti 2007. a. kevadel kui Sargvere Maakultuuri Edendamise Seltsi museum. Muuseumitube tutvustab giid Sale Talviste. Talutoa seina kaunistavad Andres Pleesi jäädvustatud Sargvere lood. 2006. a. ilmus S. Talviste koostatud raamat "Muistsete aegade lood Sargverest". Järvamaa muuseumi juhataja Tiiu Saaristi kommentaar

  14. Montanelli, Aspromonte sul Baltico / Sandro Gerbi

    Index Scriptorium Estoniae

    Gerbi, Sandro

    2003-01-01

    1930ndatel Tallinnas asunud Itaalia Kultuuri Instituudi direktorina ning Tartu Ülikooli itaalia keele ja kirjanduse lektorina tegutsenud Indro Montanelli soovitas eesti keelde tõlkida Corrado Alvaro romaani "Aspromonte rahvas". Romaan ilmus Marta Pärna tõlkes (Tartu : Loodus, 1937), eessõna kirjutas romaanile Indro Montanelli

  15. Chemical synthesis and biological evaluation of cis- and trans-12,13-cyclopropyl and 12,13-cyclobutyl epothilones and related pyridine side chain analogues

    DEFF Research Database (Denmark)

    Nicolaou, K C; Namoto, K; Ritzén, A

    2001-01-01

    -activity relationships, including the conclusion that neither the epoxide nor the stereochemistry at C12 are essential, while the stereochemistry at both C13 and C15 are crucial for biological activity. These studies also confirmed the importance of both the cyclopropyl and 5-methylpyridine moieties in conferring potent...

  16. Structural studies and antimicrobial properties of norcembrane ...

    Indian Academy of Sciences (India)

    Administrator

    The compounds have shown moderate-to-high antimicrobial activities. The structure and the relative stereochemistry of the metabolite 1 have been determined by X-ray crystallography. Keywords. Diterpene; sinularia; stereochemistry; antimicrobial; crystallography. 1. Introduction. Soft corals have been recognized as a rich ...

  17. Solistatin, an aromatic compactin analogue from Penicillium solitum

    DEFF Research Database (Denmark)

    Sørensen, Dan; Larsen, Thomas Ostenfeld; Christophersen, Carsten

    1999-01-01

    Solistatin, (+)-(3R,5R)-7-(2'-methyl-1'-naphthyl)-3-hydroxyheptan-5-olide (1), has been isolated from Penicillium solitum. The structure and relative stereochemistry were established by NMR spectroscopy and mass spectrometry. The absolute stereochemistry was determined by chemical degradation and...

  18. Stereochemistry and mechanism of the reduction of some bicyclo (2-2-1-) heptane-2-ones by metals dissolved in liquid ammonia; Stereochimie et mecanisme de la reduction de quelques bicyclo (2-2-1) heptanones-2 par les metaux dissous dans l'ammoniac liquide

    Energy Technology Data Exchange (ETDEWEB)

    Coulombeau, A. [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1969-07-01

    A systematic experimental study of the reduction of four bicyclo(2-2-1)hepta n-2-ones by dissolved alkaline and alkaline-earth metals in liquid ammonia is reported. Chapter one: models of metal-ammonia solutions and mechanisms of the reduction of ketones by these solutions are rapidly recalled. Chapter two: results obtained in the thermodynamic equilibration of three pairs of epimeric alcohols which formally derive from three of the starting ketones are presented. Chapter three: deals with the results obtained in the reduction of the ketones in the absence or the presence of a proton source. A new interpretation of these results is given and is based upon two different effects: - the torsional interaction created by the bridgehead substituent on the C-O bond which favours the formation of the endo alcohol; - the difference of steric hindrance between the two sides (exo and endo) defined by the plane of the carbonyl group of the starting molecule, which favours the attack of the metal cation from one side or the other, and therefore the formation of the exo or the endo epimer. This mechanism is generalised in a model which is tested by means of some examples published in the literature. It then appears able to construe correctly the obtained results. (author) [French] Une etude experimentale systematique de la reduction de quatre bicyclo-(2-2-1)heptanones-2 par les metaux alcalins et alcalino-terreux dissous dans l'ammoniac liquide a ete effectuee. 1er chapitre: on y rappelle rapidement les modeles proposes pour la structure des solutions metalliques dans l'ammoniac liquide, ainsi que les mecanismes de reduction des cetones par ces solutions. 2eme chapitre: on y presente les resultats obtenus lors de l'equilibration thermodynamique de trois couples d'alcools epimeres derivant de trois des cetones reduites. 3eme chapitre: il concerne les resultats obtenus lors de la reduction des cetones en l'absence ou en presence de donneurs de protons. Une interpretation nouvelle de ces resultats est donnee, fondee sur deux effets differents: - l'interaction de torsion creee par le substituant en tete de pont sur la liaison C-O et favorisant la formation de l'alcool endo; - la difference d'encombrement entre les deux cotes exo et endo, definis par le plan du carbonyle de la molecule initiale, favorisant la formation de l'alcool endo ou de l'alcool exo. Ce mecanisme est generalise sous forme d'un modele qui est alors mis a l'epreuve de quelques exemples pris dans la litterature. Il se revele alors susceptible d'interpreter correctement les resultats obtenus. (auteur)

  19. Anionic tert-butyl-calix[4]arenes substituted at the narrow and wide rim by cobalt bis(dicarbollide)(1-) ions and CMPO-groups. Effect of stereochemistry and ratios of the functional groups on the platform on the extraction efficiency for Ln(III)/An(III)

    Czech Academy of Sciences Publication Activity Database

    Grüner, Bohumír; Böhmer, V.; Dordea, C.; Selucký, P.; Bubeníková, M.

    2013-01-01

    Roč. 747, december (2013), s. 155-166 ISSN 0022-328X R&D Projects: GA ČR GA104/09/0668 Institutional support: RVO:61388980 Keywords : Actinides * Calixarenes * Carboranes * Lanthanides * Liquid-liquid extraction Subject RIV: CA - Inorganic Chemistry Impact factor: 2.302, year: 2013

  20. Euroopa Ajalooliste Kalmistute Assotsiatsioon : rahvusvahelised koostööprojektid / Ilme Mäesalu

    Index Scriptorium Estoniae

    Mäesalu, Ilme

    2005-01-01

    ASCE (Assotiation of Significant Cemeteries in Europe) peaeesmärkidest, tegevusest. Muinsuskaitsameti esindaja Ilme Mäesalu on alates liidu asutamisest 2001. a. kuulunud ASCE juhatusse. 2004. a. ilmus Bolognas koguteos "Cemeteries of Europe. A Historical Heritage to Appreciate and Restore", kus leiduvad artiklid Tallinna surnuaedade ja Tartu Raadi kalmistu kohta. 2004. a. toimus Tartus seminar "Ajalooline kalmistu - kujunemine ja tänapäev"

  1. Память о нас - это мир, в котором мы продолжаем жить (Рэм Блюм как актуальная проблема) / Евгений Голиков

    Index Scriptorium Estoniae

    Голиков, Евгений

    2005-01-01

    Rem Blum'ist kui revolutsiooniteooria käsitlejast, kui ühest vähestest, kes oleks olnud võimeline süstemaatiliselt käsitlema Oktoobrirevolutsiooni ja Nõukogude Liitu; filosoofiaringist Tartu Ülikoolis 1960-ndatel; Blum'i ideede paikapidavusest tänapäeval. Ilmus ka ajakirjas "Tallinn", 2000, nr. 19-20, lk. 113-122

  2. Emerging Identities - East! / Siiri Vallner

    Index Scriptorium Estoniae

    Vallner, Siiri, 1972-

    2006-01-01

    Ida-Euroopa noore arhitektuuri näitus Saksa Arhitektuurikeskuses Berliinis 24. 11. 2005-20. 02. 2006. Näitus esitles ligi 70 arhitektuuribüroo arhitektide töid kaheksalt maalt ja Berliinist. Kuraator Kristien Ring. Avamisega kaasnes konverents, ilmus kataloog. 15. II Baltikumi päev "Networks - young archirects in Estonia, Latvia and Lithuania". Sloveenia, Ungari ja Berliini väljapanekust

  3. Жизнь и книга

    Index Scriptorium Estoniae

    2001-01-01

    Ilmus antoloogia "Эстония в произведениях русских писателей XVIII - начала XX века" (koost., komment., eessõna: Sergei Issakov ; Tallinn : Kirj. KPD, 2001)

  4. Хранитель ценностей / Сергей Исаков ; записала Татьяна Александрова

    Index Scriptorium Estoniae

    Исаков, Сергей, 1931-2013

    2001-01-01

    Ilmus antoloogia "Эстония в произведениях русских писателей XVIII - начала XX века" (koost., komment., eessõna: Sergei Issakov ; Tallinn : Kirj. KPD, 2001)

  5. Mis see jumal meid on loonud? / Rein Veidemann

    Index Scriptorium Estoniae

    Veidemann, Rein, 1946-

    2017-01-01

    Eesti teatriuuenduse 1969 aastal lavastas Evald Hermaküla Paul-Eerik Rummo näidendi "Tuhkatriinumäng", Jaan Tooming August Kitzbergi "Laseb käele suud anda". Jaak Alliku arvustus Jaan Toominga lavastusele ilmus ajakirjas Noorus 1970. aasta märtsinumbris pealkirjaga "Mis see jumal meid on loonud?". Sama küsimuse esitab artikli autor. Elumõttest, elu eesmärgist ja tähendusest

  6. Uudised : Muusika ja mütoloogia. Heliloojate liidus. Eduard Tubina Ühingus. Virumaa noor muusika kasvab / Raivo Tarum

    Index Scriptorium Estoniae

    Tarum, Raivo

    2001-01-01

    9.-11. märtsini toimub EMAs seminar "Muusika ja mütoloogia". 27. veebr. toimunud EHLi koosviibimisest. E. Tubina Ühingu tegevusest ئ ilmus inglisekeelne broshüür E.Tubina elust ja loomingust, V. Rumessen kohtus Rootsis N. Järviga Tubina kogutud teoste väljaandmise asjus, Tubina ühingu muusikaõhtust 6. veebr. Estonia talveaias. Virumaa noorteorkestri tegemistest, esinemistest Stokholmis ja Rakveres

  7. Rahvusvaheline juhend annab suunised looduslike pühapaikade kaitsmiseks / Ahto Kaasik

    Index Scriptorium Estoniae

    Kaasik, Ahto, 1969-

    2012-01-01

    2011. aastal korraldatud uuringust selgus, et 70% eestimaalastest peab looduslike pühapaikade kaitsmist tähtsaks. Samal aastal ilmus eesti keeles Rahvsuvahelise Looduskaitseliidu juhend looduslike pühapaikade kaitsmiseks. Juhendi kohaselt on pühapaigad põlisrahvaste vanimad looduskaitsealad. Põhimõtteliselt on kogu eesti rahvas põlisrahva järeltulija. Kuna Eestis ei ole riigiusku, siis ei saa eestkostjaks olla ükski riigiasutus. Kõikide Eesti pühapaikade eestkostjaks on Maavalla koda

  8. Meie mees Walesis / Toomas Türk

    Index Scriptorium Estoniae

    Türk, Toomas

    2005-01-01

    Eestit külastanud inglise aiakujundajast Graham Rankinist, kelle ema Urve on pärit Tallinnast ja lahkus siit 1940. a. G. Rankin on töötanud Windsori pargis, taastanud 1912. a. Gertrude Jekyll'i kujundatud Hascombe Court'i, praegu taastab Walesis Aberglasney kloostriaeda. 1999. a. ilmus temalt raamat "Magnolias. Hamlyn Care Manuals". 12 värv. ill

  9. Wiiralt plaadiümbrisel

    Index Scriptorium Estoniae

    2008-01-01

    Ilmus progerockansambli King Krimsoni praeguse trummari Pat Mastelotto ja Saksa multiinstrumentalisti Markus Reuteri kahemehebändi Tuner kolmas album "Müüt", mis on salvestatud möödunud aasta oktoobris Tallinnas, Tartus ja Viljandis Jazzkaare kontsertidel. Plaadi ümbrise kujunduses on baski päritolu disainer Ritxi Ostariz kasutanud mitmeid Eduard Wiiralti tuntud töid Kumu kogudest

  10. Uudised : Pop-karneval. Hip-hop

    Index Scriptorium Estoniae

    2005-01-01

    Muusika- ja kunstikarnevalist "Beta Bubble" 1. apr. Tallinnas Von Krahlis. Pärnu taasühinenud hip-hop-bänd Noizmakaz (TommyBoy ja Alko) sõlmis lepingu plaadifirmaga Mindnote ja annab selle alt apr. keskel välja oma teise albumi "Valitud mõtted".1. apr. tuleb müügile Noizmakazi singel "Miski muu ei loe", debüüt "Social Poetry" ilmus aastal 2001

  11. Kotzebue, Eesti-Saksa lambipirn / Harry Liivrand, Kristel Pappel ; intervjueerinud Aija Sakova

    Index Scriptorium Estoniae

    Liivrand, Harry, 1961-

    2016-01-01

    Saksamaal ja Eestis korraldatavast August von Kotzebue uurimisele pühendatud interdistsiplinaarsest konverentsisarjast "Kotzebue kõnelused". Saksamaal ilmus Wehrhahni teaduskirjastuses August von Kotzebue loomingu uurimisele pühendatud artiklikogumik "August von Kotzebue im estnisch-deutschen Dialog", koostajad ja toimetajad Klaus Gerlach, Harry Liivrand ja Kristel Pappel. Intervjuu Harry Liivranna ja Kristel Pappeliga Eesti-Saksa kultuuri- ja teadussuhetest Kotzebue näitel

  12. Leedi, kes armastas jõge

    Index Scriptorium Estoniae

    2006-01-01

    Inglise taimemaalijast Margaret Ursula Mee'st (1909-1988), kellest sai 1975. a. Rio de Janeiro aukodanik ja kes 1979. a. pälvis Brasiilia kõrgeima välismaalastele mõeldud autasu: Cruzeiro do Sul. Kunstniku viimaseks tööks jäi maal Amazonase öökuningannast. 1998. a. ilmus M. Mee Amazonase reiside päeviku põhjal raamat "In Search of Flowers of the Amazon Forest"

  13. Uudised : Urmas Alenderile pühendatud festival Paides. Heiki Mätlik kirjutab Bachist. Ungari muusika Balti misjonikeskuses. Hans van Manen lavastas Pärti

    Index Scriptorium Estoniae

    2000-01-01

    25. nov. Paides toimuvast U. Alenderi loomingule pühendatud muusikafestival-konkursist Alenderfest "Südame hääl". Ilmus H. Mätliku kolmeosaline traktaat Bachi lautomuusika interpretatsioonist ja arranzheerimisest kitarrile. 20. okt. Balti misjonikeskuses toimuvast ungari pärimusmuusikakontserdist. H. van Manen kasutab uue lühiballettide kava "Tantsu laureaadid" lavastuses A. Pärdi teost "Spiegel im Spiegel"

  14. Eesti kirjandus Prantsusmaal 2002 : jälle ebaharilikult priske saak / Marek Tamm

    Index Scriptorium Estoniae

    Tamm, Marek, 1973-

    2003-01-01

    2002. a. ilmus prantsuse keeles neli eesti kirjandusteost: Antoine Chalvini koostatud novellivalimik "Les hirondelles" ("Pääsukesed"); Eva Koffi näidend " Meie isa" ("Notre père", tõlkija Eva Toulouze); Jaan Kaplinski tõlkekogu "Le désir de la poussière" ("Tolmu igatsus", koostaja ja tõlkija Antoine Chalvin); Karl Ristikivi "Inimese teekond" ("Chemin terrestre", tõlkija Tarah Montbélialtz, pseud.)

  15. Naši suvelaagris mõnitatakse Eesti presidenti

    Index Scriptorium Estoniae

    2008-01-01

    Loode-Venemaale Tveri oblastisse suvelaagrisse kogunenud noorteliikumise Naši liikmed kutsuvad seal elavat siga Toomas Hendrik Ilveseks. Info pärineb Matt Siegeli pikemast artiklist "Nashi Summer Camp Tries a New Message", mis ilmus ajalehes The Moscow Times 21. juulil 2008. Ilmunud ka: Virumaa Teataja 22. juuli 2008, lk. 4, pealk.: Eesti presidenti mõnitati Naši suvelaagris; Eesti Elu 25. juuli 2008, lk. 3

  16. Uudised : Ilmub eesti kammermuusika album. RAM ja Jaan-Eik Tulve. TÜ naiskoor 55 / Joosep Sang

    Index Scriptorium Estoniae

    Sang, Joosep

    2000-01-01

    ER poolt välja antud eesti kammermuusika albumist "Significatio", mille esitlus toimub 17. märtsil Assauwe tornis. 11. märtsil Pärnus ja 15. märtsil Viljandis toimunud RAMi kontsertidest, juhatas J.-E. Tulve. 4. märtsil alustas TÜ naiskoor oma 55. sünnipäevale pühendatud kontserdiseeriat. Ilmus ka naiskoori esimene CD-plaat "Tähemõrsja", millel V. Tormise naiskoorimuusika

  17. Raamatud ja laevasõidud / Fred Kraav ; intervjueerinud Martin Viirand

    Index Scriptorium Estoniae

    Kraav, Fred, 1923-2010

    2012-01-01

    Vestlus väliseesti meremehe ja kirjaniku Fred Kraaviga tema elust, teenistusest meremehena Teise maailmasõja ajal ja tema raamatutest "The Partisans" (New York, 1952), mis on eestindamata ja "No Other Choice", mille tõlkis käsikirjast E. Järvel ja see ilmus eesti keeles pealkirjaga "Risttules". Artikkel põhineb Rahvusringhäälingu raadiosaatel "Maailmapilt" (1998)

  18. Три книги одного лета / Ольга Титова

    Index Scriptorium Estoniae

    Титова, Ольга, 1966-

    2008-01-01

    Andrei ja Natalja Madisoni luulekogust "Письмо будущего" (sisaldab kirju ja fotosid, ilmus Peterburis), Svetlan Semenenko luulekogust "Со всеми, кем любим, кого люблю" ja rühmituse Garmonija kogust "Соцветие"

  19. Tandem Olefin Metathesis/Oxidative Cyclization: Synthesis of Tetrahydrofuran Diols from Simple Olefins.

    Science.gov (United States)

    Dornan, Peter K; Lee, Daniel; Grubbs, Robert H

    2016-05-25

    A tandem olefin metathesis/oxidative cyclization has been developed to synthesize 2,5-disubstituted tetrahydrofuran (THF) diols in a stereocontrolled fashion from simple olefin precursors. The ruthenium metathesis catalyst is converted into an oxidation catalyst in the second step and is thus responsible for both catalytic steps. The stereochemistry of the 1,5-diene intermediate can be controlled through the choice of catalyst and the type of metathesis conducted. This olefin stereochemistry then controls the THF diol stereochemistry through a highly stereospecific oxidative cyclization.

  20. Proceedings of the 9. Brazilian meeting on magnetic resonance. Short courses on NMR. Extended abstracts and program

    International Nuclear Information System (INIS)

    2006-01-01

    Theoretical and experimental papers are presented in these proceedings comprehending the following subjects: nuclear magnetic resonance, organic and non organic compounds, polymers, petroleum, stereochemistry, physical chemistry, chemical structures, molecular biology, molecular structures and proteins

  1. Single Molecule Instrument for Surface Enhanced Raman Optical Activity of Biomolecules Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Stereochemistry is an essential element of our organic life. Only certain enantiomers are useful as drugs for the human body. Raman Optical Activity (ROA) and...

  2. Learning Organic Chemistry Through Natural Products

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 1; Issue 2. Learning Organic Chemistry Through Natural Products Determination of Absolute Stereochemistry. N R Krishnaswamy. Series Article Volume 1 Issue 2 February 1996 pp 40-46 ...

  3. Single Molecule Instrument for Surface Enhanced Raman Optical Activity of Biomolecules, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Stereochemistry is an essential element of our organic life. Only certain enantiomers are useful as drugs for the human body. Raman optical activity (ROA) provides...

  4. Science Academies' Refresher Course in Chemistry

    Indian Academy of Sciences (India)

    2017-10-25

    Oct 25, 2017 ... thetic Organic Chemistry, Asymmetric Synthesis, Stereochemistry, Pericyclic Reactions, Advance. Spectroscopy, Organomettalic Chemistry, Material Chemistry and Nanotechnology, X-Ray Crys- tallography, Molecular Spectroscopy and Quantum Chemistry, Medicinal Chemistry, Bio-inorganic. Chemistry.

  5. New gamma-pyrone propionates from the Indian Ocean sacoglossam Placobranchus ocellatus

    Digital Repository Service at National Institute of Oceanography (India)

    Manzo, E.; Ciavatta, M.L.; Gavagnin, M.; Mollo, E.; Wahidullah, S.; Cimino, G.

    A new gamma-pyrone propionate, compound 9, and its peroxy derivative 10 have been isolated from the sacoglossan Placobranchus ocellatus. The structure and the relative stereochemistry of the new molecules, which displayed an unprecedented carbon...

  6. Volvatellin, caulerpenyne-related product fromt he sacoglossan Volvatella sp.

    Digital Repository Service at National Institute of Oceanography (India)

    Fontana, A; Ciavatta, M.L.; Mollo, E; Naik, C.G.; Wahidullah, S.; De; Cimino, G.

    Volvatellin (4) is a highly unstable terpene isolated from the extracts of the Indian opisthobranch mollusk Volvatella sp. The structure and the relative stereochemistry of 4 were determined by NMR methods. The paper also describes a hypothetical...

  7. Dehydrobrachylaenolide: an eudesmanetype sesquiterpene lactone

    CSIR Research Space (South Africa)

    Rademeyer, M

    2009-01-01

    Full Text Available and trans-annelated with an -methylene -lactone. The absolute structure was assigned by optical rotation measurements compared to those from the synthetic compound with known stereochemistry. The crystal packing is consolidated by C-HO interactions...

  8. Single Molecule Instrument for Surface Enhanced Raman Optical Activity of Biomolecules, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Stereochemistry is an essential element of our organic life. Only certain enantiomers are useful as drugs for the human body. Raman Optical Activity (ROA) and...

  9. Cycloaddition Reaction of Ethyl Thioxoacetate and the Dienamine Derived from Pummerer's Ketone

    Directory of Open Access Journals (Sweden)

    Brahim Kouissa

    2013-01-01

    Full Text Available The objective of this work is to study the regio- and stereochemistry of the cycloadducts obtained from the treatment of ethyl thioxoacetate and the dienamine derived from Pummerer's ketone.

  10. 3,4-O-Isopropylidene-2-C-methyl-d-galactonolactone

    Directory of Open Access Journals (Sweden)

    N. Dai

    2010-02-01

    Full Text Available X-ray crystallography unequivocally confirmed the stereochemistry of the 2-C-methyl group in the title molecule, C10H16O6, in which the 1,5-lactone ring exists in a boat conformation. The use of d-galactose in the synthesis determined the absolute stereochemistry. The crystal exists as O—H...O hydrogen-bonded layers in the ab plane, with each molecule acting as a donor and acceptor for two hydrogen bonds.

  11. Hesseltin A, a novel antiviral metabolite from Penicillium hesseltinei

    DEFF Research Database (Denmark)

    Phipps, Richard Kerry; Petersen, B.O.; Christensen, K.B.

    2004-01-01

    Hesseltin A(1), a novel compound of mixed polyketide-terpenoid origins was isolated from the filamentous fungus Penicillium hesseltinei. The structure and stereochemistry were determined from extensive one- and two-dimensional NMR and mass spectral data.......Hesseltin A(1), a novel compound of mixed polyketide-terpenoid origins was isolated from the filamentous fungus Penicillium hesseltinei. The structure and stereochemistry were determined from extensive one- and two-dimensional NMR and mass spectral data....

  12. Tandem Olefin Metathesis/Oxidative Cyclization: Synthesis of Tetrahydrofuran Diols from Simple Olefins

    OpenAIRE

    Dornan, Peter K.; Lee, Daniel; Grubbs, Robert H.

    2016-01-01

    A tandem olefin metathesis/oxidative cyclization has been developed to synthesize 2,5-disubstituted tetrahydrofuran (THF) diols in a stereocontrolled fashion from simple olefin precursors. The ruthenium metathesis catalyst is converted into an oxidation catalyst in the second step and is thus responsible for both catalytic steps. The stereochemistry of the 1,5-diene intermediate can be controlled through the choice of catalyst and the type of metathesis conducted. This olefin stereochemistry ...

  13. A new rearranged dolabellane diterpene from the soft coral Clavularia inflata.

    Science.gov (United States)

    Alea, Glenn V; Bowden, Bruce F; Ragasa, Consolacion Y

    2008-06-15

    A new dolabellane type diterpene 1 has been isolated through its acetate 1a. The structure of 1a was elucidated by extensive 1D and 2D NMR spectroscopy and confirmed by mass spectrometry. The structure of 1 was deduced by comparison of its NMR spectral data with those of 1a, while its relative stereochemistry was deduced by NOESY. The absolute stereochemistry of C-7 was determined by analyses of 1 separately esterified with R and S O-mandelic acids.

  14. Chains, clusters, inclusion compounds, paramagnetic labels, and organic rings

    CERN Document Server

    Zanello, P

    1994-01-01

    The role of stereochemistry to elucidate reaction patterns and physico-chemical properties in topical subjects ranging from inorganic to organic chemistry are treated in the fifth and final volume of this series. Detailed accounts are given to study: chaining in polyphosphates, electron-transfers in carbonyl clusters, inclusion of organometallic molecules in cyclodextrins, stereochemistry of paramagnetic metal complexes by labeling with nitroxyl radicals, stereocontrol in organic syntheses assisted by inorganic complexes.

  15. On the stereochemistry of lone pair electrons in compounds with tetravalent tellurium: Distorted TeCl/sub 6//sup 2-/-octahedron in (H/sub 3/N(CH/sub 2/)/sub 3/NH/sub 3/)TeCl/sub 6/, regular octahedral anion in (H/sub 3/N(CH/sub 2/)/sub 3/NH/sub 3/)SnCl/sub 6/

    Energy Technology Data Exchange (ETDEWEB)

    Abriel, W.; Friedrich, C.

    1985-12-01

    Using 293 K diffractometer intensity data, the structures of (H/sub 3/N(CH/sub 2/)/sub 3/NH/sub 3/)TeCl/sub 6/ and (H/sub 3/N(CH/sub 2/)/sub 3/NH/sub 3/)SnCl/sub 6/ have been determined by single crystal X-ray technique and refined to a final R/sub w/ of 0.027 and 0.029, respectively. The yellow crystals of the tellurate are orthorhombic (space group Pnma) with a=22.952(2), b=7.5414(4), c=7.801(1) A and Z=4. This structure contains distorted TeCl/sub 6//sup 2-/ octahedra (distances Te-Cl min. 2.426(1), max. 2.672(1) A) with approximate 2 mm point symmetry. In contrast, the SnCl/sub 6//sup 2-/ ion in the second title compound is octahedral with only small deviations from m 3 m symmetry (distances Sn-Cl mean: 2.438(3) A). The colourless crystals of this tin compound are orthorhombic (space group Pnma) with a=17.6082(9), b=7.1809(3), c=10.190(1) A and Z=4. Considering the TeX/sub 6//sup 2-/ (X=Cl, Br, I) salts known to data, a distorted species is an exception, although a distortion is predicted by the VSEPR theory. The results agree with the rules for the appearance of a static stereochemical effect of the lone pair electrons in the TeX/sub 6//sup 2-/ species.

  16. Muusika : Juubelikontserdid "ERSO 75". Tüür uuel CD-l. Muusikakonverentsid Tallinnas. Highlightsi festivalist "Eduard Tubin ja tema aeg". Hermanni päev / Vardo Rumessen

    Index Scriptorium Estoniae

    Rumessen, Vardo, 1942-2015

    2001-01-01

    ERSO saab detsembris 75. aastaseks ja sel puhul on kavas kontserdid nii Tartus kui Tallinnas. Ansambel Piano Circus on välja antud uue CD, millele annab nime avateos ئ Erkki-Sven Tüüri "Transmission". Eesti Muusikateaduse Selts korraldab 3.XII EMA-s sümpoosioni teemal Beethoveni muusika. 1. ja 2. XII EMA-s toimub konverents "Interpretatsioonipedagoogika probleeme II". Põhjamaade muusikaajakirja Highlights XI numbris ilmus ülevaade rahvusvahelisest muusikafestivalist "Eduard Tubin ja tema aeg". Eesti teatri- ja muusikamuuseumis toimub helilooja, ajakirjaniku, muusika- ja keeleteadlase, dr. Karl August Hermanni päev

  17. Kalaturu romantika jäädvustaja / Aime Martinson Andra ; foto: Jaanika Peerna

    Index Scriptorium Estoniae

    Andra, Aime

    2006-01-01

    Naima Rauam, temast kirjutatud artikkel ilmus ajalehes New York Times 4. detsembril 2005. Kunstnik elas ja töötas 13 aastat Manhattani lähedal Fulton Street́i kalaturul. Möödunud aasta novembris kolis kalaturg steriilsesse akendeta laohoonesse, kunstniku jaoks kadus värviküllane maailm. Naima Rauami tööd on väljas kunstinäitusel LÕÕM 06 24. märtsist - 21. aprillini New Yorgi Eesti Majas

  18. Kui päevapiltnikud Pärnusse jõudsid / Vello Paatsi

    Index Scriptorium Estoniae

    Paatsi, Vello, 1948-2015

    2012-01-01

    Praegu teadaolevalt jõudis Pärnusse esimese fotograafina dagerrotüpist Carl Borchardt. Carl Borchardti'le järgnenud fotograafidest Pärnus. Friedrich Wilhelm Louis Seidlitzist ja tema 1866. aastal avaldatud Pärnu linnavaadete albumist. 1868. aastal ilmus Seidlitzile konkurent Theodor John. Seidlitz nimetas end fotograafiks kuni 1870. aastani. Edaspidi tunti Pärnus üksnes samanimelist pudukaupmeest. Theodor John lahkus Pärnust 1870. aastal. Samal aastal asus Pärnusse fotograaf Wilhelm Carl Paul Lanz

  19. Brüssel enne Moskvat / Markus Meckel, Matthias Wissmann

    Index Scriptorium Estoniae

    Meckel, Markus

    2005-01-01

    Saksa liiduparlamendi sotsiaaldemokraatide fraktsiooni liikme Markus Meckeli ja Saksa liiduparlamendi Euroopa komisjoni esimehe Matthias Wissmanni avaldus, milles nad kutsuvad tunnistama Balti riikide ajalugu ja korraldama päev enne Moskvas toimuvat Teise maailmasõja lõppu tähistavat üritust Brüsselis sõja lõpu 60. aastapäeva mälestusürituse. Artikkel ilmus samaaegselt ajalehtedes International Herald Tribune, Die Welt, Die Presse, Le Figaro, Gazeta Wyborcza, Lietuvas rytas, Diena

  20. Bagatellid : Maailm / Nele-Eva Steinfeld, Ivo Heinloo

    Index Scriptorium Estoniae

    Steinfeld, Nele-Eva

    2010-01-01

    Muusikasõnumeid maailmast: Eesti Filharmoonia Kammerkoori plaat "Kolgata" on Gramophone Awardi nominent. Arvo Pärdi teoseid esitati Walesis Vale of Glamorgani festivalil. Chicagos on müügil maailma kalleim viiul. James Levine'i seni avaldamata ooperisalvestused nüüd saadaval. John Zornil üliproduktiivne aasta. Björk pälvis väärika auhinna. Al Jarreau jättis tuuri pooleli. Ilmus Miles Davise kaheksa kogumikku 43 CD-ga

  1. Koolipärimuse kogumisest Noarootsis ja Vormsis 2006. aasta kevadel : Rootsi-Eesti lastenaljade kogumik Det var en ko och det var poängen / Piret Voolaid

    Index Scriptorium Estoniae

    Voolaid, Piret, 1971-

    2007-01-01

    Autor käsitleb artiklis Ahvenamaa Põhjamaade Instituudi (Nordens Institut på Åland) eestvedamisel korraldatud lastepärimuse projekti, mille käigus koguti koolipärimust Soomest Ahvenamaalt ja Rootsist Gotlandilt ning Eestist endistelt rannarootsi aladelt. Kogutu põhjal ilmus rootsikeelne antoloogiline naljakogumik Det var en ko och det var poängen. Artiklis keskendutakse välitööde kogumismetoodikale ja tulemustele Eestis. Välitööd toimusid Noarootsi Koolis ja Vormsi Põhikoolis

  2. Literary awards 2002 / Piret Viires

    Index Scriptorium Estoniae

    Viires, Piret, 1963-

    2003-01-01

    Riigi kultuuripreemia - Hando Runnel (elutööpreemia) ; Balti Assamblee kirjandusauhind - Jaan Tätte ("Sild" ja "Palju õnne argipäevaks") ; A. H. Tammsaare nim. romaaniauhind - Andrus Kivirähk ("Rehepapp") ; Eesti Kultuurkapitali aastapreemia - Aleksander Suuman ("Tondihobu tõugud vetikatega") ; Kultuurkapitali kirjanduse aastapreemiad: proosa - Jüri Ehlvest ("Hobune eikusagilt"), luule - Karl Martin Sinijärv ("Artutart & 39"), esseistika - Peeter Mudist ("Ratsukäik"), näitekirjandus - Vaino Vahing ("Mängud ja kõnelused"), lastekirjandus - Heino Kiik ("Kuresaapad"), tõlge eesti keelde - Mati Sirkel (Franz Kafka "Hiina müüri ehitamisel" tõlge), tõlge eesti keelest - Antoine Chalvin (Jaan Kaplinski "Le désir de la pousicre" tõlge), artiklipreemia - Tõnu Õnnepalu ("Kui... Küpsemine. Aleksander Suumani kaks luuletust ja üks raamat ("Meil siin Hüperboreas")", ilmus Loomingus, nr. 5-6), venekeelsete autorite kirjandusauhind - Mihhail Veller (viimase 10 aasta proosaloomingu eest) ; B. Alveri kirjandusauhind - Leo Kunnas ("Sõdurjumala teener") ja Ülar Ploom ("Üks ja kogu"); 2002. a. romaanivõistluse võitja - Nikolai Baturin ("Kentaur") ; A. H. Tammsaare nim. kirjanduspreemia - Elem Treier ("Tammsaare elu härra Hansenina") ; E. Vilde nim. kirjandusauhind - Doris Kareva ("Mandragora") ; F. Tuglase novelliauhind - Jüri Ehlvest ("Hobune eikusagilt", Looming, 2002, nr. 1) ja Jaan Undusk ("Armastus raamatu vastu", ilmus kogumikus "Puudutus"); Juhan Liivi luuleauhind - Andres Ehin (luuletus "sügaval maa all elavad...", Looming, 2002, nr. 4)

  3. Jaan Krossist Kalevputrani

    Index Scriptorium Estoniae

    2012-01-01

    Välismaal ilmunud eesti kirjandusest ja eesti kirjanike tegemistest piiri taga: Eric Dickensi tõlkes ilmus inglise keeles Jaan Krossi romaan "Vastutuulelaev" (Sailing Against the Wind) ja eesti lühiproosa kogumik "The Dedalus Book of Estonian Literature" ; Indias esitleti eesti rahvuseepose "Kalevipoeg" Vishnu Khare tõlget hindi keelde ("Kalevputra") ; USA kirjandusajakiri "The Bitter Oleander" pühendas oma viimase numbri 32 lehekülge Kristiina Ehinile ja tema loomingule ; Piret Raua raamat "Printsess Luluu ja härra Kere" (läti keeles "Princese Skella un Leta kungs") võitis esikoha 2011. aasta Läti Lastežürii 3.-4. klassi vanuserühmas ; Viivi Luige teos "Varjuteater", mis ilmus 2011. aastal soome keeles, tunnistati üheks Helsingi Linnaraamatukogu iga-aastase auhinna "12 osumaa" laureaadiks ; UNESCO ülemaailmse luulepäeva tähistamiseks toimunud rahvusvahelisest luulemaratonist võttis osa ka Jüri Talvet

  4. Structure of plant bile pigments

    Energy Technology Data Exchange (ETDEWEB)

    Schoenleber, R.W.

    1983-12-01

    Selective peptide cleavage has provided a general procedure for the study of the structure, including stereochemistry, of plant bile pigments. The information derived from the synthesis and spectral analysis of a series of 2,3-dihydrodioxobilins allows the determination of the trans relative stereochemistry for ring A of the ..beta../sub 1/-phycocyanobilin from C-phycocyanin as well as for ring A of phytochrome. A complete structure proof of the five phycoerythrobilins attached to the ..cap alpha.. and ..beta.. subunits of B-phycoerythrin is described. One of these tetrapyrroles is doubly-peptide linked to a single peptide chain through two thioethers at the C-3' and C-18' positions. The four remaining phycoerythrobilins are singly-linked to the protein through thioethers at the C-3' position and all possess the probable stereochemistry C-2(R), C-3(R), C-3'(R), and C-16(R).

  5. Synthesis and Detailed Examination of Spectral Properties of (S and (R-Higenamine 4′-O-β-d-Glucoside and HPLC Analytical Conditions to Distinguish the Diastereomers

    Directory of Open Access Journals (Sweden)

    Eisuke Kato

    2017-08-01

    Full Text Available Higenamine is a tetrahydroisoquinoline present in several plants that has β-adrenergic receptor agonist activity. Study of the biosynthesis of higenamine has shown the participation of norcoclaurine synthase, which controls the stereochemistry to construct the (S-isomer. However, when isolated from nature, higenamine is found as the racemate, or even the (R-isomer. We recently reported the isolation of higenamine 4′-O-β-d-glucoside. Herein, its (R- and (S-isomers were synthesized and compared to precisely determine the stereochemistry of the isolate. Owing to their similar spectral properties, determination of the stereochemistry based on NMR data was considered inappropriate. Therefore, a high-performance liquid chromatography method was established to separate the isomers, and natural higenamine 4′-O-β-d-glucoside was determined to be a mixture of isomers.

  6. Glutamate receptor agonists

    DEFF Research Database (Denmark)

    Vogensen, Stine Byskov; Greenwood, Jeremy R; Bunch, Lennart

    2011-01-01

    stereogenic centers due to strict requirements in the agonist binding pocket of the activated state of the receptor. By contrast, there are many examples of achiral competitive antagonists. The present review addresses how stereochemistry affects the activity of glutamate receptor ligands. The review focuses...... mainly on agonists and discusses stereochemical and conformational considerations as well as biostructural knowledge of the agonist binding pockets, which is useful in the design of glutamate receptor agonists. Examples are chosen to demonstrate how stereochemistry not only determines how the agonist...

  7. Novel phenylpropanoids and lignans from Illicium verum.

    Science.gov (United States)

    Sy, L K; Brown, G D

    1998-08-01

    Nine new phenylpropanoids (2-7, 10, 12, and 14) and two compounds representing novel structural classes of 7-O-8' and 7-O-8'.8-O-7' lignans (8 and 9, respectively) have been isolated from Illicium verum and their structures established by two-dimensional NMR. Most of these compounds appear to be biogenetically derived from threo-anethole glycol: relative stereochemistries for some members of this series were established by NOESY; absolute stereochemistries of others were determined by formation of Mosher esters.

  8. Carbonylation of propargyl carbamates with palladium(II) bisoxazoline catalysts: efficient synthesis of 5-methoxy-3(2H)-furanones.

    Science.gov (United States)

    Kusakabe, Taichi; Takahashi, Takeo; Shen, Rong; Ikeda, Ayumi; Dhage, Yogesh Daulat; Kanno, Yuichro; Inouye, Yoshio; Sasai, Hiroaki; Mochida, Tomoyuki; Kato, Keisuke

    2013-07-22

    Palladium and CO: Carbonylation of 1 with [Pd(tfa)2(±)-L1] (tfa = trifluoroacetate) affords the spirofuranone 2 with inversion of the stereochemistry at C17 in 96 % yield. C17-epi-1 also gave the same product 2 with retention of the stereochemistry at C17. Labelling studies show that (13)CO was incorporated into the C5' position of the furanone ring. The first asymmetric version of this new reaction was achieved. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Synthesis of 3,3'-spirocyclic oxindoles via phosphine catalyzed [4 + 2] cyclizations.

    Science.gov (United States)

    Gicquel, Maxime; Gomez, Catherine; Retailleau, Pascal; Voituriez, Arnaud; Marinetti, Angela

    2013-08-02

    Triphenylphosphine promoted reactions between 3-arylideneoxindoles and δ-aryl-substituted penta-2,3-dienoates afford an unprecedented access to spirocyclic oxindoles with functionalized six-membered rings. In these new [4 + 2] cyclization processes, the allenoates operate as the four-carbon synthons, thanks to the involvement of the substituted δ-carbons. These reactions give excellent control of the relative stereochemistry of the three stereogenic centers. The stereochemistry of the final product has been ascertained by X-ray diffraction studies.

  10. Chemical synthesis and biological evaluation of cis- and trans-12,13-cyclopropyl and 12,13-cyclobutyl epothilones and related pyridine side chain analogues

    DEFF Research Database (Denmark)

    Nicolaou, K C; Namoto, K; Ritzén, A

    2001-01-01

    and cytotoxic agents with (12R,13S,15S)-cyclopropyl 5-methylpyridine epothilone A (11) as the most powerful compound whose potencies (e.g. IC(50) = 0.6 nM against the 1A9 ovarian carcinoma cell line) approach those of epothilone B. These investigations led to a number of important structure......-activity relationships, including the conclusion that neither the epoxide nor the stereochemistry at C12 are essential, while the stereochemistry at both C13 and C15 are crucial for biological activity. These studies also confirmed the importance of both the cyclopropyl and 5-methylpyridine moieties in conferring potent...

  11. Phe-Gly dipeptidomimetics designed for the di-/tripeptide transporters PEPT1 and PEPT2

    DEFF Research Database (Denmark)

    Våbenø, Jon; Lejon, Tore; Nielsen, Carsten Uhd

    2004-01-01

    information about the importance of flexibility and of the stereochemistry at the C(4)-position for this class of compounds. Furthermore, the intracellular uptake of 2a-4a in Caco-2 cells was investigated, showing a 3-fold reduction of the uptake of 2a in the presence of the competetive inhibitor Gly...

  12. Resonance – Journal of Science Education | Indian Academy of ...

    Indian Academy of Sciences (India)

    Ed Lorenz: Father of the 'Butterfly Effect' · G Ambika · More Details Fulltext PDF. pp 206-216 General Article. Multivariable Chinese Remainder Theorem · B Sury · More Details Fulltext PDF. pp 217-234 General Article. C-II Acid and the Stereochemistry of Abietic Acid · S N Balasubrahmanyam · More Details Fulltext PDF.

  13. LACAME 2006: Latin American conference on the applications of the Moessbauer effects. Program and Abstract Book

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-07-01

    Theoretical and experimental papers are present in these proceedings on the following subjects: Moessbauer effects and spectroscopy, minerals, structural chemical analysis, crustal structure, ion oxides, hyperfine structure, geology, catalysts, transmission and absorption spectroscopies, materials, crystal and hyperfine structures, stereochemistry and geological materials.

  14. LACAME 2006: Latin American conference on the applications of the Moessbauer effects. Program and Abstract Book

    International Nuclear Information System (INIS)

    2006-01-01

    Theoretical and experimental papers are present in these proceedings on the following subjects: Moessbauer effects and spectroscopy, minerals, structural chemical analysis, crustal structure, ion oxides, hyperfine structure, geology, catalysts, transmission and absorption spectroscopies, materials, crystal and hyperfine structures, stereochemistry and geological materials

  15. Aminodiols via stereocontrolled oxidation of methyleneaziridines.

    Science.gov (United States)

    Rigoli, Jared W; Guzei, Ilia A; Schomaker, Jennifer M

    2014-03-21

    A highly diastereoselective Ru-catalyzed oxidation/reduction sequence of bicyclic methyleneaziridines provides a facile route to complex 1-amino-2,3-diol motifs. The relative anti stereochemistry between the amine and the vicinal alcohol are proposed to result from 1,3-bischelation in the transition state by the C1 and C3 heteroatoms.

  16. A new metabotropic glutamate receptor agonist with in vivo anti-allodynic activity

    DEFF Research Database (Denmark)

    Stanley, Nathan J; Hutchinson, Mark R; Kvist, Trine

    2010-01-01

    -substituted carboxycyclopropylglycines, utilizing novel synthetic chemistry. The reaction between substituted 1,2-dioxines and an aminophosphonate furnished the cyclopropane core in a single step with all required stereochemistry of pendant groups. In vitro binding assays at metabotropic glutamate receptors revealed selective activity...

  17. Nano-self-assemblies based on synthetic analogues of mycobacterial monomycoloyl glycerol and DDA: Supramolecular structure and adjuvant efficacy

    DEFF Research Database (Denmark)

    Martin-Bertelsen, Birte; Korsholm, Karen Smith; Christensen, Dennis

    2016-01-01

    ) and hydrophobic moiety stereochemistry (MMG-6). Synchrotron small-angle X-ray scattering experiments and cryo-transmission electron microscopy revealed that DDA:MMG-1/2/5/6 dispersions consisted of unilamellar and multilamellar vesicles (ULVs/MLVs), whereas a co-existence of both ULVs and hexosomes was observed...

  18. Efficient, regioselective ring-opening of activated aziridine-2-carboxylates with [18F]fluoride

    DEFF Research Database (Denmark)

    Schjøth-Eskesen, Christina; Hansen, Paul Robert; Kjær, Andreas

    2015-01-01

    Aziridines can undergo a range of ring-opening reactions with nucleophiles. The regio- and stereochemistry of the products depend on the substituents on the aziridine. Aziridine ring-opening reactions have rarely been used in radiosynthesis. Herein we report the ring opening of activated aziridine...

  19. N-methyl-D-aspartic acid receptor agonists

    DEFF Research Database (Denmark)

    Madsen, U; Frydenvang, Karla Andrea; Ebert, B

    1996-01-01

    )-5-methyl-4-isoxazolyl]N-tert-butyl-2- [N-[(S)-1-phenylethyl]benzamido]-acetamide (16 and 17, respectively) were synthesized and separated chromatographically. The absolute stereochemistry of 16 was confirmed by an X-ray analysis. Deprotection of these intermediates did, however, provide (R)- (8...

  20. Conserved molecular superlattices in a series of homologous synthetic mycobacterial cell-wall lipids forming interdigitated bilayers

    DEFF Research Database (Denmark)

    Martin-Bertelsen, Birte; Yaghmur, Anan; Franzyk, Henrik

    2016-01-01

    excess water conditions. The MMG analogues differed in the alkyl chain lengths and in the stereochemistry of the polar glycerol headgroup or of the lipid tails (native-like versus alternative compounds). All MMG analogues formed poorly hydrated lamellar phases at low temperatures and inverse hexagonal (H...

  1. Solid-phase synthesis of complex and pharmacologically interesting heterocycles

    DEFF Research Database (Denmark)

    Nielsen, Thomas Eiland

    2009-01-01

    with significant structural complexity and diversity. This review describes some of the most systematic solid-phase approaches that are potentially suited for pharmaceutical applications, that is, the methods described are useful for the synthesis of compound collections, and exhibit tunable stereochemistry...

  2. An easy and efficient method to produce {gamma}-amino alcohols by reduction of {beta}-enamino ketones

    Energy Technology Data Exchange (ETDEWEB)

    Harris, Maria Ines N.C.; Braga, Antonio C.H. [Universidade Estadual de Campinas, SP (Brazil). Inst. de Quimica]. E-mail: herrera@iqm.unicamp.br

    2004-12-01

    Reduction of {beta}-enamino ketones 2 with NaBH{sub 4} in glacial acetic acid gave {gamma}-amino alcohols 1 in 70% to 98% yield with diastereomeric excesses, preferentially the syn product, from 44% to 90%. The stereochemistry of these compounds was confirmed by analysis of their tetrahydro-1,3-oxazine derivatives 3. (author)

  3. Synthesis and biological evaluation of flexible and conformationally constrained LpxC inhibitors

    DEFF Research Database (Denmark)

    Löppenberg, Marius; Müller, Hannes; Pulina, Carla

    2013-01-01

    , conformationally constrained C-glycosidic as well as open chained hydroxamic acids with a defined stereochemistry were prepared. Diversity was introduced by performing C–C coupling reactions like the Sonogashira and Suzuki cross-coupling reactions. The biological evaluation of the synthesized compounds revealed...

  4. De novo asymmetric synthesis and biological analysis of the daumone pheromones in Caenorhabditis elegans and in the soybean cyst nematode Heterodera glycines

    Science.gov (United States)

    The de novo asymmetric total syntheses of daumone 1, daumone 2 and analogs are described. The key steps of our approach are the diastereoselective palladium catalyzed glycosylation reaction, the Noyori reduction of a acetylfuran and a propargyl ketone, which introduce the absolute stereochemistry of...

  5. Bifunctional Derivative of p,p'-Dichlorochalcone. Part II. Synthesis of a Novel Compound 2-[2-Carboxymethylthio-2-(4-chlorophenylethyl]-2-(4-chlorophenyl-4-thiazolidinone

    Directory of Open Access Journals (Sweden)

    Roger Dommisse

    1999-07-01

    Full Text Available The synthesis of 2-[2-carboxymethylthio-2-(4-chlorophenyl ethyl]-2-(4-chlorophenyl - 4-thiazolidinone (1 from p, p'- dichlorochalcone using thioglycollic acid in the presence of ammonium carbonate is described. Structural assignment and stereochemistry are discussed.

  6. Browse Title Index

    African Journals Online (AJOL)

    Items 101 - 130 of 130 ... Vol 6, No 2 (2016), Uses of systemic approach and chemist's triangle in teaching and learning chemistry: Systemic Chemistry Triangle [SCT] as a teaching & learning strategy, Abstract PDF. A.F.M. Fahmy. Vol 3, No 2 (2013), Using stereochemistry models in teaching organic compounds nomenclature: ...

  7. Quiralidade em moléculas e cristais Chirality at molecules and crystals

    Directory of Open Access Journals (Sweden)

    Ayres Guimarães Dias

    2009-01-01

    Full Text Available The present contribution describes some concepts of stereochemistry and chirality in molecules and crystals. This paper also reports on the development of a simple and fast experiment to prepare and recognize conglomerate and true racemate of tartaric acid produced by mechanic mixture of commercial enantiomers and recristalization. Optical activity and melting point of mixtures are also used in the analysis.

  8. Total synthesis based on the originally claimed structure of mucosin.

    Science.gov (United States)

    Gallantree-Smith, Harrison C; Antonsen, Simen G; Görbitz, Carl H; Hansen, Trond V; Nolsøe, Jens M J; Stenstrøm, Yngve H

    2016-09-28

    The first total synthesis aimed at the naturally occurring eicosanoid bicycle mucosin is reported. A practical route has been devised allowing the issues relating to the previous assignment of stereochemistry to be examined. X-ray crystallography was performed on a late stage intermediate to pinpoint the topological relationship displayed by the featured bicyclo[4.3.0]non-3-ene scaffold.

  9. Isolation, Structural Analyses and Biological Activity Assays against Chronic Lymphocytic Leukemia of Two Novel Cytochalasins - Sclerotionigrin A and B

    DEFF Research Database (Denmark)

    Petersen, Lene Maj; Bladt, Tanja Thorskov; Duerr, Claudia

    2014-01-01

    Two new cytochalasins, sclerotionigrin A (1) and B (2) were isolated together with the known proxiphomin (3) from the filamentous fungus Aspergillus sclerotioniger. The structures and relative stereochemistry of 1 and 2 were determined based on comparison with 3, and from extensive 1D and 2D NMR ...

  10. The syn/anti-Dichotomy in the Palladium-Catalyzed Addition of Nucleophiles to Alkenes

    Czech Academy of Sciences Publication Activity Database

    Kočovský, Pavel; Bäckvall, J. E.

    2015-01-01

    Roč. 21, č. 1 (2015), s. 36-56 ISSN 0947-6539 Institutional support: RVO:61388963 Keywords : alkenes * catalysis * nucleophilic addition * palladium * stereochemistry Subject RIV: CC - Organic Chemistry Impact factor: 5.771, year: 2015 http://onlinelibrary.wiley.com/doi/10.1002/chem.201404070/pdf

  11. foreword 1237..1237

    Indian Academy of Sciences (India)

    structure determination of organic, inorganic and organometallic compounds over the decades. It is accurate, swift and inexpensive, accounting for its great popularity. Initially, chemists were interested in determining the structure and stereochemistry of isolated molecules. Later, attention shifted to examining patterns of ...

  12. Lactate racemase is a nickel-dependent enzyme activated by a widespread maturation system

    NARCIS (Netherlands)

    Desguin, B.; Goffin, P.; Viaene, E.; Kleerebezem, M.; Martin-Diaconescu, V.; Maroney, M.J.; Declercq, J.P.; Soumillion, P.; Hols, P.

    2014-01-01

    Racemases catalyse the inversion of stereochemistry in biological molecules, giving the organism the ability to use both isomers. Among them, lactate racemase remains unexplored due to its intrinsic instability and lack of molecular characterization. Here we determine the genetic basis of lactate

  13. Unusual Conformational Aspects of Some Novel Chiral Non-Racemic Pyridinyl-2-phosphonates

    NARCIS (Netherlands)

    Dros, A.C.; Zijlstra, R.W.J.; Duijnen, P.Th. van; Spek, A.L.; Kooijman, H.; Kellogg, R.M.

    1998-01-01

    Reaction of pyridinyl-2-phosphonyl dichloride (6) with 1-phenyl-2,2-dimethylpropane-1,3-diol (9) leads to the two epimeric 2-oxo-2-(2-pyridinyl)-4-phenyl-5,5-dimethyl-1,3,2-dioxaphosphorinanes (10a,b). These can be separated and the stereochemistry assigned on the basis of 31P NMR spectroscopy. For

  14. 4-[(1RS,5RS,7SR)-5-Methyl-2,4-dioxo-3,6-diaza­bicyclo­[3.2.1]octan-7-yl]benzonitrile

    Science.gov (United States)

    Kudryavtsev, Konstantin V.; Churakov, Andrei V.

    2012-01-01

    In the title compound, C14H13N3O2, the relative stereochemistry of the three stereogenic C atoms has been determined. In the crystal, N—H⋯O hydrogen bonds link the mol­ecules into chains of inversion dimers running along the b axis. PMID:22719507

  15. 4-[(1RS,5RS,7SR)-5-Methyl-2,4-dioxo-3,6-diaza-bicyclo-[3.2.1]octan-7-yl]benzonitrile.

    Science.gov (United States)

    Kudryavtsev, Konstantin V; Churakov, Andrei V

    2012-06-01

    In the title compound, C(14)H(13)N(3)O(2), the relative stereochemistry of the three stereogenic C atoms has been determined. In the crystal, N-H⋯O hydrogen bonds link the mol-ecules into chains of inversion dimers running along the b axis.

  16. Synthesis of (-)-Δ9-trans-Tetrahydrocannabinol - Stereocontrol via Mo-catalyzed Asymmetric Allylic Alkylation Reaction

    Science.gov (United States)

    Trost, Barry M.; Dogra, Kalindi

    2008-01-01

    Δ9-THC is synthesized in enantiomericaly pure form, where all of the stereochemistry is derived from the molybdenum catalyzed asymmetric alkylation reaction of the extremely sterically congested bis-ortho substituted cinnamyl carbonate in high regio- and enantioselectivity. PMID:17266321

  17. Bioactive compounds from the alga Dictyopteris undulata | Koker ...

    African Journals Online (AJOL)

    X-ray crystallography of zonarol confirmed the gross structure of this compound and also gave the relative stereochemistry at C- 9 and C- 10 as trans. All of these compounds were found to exhibit antimicrobial activity. Some also showed activity against L1210 cells and antiviral activity. Keywords: Bioactivity-guided isolation; ...

  18. Stereoelectronic Substituent Effects

    DEFF Research Database (Denmark)

    Bols, Mikael; Jensen, Henrik Helligsø

    2006-01-01

    An investigation was carried Out on the influence of the stereo-chemistry of substituents, particularly hydroxyl groups, on their electronic effects in piperidines, carbohydrates (pyranosides), and related compounds. Polar groups, such as OH, OR, and F, were found in the 3 and 4 position to be mu...

  19. Synthesis of monoterpene piperidines from the iridoid glucoside antirrhinoside

    DEFF Research Database (Denmark)

    Franzyk, Henrik; Frederiksen, Signe Maria; Jensen, Søren Rosendal

    1997-01-01

    to be constructed via reaction of its ditosylate with an amine; the second strategy involved a double reductive amination as the key step to the piperidine ring, which proved successful. The stereochemistry of C-5 and C-9 in the obtained piperidine monoterpenes was the same as that reported for alfa...

  20. The Acquisition of Stereochemical Knowledge by Algerian Students Intending to Teach Physical Sciences

    Science.gov (United States)

    Boukhechem, Mohamed-Salah; Dumon, Alain; Zouikri, Mohamed

    2011-01-01

    In this work we evaluated the level of difficulty found in learning stereochemistry concepts, by students intending to teach physical sciences at the Ecole Normale Superieure (ENS) Kouba (Algeria). A paper and pencil questionnaire was administered to 170 students to evaluate: their familiarity with Newman representations; their ability of linking…

  1. Chemsearch Journal Volume 4 Number 1, June, 2013

    African Journals Online (AJOL)

    Magashi

    2013-06-01

    Jun 1, 2013 ... The glass transition temperatures were in the region 13.2–21.9 0C. Both 3a and 3b had no specific melting point. It is a known fact that, liquid crystalline polymers, including side- chain liquid crystalline polymers, are atactic in their stereochemistry and their structural disorder in such systems often induces.

  2. {sup 57}Fe quadrupole splitting and isomer shift in various oxyhemoglobins: study using Moessbauer spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Oshtrakh, M. I., E-mail: oshtrakh@mail.utnet.ru [Ural Federal University (The former Ural State Technical University-UPI), Faculty of Physical Techniques and Devices for Quality Control (Russian Federation); Berkovsky, A. L. [Hematological Scientific Center of the Russian Academy of Sciences (Russian Federation); Kumar, A.; Kundu, S., E-mail: sumankundu@south.du.ac.in [University of Delhi South Campus, Department of Biochemistry (India); Vinogradov, A. V.; Konstantinova, T. S. [Ural State Medical Academy, Faculty of Internal Diseases Propedeutics (Russian Federation); Semionkin, V. A. [Ural Federal University (The former Ural State Technical University-UPI), Faculty of Physical Techniques and Devices for Quality Control (Russian Federation)

    2010-04-15

    A comparative study of normal human, rabbit and pig oxyhemoglobins and oxyhemoglobin from patients with chronic myeloleukemia and multiple myeloma using Moessbauer spectroscopy with a high velocity resolution demonstrated small variations of the {sup 57}Fe quadrupole splitting and isomer shift. These variations may be a result of small structural differences in the heme iron stereochemistry of various hemoglobins.

  3. Synthesis of sn-1 functionalized phospholipids as substrates for secretory phospholipase A2

    DEFF Research Database (Denmark)

    Linderoth, Lars; Peters, Günther H.J.; Jørgensen, K.

    2007-01-01

    -substituents attached to the sn-1 position of the glycerol backbone. The synthesis of phospholipids 1 and 2 is based upon the construction of a key aldehyde intermediate 3 which locks the stereochemistry in the sn-2 position of the final phospholipids. The aldehyde functionality serves as the site for insertion...

  4. New Fellows and Honorary Fellow

    Indian Academy of Sciences (India)

    Fellow Profile. Elected: 1976 Section: Chemistry. Nasipuri, Prof. Dhanonjoy Ph.D. and D.Sc. (Calcutta), FNA. Date of birth: 1 April 1925. Date of death: 28 December 2009. Specialization: Synthetic & Mechanistic Organic Chemistry and Stereochemistry Last known address: Suite No. 46, Surendranath Housing Society, 238, ...

  5. Resonance – Journal of Science Education | Indian Academy of ...

    Indian Academy of Sciences (India)

    https://www.ias.ac.in/article/fulltext/reso/012/05/0021-0030. Keywords. van 't Hoff – biography; chemistry in space; stereochemistry; chemical dynamics; Stassfurt salt deposits; osmotic pressure–theory; Le Bel. Author Affiliations. G Nagendrappa1. # 13, Basappa Layout, Gavipuram Extension, Bangalore 560 019, India.

  6. Fulltext PDF

    Indian Academy of Sciences (India)

    IAS Admin

    Classroom. Solution of Cubic Equations: An Alternative Method. T R Mukundan. Interconversion of Fischer and Zig-Zag Projections. Learning Stereochemistry with the Help of Hands. Syed R Hussaini. Motion of a Tiny Tool Thrown by an Astronaut towards another Astronaut inside a Spinning Space. Vehicle in a State of ...

  7. Surface enhanced Raman optical activity (SEROA)

    DEFF Research Database (Denmark)

    Abdali, Salim; Blanch, E.W.

    2008-01-01

    Raman optical activity (ROA) directly monitors the stereochemistry of chiral molecules and is now an incisive probe of biomolecular structure. ROA spectra contain a wealth of information on tertiary folding, secondary structure and even the orientation of individual residues in proteins and nucleic...

  8. Focus Area Science Technology Summer Fellowship (FAST-SF)

    Indian Academy of Sciences (India)

    Narayanan, Dr Changalur Raman D.Phil. (Allahabad). Date of birth: 17 December 1916. Date of death: 15 January 1993. Specialization: NMR Spectroscopy, Chemistry of Natural Products,. Stereochemistry and Conformation Address: D-43, No.3, Aundh Road, Khadki, Pune 411 003. YouTube; Twitter; Facebook; Blog ...

  9. Separation and structure elucidation of a new homoflavanol derivative from Pteridium aquilinum (L.) Kuhn.

    Science.gov (United States)

    Chen, Nai-Dong; Chen, Nai-Fu; Chen, Cun-Wu; Zhang, Li

    2013-01-01

    A novel homoflavanol derivative (1) with an unprecedented skeleton, as well as two known flavonoids kaempferol (2) and quercetin (3), was isolated from the plant Pteridium aquilinum (L.) Kuhn, and the structure and relative stereochemistry of the new compound (1) were elucidated on the basis of spectroscopic data.

  10. Chatterjee, Prof. Asima

    Indian Academy of Sciences (India)

    ... D.Sc. (h.c.), FNA. Date of birth: 23 September 1917. Date of death: 22 November 2006. Specialization: Natural Products & Drug Development, Reaction Mechanism, Stereochemistry and Synthetic Studies Last known address: Flat 3, Block 1, 108 Manictala Main Road, Kolkata 700 054. YouTube · Twitter · Facebook · Blog ...

  11. Stereochemical metabolism of styrene in volunteers

    NARCIS (Netherlands)

    Wenker, M. A.; Kezić, S.; Monster, A. C.; de Wolff, F. A.

    2001-01-01

    To study the stereochemistry of styrene metabolism in volunteers, and its interindividual variability. Twenty healthy male volunteers (aged 18-37 years) were exposed to 360 mg/m3 styrene for 1 h while they performed 50 W physical exercise. Venous blood was drawn during and for up to 2 h after

  12. Resonance – Journal of Science Education | Indian Academy of ...

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 15; Issue 4. Interconversion of Fischer and Zig-Zag Projections - Learning Stereochemistry with the Help of Hands. Syed R Hussaini. Classroom Volume 15 Issue 4 April 2010 pp 351-354 ...

  13. Resonance – Journal of Science Education | Indian Academy of ...

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education. Syed R Hussaini. Articles written in Resonance – Journal of Science Education. Volume 15 Issue 4 April 2010 pp 351-354 Classroom. Interconversion of Fischer and Zig-Zag Projections - Learning Stereochemistry with the Help of Hands · Syed R Hussaini.

  14. Visualizing lone pairs in compounds containing heavier congeners ...

    Indian Academy of Sciences (India)

    In this mini-review, I discuss some recent work on the stereochemistry and bonding of lone pairs of electrons in divalent compounds of the heavier carbon group elements (SnII, PbII) and in trivalent compounds of the heavier nitrogen group elements (BiIII). Recently developed methods that permit the real-space visualization ...

  15. Preparation and Reactions of the 1,1-Dithiolato Complexes of Ni(II). An Undergraduate Coordination Chemistry Experiment.

    Science.gov (United States)

    Ballester, L.; Perpinan, M. F.

    1988-01-01

    Described is an undergraduate coordination chemistry experiment that enables students to relate concepts developed in class about the stereochemistry and coordination numbers to the interpretation of the electronic and infrared spectra and their magnetic behavior. Indicates that thermal decomposition and x-ray diffraction studies can also be…

  16. synthesis, characterization and antibacterial studies of some metal ...

    African Journals Online (AJOL)

    Preferred Customer

    region due to L → L* transitions, only. As expected, the electronic spectra of these complexes do not furnish any useful information on their stereochemistry. However, on the basis of analytical, conductance and infrared spectral data, a tetrahedral geometry is proposed for the. Zn(II), Cd(II) and Hg(II) complexes. ESR and 1H ...

  17. Molecular cloning of isoflavone reductase from pea (Pisum sativum L.): evidence for a 3R-isoflavanone intermediate in (+)-pisatin biosynthesis.

    Science.gov (United States)

    Paiva, N L; Sun, Y; Dixon, R A; VanEtten, H D; Hrazdina, G

    1994-08-01

    Isoflavone reductase (IFR) reduces achiral isoflavones to chiral isoflavanones during the biosynthesis of chiral pterocarpan phytoalexins. A cDNA clone for IFR from pea (Pisum sativum) was isolated using the polymerase chain reaction and expressed in Escherichia coli. Analysis of circular dichroism (CD) spectra of the reduction product sophorol obtained using the recombinant enzyme indicated that the isoflavanone possessed the 3R stereochemistry, in contrast to previous reports indicating a 3S-isoflavanone as the product of the pea IFR. Analysis of CD spectra of sophorol produced using enzyme extracts of CuCl2-treated pea seedlings confirmed the 3R stereochemistry. Thus, the stereochemistry of the isoflavanone intermediate in (+)-pisatin biosynthesis in pea is the same as that in (-)-medicarpin biosynthesis in alfalfa, although the final pterocarpans have the opposite stereochemistry. At the amino acid level the pea IFR cDNA was 91.8 and 85.2% identical to the IFRs from alfalfa and chickpea, respectively. IFR appears to be encoded by a single gene in pea. Its transcripts are highly induced in CuCl2-treated seedlings, consistent with the appearance of IFR enzyme activity and pisatin accumulation.

  18. Interconversion of Fischer and Zig-Zag Projections

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 15; Issue 4. Interconversion of Fischer and Zig-Zag Projections - Learning Stereochemistry with the Help of Hands. Syed R Hussaini. Classroom Volume 15 Issue 4 April 2010 pp 351-354 ...

  19. Organic Lecture Demonstrations.

    Science.gov (United States)

    Silversmith, Ernest F.

    1988-01-01

    Provides a listing of 35 demonstrations designed to generate interest in organic chemistry and help put points across. Topics include opening lecture; molecular structure and properties; halogenation; nucleophilic substitution, alkenes and dienes, stereochemistry, spectroscopy, alcohols and phenols, aldehydes and ketones; carboxylic acids, amines,…

  20. Prosesterone

    Indian Academy of Sciences (India)

    55 2001 Chemistry Nobel Prize. Conlinuing Importance of Stereochemistry. Mariappan Periasamy. 66 from Shannon to Quantum Information Science. Ideas and Techniques. Rajiah Simon. BOOK REVIEWS. 90 Electrostatics of Atoms and Molecules. G Narahari Sastry. Back Cover. The Ca.Jer picture Illustrates how chiraIHy.

  1. Visualizing Molecular Chirality in the Organic Chemistry Laboratory Using Cholesteric Liquid Crystals

    Science.gov (United States)

    Popova, Maia; Bretz, Stacey Lowery; Hartley, C. Scott

    2016-01-01

    Although stereochemistry is an important topic in second-year undergraduate organic chemistry, there are limited options for laboratory activities that allow direct visualization of macroscopic chiral phenomena. A novel, guided-inquiry experiment was developed that allows students to explore chirality in the context of cholesteric liquid crystals.…

  2. Escherichia coli Phosphoenolpyruvate-Dependent Phosphotransferase System : Stereospecificity of Proton Transfer in the Phosphorylation of Enzyme I from (Z)-Phosphoenolbutyrate

    NARCIS (Netherlands)

    Hoving, H; Nowak, Thomas; Robillard, George T.

    1983-01-01

    The stereochemistry of the proton transfer in the reaction of phosphoenolbutyrate with enzyme I has been established. During the reaction of the pure Z isomer of this analogue of phosphoenolpyruvate with enzyme I, to yield phosphoenzyme I and 2-oxobutyrate, the substrate is protonated at C-3 from

  3. Reactions of charged and neutral recoil particles following nuclear transformations. Progress report No. 11, September 1976--August 1977

    International Nuclear Information System (INIS)

    Ache, H.J.

    1977-09-01

    The status of the following programs is reported: study of the stereochemistry of halogen atom reactions produced via (n,γ) nuclear reactions with diastereomeric molecules in the condensed phase; decay-induced labelling of compounds of biochemical interest; reactions of energetic tritium species in graphite; and positron lifetime measurements in γ-irradiated organic solids

  4. Learning about Regiochemistry from a Hydrogen-Atom Abstraction Reaction in Water

    Science.gov (United States)

    Sears-Dundes, Christopher; Huon, Yoeup; Hotz, Richard P.; Pinhas, Allan R.

    2011-01-01

    An experiment has been developed in which the hydrogen-atom abstraction and the coupling of propionitrile, using Fenton's reagent, are investigated. Students learn about the regiochemistry of radical formation, the stereochemistry of product formation, and the interpretation of GC-MS data, in a safe reaction that can be easily completed in one…

  5. Method for the Drawing of Newman Projections: Understanding ...

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 17; Issue 3. Method for the Drawing of Newman Projections: Understanding Newman Projections with the Help of Hands ... Keywords. Organic chemistry; stereochemistry; conformational analysis; hands-on learning/manipulatives; Newman projections.

  6. New Fellows and Honorary Fellow

    Indian Academy of Sciences (India)

    Home; Fellowship. Fellow Profile. Elected: 1934 Section: Chemistry. Singh, Bawa Kartar FNA 1940-43; Vice President 1934-40. Date of birth: 17 April 1886. Date of death: 15 June 1960. Specialization: Stereochemistry. YouTube; Twitter; Facebook; Blog ...

  7. Structure elucidation and stereoselective total synthesis of pavettamine, the causal agent of gousiekte

    CSIR Research Space (South Africa)

    Bode, ML

    2010-03-01

    Full Text Available data of the acetonide derivative. The absolute stereochemistry was established by total synthesis from (2S)-malic acid using chiral sulfoxide methodology as (2S,4R,8R,10S)-1,11-diamino-6-aza-undecane-2,4,8,10-tetraol....

  8. Journal of Chemical Sciences | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    In this mini-review, I discuss some recent work on the stereochemistry and bonding of lone pairs of electrons in divalent compounds of the heavier carbon group elements (SnII, PbII) and in trivalent compounds of the heavier nitrogen group elements (BiIII). Recently developed methods that permit the real-space visualization ...

  9. Patrika-September-14-New - 30-09-14.pmd

    Indian Academy of Sciences (India)

    latha

    2014-09-01

    Sep 1, 2014 ... explained why Raman spectroscopy was a powerful tool in unraveling the physics of solids, and in .... Controlling stereochemistry at the quaternary center through olefin functionalization and ..... provided a very useful tool for producing and probing atomic species with higher efficiency and better precision ...

  10. New Fellows and Honorary Fellow

    Indian Academy of Sciences (India)

    Pradhan, Prof. Suresh Krishnarao Ph.D. (London), FNA. Date of birth: 6 September 1929. Date of death: 23 May 2002. Specialization: Organic Chemistry, Stereochemistry, Reaction Mechanism, Synthesis and Natural Products Last known address: Flat A-32, Building No.11,, Jankalyan Nagar, Malad (West), Mumbai 400 095.

  11. Synthetic Strategies for Converting Carbohydrates into Carbocycles by the Use of Olefin Metathesis

    DEFF Research Database (Denmark)

    Madsen, Robert

    2007-01-01

    This microreview covers recent advances in the use of ring-closing metathesis for the synthesis of carbocycles from carbohydrates. Various strategies for the synthesis of a,w-dienes from carbohydrates are presented, which give rise to a large variety of dienes with different stereochemistry, prot...

  12. Bulletin of the Chemical Society of Ethiopia - Vol 25, No 3 (2011)

    African Journals Online (AJOL)

    Pollution effect of food and beverages effluents on the Alaro river in Ibadan City, Nigeria · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT ... Synthesis, stereochemistry and antimicrobial activity of copper(II) and nickel(II) complexes of 4-phenylsemicarbazones · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT

  13. Jacobus Henricus van't Hoff-A Short Biographical Sketch

    Indian Academy of Sciences (India)

    http://www.ias.ac.in/article/fulltext/reso/012/05/0021-0030. Keywords. van 't Hoff – biography; chemistry in space; stereochemistry; chemical dynamics; Stassfurt salt deposits; osmotic pressure–theory; Le Bel. Author Affiliations. G Nagendrappa1. # 13, Basappa Layout, Gavipuram Extension, Bangalore 560 019, India.

  14. Formation and Structural Analysis of Novel Dibornyl Ethers | Kaye ...

    African Journals Online (AJOL)

    One- and two-dimensional NMR spectroscopy has been used to establish the regio- and stereochemistry of novel dibornyl ethers, obtained by acid-catalysed condensation of camphor-derived a-hydroxybornanones. South African Journal of Chemistry Vol.55 2002: 111-118 ...

  15. Preparation and structural characterization of the intermediate complex [Er{H2C8H16N4(CH2COO)3(CH2(Ph)PO2)}(H2O)2]2Cl2.xH2O in the reaction of Er3+ and the dota-type ligand. An interesting example of two stereoforms of a lanthanide complex

    Czech Academy of Sciences Publication Activity Database

    Vojtíšek, P.; Rohovec, Jan

    2006-01-01

    Roč. 71, č. 2 (2006), s. 264-278 ISSN 0010-0765 Institutional research plan: CEZ:AV0Z30130516 Keywords : x-ray diffraction * lanthanoids * lanthanide complexes * erbium * stereochemistry Subject RIV: DD - Geochemistry Impact factor: 0.881, year: 2006

  16. New approaches towards the synthesis of the side-chain of mycolactones A and B

    NARCIS (Netherlands)

    van Summeren, RP; Feringa, BL; Minnaard, AJ; Summeren, Ruben P. van

    2005-01-01

    New approaches towards the synthesis of the C1' - C16' side-chain of mycolactones A and B from Mycobacterium ulcerans are reported. Chiral building block 4 ( Fig. 2) with the correct stereochemistry was obtained starting from naturally occurring monosaccharides, i.e. D-glucose or L-rhamnose. The

  17. foreword 1237..1237

    Indian Academy of Sciences (India)

    the decades. It is accurate, swift and inexpensive, accounting for its great popularity. Initially, chemists were interested in determining the structure and stereochemistry of isolated molecules. Later, attention shifted to examining patterns of molecules, held together by intermolecular interactions, the most important of which is.

  18. Isolation of Stilbenoids and Lignans from Dendrobium hongdie

    African Journals Online (AJOL)

    (Scrophulariaceae): isolation and stereochemistry of liriodendrin, a symmetrically substituted furofuranoid lignan diglucoside. J Org Chem, 1980; 45: 1327-. 1329. 14. Hernandez-Romero Y, Rojas JI, Castillo R, Rojas A,. Mata R. Spasmolytic effects, mode of action, and structure-activity relationships of stilbenoids from.

  19. r-es-onance--i-ju-iy-1-99-7---------------~------------------------------8-7

    Indian Academy of Sciences (India)

    In the February 1997 issue of Resonance, two multi-step reaction sequences involving some pericyclic reactions and a few other important reactions were shown (Schemes 1 and 2). We had posed questions concerning the mechanistic details of the steps marked A-I and also on the stereochemistry of the products X and Y.

  20. A Conformational Model for MTPA Esters of Chiral N-(2-Hydroxyalkylacrylamides

    Directory of Open Access Journals (Sweden)

    Eduardo M. Rustoy

    2014-01-01

    Full Text Available The absolute stereochemistry of novel chiral N-(2-hydroxylalkylacrylamides prepared by a lipase-catalyzed resolution was successfully determined by 1H NMR of their MTPA esters. The method was validated for this particular case by computational experiments.

  1. Furanoid lignans from Larrea tridentata.

    Science.gov (United States)

    Konno, C; Lu, Z Z; Xue, H Z; Erdelmeier, C A; Meksuriyen, D; Che, C T; Cordell, G A; Soejarto, D D; Waller, D P; Fong, H H

    1990-01-01

    From the leaves and stems of Larrea tridentata six new furanoid lignans, compounds 1-6, have been isolated and their structures determined through interpretation of physical and spectroscopic properties. The use of 1D and 2D nOe experiments was of particular importance in assigning the stereochemistry.

  2. Interconversion of Fischer and Zig-Zag Projections Learning ...

    Indian Academy of Sciences (India)

    IAS Admin

    tional analysis, hands-on learn- ing, Fischer projections, zig-zag projection, C–C bond rotations. Interconversion of Fischer and Zig-Zag Projections. Learning Stereochemistry with the Help of Hands. Visualization of molecules in three dimensions is an important aspect of organic chemistry. The use of hands has been ...

  3. Cu(II), Zn(II)

    African Journals Online (AJOL)

    stereochemistry has been suggested to Zn(II), Cd(II) and Hg(II) complexes. The thermal analysis data provided the kinetic parameters as order of decomposition reaction, activation energy and frequency factor. All theoretical calculations of the ligand and the Cu(II) and Zn(II) complexes were made using Gaussian 03 rev.

  4. Browse Title Index

    African Journals Online (AJOL)

    Items 51 - 100 of 391 ... Vol 2, No 3 (1999): Special Edition, Comparative clinical studies of three plant leaves as sources of pritein using albino rats, Abstract. PA Wallace, EK ... Vol 2, No 1 (2000):, Determination of the stereochemistry of 4-chromenecarbaldehydes using Nuclear Overhauser Enhancements (NOE), Abstract.

  5. New phenolic esters from the resinous exudate of Haplopappus taeda.

    Science.gov (United States)

    Faini, Francesca; Labbé, Cecilia; Torres, René; Rodilla, Jesús M; Silva, Lucía; Delle Monache, Franco

    2007-12-01

    Two new phenolic esters 9-trans-p-coumaroyloxy-alpha-terpineol (1) and 7-trans-p-coumaroyloxy-taedol (2), both endowed with free radical scavenger activity and cleroda-3,13 (E)-dien-15,18-diol (3) for which a cis stereochemistry at the decalin junction was found, were isolated from the resinous exudate from Haplopappus taeda upper parts.

  6. Titanium-catalysed dehydrocoupling of chiral carbosilanes

    Indian Academy of Sciences (India)

    Administrator

    Transition metal-catalysed dehydrocoupling of organosilanes containing primary, secondary and tertiary SiH groups has been developed as an effective route to short chain oligosilanes 1. Studies have been extended using NMR spectroscopy 2 to understand the underlying stereochemistry of these oligomers.

  7. Giulio Natta and the Origins of Stereoregular Polymers

    Indian Academy of Sciences (India)

    only liquid products, dimerisate.” It was on account of this obser- vation that when Ziegler drafted the .... Natta's creative skills are evident in the way he used both concepts and experiments to deduce the structure of polypropylene. Thus was born one of the most fascinating fields of polymer science – the stereochemistry.

  8. Page 1 O-methylene proton anisochrony in ethyl esters 29 CO2CHA ...

    Indian Academy of Sciences (India)

    The elucidation of the structures and stereochemistry of diterpene acids, typically represented by abietic and agathic acids, (26 and 27; see references under Ruzicka), can be said to have played a significant role in the formative period of ideas relating to biosynthesis not only of these substances but also of a host of other ...

  9. Efforts toward rapid construction of the cortistatin A carbocyclic core via enyne-ene metathesis

    KAUST Repository

    Baumgartner, Corinne

    2010-01-01

    Our efforts toward the construction of the carbocylic core of cortistatin A via an enyne-ene metathesis are disclosed. Interestingly, an attempted S N2 inversion of a secondary mesylate in our five-membered D-ring piece gave a product with retention of stereochemistry. © 2010 The Royal Society of Chemistry.

  10. Greening Wittig Reactions: Solvent-Free Synthesis of Ethyl Trans-Cinnamate and Trans-3-(9-Anthryl)-2-Propenoic Acid Ethyl Ester

    Science.gov (United States)

    Nguyen, Kim Chi; Weizman, Haim

    2007-01-01

    Green procedure is used to create solvent-free alternatives for conventional Wittig reactions, which are widely used to install a double bond in a highly selective manner. Solvent-free reactions reduce health and environmental risks and provide a basis for an inquiry-based discussion of the stereochemistry of the Wittig reaction and the factors…

  11. Synthesis of the ABCD and ABCDE ring systems of azaspiracid-1†‡

    Science.gov (United States)

    Zhou, Xiao-Ti; Carter, Rich G.

    2008-01-01

    The efficient syntheses of the ABCD ring system of the originally proposed structure of azaspiracid-1 and the ABCDE ring system of the revised structure of azaspiracid-1 containing the correct stereochemistry at C6, C10, C13, C14, C16, C17, C19, C21, C22, C24 and C25 have been achieved. PMID:15467841

  12. Synthesis of the ABCD and ABCDE ring systems of azaspiracid-1.

    Science.gov (United States)

    Zhou, Xiao-Ti; Carter, Rich G

    2004-10-07

    The efficient syntheses of the ABCD ring system of the originally proposed structure of azaspiracid-1 and the ABCDE ring system of the revised structure of azaspiracid-1 containing the correct stereochemistry at C(6), C(10), C(13), C(14), C(16), C(17), C(19), C(21), C(22), C(24) and C(25) have been achieved.

  13. R-ES-O-N-A-N-C-E--I-JU-I-Y-1-99-7---------------~----------------------------

    Indian Academy of Sciences (India)

    In the February 1997 issue of Resonance, two multi-step reaction sequences involving some pericyclic reactions and a few other important reactions were shown (Schemes 1 and 2). We had posed questions concerning the mechanistic details of the steps marked A-I and also on the stereochemistry of the products X and Y.

  14. Efficient asymmetric Baeyer–Villiger oxidation of prochiral ...

    Indian Academy of Sciences (India)

    The stereochemistry of the B–V reaction is dictated by two factors: face selectivity in oxidant addi- tion and enantiotopos selectivity in migration. How- ever, as Criegee adduct formation is a reversible step and its migration to lactone is an irreversible and rate- determining one, topos-selection in the migration step is.

  15. Neglschisandrins A-B: Two New Dibenzocyclooctene Lignans from Schisandra neglecta

    Directory of Open Access Journals (Sweden)

    Chengzhi Huang

    2008-03-01

    Full Text Available Two new dibenzocyclooctene lignans, neglschisandrins A-B (1-2, were isolatedfrom the stems of Schisandra neglecta. Their structures and stereochemistries wereelucidated by spectroscopic methods, including 1D- and 2D-NMR and HR-ESI-MStechniques.

  16. Chatterjee, Prof. Asima

    Indian Academy of Sciences (India)

    Date of birth: 23 September 1917. Date of death: 22 November 2006. Specialization: Natural Products & Drug Development, Reaction Mechanism, Stereochemistry and Synthetic Studies Last known address: Flat 3, Block 1, 108 Manictala Main Road, Kolkata 700 054. YouTube; Twitter; Facebook; Blog ...

  17. Barnumi tsirkus ja kultuurkapitali vene preemia / P. I. Filimonov

    Index Scriptorium Estoniae

    Filimonov, P. I., pseud., 1975-

    2009-01-01

    Artikkel vaidlustab Eesti Kultuurkapitali venekeelse autori kirjandusauhinna žürii selleaastase valiku: Tatjana Kašneva (Zolotova) "Земная коротка наша память..." (kirj. Aleksandra) ja Josef Katsi "Старый Таллинн : четыре времени города" (КПД). T. Kašneva memuaaride esitrükk ilmus 1993. a., J. Katsi raamat aga ei mahu esseežanri alla

  18. Psoralen-deoxyribonucleic acid photoreaction. Characterization of the monoaddition products from 8-methoxypsoralen and 4,5',8-trimethylpsoralen

    International Nuclear Information System (INIS)

    Kanne, D.; Straub, K.; Rapoport, H.; Hearst, J.E.

    1982-01-01

    The isolation and structural characterization are described of the major monoaddition products formed in the photoreaction of two naturally occurring psoralens, 8-methoxypsoralen and 4,5',8-trimethylpsoralen, with high molecular weight, double-stranded DNA. Hydrolysis of the psoralen-modified DNA and subsequent chromatography resulted in the isolation of four modified nucleosides from each psoralen. Structural characterization was accomplished by mass spectrometry and 1 H NMR analysis. The major products, accounting for 44 to 52% of the covalently bound psoralen, are two diastereomeric thymidine adducts formed by cycloaddition between the 5,6 double bond of the pyrimidine and the 4',5' (furan) double bond of the psoralen. All of the isolated adducts have cis-syn stereochemistry. The stereochemistry and product distribution of the adducts are determined in part by the constraints imposed by the DNA helix on the geometry of the noncovalent intercalation complex formed by psoralen and DNA prior to irradiation

  19. 7-epizingiberene, a novel bisabolane sesquiterpene from wild tomato leaves

    International Nuclear Information System (INIS)

    Breeden, D.C.; Coates, R.M.

    1994-01-01

    A C 15 hydrocarbon isolated from the leaves of 2 wild tomato species, Lycopersicon hirsutum f glabratum PI 199381 and Lycopersicon hirsutum PI 365906, has been identified as 7 - epizingiberene (2), a diastereomer of zingiberene (1) that occurs in essential oil of ginger. The structure assignment for 2 is based upon its 1 H NMR, 13 C NMR, IR, UV, and mass spectral characteristics. All spectral data for zingiberene and epizingiberene are identical except for 9 of 15 13C NMR resonances, which establish the diastereomeric relationship of these sesquiterpenes. The 4S, 7R stereochemistry of epizingiberene was proven by dehydrogenation to (7R)- ar - curcumene (4). The opposite 7R and 7S stereochemistry of the zingiberenes implicates the probable occurrence of opposite sidechain rotations of a common (S)-bisabolyl carbocation intermediate (1OA) to allow stereoelectronically favorable hydride shifts in their respective biosyntheses from (E, E)-farnesyl diphosphate. (author)

  20. Glutamate receptor agonists

    DEFF Research Database (Denmark)

    Vogensen, Stine Byskov; Greenwood, Jeremy R; Bunch, Lennart

    2011-01-01

    The neurotransmitter (S)-glutamate [(S)-Glu] is responsible for most of the excitatory neurotransmission in the central nervous system. The effect of (S)-Glu is mediated by both ionotropic and metabotropic receptors. Glutamate receptor agonists are generally a-amino acids with one or more...... stereogenic centers due to strict requirements in the agonist binding pocket of the activated state of the receptor. By contrast, there are many examples of achiral competitive antagonists. The present review addresses how stereochemistry affects the activity of glutamate receptor ligands. The review focuses...... mainly on agonists and discusses stereochemical and conformational considerations as well as biostructural knowledge of the agonist binding pockets, which is useful in the design of glutamate receptor agonists. Examples are chosen to demonstrate how stereochemistry not only determines how the agonist...

  1. E-Z isomerization in Suzuki cross-couplings of haloenones: ligand effects and evidence for a separate catalytic cycle.

    Science.gov (United States)

    Chehal, Navneet K; Budzelaar, Peter H M; Hultin, Philip G

    2018-02-14

    Suzuki cross-coupling of haloalkenes is generally assumed to occur with retention of the alkene stereochemistry. While studying Suzuki cross-couplings on E-1,2-dichlorovinyl phenyl ketone, we were surprised to observe extensive isomerization. More surprisingly, the ligand employed strongly influenced the degree of isomerization: DPEphos and Xantphos led to 96% isomerized cross-coupled product whereas reactions in the absence of a phosphine ligand, or reactions employing t-BuXantphos, gave 94% retention of stereochemistry. While E-Z isomerization in Pd-catalyzed vinylic couplings has previously been attributed to events within the cross-coupling catalytic cycle, we present experimental and computational evidence for a separate Pd-catalyzed isomerization process in these reactions.

  2. Catalytic Stereoinversion of L-Alanine to Deuterated D-Alanine.

    Science.gov (United States)

    Moozeh, Kimia; So, Soon Mog; Chin, Jik

    2015-08-03

    A combination of an achiral pyridoxal analogue and a chiral base has been developed for catalytic deuteration of L-alanine with inversion of stereochemistry to give deuterated D-alanine under mild conditions (neutral pD and 25 °C) without the use of any protecting groups. This system can also be used for catalytic deuteration of D-alanine with retention of stereochemistry to give deuterated D-alanine. Thus a racemic mixture of alanine can be catalytically deuterated to give an enantiomeric excess of deuterated D-alanine. While catalytic deracemization of alanine is forbidden by the second law of thermodynamics, this system can be used for catalytic deracemization of alanine with deuteration. Such green and biomimetic approach to catalytic stereocontrol provides insights into efficient amino acid transformations. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. ATP Depletion Assay Led to the Isolation of New 36-Membered Polyol Macrolides Deplelides A and B from Streptomyces sp. MM581-NF15.

    Science.gov (United States)

    Takeuchi, Toshifumi; Hatano, Masaki; Umekita, Maya; Hayashi, Chigusa; Wada, Shun-Ichi; Nagayoshi, Miho; Sawa, Ryuichi; Kubota, Yumiko; Kawada, Manabu; Igarashi, Masayuki; Shibasaki, Masakatsu

    2017-08-18

    New 36-membered polyol macrolides deplelides A and B were isolated from the culture of Streptomyces MM581-NF15 by bioassay-guided fractionation using an ATP depletion assay. The planar structures of these novel compounds were identified by interpretation of the spectroscopic data (1D/2D NMR, MS, and IR). The relative stereochemistry was partially established using the universal NMR database method and J-based configuration analysis using 1 H- 1 H and long-range 1 H- 13 C coupling constants determined by 1 H NMR or E.COSY and J-resolved HMBC analysis or another HMBC-based technique, respectively. The absolute stereochemistry was partially determined by a modified Mosher's method. These new compounds displayed highly potent ATP depletion activities (IC 50 33 nM) and antiproliferative activities against several tumor cell lines, such as HGC-27 (IC 50 47 nM).

  4. Diastereoselective synthesis of substituted 2-amino-1,3-propanediols from Morita-Baylis-Hillman adducts

    Energy Technology Data Exchange (ETDEWEB)

    Paioti, Paulo H.S.; Rezende, Patricia; Coelho, Fernando [Laboratorio de Sintese de Produtos Naturais e Farmacos, Instituto de Quimica, Universidade Estadual de Campinas (UNICAMP), SP (Brazil)

    2012-07-01

    We report herein a new diastereoselective approach to substituted 2-amino-1,3-propanediols with anti relative stereochemistry from Morita-Baylis-Hillman (MBH) adducts. These structural moieties have been used as intermediates for the synthesis of several compounds with relevant pharmacological and commercial interest. In this strategy, substituted anti 2-amino-1,3-propanediols were readily prepared via ozonolysis of allylic diols obtained from MBH adducts, followed by a diastereoselective reductive amination of the substituted 2-oxo-1,3-propanediols. To demonstrate the synthetic utility of these aminodiols, they were transformed into substituted oxazolidine-2-ones, which were also used in the indirect determination of the relative stereochemistry of the aminodiols. (author)

  5. Structural studies of naturally occurring toxicogenic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Springer, J. P.

    1977-10-01

    The paralytic shellfish poison (PSP), saxitoxin, is a neurotoxin isolated from Alaska butter clams (Saxidomus giganteus), mussels (Mytilus californianus) and axenic cultures of the dinoflagellate Gonyaulax catenella. The structure of saxitoxin has been determined through the use of single crystal X-ray diffraction. It possesses a unique tricyclic arrangement of atoms containing two guanidinium moieties and also a hydrated ketone. The relative stereochemistry is presented as well as the absolute configuration. The chemical constitution of a tremorgenic metabolite, paxilline, isolated from extracts of the fungus Penicillium paxilli Bainier has been determined. Paxilline represents a previously unreported class of natural compounds formed by the combination of tryptophan and mevalonate subunits. The complete stereostructure of two other fungal metabolites, paspaline and paspalicine, closely related to paxilline but isolated from Claviceps paspali Stammes have also been determined and are presented. The stereochemistries of paxilline, paspaline and paspalicine are identical at corresponding chiral centers.

  6. Stereocontrolled Syntheses of Seven-Membered Carbocycles by Tandem Allene Aziridination/[4+3] Reaction.

    Science.gov (United States)

    Gerstner, Nels C; Adams, Christopher S; Tretbar, Maik; Schomaker, Jennifer M

    2016-10-10

    A tandem allene aziridination/[4+3]/reduction sequence converts simple homoallenic sulfamates into densely functionalized aminated cycloheptenes, where the relative stereochemistry at five contiguous asymmetric centers can be controlled through the choice of the solvent and the reductant. The products resulting from this chemistry can be readily transformed into complex molecular scaffolds which contain up to seven contiguous stereocenters. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Antimalarial sesquiterpene lactones from oncosiphon piluliferum

    CSIR Research Space (South Africa)

    Pillay, P

    2006-02-01

    Full Text Available to the marked instability of the germacranolide (1), the structural elucidation and bioassaying was conducted on the acetylated derivative (1a). Mosher’s method was applied to determine the absolute stereochemistry of the major compound (5), identifying..., Botanic Gardens Road, Durban, 4001 3Department of Pharmacology, University of Cape Town, Observatory, 7925 4Department of Chemistry, University of Pretoria, Pretoria, 0002 1Email: ppillay@csir.co.za K-4570 [ww w .kashangroup.com ] Figure 1: X...

  8. The Chemistry of Perfumes Based on Labdane Diterpenoids

    Science.gov (United States)

    Vlad, Pavel F.

    1982-07-01

    The advances in the synthesis of C14-C19 perfumes derived from bicyclic labdane diterpenoids and their enantiomers as well as data concerning the sources of the starting materials are presented. The dependence of the odour of the above compounds on their structure and stereochemistry and the questions arising in the manufacture of some of them and their practical applications are considered. The bibliography includes 242 references

  9. 2-[(1RS,3RS,3aRS,6aSR-5-Benzyl-4,6-dioxo-3-phenyloctahydropyrrolo[3,4-c]pyrrol-1-yl]acetamide

    Directory of Open Access Journals (Sweden)

    Konstantin V. Kudryavtsev

    2011-12-01

    Full Text Available In the title compound, C21H21N3O3, the relative stereochemistry of the four stereogenic C atoms has been determined. The dihedral angle between the phenyl rings is 77.63 (7°. In the crystal, ribbons spread along the a axis are formed by N—H...O hydrogen bonds. C—H...π interactions also occur.

  10. 2-[(1RS,3RS,3aRS,6aSR)-5-Benzyl-4,6-dioxo-3-phenyl-octa-hydro-pyrrolo-[3,4-c]pyrrol-1-yl]acetamide.

    Science.gov (United States)

    Kudryavtsev, Konstantin V; Churakov, Andrei V; Dogan, Ozdemir

    2011-12-01

    In the title compound, C(21)H(21)N(3)O(3), the relative stereochemistry of the four stereogenic C atoms has been determined. The dihedral angle between the phenyl rings is 77.63 (7)°. In the crystal, ribbons spread along the a axis are formed by N-H⋯O hydrogen bonds. C-H⋯π inter-actions also occur.

  11. 2-[(1RS,3RS,3aRS,6aSR)-5-Benzyl-4,6-dioxo-3-phenyl­octa­hydro­pyrrolo­[3,4-c]pyrrol-1-yl]acetamide

    Science.gov (United States)

    Kudryavtsev, Konstantin V.; Churakov, Andrei V.; Dogan, Ozdemir

    2011-01-01

    In the title compound, C21H21N3O3, the relative stereochemistry of the four stereogenic C atoms has been determined. The dihedral angle between the phenyl rings is 77.63 (7)°. In the crystal, ribbons spread along the a axis are formed by N—H⋯O hydrogen bonds. C—H⋯π inter­actions also occur. PMID:22199707

  12. Ethyl (1R*,10S*,12R*,15S*-4-Hydroxy-2-oxo-15- (2-oxo-1-pyrrolidinyl-9-oxatetracyclo[10.2.2.01,10.03,8]hexadeca-3,5,7,13-tetraene-13-carboxylate

    Directory of Open Access Journals (Sweden)

    Jorge Heredia-Moya

    2017-01-01

    Full Text Available N-Vinylpirrolidinone reacts with (E-ethyl 5-hydroxy-3-(4-oxo-4H-chromen-3-yl acrylate (1 through a domino reaction similar to that reported reaction for ethyl vinyl ether. Inverse electron demand Diels–Alder (IEDDA–elimination-IEDDA generates isomeric tetracycles 5 and 6. The assignment of the relative stereochemistry of the products was made by comparing the proton couplings with those obtained by reaction with ethyl vinyl ether.

  13. High energy halogen atom reactions activated by nuclear transformations

    International Nuclear Information System (INIS)

    Rack, E.P.

    1990-05-01

    This program, which has been supported for twenty-four years by the Us Atomic Energy Commission and its successor agencies, has produced significant advances in the understanding of the mechanisms of chemical activation by nuclear processes; the stereochemistry of radioactivity for solution of specific problems. This program was contributed to the training of approximately seventy scientists at various levels. This final report includes a review of the areas of research and chronological tabulation of the publications

  14. Novel meroditerpenes from the brown alga Cystoseira sp.

    Science.gov (United States)

    Navarro, Guillermo; Fernández, José J; Norte, Manuel

    2004-03-01

    Five new meroditerpenes have been isolated from a brown alga of the genus Cystoseira collected around the Canary Islands. One, cystoseirone diacetate (3), possesses a new rearranged structure with an unusual ether linkage in the diterpene side chain. Its biogenetic origin was explained as derived from the oxidation of amentol chromane diacetate (2) and subsequent cyclization. Structures were determined through the interpretation of the spectral data and by means of chemical transformations. The relative stereochemistry was proposed on the basis of ROESY correlations.

  15. The synthesis and structure of new vinylogous carbamates of sparteine

    Science.gov (United States)

    Włodarczak, Jacek; Wysocka, Waleria; Katrusiak, Andrzej

    2010-05-01

    Synthesis of new ( E)-(-)-[2-methyl ( 2), ethyl ( 3), isopropyl ( 4), benzyl ( 5) and phenyl ( 6)] carbonylmethylideno-17-oxosparteine by the Eschenmoser coupling reaction has been described. Stereochemistry of these compounds has been determined by 13C and 1H NMR and that of compound 2 additionally by X-ray analysis. The Haasnoot equation has been used to determine the HCCH dihedral angle in ( E)-(-)-2-methyl-(methylcarbonylomethylideno)-17-oxosparteine on the basis of NMR spectroscopy.

  16. Novel synthesis of highly functionalized 14-beta-hydroxysteroids related to batrachotoxin and ouabain.

    Science.gov (United States)

    Trudeau, Stéphane; Deslongchamps, Pierre

    2004-02-06

    The use of anionic polycyclization was investigated in an effort to develop a versatile and convergent synthesis of advanced tetracyclic intermediates of batrachotoxin and ouabain analogues. Two new 5-(trialkylsilyl)-2-cyclohexenones as A ring precursors and a new Nazarov intermediate (D ring precursor) were prepared for this purpose. The reaction of the unsaturated beta-keto aldehyde A ring precursor with the enolate of the Nazarov intermediate afforded, after subsequent transformations, a 14-beta-hydroxysteroid with complete control of stereochemistry.

  17. Rapid and Controllable Hydrogen/Deuterium Exchange on Aromatic Rings of α-Amino Acids and Peptides

    OpenAIRE

    Murai, Yuta; Wang, Lei; Masuda, Katsuyoshi; Sakihama, Yasuko; Hashidoko, Yasuyuki; Hatanaka, Yasumaru; Hashimoto, Makoto

    2013-01-01

    Novel hydrogen/deuterium exchange for aromatic α-amino acids and their corresponding peptides were performed through the use of deuterated trifluoromethanesulfonic acid (TfOD). Detailed analysis of the exchange revealed that equal hydrogen/deuterium exchange was observed for phenylalanine, and specific exchange at the ortho-positions of phenol for tyrosine was also detected. The stereochemistry of the aromatic α-amino acids was retained under the exchange conditions. The hydrogen/deuterium ex...

  18. Synthesis of All Stereoisomers of 1-(4-Methoxyphenyl-2,3,4,9-tetrahydro-N-methyl-1H-pyrido[3,4-b]indole-3-carboxamide

    Directory of Open Access Journals (Sweden)

    Momoko Onda

    2018-01-01

    Full Text Available In this study, all four stereoisomers of tryptoline or tetrahydro-β-carboline were synthesized in high yields by the catalyst-free amidation of methyl ester using methylamine under mild conditions. All isomers of the obtained amide and the precursor methyl ester were subjected to cell viability measurements on HeLa cells. The results indicated that the stereochemistry of the derivatives is clearly related to cell viability.

  19. High Trans Kinetic Selectivity in Ruthenium-Based Olefin Cross-Metathesis through Stereoretention.

    Science.gov (United States)

    Johns, Adam M; Ahmed, Tonia S; Jackson, Bradford W; Grubbs, Robert H; Pederson, Richard L

    2016-02-19

    The first kinetically controlled, highly trans-selective (>98%) olefin cross-metathesis reaction is demonstrated using Ru-based catalysts. Reactions with either trans or cis olefins afford products with highly trans or cis stereochemistry, respectively. This E-selective olefin cross-metathesis is shown to occur between two trans olefins and between a trans olefin and a terminal olefin. Additionally, new stereoretentive catalysts have been synthesized for improved reactivity.

  20. Diketopiperazines produced by an Aspergillus fumigatus Brazilian strain

    Energy Technology Data Exchange (ETDEWEB)

    Furtado, Niege A.J.C; Pupo, Monica T.; Carvalho, Ivone; Campo, Vanessa L. Campo; Bastos, Jairo K. [Sao Paulo Univ., Ribeirao Preto, SP (Brazil). Faculdade de Ciencias Farmaceuticas]. E-mail: jkbastos@fcfrp.usp.br; Duarte, Marta Cristina T. [Universidade Estadual de Campinas, SP (Brazil). Centro Pluridisciplinar de Pesquisas Quimicas, Biologicas e Agricolas

    2005-11-15

    Seven diketopiperazines, corresponding to the cycles (L)-Pro-(L)-Phe, (L)-Pro-Gly, (L)-Pro- (L)-Pro, (L)-Pro-(L)-Val, (L)-4-OH-Pro-(L)-Leu, (L)-4-OH-Pro-(L)-Phe, and (L)-Pro-(L)-Leu, were isolated from the Aspergillus fumigatus fermentation broth. The relative and absolute stereochemistries were determined on the basis of NOESY experiments and by using a modified version of Marfey's method using HPLC, respectively. (author)

  1. Efficient ring perception for the Chemistry Development Kit

    OpenAIRE

    May, John W; Steinbeck, Christoph

    2014-01-01

    Background The Chemistry Development Kit (CDK) is an open source Java library for manipulating and processing chemical information. A key aspect in handling chemical structures is the determination of the chemical rings. The rings of a structure are used areas including descriptors, stereochemistry, similarity, screening and atom typing. The CDK includes multiple algorithms for determining the rings of a structure on demand. Non-unique descriptions of rings were often used due to the slower p...

  2. Phosphine-catalyzed synthesis of 3,3-spirocyclopenteneoxindoles from γ-substituted allenoates: systematic studies and targeted applications.

    Science.gov (United States)

    Gomez, Catherine; Gicquel, Maxime; Carry, Jean-Christophe; Schio, Laurent; Retailleau, Pascal; Voituriez, Arnaud; Marinetti, Angela

    2013-02-15

    The phosphine-promoted [3 + 2] cyclizations between γ-substituted allenoates and arylideneoxindoles have been applied to the stereoselective synthesis of spiro(cyclopentene)oxindoles with trisubstituted cyclopentene units. It has been demonstrated that PPh(3) operates a very efficient control of the relative stereochemistry of the three stereogenic centers of the final spiranic products. Focused experiments have been carried out then so as to access carbocyclic analogues of an important series of anticancer agents inhibiting MDM2-p53 interactions.

  3. Self-Administration of Cannabinoids by Experimental Animals and Human Marijuana Smokers

    OpenAIRE

    Justinova, Zuzana; Goldberg, Steven R.; Heishman, Stephen J.; Tanda, Gianluigi

    2005-01-01

    Drug self-administration behavior has been one of the most direct and productive approaches for studying the reinforcing effects of psychoactive drugs, which are critical in determining their abuse potential. Cannabinoids, which are usually abused by humans in the form of marijuana, have become the most frequently abused illicit class of drugs in the United States. The early elucidation of the structure and stereochemistry of delta-9-tetrahydrocannabinol (THC) in 1964, which is now recognized...

  4. Deuterium exchange in carbonyl compounds

    International Nuclear Information System (INIS)

    Lamaty, G.

    1976-01-01

    After giving a brief outline of the theoretical study of H/D exchange the reaction mechanisms of enolization of ketones and of ketonization of enols are discussed. The orientation of the exchange in aliphatic ketones and the stereochemistry of the exchange in rigid cyclic ketones are dealt with. Some other ketonic systems and carboxylic acids and their derivatives are also considered. (B.R.H.)

  5. Reactions of charged and neutral recoil particles following nuclear transformations

    International Nuclear Information System (INIS)

    Ache, H.J.

    1975-09-01

    The status of the following programs is reported: study of the stereochemistry of halogen atom or ion reactions produced via (eta,γ) or (IT) nuclear reactions with diastereomeric molecules; study of nuclear decay induced reactions of halogen species with organic compounds in the gas phase; decay-induced labelling of compounds of biochemical interest; energetics and mechanisms involved in the reactions of highly energetic carbon-11 atoms with simple organic molecules; and chemistry of the positronium. (LK)

  6. Synthesis of gamma,delta-unsaturated and delta,epsilon-unsaturated alpha-amino acids from fragmentation of gamma- and delta-lactones.

    Science.gov (United States)

    Tarver, James E; Joullié, Madeleine M

    2004-02-06

    A noncoded amino acid of cyclomarin A (1) was synthesized in a racemic fashion. The method employs a six-membered ring template to control the relative stereochemistry and introduction of the functional groups. Ultimately, Pd-catalyzed fragmentation of the lactone provided gamma,delta-unsaturated and delta,epsilon-unsaturated alpha-amino acids. A Pd-catalyzed ring opening of a gamma-lactone is also reported.

  7. Chemistry of renieramycins. Part 3.(1) isolation and structure of stabilized renieramycin type derivatives possessing antitumor activity from Thai sponge Xestospongia species, pretreated with potassium cyanide.

    Science.gov (United States)

    Suwanborirux, Khanit; Amnuoypol, Surattana; Plubrukarn, Anuchit; Pummangura, Sunibhond; Kubo, Akinori; Tanaka, Chieko; Saito, Naoki

    2003-11-01

    Renieramycins M (1m) and N (1n) were isolated from the Thai sponge Xestospongia sp., pretreated with potassium cyanide in methanolic buffer solution, and their structures and relative stereochemistries were elucidated on the basis of spectroscopic data. This strategy is the first example of the gram-scale preparation of this series of compounds and presents a potential solution for increasing the gram-scale supply of novel natural products from marine sources.

  8. Determination of relative configurations and conformations of oxindole alkaloids from Uncaria guianensis by NMR; Determinacao por RMN das configuracoes relativas e conformacoes de alcaloides oxindolicos isolados de Uncaria guianensis

    Energy Technology Data Exchange (ETDEWEB)

    Carbonezi, Carlos Alberto; Hamerski, Lidilhone; Flausino Junior, Otavio Aparecido; Furlan, Maysa; Bolzani, Vanderlan da Silva [UNESP, Araraquara, SP (Brazil). Inst. de Quimica]. E-mail: bolzaniv@iq.unesp.br; Young, Maria Claudia Marx [Instituto de Botanica, Sao Paulo, SP (Brazil). Secao de Fisiologia e Bioquimica de Plantas

    2004-12-01

    Phytochemical studies with leaves of Uncaria guianensis resulted in the isolation of the oxindole alkaloids isomitraphylline (1), 3-isoajmalicine (2) mitraphylline (3), and isomitraphylinic acid (4). Structural assignments of these alkaloids, including relative configurations and conformations, were performed through spectral data and physical properties. 1D and 2D homonuclear and heteronuclear NMR spectroscopy was a valuable tool for the establishment of the relative stereochemistry of those compounds. (author)

  9. Determinação por RMN das configurações relativas e conformações de alcalóides oxindólicos isolados de Uncaria guianensis Determination of relative configurations and conformations of oxindole alkaloids from Uncaria guianensis by NMR

    Directory of Open Access Journals (Sweden)

    Carlos Alberto Carbonezi

    2004-12-01

    Full Text Available Phytochemical studies with leaves of Uncaria guianensis resulted in the isolation of the oxindole alkaloids isomitraphylline (1, 3-isoajmalicine (2 mitraphylline (3, and isomitraphylinic acid (4. Structural assignments of these alkaloids, including relative configurations and conformations, were performed through spectral data and physical properties. 1D and 2D homonuclear and heteronuclear NMR spectroscopy was a valuable tool for the establishment of the relative stereochemistry of those compounds.

  10. Discovery of Azetidinone Acids as Conformationally-Constrained Dual PPARalpha/gamma Agonists

    Energy Technology Data Exchange (ETDEWEB)

    Wang, W.; Devasthale, P; Farrelly, D; Gu, L; Harrity, T; Cap, M; Chu, C; Kunselman, L; Morgan, N; et. al.

    2008-01-01

    A novel class of azetidinone acid-derived dual PPAR{alpha}/{gamma} agonists has been synthesized for the treatment of diabetes and dyslipidemia. The preferred stereochemistry in this series for binding and functional agonist activity against both PPARa and PPAR? receptors was shown to be 3S,4S. Synthesis, in vitro and in vivo activities of compounds in this series are described. A high-yielding method for N-arylation of azetidinone esters is also described.

  11. ruthenium(II). Nitro–nitroso derivatives and

    Indian Academy of Sciences (India)

    Unknown

    2006-09-18

    Sep 18, 2006 ... for the appearance of intense stretching at 1300–. 1335 and 1250–1280 cm–1 with concomitant loss of ν(Ru–Cl) at 320–340 cm–1. They are assigned to ... and binds both in the linear and bent N–O fashion. (table 1). The stretching frequency ν(NO) qualita- tively determines the stereochemistry of M–N–O.

  12. A facile regioselective synthesis of novel spiroacenaphthene pyrroloisoquinolines through 1,3-dipolar cycloaddition reactions

    Energy Technology Data Exchange (ETDEWEB)

    Sarrafi, Yaghoub; Asghari, Asieh; Sadatshahabi, Marzieh, E-mail: ysarrafi@umz.ac.ir [Department of Organic Chemistry, Faculty of Chemistry, University of Mazandaran (Iran, Islamic Republic of); Hamzehloueian, Mahshid [Department of Chemistry, Jouybar Branch, Islamic Azad University, Jouybar (Iran, Islamic Republic of); Alimohammadi, Kamal [Department of Chemistry, Dr. Shariati Branch, University of Farhangian, Sari (Iran, Islamic Republic of)

    2013-12-01

    An efficient one-pot three-component procedure for the synthesis of novel spiroacenaphthene pyrroloisoquinolines with high regioselectivity is described. These compounds were prepared from 1,3-dipolar cycloaddition of an azomethine ylide generated from acenaphthenequinone and 1,2,3,4-tetrahydroisoquinoline via [1,5]-H shift, with chalcone and nitrostyrene derivatives as dipolarophiles. The structure and stereochemistry of the cycloadducts have been established by single crystal X-ray structure and spectroscopic techniques. (author)

  13. Highly enantio- and diastereoselective reactions of γ-substituted butenolides through direct vinylogous conjugate additions

    KAUST Repository

    Zhang, Wen

    2012-09-05

    The strength of the weak: An L-tert-leucine-derived amine-thiourea catalyst (see scheme, green box) promotes the asymmetric vinylogous conjugate addition reaction between γ-aryl- and alkyl-substituted butenolides with the butenamides and enoates shown. Computational studies show the preference for the observed stereochemistry is a result of favourable weak non-bonding interactions, which stabilize the transition state. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Synthesis of the reported structure of piperazirum using a nitro-Mannich reaction as the key stereochemical determining step

    Directory of Open Access Journals (Sweden)

    James C. Anderson

    2013-08-01

    Full Text Available Piperazirum, isolated from Arum palaestinum Boiss, was originally assigned as r-3,c-5-diisobutyl-c-6-isopropylpiperazin-2-one. The reported structure was synthesised diastereoselectively using a key nitro-Mannich reaction to set up the C5/C6 relative stereochemistry. The structure was unambiguously assigned by single crystal X-ray diffraction but the spectroscopic data did not match those reported for the natural product. The structure of the natural product must therefore be revised.

  15. N-Benzyl-1,3-dideoxy-1,3-imino-l-xylitol

    Directory of Open Access Journals (Sweden)

    Sarah F. Jenkinson

    2011-09-01

    Full Text Available The structure determination confirms the stereochemistry of the title compound, C12H17NO3, which contains a four-membered azetidine ring system. The absolute configuration was determined by the use of d-glucose as the starting material. In the crystal, O—H...O and O—H...N hydrogen bonds link the molecules into layers in the ab plane.

  16. Ethyl ent-15α-[(2-nitro­benz­yloxy)meth­yl]-16-oxobeyeran-20-oate

    Science.gov (United States)

    Wu, Ya; Wang, Xia; Gong, Jian-hong; Tao, Jing-chao

    2012-01-01

    In the title compound, C30H41NO6, the three six-membered rings adopt chair conformations and the stereochemistry of the A/B and B/C ring junctions are trans. The five-membered ring D adopts an envelope conformation, with the methyl­ene C atom as the flap. The title compound was synthesized via esterification, Tollens reaction, 1,5-hydride shift from the natural tetracyclic diterpenoid isosteviol PMID:22904810

  17. Ethyl ent-15α-[(2-nitrobenzyloxymethyl]-16-oxobeyeran-20-oate

    Directory of Open Access Journals (Sweden)

    Ya Wu

    2012-08-01

    Full Text Available In the title compound, C30H41NO6, the three six-membered rings adopt chair conformations and the stereochemistry of the A/B and B/C ring junctions are trans. The five-membered ring D adopts an envelope conformation, with the methylene C atom as the flap. The title compound was synthesized via esterification, Tollens reaction, 1,5-hydride shift from the natural tetracyclic diterpenoid isosteviol

  18. Ethyl ent-15α-[(2-nitro-benz-yloxy)meth-yl]-16-oxobeyeran-20-oate.

    Science.gov (United States)

    Wu, Ya; Wang, Xia; Gong, Jian-Hong; Tao, Jing-Chao

    2012-08-01

    In the title compound, C(30)H(41)NO(6), the three six-membered rings adopt chair conformations and the stereochemistry of the A/B and B/C ring junctions are trans. The five-membered ring D adopts an envelope conformation, with the methyl-ene C atom as the flap. The title compound was synthesized via esterification, Tollens reaction, 1,5-hydride shift from the natural tetracyclic diterpenoid isosteviol.

  19. Glutamate receptor ligands

    DEFF Research Database (Denmark)

    Guldbrandt, Mette; Johansen, Tommy N; Frydenvang, Karla Andrea

    2002-01-01

    Homologation and substitution on the carbon backbone of (S)-glutamic acid [(S)-Glu, 1], as well as absolute stereochemistry, are structural parameters of key importance for the pharmacological profile of (S)-Glu receptor ligands. We describe a series of methyl-substituted 2-aminoadipic acid (AA...... or slightly lower potencies than (S)-AA [e.g., EC(50) = 76 microM for (2S,4S)-4-methyl-AA (5a) as compared to EC(50) = 35 microM for (S)-AA]. The position of the methyl substituent had a profound effect on the observed pharmacology, whereas the absolute stereochemistry at the methylated carbon atom had a very......) analogs, and the synthesis, stereochemistry, and enantiopharmacology of 3-methyl-AA (4a-d), 4-methyl-AA (5a-d), 5-methyl-AA (6a-d), and (E)-Delta(4)-5-methyl-AA (7a and 7b) are reported. The compounds were resolved using chiral HPLC and the configurational assignments of the enantiomers were based on X...

  20. Muusika : Brahmsi reekviem Tõnu Kaljustega. Rahvusooperi nõukogus. Võimalus veeta õhtu La Scalas. Rene Eespere uus CD. Jukka Savijoki käis Eestis. Võistlesid pianistid. Jõulukontserdid / Peeter Olesk

    Index Scriptorium Estoniae

    Olesk, Peeter, 1953-

    2001-01-01

    Tõnu Kaljuste juhatab Ljubljana Gallus Hallis Johannes Brahmsi "Saksa reekviemi". EMA kuratooriumi ja rahvusooperi Estonia nõukogu arutasid ühisistungil Eesti ooperikunsti, muusikateatri ja kõrgema muusikalise hariduse probleeme. 7. XII kell 19.00 saab "Klassikaraadiost" kuulata Milano La Scala hooaja avaetenduse otseülekannet. Antese väljaandel ilmus CD Rene Eespere kammerteostega. 29.XI ئ 2.XII viibis Eestis Sibeliuse akadeemia klassikalise kitarri õppejõud Jukka Savijoki. 23. ja 24. XI toimus Tartus kolme keskastme muusikakooli noorte pianistide konkurss. 8.XII toimub EMA kammersaalis suur jõulukontsert, kus esinevad parimad EMA üliõpilased. Kontserdiagentuuri Concerto Grosso sari "Advendiaeg poistekooridega" viib kontserte Eestimaa erinevatesse linnadesse. Plaadi "Kahest üks" esitluskontserdiga, kus tuleb esiettekandele Urmas Sisaski kantaat "Armastusesle", tähistab TTÜ Akadeemiline Naiskoor oma 50. aastapäeva . Eesti Naistelaulu Seltsi korraldusel toimus 2. XII Balti Misjonikeskuses Tallinna naiskooride advendikontsert. 28. XI toimus Estonia talveaias Tarmo Lepiku 55. sünniaastapäevale pühendatud mälestuskontsert. 17.XI toimus Põlva kultuuri ja huvikeskuses VII Lõuna-Eesti meestelaulu päev

  1. Solid‐Phase Synthesis of Structurally Diverse Heterocycles by an Amide–Ketone Condensation/N‐Acyliminium Pictet–Spengler Sequence

    DEFF Research Database (Denmark)

    Komnatnyy, Vitaly V.; Givskov, Michael Christian; Nielsen, Thomas Eiland

    2012-01-01

    of a tethered nucleophile, a second cyclization reaction results in the formation of a fused bicyclic ring system. The scope of the methodology was demonstrated by several combinations of substituted ketones and nucleophiles, the latter conveniently originating from amino acids with functionalized side chains......, such as tryptophan, substituted phenylalanines, and cysteine. The cyclization sequence provides diastereomerically pure products in high yields. In one extension of the methodology, the resulting relative stereochemistry of the products enables the formation of bridged ring systems by a unique cyclative release...

  2. Photoreaction of 8-methoxypsoralen with thymidine

    International Nuclear Information System (INIS)

    Shim, S.C.; Kim, Y.Z.

    1983-01-01

    The photoreaction of 8-methoxypsoralen (8-MOP) with thymidine in solid film state yielded two 4',5'-monoadducts (a pair of diastereomers) and three 3,4-monoadducts. The stereochemistry of two 4',5'monoadducts was found to be cis-syn and trans-syn and one 3,4-monoadduct was cis-anti. In addition to these monoadducts, 3,4-, 4',5-biadducts were also formed during the reaction, but the isolation of each isomer of these adducts was not successful; however, the formation of these biadducts was confirmed by UV, IR, TLC and photosplitting experiments. (author)

  3. Synthesis and muscarinic receptor pharmacology of a series of 4,5,6,7-tetrahydroisothiazolo[4,5-c]pyridine bioisosteres of arecoline

    DEFF Research Database (Denmark)

    Pedersen, H; Bräuner-Osborne, H; Ball, R G

    1999-01-01

    A series of O- and ring-alkylated derivatives of 4,5,6,7-tetrahydroisothiazolo[4,5-c]pyridin-3-ol was synthesized via treatment of appropriately substituted 4-benzylamino-1,2,5,6-tetrahydropyridine-3-carboxamides with hydrogen sulfide and subsequent ring closure by oxidation with bromine. The mus...... of a selected series of chiral analogues, with established absolute stereochemistry, were studied using receptor selection and amplification technology (R-SAT). The potency, relative efficacy, and receptor subtype selectivity of these compounds were related to the structure of the O...

  4. GABAB antagonists

    DEFF Research Database (Denmark)

    Frydenvang, Karla Andrea; Hansen, J J; Krogsgaard-Larsen, P

    1994-01-01

    chromatographic techniques. The absolute stereochemistry of (-)-(R)-phaclofen was established by X-ray crystallographic analysis. (-)-(R)-Phaclofen was shown to inhibit the binding of [3H]-(R)-baclofen to GABAB receptor sites on rat cerebellar membranes (IC50 = 76 +/- 13 microM), whereas (+)-(S......)-baclofen and the antagonist (-)-(R)-phaclofen suggests that these ligands interact with the GABAB receptor sites in a similar manner. Thus, it may be concluded that the different pharmacological effects of these compounds essentially result from the different spatial and proteolytic properties of their acid groups....

  5. [6]Saddlequat: a [6]helquat captured on its racemization pathway

    Czech Academy of Sciences Publication Activity Database

    Adriaenssens, Louis; Severa, Lukáš; Koval, Dušan; Císařová, I.; Belmonte, M. M.; Escudero-Adán, E. C.; Novotná, P.; Sázelová, Petra; Vávra, Jan; Pohl, Radek; Šaman, David; Urbanová, M.; Kašička, Václav; Teplý, Filip

    2011-01-01

    Roč. 2, č. 12 (2011), s. 2314-2320 ISSN 2041-6520 R&D Projects: GA ČR GA203/09/1614; GA ČR GAP207/10/2391; GA ČR(CZ) GA203/08/1428; GA ČR GP203/09/P485 Institutional research plan: CEZ:AV0Z40550506 Keywords : dynamic stereochemistry * kinetic [2+2+2] cycloaddition * DFT and spectroscopy Subject RIV: CC - Organic Chemistry Impact factor: 7.525, year: 2011

  6. Antiplatelet Aggregation Coumarins from the Leaves of Murraya omphalocarpa

    Directory of Open Access Journals (Sweden)

    Yang-Chang Wu

    2008-01-01

    Full Text Available Using a bioactivity-guided fractionation method, two coumarins: minumicrolineacetonide (1 and epimurpaniculol senecioate (2, were isolated from the leaves ofMurraya omphalocarpa Hayata (Rutaceae. Compound 1 had been previously synthesizedand was now isolated from natural sources for the first time, and compound 2, possessing anegative optical rotation value, is new. The structures and their stereochemistry were fullyelucidated on the basis of spectroscopic and X-ray crystallographic techniques. Bothcompounds 1 and 2 are active in the antiplatelet aggregation assay. Interestingly, thepossible acetonide artifact 1 displayed significant antiplatelet aggregation induced not onlyby AA and collagen but also by platelet activating factor (PAF.

  7. Allylic azides as potential building blocks for the synthesis of nitrogenated compounds

    Directory of Open Access Journals (Sweden)

    Sá Marcus M.

    2003-01-01

    Full Text Available The synthetic potential of multifunctional allylic azides and imines in attempted intramolecular cyclizations to nitrogen-containing heterocycles was investigated. Tandem Staudinger/aza-Wittig reaction of (E-3-aryl-2-(azidomethylpropenoates with triphenylphosphine and aldehydes yielded N-allylic imines in good yield. The (E-stereochemistry of C=C and C=N bonds was assigned based on NOESY experiments. AlCl3 mediated formation of 3-carbomethoxyquinoline from methyl (E-2-(azidomethyl-3-phenylpropenoate is also described.

  8. Iridoids and sesquiterpenoids of Valeriana stenoptera and their effects on NGF-induced neurite outgrowth in PC12 cells.

    Science.gov (United States)

    Dong, Fa-Wu; Wu, Zhi-Kun; Yang, Liu; Zi, Chen-Ting; Yang, Dan; Ma, Rui-Jing; Liu, Zhen-Hua; Luo, Huai-Rong; Zhou, Jun; Hu, Jiang-Miao

    2015-10-01

    Twenty-one compounds (nine iridoids and twelve sesquiterpenoids), including ten previously unknown (five iridoids and five sesquiterpenoids) were isolated from whole dried material of Valeriana stenoptera. Structures were established on the basis of extensive spectroscopic analysis and the relative stereochemistry of 13-hydroxypatchoulol A was further confirmed by X-ray crystallographic data. All isolates were evaluated for their effects on nerve growth factor (NGF)-mediated neurite outgrowth in pheochromocytoma (PC12) cells and seven compounds showed potent promoting effects. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Experimental and theoretical investigation of 1J(CC) and (n)J(CC) coupling constants in strychnine.

    Science.gov (United States)

    Williamson, R Thomas; Buevich, Alexei V; Martin, Gary E

    2012-10-05

    A relatively unexplored and unexploited means of establishing molecular structure, stereochemistry, and probing vicinal bond angles is through the use of long-range (13)C-(13)C coupling constants. The measurement of these multifunctional, diagnostic (3)J(CC) couplings has not been reported on sample amounts viable for the practicing organic chemist. A generalized protocol for the measurement of (1)J(CC) and (3)J(CC) couplings using a 4.6 mg sample of strychnine as a model compound is described, and the utility of DFT calculations for the prediction of these useful molecular descriptors and the congruence of the calculated and experimental data is demonstrated.

  10. (1SR,3RS,3aSR,6aRS)-Methyl 5-methyl-4,6-dioxo-3-[2-(trifluoro-meth-yl)phen-yl]octa-hydro-pyrrolo-[3,4-c]pyrrole-1-carboxyl-ate.

    Science.gov (United States)

    Kudryavtsev, Konstantin V; Ivantcova, Polina M; Churakov, Andrei V

    2013-02-01

    In the title compound, C(16)H(15)F(3)N(2)O(4), the relative stereochemistry of the four stereogenic C atoms has been determined. The carb-oxy-methyl and 2-(trifluoro-meth-yl)-phenyl substituents of the pyrrolidine cycle have a cis mutual arrangement. The five-membered saturated aza-cycle adopts an envelope conformation with the N atom occupying the flap position. In the crystal, adjacent mol-ecules are combined in centrosymmetric dimers by two weak N-H⋯O hydrogen bonds.

  11. (1SR,3RS,3aSR,6aRS)-Methyl 5-methyl-4,6-dioxo-3-[2-(trifluoro­meth­yl)phen­yl]octa­hydro­pyrrolo­[3,4-c]pyrrole-1-carboxyl­ate

    Science.gov (United States)

    Kudryavtsev, Konstantin V.; Ivantcova, Polina M.; Churakov, Andrei V.

    2013-01-01

    In the title compound, C16H15F3N2O4, the relative stereochemistry of the four stereogenic C atoms has been determined. The carb­oxy­methyl and 2-(trifluoro­meth­yl)­phenyl substituents of the pyrrolidine cycle have a cis mutual arrangement. The five-membered saturated aza­cycle adopts an envelope conformation with the N atom occupying the flap position. In the crystal, adjacent mol­ecules are combined in centrosymmetric dimers by two weak N—H⋯O hydrogen bonds. PMID:23424450

  12. Hexaaquamanganese(II) bis[hydrogen (4-aminophenyl)arsonate] tetrahydrate

    OpenAIRE

    Graham Smith; Urs D. Wermuth

    2016-01-01

    In the structure of the complex salt formed from the reaction of manganese(II) acetate with (4-aminophenyl)arsonic acid (p-arsanilic acid), [Mn(H2O)6](C6H7AsNO3)2·4H2O, the centrosymmetric Mn(H2O)6 coordination polyhedron has slightly distorted octahedral stereochemistry, with the two hydrogen (4-aminophenyl)arsonate anions and the four water molecules of solvation related by inversion. Extensive O—H...O, O—H...N and N—H...O hydrogen bonds link all species, giving an overall three-dimensional...

  13. Spectroscopy and crystal structures of natural stereoisomers of neoclerodane diterpenoids from Teucrium yemense of Saudi medicinal plant

    Science.gov (United States)

    Nur-e-Alam, Mohammad; Kanthasamy, Gopikkaa; Yousaf, Muhammad; Alqahtani, Ali S.; Ghabbour, Hazem A.; Al-Rehaily, Adnan J.

    2017-11-01

    3-O-deacetylteugracilin (1) and teugracilin B (2), two natural stereoisomers, are isolated from Teucrium yemense (Defl). These two compounds are almost identical to each other, differing only at the C6 stereocenter. We now crystallise these two compounds and for the first time, determine the crystal structure through single crystal X-ray diffraction, and the stereochemistry for all positions using spectroscopic data. These techniques enable us to establish the difference between the two compounds. Careful interpretation of the results indicates that HRMS and 1 and 2D NMR spectroscopy, are in agreement with single crystal X-ray diffraction data.

  14. A Brønsted base-promoted diastereoselective dimerization of azlactones

    Directory of Open Access Journals (Sweden)

    Danielle L. J. Pinheiro

    2017-12-01

    Full Text Available A novel Brønsted base system for the diastereoselective dimerization of azlactones using trichloroacetate salts and acetonitrile has been developed. Desired products were obtained in good yields (60–93% and with up to >19:1 dr after one hour of reaction. Additionally, the relative stereochemistry of the major dimer was assigned as being trans, by X-ray crystallographic analysis. The kinetic reaction profile was determined by using 1H NMR reaction monitoring and revealed a second order overall kinetic profile. Furthermore, by employing this methodology, a diastereoselective total synthesis of a functionalized analogue of streptopyrrolidine was accomplished in 65% overall yield.

  15. Structure of alkaloid 275A, a novel 1-azabicyclo[5.3.0]decane from a dendrobatid frog, Dendrobates lehmanni: synthesis of the tetrahydrodiastereomers.

    Science.gov (United States)

    Garraffo, H M; Jain, P; Spande, T F; Daly, J W; Jones, T H; Smith, L J; Zottig, V E

    2001-04-01

    The principal alkaloid 275A in skins of the Colombian poison frog Dendrobates lehmanni has been identified as the pyrrolo[1,2-a]azepane (1), the first occurrence in nature of this "izidine" system. Tetrahydro-1 proved identical to one of the four synthetic diastereomers, 2a--2d, thereby establishing that 1 has the 5Z,10E relative stereochemistry. Alkaloid 1 is often accompanied by other congeners, in particular a 5Z,10Z diastereomer 15, a dihydro analogue 16, and a ketone 17. Such izidines in frogs may arise from dietary ants, as do other classes of izidines.

  16. Arabidopsis thaliana RGXT1 and RGXT2 encode Golgi-localized (1,3)-alpha-D-xylosyltransferases involved in the synthesis of pectic rhamnogalacturonan-II

    DEFF Research Database (Denmark)

    Madsen, Jack Egelund; Petersen, Bent Larsen; Motawia, Mohammed Saddik

    2006-01-01

    was catalyzed by beta-xylosidase. Furthermore, the regio- and stereochemistry of the methyl xylosyl-fucoside was determined by nuclear magnetic resonance to be an alpha-(1,3) linkage, demonstrating the isolated glycosyltransferases to be (1,3)-alpha-d-xylosyltransferases. This particular linkage is only known......-enhanced green fluorescent protein constructs in Arabidopsis revealed that both fusion proteins were targeted to a Brefeldin A-sensitive compartment and also colocalized with the Golgi marker dye BODIPY TR ceramide, consistent with targeting to the Golgi apparatus. Taken together, these results suggest...

  17. Unexpected Retroaldol-Aldol Reaction during O-Alkylation of Hydroxylated Vince Lactam Derivatives.

    Science.gov (United States)

    Bengtsson, Christoffer; Wetzel, Alexander; Bergman, Joakim; Brånalt, Jonas

    2016-01-15

    The unexpected retroaldol-aldol reaction during O-alkylation of a β-hydroxy lactam was found to be highly dependent on the temperature and shows a remarkable solvent effect. In DMF, O-alkylation is faster than retroaldol-aldol rearrangement giving exclusively products with retention of configuration. In THF, O-alkylation is slower than rearrangement, giving selectively products with inversion of stereochemistry. In DMSO, a retroaldol reaction followed by fast intramolecular proton transfer occurs to give the ring-opened aldehyde.

  18. Polyketide stereocontrol: a study in chemical biology

    Directory of Open Access Journals (Sweden)

    Kira J. Weissman

    2017-02-01

    Full Text Available The biosynthesis of reduced polyketides in bacteria by modular polyketide synthases (PKSs proceeds with exquisite stereocontrol. As the stereochemistry is intimately linked to the strong bioactivity of these molecules, the origins of stereochemical control are of significant interest in attempts to create derivatives of these compounds by genetic engineering. In this review, we discuss the current state of knowledge regarding this key aspect of the biosynthetic pathways. Given that much of this information has been obtained using chemical biology tools, work in this area serves as a showcase for the power of this approach to provide answers to fundamental biological questions.

  19. Relevance of the C-5 Position to Schweinfurthin Induced Cytotoxicity

    Science.gov (United States)

    Topczewski, Joseph J.; Callahan, Michael P.; Kodet, John G.; Inbarasu, Jery D.; Mente, Nolan R.; Beutler, John A.; Wiemer, David F.

    2011-01-01

    The schweinfurthins are an intriguing group of anti-proliferative agents that display low nanomolar activities against several cell types, including the human-derived glioblastoma cell line SF-295, but have little impact on other cell lines even at micromolar concentrations. This activity has inspired the synthesis of seven of the natural schweinfurthins, all with the correct absolute stereochemistry, and a variety of analogues designed to probe different facets of the pharmacophore. Reported herein is the synthesis of several new schweinfurthin analogues varied at the C-5 position along with data on their biological activity in the NCI 60 cell-line assay. PMID:22055715

  20. ENANTIOPURE R(--3-AMINOISOBUTYRIC ACID SYNTHESIS USING Pseudomonas aeruginosa AS ENANTIOSPECIFIC BIOCATALYST

    Directory of Open Access Journals (Sweden)

    M. V. C. B. Cortes

    2015-03-01

    Full Text Available Abstract The main goal of this research was the synthesis of enantiopure R(--3-aminoisobutyric acid from dihydrothymine with good yield, high stereospecificity and relative simplicity. Seventy two percent yield of the product was obtained in three steps. Step one consisted of dihydrothymine racemization. Step two was a dihydropyrimidinase reaction involving the Pseudomonas aeruginosa 10145 bacterial strain as the biocatalyst. Step three was performed with a diazotization reaction. The bacteria's enzymes determined the stereochemistry of the process since the diazotization reaction did not interfere at this point. The results of this work provide an interesting method for the production of commercial β-amino acids from other substituteddihydrothymines.

  1. Recoil generated radiotracers in studies of molecular dynamics

    International Nuclear Information System (INIS)

    Spicer, L.D.

    1981-01-01

    This chapter summarizes many of the contributions that the recoil technique of generating excited radiotracer atoms in the presence of a thermal environment is making to the field of chemical dynamics. Specific topics discussed critically include characterization of the generation and behavior of excited molecules including fragmentation kinetics and energy transfer, measurement of thermal and hot kinetic parameters, and studies of reaction mechanisms and stereochemistry as a function of reaction energy. Distinctive features that provide unique approaches to dynamical problems are evaluated in detail and the complementarity with more conventional techniques is addressed. Prospects for future applications are also presented

  2. Megastigmane glucosides and an unusual monoterpene from the leaves of Cananga odorata var. odorata, and absolute structures of megastigmane glucosides isolated from C. odorata var. odorata and Breynia officinalis.

    Science.gov (United States)

    Matsunami, Katsuyoshi; Nagashima, Jiro; Sugimoto, Sachiko; Otsuka, Hideaki; Takeda, Yoshio; Lhieochaiphant, Duangporn; Lhieochaiphant, Sorasak

    2010-10-01

    From a 1-BuOH-soluble fraction of a MeOH extract of Cananga odorata var. odorata, collected at the Botanical Garden of Chiang Mai University, a new megastigmane glucoside, named canangaionoside, and an irregular monoterpene were isolated. A known compound, breyniaionoside A, which has been obtained from the leaves of Breynia officinalis, was also isolated, and its absolute structure was substantiated for the first time in this study. On this occasion, the absolute stereochemistries of structurally related megastigmane glucosides, breyniaionosides B and C, isolated from B. officinalis were examined.

  3. Synthesis and muscarinic receptor pharmacology of a series of 4,5,6,7-tetrahydroisothiazolo[4,5-c]pyridine bioisosteres of arecoline

    DEFF Research Database (Denmark)

    Pedersen, H; Bräuner-Osborne, H; Ball, R G

    1999-01-01

    . The muscarinic receptor affinity as well as estimated relative efficacy and subtype selectivity of this series of bicyclic arecoline bioisosteres were determined using rat brain membranes and a number of tritiated muscarinic receptor ligands. The effects at the five cloned human muscarinic receptor subtypes...... of a selected series of chiral analogues, with established absolute stereochemistry, were studied using receptor selection and amplification technology (R-SAT). The potency, relative efficacy, and receptor subtype selectivity of these compounds were related to the structure of the O...

  4. Molecular geometry

    CERN Document Server

    Rodger, Alison

    1995-01-01

    Molecular Geometry discusses topics relevant to the arrangement of atoms. The book is comprised of seven chapters that tackle several areas of molecular geometry. Chapter 1 reviews the definition and determination of molecular geometry, while Chapter 2 discusses the unified view of stereochemistry and stereochemical changes. Chapter 3 covers the geometry of molecules of second row atoms, and Chapter 4 deals with the main group elements beyond the second row. The book also talks about the complexes of transition metals and f-block elements, and then covers the organometallic compounds and trans

  5. Macrocyclic olefin metathesis at high concentrations by using a phase-separation strategy.

    Science.gov (United States)

    Raymond, Michaël; Holtz-Mulholland, Michael; Collins, Shawn K

    2014-09-26

    Macrocyclic olefin metathesis has seen advances in the areas of stereochemistry, chemoselectivity, and catalyst stability, but strategies aimed at controlling dilution effects in macrocyclizations are rare. Herein, a protocol to promote macrocyclic olefin metathesis, one of the most common synthetic tools used to prepare macrocycles, at relatively high concentrations (up to 60 mM) is described by exploitation of a phase-separation strategy. A variety of macrocyclic skeletons could be prepared having either different alkyl, aryl, or amino acids spacers. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Stereodivergent-at-metal synthesis of [60]fullerene hybrids

    Energy Technology Data Exchange (ETDEWEB)

    Marco-Martinez, Juan; Vidal, Sara; Fernandez, Israel; Filippone, Salvatore [Departamento de Quimica Organica I, Facultad de Ciencias Quimicas, Universidad Complutense de Madrid (Spain); Martin, Nazario [Departamento de Quimica Organica I, Facultad de Ciencias Quimicas, Universidad Complutense de Madrid (Spain); IMDEA-Nanociencia, C/Faraday, Universidad Autonoma de Madrid (Spain)

    2017-02-13

    Chiral fullerene-metal hybrids with complete control over the four stereogenic centers, including the absolute configuration of the metal atom, have been synthesized for the first time. The stereochemistry of the four chiral centers formed during [60]fullerene functionalization is the result of both the chiral catalysts employed and the diastereoselective addition of the metal complexes used (iridium, rhodium, or ruthenium). DFT calculations underpin the observed configurational stability at the metal center, which does not undergo an epimerization process. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  7. Butane-1,2,3,4-tetraol-based amphiphilic stereoisomers for membrane protein study: importance of chirality in the linker region

    DEFF Research Database (Denmark)

    Das, Manabendra; Du, Yang; Mortensen, Jonas S.

    2017-01-01

    Amphiphile selection is a crucial step in membrane protein structural and functional study. As conventional detergents have limited scope and utility, novel agents with enhanced efficacy need to be developed. Although a large number of novel agents have been reported, so far there has been...... of the targeted membrane proteins depending on the chirality of the linker region. These findings indicate an important role for detergent stereochemistry in membrane protein stabilization. In addition, we generally observed enhanced detergent efficacy with increasing alkyl chain length, reinforcing...

  8. Marine natural products.

    Science.gov (United States)

    Blunt, John W; Copp, Brent R; Keyzers, Robert A; Munro, Murray H G; Prinsep, Michèle R

    2016-03-01

    This review covers the literature published in 2014 for marine natural products (MNPs), with 1116 citations (753 for the period January to December 2014) referring to compounds isolated from marine microorganisms and phytoplankton, green, brown and red algae, sponges, cnidarians, bryozoans, molluscs, tunicates, echinoderms, mangroves and other intertidal plants and microorganisms. The emphasis is on new compounds (1378 in 456 papers for 2014), together with the relevant biological activities, source organisms and country of origin. Reviews, biosynthetic studies, first syntheses, and syntheses that lead to the revision of structures or stereochemistries, have been included.

  9. Self-assembled three-dimensional chiral colloidal architecture

    Science.gov (United States)

    Ben Zion, Matan Yah; He, Xiaojin; Maass, Corinna C.; Sha, Ruojie; Seeman, Nadrian C.; Chaikin, Paul M.

    2017-11-01

    Although stereochemistry has been a central focus of the molecular sciences since Pasteur, its province has previously been restricted to the nanometric scale. We have programmed the self-assembly of micron-sized colloidal clusters with structural information stemming from a nanometric arrangement. This was done by combining DNA nanotechnology with colloidal science. Using the functional flexibility of DNA origami in conjunction with the structural rigidity of colloidal particles, we demonstrate the parallel self-assembly of three-dimensional microconstructs, evincing highly specific geometry that includes control over position, dihedral angles, and cluster chirality.

  10. Aspergilones A and B, two benzylazaphilones with an unprecedented carbon skeleton from the gorgonian-derived fungus Aspergillus sp.

    KAUST Repository

    Shao, Chang Lun

    2011-01-01

    Two novel benzylazaphilone derivatives with an unprecedented carbon skeleton, aspergilone A (1), and its symmetrical dimer with a unique methylene bridge, aspergilone B (2), have been isolated from the culture broth of a marine-derived fungus Aspergillus sp. from a gorgonian Dichotella gemmacea. Their structures and relative stereochemistries of 1 and 2 were elucidated using a combination of NMR spectroscopy and X-ray crystallography. Compound 1 not only exhibited in vitro selective cytotoxicity but also showed potent antifouling activity. © 2010 Elsevier Ltd. All rights reserved.

  11. Co-catalyzed cross-coupling of alkyl halides with tertiary alkyl Grignard reagents using a 1,3-butadiene additive.

    Science.gov (United States)

    Iwasaki, Takanori; Takagawa, Hiroaki; Singh, Surya P; Kuniyasu, Hitoshi; Kambe, Nobuaki

    2013-07-03

    The cobalt-catalyzed cross-coupling of alkyl (pseudo)halides with alkyl Grignard reagents in the presence of 1,3-butadiene as a ligand precursor and LiI is described. Sterically congested quaternary carbon centers could be constructed by using tertiary alkyl Grignard reagents. This reaction proceeds via an ionic mechanism with inversion of stereochemistry at the reacting site of the alkyl halide and is compatible with various functional groups. The use of both 1,3-butadiene and LiI was essential for achieving high yields and high selectivities.

  12. Resolution of ibuprofen: a project for an experimental organic chemistry course; Resolucao do ibuprofeno: um projeto para disciplina de quimica organica experimental

    Energy Technology Data Exchange (ETDEWEB)

    Romero, Adriano L.; Baptistella, Lucia H.B.; Coelho, Fernando; Imamura, Paulo M., E-mail: imam@iqm.unicamp.br [Universidade Estadual de Campinas, SP (Brazil). Inst. de Quimica

    2012-07-01

    A practical and didactic sequence of experiments was proposed to illustrate the stereochemistry concept, optically active compounds, resolution of racemates, and use of the NMR technique, including 2D-COSY for identification of organic compounds, on a laboratory course for undergraduate students. The sequence was: extractions of racemic ibuprofen and chiral naproxen from commercial tablets; syntheses of diastereoisomeric amides reacting chiral (S)-(-)-{alpha}-methylbenzylamine with (+-)-ibuprofen; separation and determination of absolute configuration of amides by {sup 1}H NMR spectroscopy and GC analysis, and hydrolysis of amides to obtain (+)- and (-)-ibuprofen. (author)

  13. Sesquiterpenes produced by endophytic fungus Phomopsis cassiae with antifungal and acetylcholinesterase inhibition activities; Sesquiterpenos produzidos pelo fungo endofitico Phomopsis cassiae com atividade antifungica e inibidora de acetilcolinesterase

    Energy Technology Data Exchange (ETDEWEB)

    Zanardi, Lisineia M.; Bolzani, Vanderlan da S.; Cavalheiro, Alberto J.; Silva, Dulce H. Siqueira; Trevisan, Henrique C.; Araujo, Angela R. [UNESP, Araraquara, SP (Brazil). Inst. de Quimica; Silva, Geraldo H. [Universidade Federal de Sergipe (UFS), Aracaju, SE (Brazil). Centro de Ciencias Exatas e Tecnologia; Teles, Helder L. [Universidade Federal do Mato Grosso (UFMT), Rondonopolis, MT (Brazil). Dept. de Ciencias Biologicas; Young, Maria Claudia M., E-mail: araujoar@iq.unesp.br [Instituto de Botanica, Sao Paulo, SP (Brazil). Seccao de Fisiologia e Bioquimica de Plantas

    2012-07-01

    Two new diastereoisomeric cadinanes sesquiterpenes 3,9-dihydroxycalamenene (1-2), along with the known 3-hydroxycalamen-8-one (3) and aristelegone-A (4), were isolated from ethyl acetate extract of Phomopsis cassiae, an endophytic fungus in Cassia spectabilis. Their structures, including relative stereochemistry, were determined on the basis of detailed interpretation of 2D NMR spectra and comparison with related known compounds. Compounds 1-4 displayed antifungal activity against the phytopathogenic fungi Cladosporium cladosporioides and C. sphaerospermum, as well as inhibition of acetylcholinesterase. (author)

  14. Radioimmunoassay for the citrus bitter principle, naringin, and related flavonoid-7-O-neohesperidosides

    Energy Technology Data Exchange (ETDEWEB)

    Jourdan, P.S.; Weiler, E.W.; Mansell, R.L.

    1982-02-01

    An immunoassay for the citrus bitter principle, naringin, and related flavonoid-7-O-neohesperidosides is reported. The assay detects ca. 2 ng of naringin and can be used to quantify this compound in the parts per billion (ppb) range in crude grapefruit juice and extracts of other plant tissues. The antiserum used is highly reactive with the 2-rhamnosyl-1-glucopyranose at the C-7 position but not with e.g. the isomeric 6-rhamnosyl-1-glucopyranose moiety and can, thus, be used to identify the stereochemistry of this disaccharide moiety at the C-7 position of flavanoids. The assay involves a directly iodinated naringin-(/sup 125/I) as immunotracer.

  15. Chiral Building Blocks: Enantioselective Syntheses of Benzyloxymethyl Phenyl Propionic Acids

    OpenAIRE

    Parsons, Jack G.; Stachurska-Buczek, Danuta; Choi, Neil; Griffiths, Peter G.; Huggins, Daniel A.; Krywult, Beata M.; Marino, Sharon T.; Nguyen, Thao; Sheehan, Craig S.; James, Ian W.; Bray, Andrew M.; White, Jonathan M.; Boyce, Rustum S.

    2004-01-01

    The synthesis of (2S)-2-benzyloxymethyl-3-(2-fluoro-4-methoxyphenyl)- propionic acid, (2S)-2-benzyloxymethyl-3-(2-fluoro-4-methylphenyl)propionic acid and (2S)-2-benzyl-oxymethyl-3-(2,4-dimethylphenyl)propionic acid has been achieved by TiCl4 mediated alkylation of the corresponding (4R)-4-benzyl-3-[3-(2-fluoro-4-methoxyphenyl-, 2-fluoro-4-methylphenyl-, 2,4- dimethylphenyl-)propionyl]-2-oxazolidinones, followed by hydrolysis of the chiral auxiliary. The stereochemistry of the alkylation reac...

  16. Highly Diastereoselective Synthesis of 2-(1-N-Boc-aminoalkyl)thiazole-5-carboxylates by Reduction of tert-Butylsulfinyl Ketimines.

    Science.gov (United States)

    Magata, Takuji; Hirokawa, Yoshimi; Furokawa, Aya; Takeuchi, Kazuhisa; Ohtomo, Yoshiaki; Kino, Toshitaka; Kominami, Jun; Nakai, Yuto; Kitamura, Maria; Maezaki, Naoyoshi

    2018-01-01

    Positional isomers of naturally occurring peptide subunits were synthesized via highly diastereoselective reduction of tert-butylsulfinyl ketimines as a key reaction. While NaBH 4 reduction of ketimines derived from 2-thiazolyl ketones afforded the (R S ,R)-isomer with moderate diastereoselectivity, L-Selectride ® reduction afforded the (R S ,S)-isomer as the sole product. In contrast, ketimines derived from tert-butyl 2-thiazolyl ketone afforded the (R S ,R)-isomer with low diastereoselectivity by both NaBH 4 and L-Selectride ® reduction. Stereochemistry of the reaction was discussed based on calculation of the conformational energies for ketimines.

  17. Study on the spatial structure of annomuricatin A, a cyclohexapeptide from the seeds of Annona muricata

    Science.gov (United States)

    Wu, Li; Lu, Yang; Zheng, Qi-Tai; Tan, Ning-Hua; Li, Chao-Ming; Zhou, Jun

    2007-02-01

    A cyclic hexapeptide, annomuricatin A (the molecular formula: C 27H 38N 6O 7), was isolated from the seeds of Annona muricata. The types and sequence of the amino acids were confirmed by X-ray diffraction analysis. The stereochemistry of the title cyclopeptide was clarified by X-ray crystallographic study. The backbone contains two β-turns, one is type I β-turn and the other is type II, which are stabilized by two transannular 4 → 1 backbone hydrogen bonds between Ala and Phe. There are intermolecular hydrogen bonds between the cyclopeptide and the solvent molecules which maintained the steady spatial arrangement in crystal.

  18. Total synthesis of (±)-antroquinonol d.

    Science.gov (United States)

    Sulake, Rohidas S; Jiang, Yan-Feng; Lin, Hsiao-Han; Chen, Chinpiao

    2014-11-21

    Total synthesis of (±)-antroquinonol D, which is isolated from very expensive and rarely found Antrodia camphorata and which has potential anticancer properties, was achieved from 4-methoxyphenol. In addition, a Michael addition to dimethoxy cyclohexadienones was studied. The main step involved chelation and substrate-controlled diastereoselective reduction of cyclohexenone and lactonization. Lactone synthesis facilitated the diastereoselective reduction of ketone, which help control the desired stereochemistry at the crucial stereogenic center in the natural product. Other key reactions in the synthesis involved a Michael addition of dimethyl malonate on cyclohexadienone, dihydroxylation, and Wittig olefination. A sesquiterpene side chain was synthesized through coupling with geranyl phenyl sulfide and Bouveault-Blanc reduction.

  19. Isolation and structure of prorocentrolide B, a fast-acting toxin from Prorocentrum maculosum.

    Science.gov (United States)

    Hu, T; deFreitas, A S; Curtis, J M; Oshima, Y; Walter, J A; Wright, J L

    1996-11-01

    A new toxin, prorocentrolide B (1), has been isolated following bioassay-guided fractionation of a BuOH extract of the tropical dinoflagellate, Prorocentrum maculosum Faust. This compound produces a rapid toxic response in the mouse bioassay, a type of activity not accounted for by other diarrhetic shellfish poisoning toxins produced by P. maculosum. The structure 1 was established by NMR and MS and is similar to prorocentrolide (2), a toxin from a strain of Prorocentrum lima. NMR data and the modeling program ConGen have been used to establish the relative stereochemistry of some individual ether ring systems and the hexahydroisoquinoline ring.

  20. Palladium-catalyzed arylation of enoates with iodobenzene: stereoselective synthesis of trisubstituted olefins

    International Nuclear Information System (INIS)

    Fernandes, Talita de A.; Universidade Federal do Rio de Janeiro; Silva, Alcides J.M. da; Costa, Paulo R.R.; Esteves, Pierre M.; Eberlin, Marcos N.; Vaz, Boniek G.; Universidade Federal de Goias

    2013-01-01

    The Heck reaction between E- and Z-enoates and iodobenzene was studied in the presence of Pd(OAc) 2 . The stereochemistry in resulting adducts was dependent on the enoate geometry (stereospecific reaction). Best yields were obtained from Z-isomers in acetone using Ag 2 CO 3 as base. The main cationic palladium intermediates possibly involved in the catalytic cycle could be intercepted and characterized by electrospray ionization mass spectrometry (ESI-MS). The stereoselectivity observed was rationalized through the classic mechanism of the Heck reaction. (author)

  1. New dammarane triterpenes from the aerial parts of Ibicella lutea grown in Argentina.

    Science.gov (United States)

    Simirgiotis, Mario J; Jiménez, Carlos; Rodríguez, Jaime; Giordano, Oscar S; Tonn, Carlos E

    2003-12-01

    Two new dammarane triterpenes have been isolated from the aerial parts of Ibicella lutea, 3-acetyl-24-epi-polacandrin (1) and 1,3-diacetyl-24-epi-polacandrin (2), and were obtained along with the known compounds 20S,24S-epoxy-3beta,12beta,25-trihydroxydammarane (3) and apigenin. The structures of compounds 1 and 2 were deduced by spectroscopic studies and by chemical transformations leading to the preparation of derivatives 4-11. The structure and relative stereochemistry of 1 were verified by single-crystal X-ray analysis. The natural compounds and selected semisynthetic derivatives were evaluated against several tumor cells.

  2. Chiral transfer in coordination complexes: towards molecular materials.

    Science.gov (United States)

    Crassous, Jeanne

    2009-03-01

    In this critical review we present examples of coordination complexes with efficient chiral transfer determining stereochemistry at the metal centre and throughout the overall molecular assembly. The general features controlling the transmission of chirality are presented. The transfer of chirality are considered here with the special purpose of obtaining a molecular material displaying a particular property or function. Coordination complexes in fields as diverse as chiral luminescent materials, homochiral MOFs, chiral liquid crystals, enantioselective sensors, chiroptical switches, and magnetochiral compounds are presented (162 references).

  3. New catalysts and new synthetic applications for hydroformylation

    Energy Technology Data Exchange (ETDEWEB)

    Breit, B. [Albert-Ludwigs-Univ. Freiburg (Germany). Inst. fuer Organische Chemie und Biochemie

    2006-07-01

    In the course of this lecture most recent advances in rhodium catalyzed hydroformylation and its use in organic synthesis are presented. Particular emphasis is given to regioselective hydroformylation of terminal alkenes and its application to fine chemical synthesis as well as latest results and applications of asymmetric hydroformylation. Furthermore, a new concept for simultaneous control of regio- and stereochemistry employing catalyst-directing groups will be discussed in detail. Finally, a new concept for catalyst library generation based on ligand-self-assembly through complementary hydrogen bonding and its application to regioselective hydroformylation as well as asymmetric hydrogenation is presented. (orig.)

  4. Palladium-catalyzed arylation of enoates with iodobenzene: stereoselective synthesis of trisubstituted olefins

    Energy Technology Data Exchange (ETDEWEB)

    Fernandes, Talita de A. [Universidade Federal do Rio de Janeiro (UFRJ/LQB), RJ (Brazil). Nucleo de Pesquisas de Produtos Naturais. Laboratorio de Quimica Bioorganica; Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Instituto de Quimica. Interlab; Silva, Alcides J.M. da; Costa, Paulo R.R., E-mail: prrcosta2011@gmail.com [Universidade Federal do Rio de Janeiro (UFRJ/LQB), RJ (Brazil). Nucleo de Pesquisas de Produtos Naturais. Laboratorio de Quimica Bioorganica; Esteves, Pierre M. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Instituto de Quimica. Interlab; Eberlin, Marcos N., E-mail: eberlin@iqm.unicamp.br [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Instituto de Quimica. Laboratorio ThoMSon de Espectrometria de Massas; Vaz, Boniek G. [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Instituto de Quimica. Laboratorio ThoMSon de Espectrometria de Massas; Universidade Federal de Goias (UFGO), Goiania, GO (Brazil). Instituto de QuImica

    2013-03-15

    The Heck reaction between E- and Z-enoates and iodobenzene was studied in the presence of Pd(OAc){sub 2}. The stereochemistry in resulting adducts was dependent on the enoate geometry (stereospecific reaction). Best yields were obtained from Z-isomers in acetone using Ag{sub 2} CO{sub 3} as base. The main cationic palladium intermediates possibly involved in the catalytic cycle could be intercepted and characterized by electrospray ionization mass spectrometry (ESI-MS). The stereoselectivity observed was rationalized through the classic mechanism of the Heck reaction. (author)

  5. Synthesis of Silyloxy Dienes by Silylene Tranfer to Divinyl Ketones: Application to the Asymmetric Sythesis of Substituted Cyclohexanes

    Science.gov (United States)

    Ventocilla, Christian C.; Woerpel, K. A.

    2012-01-01

    Silver-catalyzed silylene transfer to divinyl ketones provided 2-silyloxy-1,3-dienes with control of stereochemistry and regioselectivity. The products participated in Diels–Alder reactions with electron-deficient alkenes and imines to form six-membered ring products diastereoselectively. Cycloaddition reactions with alkenes bearing chiral auxiliaries provided access to chiral, non-racemic cyclohexenes. The methodology therefore represents a synthesis of diastereomerically and enantiomerically pure products in a single flask. The highly substituted cyclohexene products could be functionalized stereoselectively to provide cyclohexanols after oxidation of the carbon–silicon bond. PMID:22372733

  6. Synthesis of silyloxy dienes by silylene transfer to divinyl ketones: application to the asymmetric synthesis of substituted cyclohexanes.

    Science.gov (United States)

    Ventocilla, Christian C; Woerpel, K A

    2012-04-06

    Silver-catalyzed silylene transfer to divinyl ketones provided 2-silyloxy-1,3-dienes with control of stereochemistry and regioselectivity. The products participated in Diels-Alder reactions with electron-deficient alkenes and imines to form six-membered-ring products diastereoselectively. Cycloaddition reactions with alkenes bearing chiral auxiliaries provided access to chiral, nonracemic cyclohexenes. The methodology, therefore, represents a synthesis of diastereomerically and enantiomerically pure products in a single flask. The highly substituted cyclohexene products could be functionalized stereoselectively to provide cyclohexanols after oxidation of the carbon-silicon bond.

  7. Synthesis and Microbiological Evaluation of Novel Tetracyclic Fluoroquinolones.

    Science.gov (United States)

    Wagman, Allan S; Cirz, Ryan; McEnroe, Glenn; Aggen, James; Linsell, Martin S; Goldblum, Adam A; Lopez, Sara; Gomez, Marcela; Miller, George; Simons, Lloyd J; Belliotti, Thomas R; Harris, Christina R; Poel, Toni-Jo; Melnick, Michael J; Gaston, Ricky D; Moser, Heinz E

    2017-10-20

    Conformationally constrained tetracyclic fluoroquinolones (FQs) were synthesized and profiled for their microbiological spectrum. The installation of a seven-membered ring between the pyrrolidine substituents and the C8 position on the FQ core scaffold resulted in a remarkable enhancement of microbiological potency toward both Gram-positive and Gram-negative bacteria. Focused optimization of seven-membered ring composition, stereochemistry, and amine placement led to the discovery of the two lead compounds that were selected for further progression. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Solid-phase synthesis of complex and pharmacologically interesting heterocycles

    DEFF Research Database (Denmark)

    Nielsen, Thomas Eiland

    2009-01-01

    with significant structural complexity and diversity. This review describes some of the most systematic solid-phase approaches that are potentially suited for pharmaceutical applications, that is, the methods described are useful for the synthesis of compound collections, and exhibit tunable stereochemistry......Efficient routes for the creation of heterocycles continue to be one of the primary goals for solid-phase synthesis. Recent advances in this field rely most notably on transition-metal-catalysis and N-acyliminium chemistry to mediate a range of cyclization processes for the generation of compounds...

  9. Camphor: a good model for illustrating NMR techniques; Canfora: um bom modelo para ilustrar tecnicas de RMN

    Energy Technology Data Exchange (ETDEWEB)

    Yoneda, Julliane Diniz; Leal, Katia Zaccur [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil). Dept. de Fisico-Quimica]. E-mail: kzl@rmn.uff.br; Seidl, Peter Rudolf [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Escola de Quimica. Dept. de Processos Organicos; Azeredo, Rodrigo Bagueira de V. [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil). Inst. de Quimica. Dept. de Quimica Organica; Kleinpeter, Erich [Universitaet Potsdam (Germany). Chemisches Institut

    2007-07-01

    The use of Nuclear Magnetic Resonance spectroscopy to establish the three-dimensional structures of molecules is an important component of modern Chemistry courses. The combination of techniques that can be used for this purpose is conveniently illustrated by their application to the camphor molecule. This paper presents applications of several techniques used in NMR spectral interpretation in an increasing order of complexity. The result of individual experiments is illustrated in order to familiarize the user with the way connectivity through bonds and through space is established from 1D/2D-NMR spectra and molecular stereochemistry is determined from different NMR experiments. (author)

  10. Cânfora: um bom modelo para ilustrar técnicas de RMN Camphor: a good model for illustrating NMR techniques

    Directory of Open Access Journals (Sweden)

    Julliane Diniz Yoneda

    2007-01-01

    Full Text Available The use of Nuclear Magnetic Resonance spectroscopy to establish the three-dimensional structures of molecules is an important component of modern Chemistry courses. The combination of techniques that can be used for this purpose is conveniently illustrated by their application to the camphor molecule. This paper presents applications of several techniques used in NMR spectral interpretation in an increasing order of complexity. The result of individual experiments is illustrated in order to familiarize the user with the way connectivity through bonds and through space is established from 1D/2D-NMR spectra and molecular stereochemistry is determined from different NMR experiments.

  11. SÍNTESE E DETERMINAÇÃO DA ESTEREOQUÍMICA RELATIVA DE UM NOVO EPÓXIDO ALDEÍDO CICLOPENTANO MONOTERPENÓIDE

    Directory of Open Access Journals (Sweden)

    Reginaldo B. dos Santos

    2015-12-01

    Full Text Available In this study, we report the preparation of a new tetra-substituted epoxide aldehyde cyclopentane, which acts as a starting material for the synthesis of plinol, from (R-(+-epoxy-limonene. The synthesis was performed in three steps and resulted in a good yield. The structural determination was performed by 1H and 13C NMR, and the relative stereochemistry was defined by nuclear Overhauser effect (NOE experiments with computer calculations of molecular modeling, particularly with respect to indirect coupling constant calculations.

  12. (+)-7S-Hydroxyxestospongin A from the marine sponge Xestospongia sp. and absolute configuration of (+)-xestospongin D.

    Science.gov (United States)

    Moon, Surk-Sik; MacMillan, John B; Olmstead, Marilyn M; Ta, Tram Anh; Pessah, Isaac N; Molinski, Tadeusz F

    2002-03-01

    The structure of the title compound, (+)-7S-hydroxyxestospongin A was solved by single-crystal X-ray diffraction analysis and the absolute stereochemistry obtained by analysis of the derived R and S Mosher's esters. The absolute configuration of xestospongin D was determined for the first time by analysis of anomalous scattering from the X-ray crystal diffraction data set. Xestospongins A, C, and D, araguspongine C, and demethylxestospongin B exhibited modest antifungal activity (MIC 30-100 g/mL) against various fluconazole-resistant Candida spp., but 7S-hydroxyxestospongin A was inactive.

  13. Synthesis of Pyrrolo[1,2-a]pyrimidine Enantiomers via Domino Ring-Closure followed by Retro Diels-Alder Protocol.

    Science.gov (United States)

    Fekete, Beáta; Palkó, Márta; Haukka, Matti; Fülöp, Ferenc

    2017-04-13

    From 2-aminonorbornene hydroxamic acids, a simple and efficient method for the preparation of pyrrolo[1,2- a ]pyrimidine enantiomers is reported. The synthesis is based on domino ring-closure followed by microwave-induced retro Diels-Alder (RDA) protocols, where the chirality of the desired products is transferred from norbornene derivatives. The stereochemistry of the synthesized compounds was proven by X-ray crystallography. The absolute configuration of the product is determined by the configuration of the starting amino hydroxamic acid.

  14. Synthesis of Pyrrolo[1,2-a]pyrimidine Enantiomers via Domino Ring-Closure followed by Retro Diels-Alder Protocol

    Directory of Open Access Journals (Sweden)

    Beáta Fekete

    2017-04-01

    Full Text Available From 2-aminonorbornene hydroxamic acids, a simple and efficient method for the preparation of pyrrolo[1,2-a]pyrimidine enantiomers is reported. The synthesis is based on domino ring-closure followed by microwave-induced retro Diels-Alder (RDA protocols, where the chirality of the desired products is transferred from norbornene derivatives. The stereochemistry of the synthesized compounds was proven by X-ray crystallography. The absolute configuration of the product is determined by the configuration of the starting amino hydroxamic acid.

  15. Umezawamides, new bioactive polycyclic tetramate macrolactams isolated from a combined-culture of Umezawaea sp. and mycolic acid-containing bacterium.

    Science.gov (United States)

    Hoshino, Shotaro; Wong, Chin Piow; Ozeki, Masahiro; Zhang, Huiping; Hayashi, Fumiaki; Awakawa, Takayoshi; Asamizu, Shumpei; Onaka, Hiroyasu; Abe, Ikuro

    2018-03-14

    New polycyclic tetramate macrolactams, Umezawamides A (1) and B (2) were isolated from a combined-culture of Umezawaea sp. RD066910 and mycolic-acid containing bacterium Tsukamurella pulmonis TP-B0596. Their planar structures and partial stereochemistries were determined based on the spectroscopic analysis, MMFF conformational search, and ECD calculations. Umezawamides are the first secondary metabolites isolated from the genus Umezawaea and they exhibited cytotoxicities to P388 murine leukemia cells. Furthermore, umezawamide A (1) showed growth inhibitory activity against Candida albicans.

  16. Emil Fischer and the "art of chemical experimentation".

    Science.gov (United States)

    Jackson, Catherine M

    2017-03-01

    What did nineteenth-century chemists know? This essay uses Emil Fischer's classic study of the sugars in 1880s and 90s Germany to argue that chemists' knowledge was not primarily vested in the theories of valence, structure, and stereochemistry that have been the subject of so much historical and philosophical analysis of chemistry in this period. Nor can chemistry be reduced to a merely manipulative exercise requiring little or no intellectual input. Examining what chemists themselves termed the "art of chemical experimentation" reveals chemical practice as inseparable from its cognitive component, and it explains how chemists integrated theory with experiment through reason.

  17. Organocatalytic highly enantioselective nitroaldol reaction of alpha-ketophosphonates and nitromethane.

    Science.gov (United States)

    Mandal, Tanmay; Samanta, Sampak; Zhao, Cong-Gui

    2007-03-01

    [reaction: see text] The first organocatalytic highly enantioselective nitroaldol reaction of alpha-ketophosphonates and nitromethane has been realized by using cupreine (2) or 9-O-benzylcupreine (3) as the catalyst. Both catalysts are highly reactive and highly enantioselective. alpha-Hydroxy-beta-nitrophosphonates have been synthesized in good yields and excellent enantioselectivities (>or=90% ee) at a low catalyst loading (5 mol %). These nitroaldol products may be reduced to the biologically significant beta-amino-alpha-hydroxyphosphonates with complete retention of the stereochemistry.

  18. Structural aspects of some hydrobenzofuran neolignans

    International Nuclear Information System (INIS)

    Yoshida, Massayoshi

    2012-01-01

    The neolignans are defined as dimers of allylphenol and propenylphenol between itself or crossed, whose bond does not occur by the 8-8' carbons like lignans. This review centered on stereochemical aspects of the hydrobenzofuran type, a widespread skeleton among neolignans. The chemical structures established based on spectrometric data are registered in the literature. The absolute configurations reported previously were determined by chiroptical techniques. Some chemical transformations with neolignans, performed in previous studies, afforded products which are accumulated in other vegetal species and contributed to assign the unknown stereochemistry of these natural compounds. Possible biosynthetic pathways are also proposed. (author)

  19. The three-dimensional crystal structure of cholera toxin

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Rong-Guang; Westbrook, M.L.; Nance, S.; Spangler, B.D. [Argonne National Lab., IL (United States); Scott, D.L. [Yale Univ., New Haven, CT (United States). Dept. of Molecular Biophysics and Biochemistry; Westbrook, E.M. [Northwestern Univ., Evanston, IL (United States)

    1996-02-01

    The clinical manifestations of cholera are largely attributable to the actions of a secreted hexameric AB{sub 5} enterotoxin (choleragen). We have solved the three-dimensional structure of choleragen at 2.5 {Angstrom} resolution and compared the refined coordinates with those of choleragenoid (isolated B pentamer) and the heat-labile enterotoxin from Escherichia coli (LT). The crystalline coordinates provide a detailed view of the stereochemistry implicated in binding to GM1 gangliosides and in carrying out ADP-ribosylation. The A2 chain of choleragen, in contrast to that of LT, is a nearly continuous {alpha}-helix with an interpretable carboxyl tail.

  20. A novel alkaloid isolated from Crotalaria paulina and identified by NMR and DFT calculations

    Science.gov (United States)

    Oliveira, Ramon Prata; Demuner, Antonio Jacinto; Alvarenga, Elson Santiago; Barbosa, Luiz Claudio Almeida; de Melo Silva, Thiago

    2018-01-01

    Pyrrolizidine alkaloids (PAs) are secondary metabolites found in Crotalaria genus and are known to have several biological activities. A novel macrocycle bislactone alkaloid, coined ethylcrotaline, was isolated and purified from the aerial parts of Crotalaria paulina. The novel macrocycle was identified with the aid of high resolution mass spectrometry and advanced nuclear magnetic resonance techniques. The relative stereochemistry of the alkaloid was defined by comparing the calculated quantum mechanical hydrogen and carbon chemical shifts of eight candidate structures with the experimental NMR data. The best fit between the eight candidate structures and the experimental NMR chemical shifts was defined by the DP4 statistical analyses and the Mean Absolute Error (MAE) calculations.