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Sample records for ansamblil stereochemistry ilmus

  1. 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"

  2. 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")

  3. Bagatellid : maailm / Nele-Eva Steinfeld, Ivo Heinloo

    Index Scriptorium Estoniae

    Steinfeld, Nele-Eva

    2010-01-01

    Lühisõnumaid maailmast: Vene pianist Julianna Avdejeva saavutas XVI rahvusvahelisel Chopini konkursil Varssavis võidu. Suri poola helilooja Henryk Mikolaj Gorecki. Daniel Barenboimi 60 lava-aastat. Suri dirigent ja vioolamängija Rudolf Baršai. Kitarrilegend Sonny Sharrock sai oma kodulinnas enda nimelise tänava. 23. Thelonious Monki nimelise jazzkonkursi võitis Cecile McLorin Salvant. Youn Sun Nah Prantsuse müügiedetabeli tipus. Ansamblil Jamiroquai ilmus uus plaat. Suri saksofonist Marion Brown

  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. 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”)

  6. 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.

  7. 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.

  8. Stereochemistry in subcomponent self-assembly.

    Science.gov (United States)

    Castilla, Ana M; Ramsay, William J; Nitschke, Jonathan R

    2014-07-15

    CONSPECTUS: As Pasteur noted more than 150 years ago, asymmetry exists in matter at all organization levels. Biopolymers such as proteins or DNA adopt one-handed conformations, as a result of the chirality of their constituent building blocks. Even at the level of elementary particles, asymmetry exists due to parity violation in the weak nuclear force. While the origin of homochirality in living systems remains obscure, as does the possibility of its connection with broken symmetries at larger or smaller length scales, its centrality to biomolecular structure is clear: the single-handed forms of bio(macro)molecules interlock in ways that depend upon their handednesses. Dynamic artificial systems, such as helical polymers and other supramolecular structures, have provided a means to study the mechanisms of transmission and amplification of stereochemical information, which are key processes to understand in the context of the origins and functions of biological homochirality. Control over stereochemical information transfer in self-assembled systems will also be crucial for the development of new applications in chiral recognition and separation, asymmetric catalysis, and molecular devices. In this Account, we explore different aspects of stereochemistry encountered during the use of subcomponent self-assembly, whereby complex structures are prepared through the simultaneous formation of dynamic coordinative (N → metal) and covalent (N═C) bonds. This technique provides a useful method to study stereochemical information transfer processes within metal-organic assemblies, which may contain different combinations of fixed (carbon) and labile (metal) stereocenters. We start by discussing how simple subcomponents with fixed stereogenic centers can be incorporated in the organic ligands of mononuclear coordination complexes and communicate stereochemical information to the metal center, resulting in diastereomeric enrichment. Enantiopure subcomponents were then

  9. 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,…

  10. using stereochemistry models in teaching organic compounds

    African Journals Online (AJOL)

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    The purpose of the study was to find out the effect of stereochemistry models on students' ... consistent with the names given to organic compounds. Some of ... Considering class level, what is the performance of the students in naming organic.

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

    African Journals Online (AJOL)

    Determination of the stereochemistry of 4-chromenecarbaldehydes using Nuclear Overhauser Enhancements (NOE) ... Journal of the Ghana Science Association ... The paper reports studies on the use of 4-chromenecarbaldehydes as suitable substrates for the assessment of the accuracy of interpretations of Nuclear ...

  12. Stereochemistry of 1,2-elimination and proton-transfer reactions: toward a unified understanding.

    Science.gov (United States)

    Mohrig, Jerry R

    2013-07-16

    Many mechanistic and stereochemical studies have focused on the breaking of the C-H bond through base-catalyzed elimination reactions. When we began our research, however, chemists knew almost nothing about the stereospecificity of addition-elimination reactions involving conjugated acyclic carbonyl compounds, even though the carbonyl group is a pivotal functional group in organic chemistry. Over the last 25 years, we have studied the addition-elimination reactions of β-substituted acyclic esters, thioesters, and ketones in order to reach a comprehensive understanding of how electronic effects influence their stereochemistry. This Account brings together our understanding of the stereochemistry of 1,2-elimination and proton-transfer reactions, describing how each study has built upon previous work and contributed to our understanding of this field. When we began, chemists thought that anti stereospecificity in base-catalyzed 1,2-elimination reactions occurred via concerted E2 mechanisms, which provide a smooth path for anti elimination. Unexpectedly, we discovered that some E1cBirrev reactions produce the same anti stereospecificity as E2 reactions even though they proceed through diffusionally equilibrated, "free" enolate-anion intermediates. This result calls into question the conventional wisdom that anti stereochemistry must result from a concerted mechanism. While carrying out our research, we developed insights ranging from the role of historical contingency in the evolution of hydratase-dehydratase enzymes to the influence of buffers on the stereochemistry of H/D exchange in D2O. Negative hyperconjugation is the most important concept for understanding our results. This idea provides a unifying view for the largely anti stereochemistry in E1cBirrev elimination reactions and a basis for understanding the stereoelectronic influence of electron-withdrawing β-substituents on proton-transfer reactions.

  13. 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.

  14. 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

  15. Hexuronic Acid Stereochemistry Determination in Chondroitin Sulfate Glycosaminoglycan Oligosaccharides by Electron Detachment Dissociation

    Science.gov (United States)

    Leach, Franklin E.; Ly, Mellisa; Laremore, Tatiana N.; Wolff, Jeremy J.; Perlow, Jacob; Linhardt, Robert J.; Amster, I. Jonathan

    2012-09-01

    Electron detachment dissociation (EDD) has previously provided stereo-specific product ions that allow for the assignment of the acidic C-5stereochemistry in heparan sulfate glycosaminoglycans (GAGs), but application of the same methodology to an epimer pair in the chondroitin sulfate glycoform class does not provide the same result. A series of experiments have been conducted in which glycosaminoglycan precursor ions are independently activated by electron detachment dissociation (EDD), electron induced dissociation (EID), and negative electron transfer dissociation (NETD) to assign the stereochemistry in chondroitin sulfate (CS) epimers and investigate the mechanisms for product ion formation during EDD in CS glycoforms. This approach allows for the assignment of electronic excitation products formed by EID and detachment products to radical pathways in NETD, both of which occur simultaneously during EDD. The uronic acid stereochemistry in electron detachment spectra produces intensity differences when assigned glycosidic and cross-ring cleavages are compared. The variations in the intensities of the doubly deprotonated 0,2X3 and Y3 ions have been shown to be indicative of CS-A/DS composition during the CID of binary mixtures. These ions can provide insight into the uronic acid composition of binary mixtures in EDD, but the relative abundances, although reproducible, are low compared with those in a CID spectrum acquired on an ion trap. The application of principal component analysis (PCA) presents a multivariate approach to determining the uronic acid stereochemistry spectra of these GAGs by taking advantage of the reproducible peak distributions produced by electron detachment.

  16. DAG tales: the multiple faces of diacylglycerol--stereochemistry, metabolism, and signaling.

    Science.gov (United States)

    Eichmann, Thomas Oliver; Lass, Achim

    2015-10-01

    The neutral lipids diacylglycerols (DAGs) are involved in a plethora of metabolic pathways. They function as components of cellular membranes, as building blocks for glycero(phospho)lipids, and as lipid second messengers. Considering their central role in multiple metabolic processes and signaling pathways, cellular DAG levels require a tight regulation to ensure a constant and controlled availability. Interestingly, DAG species are versatile in their chemical structure. Besides the different fatty acid species esterified to the glycerol backbone, DAGs can occur in three different stereo/regioisoforms, each with unique biological properties. Recent scientific advances have revealed that DAG metabolizing enzymes generate and distinguish different DAG isoforms, and that only one DAG isoform holds signaling properties. Herein, we review the current knowledge of DAG stereochemistry and their impact on cellular metabolism and signaling. Further, we describe intracellular DAG turnover and its stereochemistry in a 3-pool model to illustrate the spatial and stereochemical separation and hereby the diversity of cellular DAG metabolism.

  17. 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....

  18. Stereogame: An Interactive Computer Game That Engages Students in Reviewing Stereochemistry Concepts

    Science.gov (United States)

    da Silva, Jose´ Nunes, Jr.; Lima, Mary Anne Sousa; Moreira, Joao Victor Xerez; Alexandre, Francisco Serra Oliveira; de Almeida, Diego Macedo; de Oliveira, Maria da Conceicao Ferreira; Leite, Antonio Jose´ Melo, Jr.

    2017-01-01

    This report provides information about an interactive computer game that allows undergraduate students to review individually stereochemistry topics in an engaging way by responding to 230 novel questions distributed at three difficulty levels. Responses from students and instructors who have played the game have been quite positive. Stereogame is…

  19. Sesquiterpene lactone stereochemistry influences herbivore resistance and plant fitness in the field.

    Science.gov (United States)

    Ahern, Jeffrey R; Whitney, Kenneth D

    2014-03-01

    Stereochemical variation is widely known to influence the bioactivity of compounds in the context of pharmacology and pesticide science, but our understanding of its importance in mediating plant-herbivore interactions is limited, particularly in field settings. Similarly, sesquiterpene lactones are a broadly distributed class of putative defensive compounds, but little is known about their activities in the field. Natural variation in sesquiterpene lactones of the common cocklebur, Xanthium strumarium (Asteraceae), was used in conjunction with a series of common garden experiments to examine relationships between stereochemical variation, herbivore damage and plant fitness. The stereochemistry of sesquiterpene lactone ring junctions helped to explain variation in plant herbivore resistance. Plants producing cis-fused sesquiterpene lactones experienced significantly higher damage than plants producing trans-fused sesquiterpene lactones. Experiments manipulating herbivore damage above and below ambient levels found that herbivore damage was negatively correlated with plant fitness. This pattern translated into significant fitness differences between chemotypes under ambient levels of herbivore attack, but not when attack was experimentally reduced via pesticide. To our knowledge, this work represents only the second study to examine sesquiterpene lactones as defensive compounds in the field, the first to document herbivore-mediated natural selection on sesquiterpene lactone variation and the first to investigate the ecological significance of the stereochemistry of the lactone ring junction. The results indicate that subtle differences in stereochemistry may be a major determinant of the protective role of secondary metabolites and thus of plant fitness. As stereochemical variation is widespread in many groups of secondary metabolites, these findings suggest the possibility of dynamic evolutionary histories within the Asteraceae and other plant families showing

  20. 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.

  1. 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 chloride anion shows that the first coordination spheres of the chlorides are essentially constituted by hydrogen bond donors. Amongst the side-chains positively charged, arginine interacts with chlorides much more frequently than lysine. Although the most common coordination number is 4, the coordination stereochemistry is closer to the expected geometry when the coordination number is 5, suggesting that this is the coordination number towards which the chlorides tend when they interact with proteins. The results of these analyses are useful in interpreting, describing, and validating new protein crystal structures that contain chloride anions.

  2. 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.

  3. Correlation between stereochemistry and optical activity of chiral dimolybdenum tetracarboxylates and related compounds

    International Nuclear Information System (INIS)

    Klyagina, A.P.; Golovaneva, I.F.; Sadikova, G.G.

    1990-01-01

    Using one-electron model of optical activity sector rules for chiral tetracarboxylates of molybdenum and related compounds are derived. Correlation between the sign of the Cotton effect (CE) of δ-δ * -transition and stereochemistry of this type of binuclear clusters is expressed in the form of hexadecant rule, in which positive sign of CE corresponds to the negative sign of pseudoscalar function xyz(x 2 -y 2 ) of the cluster atoms. Negative sign of CE is predicted for δ-δ * -transition in cis-(L-isoleucine) 2 (NCS) 4 Mo 2

  4. 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

  5. Stereochemistry of quinoxaline antagonist binding to a glutamate receptor investigated by Fourier transform infrared spectroscopy.

    Science.gov (United States)

    Madden, D R; Thiran, S; Zimmermann, H; Romm, J; Jayaraman, V

    2001-10-12

    The stereochemistry of the interactions between quinoxaline antagonists and the ligand-binding domain of the glutamate receptor 4 (GluR4) have been investigated by probing their vibrational modes using Fourier transform infrared spectroscopy. In solution, the electron-withdrawing nitro groups of both compounds establish a resonance equilibrium that appears to stabilize the keto form of one of the cyclic amide carbonyl bonds. Changes in the 6,7-dinitro-2,3-dihydroxyquinoxaline vibrational spectra on binding to the glutamate receptor, interpreted within the framework of a published crystal structure, illuminate the stereochemistry of the interaction and suggest that the binding site imposes a more polarized electronic bonding configuration on this antagonist. Similar spectral changes are observed for 6-cyano-7-dinitro-2,3-dihydroxyquinoxaline, confirming that its interactions with the binding site are highly similar to those of 6,7-dinitro-2,3-dihydroxyquinoxaline and leading to a model of the 6-cyano-7-dinitro-2,3-dihydroxyquinoxaline-S1S2 complex, for which no crystal structure is available. Conformational changes within the GluR ligand binding domain were also monitored. Compared with the previously reported spectral changes seen on binding of the agonist glutamate, only a relatively small change is detected on antagonist binding. This correlation between the functional effects of different classes of ligand and the magnitude of the spectroscopic changes they induce suggests that the spectral data reflect physiologically relevant conformational processes.

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

    International Nuclear Information System (INIS)

    Cruz, Elizabete R.; Villar, J. Daniel Figueroa

    1995-01-01

    Since the discovery of the 5-deazaflavin cofactor (coenzyme F 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

  7. 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.

  8. 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…

  9. Eesti viib Rostrumile kolm teost

    Index Scriptorium Estoniae

    2001-01-01

    11. juunil algab Pariisis rahvusvaheline heliloojate Rostrum, millel osalevad ka kolme noore eesti helilooja teosed: Mirjam Tally :Swinburne" Hasso Krulli luulele, Tõnis Kaumanni "Long Play" brass ansamblile ja Helena Tulve "Traces"

  10. 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

  11. 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.

  12. Correlation between the Stereochemistry and Bioactivity in Octahedral Rhodium Prolinato Complexes.

    Science.gov (United States)

    Rajaratnam, Rajathees; Martin, Elisabeth K; Dörr, Markus; Harms, Klaus; Casini, Angela; Meggers, Eric

    2015-08-17

    Controlling the relative and absolute configuration of octahedral metal complexes constitutes a key challenge that needs to be overcome in order to fully exploit the structural properties of octahedral metal complexes for applications in the fields of catalysis, materials sciences, and life sciences. Herein, we describe the application of a proline-based chiral tridentate ligand to decisively control the coordination mode of an octahedral rhodium(III) complex. We demonstrate the mirror-like relationship of synthesized enantiomers and differences between diastereomers. Further, we demonstrate, using the established pyridocarbazole pharmacophore ligand as part of the organometallic complexes, the importance of the relative and absolute stereochemistry at the metal toward chiral environments like protein kinases. Protein kinase profiling and inhibition data confirm that the proline-based enantiopure rhodium(III) complexes, despite having all of the same constitution, differ strongly in their selectivity properties despite their unmistakably mutual origin. Moreover, two exemplary compounds have been shown to induce different toxic effects in an ex vivo rat liver model.

  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. 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

  15. 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

  16. Correlations among experimental and theoretical NMR data to determine the absolute stereochemistry of darcyribeirine, a pentacyclic indole alkaloid isolated from Rauvolfia grandiflora

    Science.gov (United States)

    Cancelieri, Náuvia Maria; Ferreira, Thiago Resende; Vieira, Ivo José Curcino; Braz-Filho, Raimundo; Piló-Veloso, Dorila; Alcântara, Antônio Flávio de Carvalho

    2015-10-01

    Darcyribeirine (1) is a pentacyclic indole alkaloid isolated from Rauvolfia grandiflora. Stereochemistry of 1 was previously proposed based on 1D (coupling constant data) and 2D (NOESY correlations) NMR techniques, having been established a configuration 3R, 15S, and 20R (isomer 1a). Stereoisomers of 1 (i.e., 1a-1h) can be grouped into four sets of enantiomers. Carbon chemical shifts and hydrogen coupling constants were calculated using BLYP/6-31G* theory level for the eight isomers of 1. Calculated NMR data of 1a-1h were correlated with the corresponding experimental data of 1. The best correlations between theoretical and experimental carbon chemical shift data were obtained for the set of enantiomers 1e/1f to structures in the gaseous phase and considering solvent effects (using PCM and explicit models). Similar results were obtained when the same procedure was performed to correlations between theoretical and experimental coupling constant data. Finally, optical rotation calculations indicate 1e as its absolute stereochemistry. Orbital population analysis indicates that the hydrogen bonding between N-H of 1e and DMSO is due to contributions of its frontier unoccupied molecular orbitals, mainly LUMO+1, LUMO+2, and LUMO+3.

  17. "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

  18. 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.

  19. 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.

  20. Study of the Stereochemistry and Oxidation Mechanism of Plant Polyphenols, Assisted by Computational Chemistry.

    Science.gov (United States)

    Matsuo, Yosuke

    2017-01-01

    In recent years, plant polyphenols have attracted great attention due to their wide range of biological activities. Certain kinds of polyphenols have complex structures; therefore, it is difficult to elucidate their total structure, including stereochemistry. In this study, we reinvestigated the stereostructures of two major C-glycosidic ellagitannins contained in Quercus plants, vescalagin and castalagin, and revised their stereostructures based on theoretical calculations of spectroscopic data. We also determined the structures of quercusnins A and B, isolated from the sapwood of Quercus crispula, based on theoretical calculations of NMR data. The oxidation mechanism of polyphenols has not been entirely elucidated. Therefore, we have also studied the oxidation mechanism of tea catechins during black tea production. Our investigation of the oxidation mechanism of black tea pigment theaflavins revealed that the difference in the position of the galloyl ester affords different oxidation products of theaflavins. In addition, oxidation products of pyrogallol-type catechins could be classified into three types-dehydrotheasinensins, theacitrins, and proepitheaflagallins; their detailed production and degradation mechanisms were also examined.

  1. 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.

  2. 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.

  3. 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

  4. 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

  5. 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

  6. Stereochemistry of Furfural Reduction by a Saccharomyces cerevisiae Aldehyde Reductase That Contributes to In Situ Furfural Detoxification▿

    Science.gov (United States)

    Bowman, Michael J.; Jordan, Douglas B.; Vermillion, Karl E.; Braker, Jay D.; Moon, Jaewoong; Liu, Z. Lewis

    2010-01-01

    Ari1p from Saccharomyces cerevisiae, recently identified as an intermediate-subclass short-chain dehydrogenase/reductase, contributes in situ to the detoxification of furfural. Furfural inhibits efficient ethanol production by yeast, particularly when the carbon source is acid-treated lignocellulose, which contains furfural at a relatively high concentration. NADPH is Ari1p's best known hydride donor. Here we report the stereochemistry of the hydride transfer step, determined by using (4R)-[4-2H]NADPD and (4S)-[4-2H]NADPD and unlabeled furfural in Ari1p-catalyzed reactions and following the deuterium atom into products 2-furanmethanol or NADP+. Analysis of the products demonstrates unambiguously that Ari1p directs hydride transfer from the si face of NADPH to the re face of furfural. The singular orientation of substrates enables construction of a model of the Michaelis complex in the Ari1p active site. The model reveals hydrophobic residues near the furfural binding site that, upon mutation, may increase specificity for furfural and enhance enzyme performance. Using (4S)-[4-2H]NADPD and NADPH as substrates, primary deuterium kinetic isotope effects of 2.2 and 2.5 were determined for the steady-state parameters kcatNADPH and kcat/KmNADPH, respectively, indicating that hydride transfer is partially rate limiting to catalysis. PMID:20525870

  7. Versatile transformations of hydrocarbons in anaerobic bacteria: substrate ranges and regio- and stereo-chemistry of activation reactions†

    Science.gov (United States)

    Jarling, René; Kühner, Simon; Basílio Janke, Eline; Gruner, Andrea; Drozdowska, Marta; Golding, Bernard T.; Rabus, Ralf; Wilkes, Heinz

    2015-01-01

    Anaerobic metabolism of hydrocarbons proceeds either via addition to fumarate or by hydroxylation in various microorganisms, e.g., sulfate-reducing or denitrifying bacteria, which are specialized in utilizing n-alkanes or alkylbenzenes as growth substrates. General pathways for carbon assimilation and energy gain have been elucidated for a limited number of possible substrates. In this work the metabolic activity of 11 bacterial strains during anaerobic growth with crude oil was investigated and compared with the metabolite patterns appearing during anaerobic growth with more than 40 different hydrocarbons supplied as binary mixtures. We show that the range of co-metabolically formed alkyl- and arylalkyl-succinates is much broader in n-alkane than in alkylbenzene utilizers. The structures and stereochemistry of these products are resolved. Furthermore, we demonstrate that anaerobic hydroxylation of alkylbenzenes does not only occur in denitrifiers but also in sulfate reducers. We propose that these processes play a role in detoxification under conditions of solvent stress. The thermophilic sulfate-reducing strain TD3 is shown to produce n-alkylsuccinates, which are suggested not to derive from terminal activation of n-alkanes, but rather to represent intermediates of a metabolic pathway short-cutting fumarate regeneration by reverse action of succinate synthase. The outcomes of this study provide a basis for geochemically tracing such processes in natural habitats and contribute to an improved understanding of microbial activity in hydrocarbon-rich anoxic environments. PMID:26441848

  8. 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

  9. 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

  10. 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

  11. Biosynthesis of monoterpenes. Stereochemistry of the enzymatic cyclizations of geranyl pyrophosphate to (+)-alpha-pinene and (-)-beta-pinene

    International Nuclear Information System (INIS)

    Croteau, R.; Satterwhite, D.M.; Wheeler, C.J.; Felton, N.M.

    1989-01-01

    The conversion of geranyl pyrophosphate to (+)-alpha-pinene and to (-)-beta-pinene is considered to proceed by the initial isomerization of the substrate to (-)-(3R)- and to (+)-(3S)-linalyl pyrophosphate, respectively, and the subsequent cyclization of the anti, endo-conformer of these bound intermediates by mirror-image sequences which should result in the net retention of configuration at C1 of the geranyl precursor. Incubation of (1R)-[2-14C,1-3H]- and (1S)-[2-14C,1-3H]geranyl pyrophosphate with (+)-pinene cyclase and with (-)-pinene cyclase from common sage (Salvia officinalis) gave labeled (+)-alpha- and (-)-beta-pinene of unchanged 3H/14C ratio in all cases, and the (+)- and (-)-olefins were stereoselectively converted to (+)- and (-)-borneol, respectively, which were oxidized to the corresponding (+)- and (-)-isomers of camphor, again without change in isotope ratio. The location of the tritium was determined in each case by stereoselective, base-catalyzed exchange of the exo-alpha-hydrogens of these derived ketones. The results indicated that the configuration at C1 of the substrate was retained in the enzymatic transformations to the (+)- and (-)-pinenes, which is entirely consistent with the syn-isomerization of geranyl pyrophosphate to linalyl pyrophosphate, transoid to cisoid rotation, and anti, endo-cyclization of the latter. The absolute stereochemical elements of the antipodal reaction sequences were confirmed by the selective enzymatic conversions of (3R)- and (3S)-1Z-[1-3H]linalyl pyrophosphate to (+)-alpha-pinene and (-)-beta-pinene, respectively, and by the location of the tritium in the derived camphors as before. The summation of the results fully defines the overall stereochemistry of the coupled isomerization and cyclization of geranyl pyrophosphate to the antipodal pinenes

  12. 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

  13. 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

  14. 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

  15. 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"

  16. Märts - kirjutajate lõikuskuu / Rein Veidemann

    Index Scriptorium Estoniae

    Veidemann, Rein, 1946-

    2003-01-01

    Kultuurkapitali kirjandusauhindadest ja nende saajatest. Proosa - Jüri Ehlvest, "Hobune eikusagilt"; luule - Karl Martin Sinijärv, "Artutart & 39"; näitekirjandus - Vaino Vahing, "Mängud ja kõnelused" ; lastekirjandus - Heino Kiik, "Kuresaapad"; esseistika - Peeter Mudist, "Ratsukäik"; tõlge eesti keelde - Mati Sirkel, Franz Kafka "Hiina müüri ehitamisel"; tõlge eesti keelest (Via Estica) - Antoine Chalvin, Jaan Kaplinski "Le désir de la pousière"; artiklipreemia - Tõnu Õnnepalu, "Kui...Küpsemine. Aleksander Suumani kaks luuletust ja üks raamat ("Meil siin Hüperboreas")", ilmus Loomingus, nr. 5-6; venekeelsete autorite auhind - Mihhail Veller - viimase 10 aasta proosaloomingu eest, ka ilmus 2002. a. eesti keeles tema "Nulltund"

  17. 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

  18. 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

  19. 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

  20. 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

  1. 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)

  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. 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

  4. 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

  5. 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"

  6. 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

  7. Koomiksiraamatu avab külmetav kuningas / Raimu Hanson

    Index Scriptorium Estoniae

    Hanson, Raimu, 1957-

    2008-01-01

    Ilmus Joonas Sildre kujundatud koomiksiraamat "Teistmoodi Tammsaare", toimetaja Mari Laaniste. Raamat sisaldab ka lühikokkuvõtte Anton Hansen Tammsaare elust ja loomingust ning ülevaate eesti koomiksi ajaloost

  8. 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.

  9. 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

  10. Veel "Uue kunsti raamatust" ja Theo Doesburgist / Jüri Hain

    Index Scriptorium Estoniae

    Hain, Jüri, 1941-

    1987-01-01

    Berliinis ilmuvas rakenduskunsti ajakirjas "Die Form" 1929, nr. 21 ilmus Theo van Doesburgi artikkel "Raamat ja selle kujundus", kus on ära toodud "Uue kunsti raamatu" kaanepilt koos kiitva hinnanguga

  11. 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

  12. 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

  13. 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

  14. 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

  15. 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

  16. Concordia Klari mitu palet sai kaante vahele / Ave Randviir

    Index Scriptorium Estoniae

    Randviir, Ave, 1981-

    2006-01-01

    2006. a. jaanuaris ilmus eesti- ja ingliskeelne mälestusteraamat Concordia Klarist. Teksti autorid: Mai Levin, Vappu Thurlow ja Anne Untera ning kunstniku pereliikmed. Kujundas Jüri Kass, toimetas Mai Levin

  17. 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

  18. 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

  19. 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

  20. 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

  1. 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

  2. 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

  3. 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

  4. 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

  5. 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

  6. 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

  7. 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

  8. 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

  9. 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

  10. "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

  11. 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"

  12. Skandaal USAs : Obamat kujutati islamiterroristina / Aadu Hiietamm

    Index Scriptorium Estoniae

    Hiietamm, Aadu, 1954-

    2008-01-01

    The New Yorkeri esiküljel ilmus karikatuur, kus USA demokraatide presidendikandidaati Barack Obamat ja tema abikaasat Michelle'i kujutati islamiterroristidena, karikaturisti väitel joonistas ta selle Obama laimajate naeruvääristamiseks

  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. 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

  15. 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

  16. 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

  17. Kultuurkapitali kirjandusauhinnad jagatud

    Index Scriptorium Estoniae

    2003-01-01

    Proosa - Jüri Ehlvest, "Hobune eikusagilt"; luule - Karl Martin Sinijärv, "Artutart & 39"; näitekirjandus - Vaino Vahing, "Mängud ja kõnelused" ; lastekirjandus - Heino Kiik, "Kuresaapad"; esseistika - Peeter Mudist, "Ratsukäik"; tõlge eesti keelde - Mati Sirkel, Franz Kafka "Hiina müüri ehitamisel"; tõlge eesti keelest (Via Estica) - Antoine Chalvin, Jaan Kaplinski "Le désir de la pousière"; artiklipreemia - Tõnu Õnnepalu, "Kui...Küpsemine. Aleksander Suumani kaks luuletust ja üks raamat ("Meil siin Hüperboreas"), ilmus Loomingus, nr. 5-6; venekeelsete autorite auhind - Mihhail Veller - viimase 10 aasta proosaloomingu eest, ka ilmus 2002. a. eesti keeles tema "Nulltund". Vt. ka: Postimees, 7. märts, lk. 15 ; Eesti Päevaleht : Arkaadia, 7. märts, lk. 20 ; Looming, 2003, nr. 4, lk. 632-633

  18. 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"

  19. 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

  20. 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

  1. 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

  2. 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

  3. 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

  4. 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

  5. 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

  6. 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

  7. Muretsemise mõjust kirjandusretseptsioonile / Meelis Oidsalu

    Index Scriptorium Estoniae

    Oidsalu, Meelis, 1978-

    2010-01-01

    2000-ndate eesti kirjanduse diskussioonist (ilmus peamiselt ajakirjas Looming). Ka Mihkel Kunnuse arvustusest "Tragöödia sünd heaolu talumatust ebaheroilisusest", Sirp, 17. sept., mis käsitles Tuuli Tauli luulekogu "Täiuslik ja turvaline"

  8. Ühe novelli lugu : subjektiivne kirjanduslooline etüüd / Aivar Kull

    Index Scriptorium Estoniae

    Kull, Aivar, 1955-

    2015-01-01

    Mait Metsanurga pikemast novellist "Dora Praats", mis ilmus 1943. a. vene keeles; avaldatud ka 16-osalise järjejutuna Toronto ajalehes "Vaba Eestlane" (8. veebr. - 2. aprill 1958) ning Mait Metsanurga novellikogumikus "Kreeps" (Tallinn : Eesti Raamat, 2005)

  9. 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

  10. Formirovanije literaturnogo kanona v knige Ariadnõ Tõrkovoi-Viljams "Zhizn Pushkina" / Alexandra Smith

    Index Scriptorium Estoniae

    Smith, Alexandra

    2000-01-01

    Bibl. märkustes, lk. 280-281 Kokkuvõte inglise k. lk. 444-445. Ariadna Tyrkova-Williamsi kirjutatud Pushkini biograafiast "Zhizn Pushkina" (1. osa ilmus Pariisis 1929. a., 2. osa 1948). Ka A. Tyrkova-Williamsist (1869-1962)

  11. 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.

  12. 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

  13. 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

  14. 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.

  15. Kanepikasvatajate unine suvi / Jüri Ehlvest

    Index Scriptorium Estoniae

    Ehlvest, Jüri, 1967-2006

    2002-01-01

    Arkaadia järjejutust, ilmus juuni - august 2002 Eesti Päevalehes, autorid: Wimberg, Veiko Märka, Urmas Vadi, Jürgen Rooste, Aapo Ilves, Aarne Ruben, Matt Barker, Hedda Maurer, Ivar Sild, Karen Orlau, Indrek Hargla, Jan Kaus, Mehis Heinsaar

  16. 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

  17. 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

  18. 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

  19. 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..."

  20. 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.

  1. Ilmus teos "Rektor Johan Kõpp" / Aksel Mark

    Index Scriptorium Estoniae

    Mark, Aksel, 1913-2014

    2007-01-01

    rets. rmt.: Rohtmets, Priit. Rektor Johan Kõpp / toimetaja Mart Orav; resümeede tõlge: saksa keelde Reet Bender, inglise keelde Saskia Kangro, vene keelde A&A Lingua; kujundus Kalle Toompere. Tallinn : Aasta Raamat, 2007. 144 lk.

  2. 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".

  3. 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

  4. 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

  5. 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

  6. 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

  7. 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

  8. Mõjukas Prantsuse leht imetles Eesti IT-edu / Margo Pajuste

    Index Scriptorium Estoniae

    Pajuste, Margo

    2006-01-01

    Ilmunud ka: Postimees : na russkom jazõke 30. jaan. lk. 4. Mõjukas Prantsuse majanduslehes La Tribune ilmus kaks artiklit, milles tunnustatakse Eesti infotehnoloogilist arengut, loetletud olid mitmed tuntud eduprojektid - e-valitsus, interneti teel hääletamine, Hotmail ja Skype

  9. Vaheta vanaema suvepiiga vastu - üllatushinnad! / Tiia Penjam

    Index Scriptorium Estoniae

    Penjam, Tiia, 1955-

    2009-01-01

    Vastukaja artiklile: Laisk, Mart. Dehumaniseeritud koolisüsteem. Postimees, 27.05.2009. Samas ka kultuuritusest ja lahmivast halvustamisest omakasupüüdlikel ajenditel TEA kirjastuse koduleheküljel. Samas ka Urmas Vadi luuletus "Vahetus", mis ilmus 28. mai "EE Areenis"

  10. Effect of stereochemistry, chain length and sequence pattern on antimicrobial properties of short synthetic β-sheet forming peptide amphiphiles.

    Science.gov (United States)

    Ong, Zhan Yuin; Cheng, Junchi; Huang, Yuan; Xu, Kaijin; Ji, Zhongkang; Fan, Weimin; Yang, Yi Yan

    2014-01-01

    In the face of mounting global antibiotics resistance, the identification and development of membrane-active antimicrobial peptides (AMPs) as an alternative class of antimicrobial agent have gained significant attention. The physical perturbation and disruption of microbial membranes by the AMPs have been proposed to be an effective means to overcome conventional mechanisms of drug resistance. Recently, we have reported the design of a series of short synthetic β-sheet folding peptide amphiphiles comprised of recurring (X1Y1X2Y2)n-NH2 sequences where X: hydrophobic amino acids, Y: cationic amino acids and n: number of repeat units. In efforts to investigate the effects of key parameters including stereochemistry, chain length and sequence pattern on antimicrobial effects, systematic d-amino acid substitutions of the lead peptides (IRIK)2-NH2 (IK8-all L) and (IRVK)3-NH2 (IK12-all L) were performed. It was found that the corresponding D-enantiomers exhibited stronger antimicrobial activities with minimal or no change in hemolytic activities, hence translating very high selectivity indices of 407.0 and >9.8 for IK8-all D and IK12-all D respectively. IK8-all D was also demonstrated to be stable to degradation by broad spectrum proteases trypsin and proteinase K. The membrane disrupting bactericidal properties of IK8-all D effectively prevented drug resistance development and inhibited the growth of various clinically isolated MRSA, VRE, Acinetobacter baumanni, Pseudomonas aeruginosa, Cryptococcus. neoformans and Mycobacterium tuberculosis. Significant reduction in intracellular bacteria counts was also observed following treatment with IK8-all D in the Staphylococcus. aureus infected mouse macrophage cell line RAW264.7 (P < 0.01). These results suggest that the d-amino acids substituted β-sheet forming peptide IK8-all D with its enhanced antimicrobial activities and improved protease stability, is a promising therapeutic candidate with potential to combat

  11. 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

  12. 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

  13. 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

  14. Tammsaare segase saatusega tähtis teenetemärk / Maarja Vaino

    Index Scriptorium Estoniae

    Vaino, Maarja, 1976-

    2009-01-01

    Anton Hansen Tammsaarele 1938. aastal antud Eesti Punase Risti II klassi teenetemärgist. Samas ka tsitaadid Anton Hanseni kirjutisest iseenesele romaani "Tõde ja Õigus" asjus "Avalik kiri kirjanik A. H. Tammsaarele", mis ilmus ajalehes Vaba Maa 11. märtsil 1927

  15. 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

  16. 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

  17. 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

  18. 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

  19. 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"

  20. 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

  1. 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.

  2. 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

  3. 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

  4. Osama bin Ladeni uus imidzh / Urmas Kiil

    Index Scriptorium Estoniae

    Kiil, Urmas

    2007-01-01

    Pärast kolm aastat kestnud pausi ilmus terroriorganisatsiooni al-Qaeda liider Osama bin Laden kahel korral taas maailma avalikkuse ette. Enamik asjatundjad on seisukohal, et maailma esiterroristi videopöördumised olid autentsed ja tõenäoliselt olid need salvestatud juulis või augustis

  5. 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"

  6. 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

  7. 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

  8. Z-sinapinic acid: the change of the stereochemistry of cinnamic acids as rational synthesis of a new matrix for carbohydrate MALDI-MS analysis.

    Science.gov (United States)

    Salum, María L; Itovich, Lucia M; Erra-Balsells, Rosa

    2013-11-01

    Successful application of matrix-assisted laser desorption/ionization (MALDI) MS started with the introduction of efficient matrices such as cinnamic acid derivatives (i.e. 3,5-dimethoxy-4-hydroxycinnamic acid, SA; α-cyano-4-hydroxycinnamic acid). Since the empirical founding of these matrices, other commercial available cinnamic acids with different nature and location of substituents at benzene ring were attempted. Rational design and synthesis of new cinnamic acids have been recently described too. Because the presence of a rigid double bond in its molecule structure, cinnamic acids can exist as two different geometric isomers, the E-form and Z-form. Commercial available cinnamic acids currently used as matrices are the geometric isomers trans or E (E-cinnamic and trans-cinnamic acids). As a new rational design of MALDI matrices, Z-cinnamic acids were synthesized, and their properties as matrices were studied. Their performance was compared with that of the corresponding E-isomer and classical crystalline matrices (3,5-dihydroxybenzoic acid; norharmane) in the analysis of neutral/sulfated carbohydrates. Herein, we demonstrate the outstanding performance for Z-SA. Sulfated oligosaccharides were detected in negative ion mode, and the dissociation of sulfate groups was almost suppressed. Additionally, to better understand the quite different performance of each geometric isomer as matrix, the physical and morphological properties as well as the photochemical stability in solid state were studied. The influence of the E/Z photoisomerization of the matrix during MALDI was evaluated. Finally, molecular modeling (density functional theory study) of the optimized geometry and stereochemistry of E-cinnamic and Z-cinnamic acids revealed some factors governing the analyte-matrix interaction. Copyright © 2013 John Wiley & Sons, Ltd.

  9. Oxfordi filosoofialeksikon ja Shakespeare'i luuleraamat ilmunud

    Index Scriptorium Estoniae

    2002-01-01

    Ilmus ka Eesti Päevaleht 1. nov., lk. 18. Shakespeare, William. Poeemid, sonetid ja muud luuletused / tõlkinud H. Rajamets, G. Meri. Tallinn : Eesti Keele Sihtasutus, 2002 ; Blackburn, Simon. Oxfordi filosoofialeksikon / Simon Blackburn ; tõlkinud Märt Väljataga ja Bruno Mölder. Tallinn : Vagabund, 2002

  10. 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

  11. 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

  12. 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

  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. 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

  15. Uudised : Muusikafestival Hiiumaal. Spirituaalide õhtu Joseph Jenningsiga. Teised meist

    Index Scriptorium Estoniae

    2001-01-01

    13.-15. juulini toimuvatest III Hiiumaa kammermuusikapäevadest. EFK esitab J.Jenningsi juhatusel Pärnus, Tallinnas ja Kuressaares spirituaalide kava. Venemaa Heliloojate Liidu väljaandes Rossiiskaja Muzõkalnaja Gazeta (nr. 5/ 2001) ilmus A. Grigorjeva artikkel tänavustest eesti muusika päevadest

  16. "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

  17. 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)

  18. 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

  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. "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

  2. Из Прибалтики - в Европу / Сергей Исаков

    Index Scriptorium Estoniae

    Исаков, Сергей, 1931-2013

    2004-01-01

    1831. a. Tallinnas ilmunud Aleksandr Gribojedovi näidendi "Häda mõistuse pärast" tõlkest saksa keelde (tõlkija Karl Knorring). Tõlge ilmus K. Knorringi välja antud seerias "Russische Bibliothek für Deutsche". Ka tõlke tsenseerimisest ja tsensorist Johann Friedrich von Erdmannist

  3. 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...

  4. "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")

  5. 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

  6. Tõnis Palts ei ole veel Tallinna linn / Peeter Ristmägi

    Index Scriptorium Estoniae

    Ristmägi, Peeter

    2005-01-01

    BLRT Grupp AS-i juhatuse referent kritiseerib Tallinna linnapea nõuniku Jaano-Martin Otsa seisukohti artiklis "Äri versus linlaste huvid", mis ilmus 8. augusti Eesti Päevalehes, ning teatab, et BLRT Grupi juhatus peab Tallinna linnavõimude otsust lammutada Tallinna laevatehase angaar ebaadekvaatseks ja ebaseaduslikuks ning on selle vaidlustanud

  7. Ameerika kirjastus käis Eestis talente otsimas

    Index Scriptorium Estoniae

    2011-01-01

    31. jaanuarist 3. veebruarini viibisid Tallinnas USA tõlkekirjastuse Dalkey Archive Pressi esindajad, et välja anda eesti kirjanduse tõlkeid. Kirjastus annab välja ka Euroopa lühiproosat koondavat kogumikku "Best of new European fiction anthology", mille esimeses numbris ilmus Elo Viidingu, teises Toomas Vindi jutustus

  8. 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)

  9. 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

  10. 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...

  11. 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

  12. Sanãtana dharma / René Guénon ; tõlkinud ja kommenteerinud Haljand Udam

    Index Scriptorium Estoniae

    Guénon, René

    2004-01-01

    René Guénoni essee "Sanãtana dharma" ilmus 1949. a. ja uuesti 1989. a. raamatus "Études sur ľhindouisme" lk. 105-116 ja käsitleb mõiste "sanãtana dharma" ja "philosophia perennis" tõlgendusi ja tähendust. Esseele on lisatud põhjalik tõlkijapoolne kommentaar

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

    Indian Academy of Sciences (India)

    IAS Admin

    Stereochemistry, conforma- 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.

  14. 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

  15. 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)

  16. "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

  17. 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

  18. 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

  19. 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

  20. Eesti luule inglise keeles

    Index Scriptorium Estoniae

    2007-01-01

    2006. aasta lõpus ilmus India kirjastuse Sarup & Sons vahendusel Jüri Talveti koostatud ingliskeelne raamat eesti luulest "On the way home. An anthology of contemporary estonian poetry", mis koondab luulet Andres Ehinilt, Jaan Kaplinskilt, Hasso Krullilt, Ene Mihkelsonilt, Paul-Eerik Rummolt, Hando Runnelilt, Triin Soometsalt, Jüri Talvetilt, Mari Vallisoolt ja Juhan Viidingult

  1. 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...

  2. 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"

  3. 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

  4. Eesti kirjandus teisel pool merd ja piire

    Index Scriptorium Estoniae

    2016-01-01

    Islandi keeles ilmus Kätlin Kaldmaa lasteraamat "Lugu Keegi Eikellegitütre isast", Arvo Valton pälvis Venemaa kirjandusauhinna Dmitri Mizgulini raamatu "Kui päike oli jumalaks" 2015. a. parima tõlke eest ja Inglise luuleajakiri "Modern Poetry in Translation" andis välja antoloogia "Centres of Cataclysm", milles on avaldatud Kristiina Ehini luuletus"Merest tulevad lehmad"

  5. 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)

  6. 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

  7. 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

  8. Muusika. Viis aastat Elleri muusikapreemiat. Asutati MTÜ Eesti Muusikafestivalid. Mati Palm taas Moskvas. Trio Romanss Helsingis. Rondelluse uus CD. Noored tshellistid jälle koos / Alo Põldmäe

    Index Scriptorium Estoniae

    Põldmäe, Alo, 1945-

    2002-01-01

    Viiendat korda välja antavad Heino Elleri muusikapreemiaid said sel korral T. Steiner, A. Juozepenaite-Eesmaa ja T. Kaljuste. 5. III asutati Kultuuriministeeriumis MTÜ Eesti Muusikafestivalid. Mati Palm esines Moskvas Venemaa Kultuurifondi saalis. Trio Romanss esines veebruari lõpus Helsingis. Vanamuusika ansamblilt Rondellus ilmus uus CD "Sabbatum". 2.III leidis Tartus H. Elleri Muusikakoolis aset II Eesti noorte tshellistide festival

  9. 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

  10. 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"

  11. Theonellapeptolide IIIe, a new cyclic peptolide from the New Zealand deep water sponge, Lamellomorpha strongylata.

    Science.gov (United States)

    Li, S; Dumdei, E J; Blunt, J W; Munro, M H; Robinson, W T; Pannell, L K

    1998-06-26

    The structure, stereochemistry, and conformation of theonellapeptolide IIIe (1), a new 36-membered ring cyclic peptolide from the New Zealand deep-water sponge Lamellomorpha strongylata, is described. The sequence of the cytotoxic peptolide was determined through a combination of NMR and MS-MS techniques and confirmed by X-ray crystal structure analysis, which, with chiral HPLC, established the absolute stereochemistry.

  12. 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

  13. Золотова: Мой отец отказал Ленину / Татьяна Золотова ; интервьюировал Андрей Бабин

    Index Scriptorium Estoniae

    Золотова, Татьяна, 1909-2010

    2009-01-01

    100. sünnipäeva tähistab 1914. aastast tallinlane Tatjana Zolotova, sünd. Kašneva, kasutas seda ka kirjanikunimena. Kirjastus Aleksandra andis sel puhul välja tema mälestusteraamatu "Земная коротка наша память..." kordustrüki (1. tr. ilmus 1993. a.)

  14. 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"

  15. 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.)

  16. 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

  17. 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

  18. 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

  19. 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.

  20. 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.

  1. 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

  2. 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"

  3. The stereochemistry of chlorophyll-c₃ from the haptophyte Emiliania huxleyi: the (13²R)-enantiomers of chlorophylls-c are exclusively selected as the photosynthetically active pigments in chromophyte algae.

    Science.gov (United States)

    Mizoguchi, Tadashi; Kimura, Yuki; Yoshitomi, Taichi; Tamiaki, Hitoshi

    2011-11-01

    Chlorophyll(Chl)-c pigments in algae, diatoms and some prokaryotes are characterized by the fully conjugated porphyrin π-system as well as the acrylate residue at the 17-position. The precise structural characterization of Chl-c(3) from the haptophyte Emiliania huxleyi was performed. The conformations of the π-conjugated peripheral substituents, the 3-/8-vinyl, 7-methoxycarbonyl and 17-acrylate moieties were evaluated, in a solution, using nuclear Overhauser enhancement correlations and molecular modeling calculations. The rotation of the 17-acrylate residue was considerably restricted, whereas the other three substituents readily rotated at ambient temperature. Moreover, the stereochemistry at the 13²-position was determined by combination of chiral high-performance liquid chromatography (HPLC) with circular dichroism (CD) spectroscopy. Compared with the CD spectra of the structurally related, synthetic (13²R)- and (13²S)-protochlorophyllide(PChlide)-a, naturally occurring Chl-c₃ had exclusively the (13²R)-configuration. To elucidate this natural selection of a single enantiomer, we analyzed the three major Chl-c pigments (Chl-c₁, c₂ and c₃) in four phylogenetically distinct classes of Chl-c containing algae, i.e., heterokontophyta, dinophyta, cryptophyta and haptophyta using chiral HPLC. All the photosynthetic organisms contained only the (13²R)-enantiomerically pure Chls-c, and lacked the corresponding enantiomeric (13²S)-forms. Additionally, Chl-c₂ was found in all the organisms as the common Chl-c. These results throw a light on the biosynthesis as well as photosynthetic function of Chl-c pigments: Chl-c₂ is derived from 8-vinyl-PChlide-a by dehydrogenation of the 17-propionate to acrylate residues as generally proposed, and the (13²R)-enantiomers of Chls-c function as photosynthetically active, light-harvesting pigments together with the principal Chl-a and carotenoids. 2011 Elsevier B.V. All rights reserved.

  4. 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

  5. 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

  6. 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

  7. Austraalias ilmus välja Pätsi kõne salvestis

    Index Scriptorium Estoniae

    2009-01-01

    Sydney Eesti Majas leiti Konstantin Pätsi kõne salvestis 1937/38 aasta vahetusest ja Välis-Eesti Ühingu esimehe Jakob Kristelsteini kõne, neid saab kuulata Sydney Eesti Maja filmiarhiivi veebilehelt

  8. 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

  9. Eesti proosa 2007 - kultuuri ja tsivilisatsiooni vahel / Peeter Helme

    Index Scriptorium Estoniae

    Helme, Peeter, 1978-

    2010-01-01

    2007. a. ilmunud proosaraamatutest: Tiina Laanemi "Väikesed vanamehed", Ene Mihkelsoni "Katkuhaud", Toomas Vindi "Mäluauguga naine", Vahur Afanasjevi "Kaadrid otsustavad", Armin Kõomäe "Nägu, mis jäi üle" (ilmus 2006. a.), Jaan Kaplinski "Seesama jõgi", Tõnu Õnnepalu "Flandria päevik", Maimu Bergi "Unustatud inimesed", Mehis Heinsaare "Rändaja õnn", Mihkel Muti "Siseemigrant", Aarne Biini "Linna valitsemine", Ivar Silla "Tantsiv linn" ja Epp Annuse "Sina, Matilda"

  10. 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

  11. Indira Gandhi sattus KGB konksu otsa / ref. Ralf R. Parve

    Index Scriptorium Estoniae

    2005-01-01

    29. jaanuaril suri Londonis 1984. aastani Moskvas KGB arhiivis töötanud erumajor Vassili Mitrohhin, kes koostas koos Christopher Andrew'ga KGB arhiivist kaasa võetud dokumentide alusel raamatu "Mitrohhini arhiiv". Septembris ilmus raamatu II osa "KGB ja kogu maailm", mille tegevustik toimub Indias. Professor Andrew püüab raamatus tõestada India endiste peaministrite Indira ja Radjiv Gandhi täielikku sõltuvust KGB-st. Lisad: Indira Priyadarashani Gandhi; Radjiv Gandhi

  12. 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

  13. 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.

  14. 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).

  15. BCL::EMAS — Enantioselective Molecular Asymmetry Descriptor for 3D-QSAR

    Directory of Open Access Journals (Sweden)

    Mariusz Butkiewicz

    2012-08-01

    Full Text Available Stereochemistry is an important determinant of a molecule’s biological activity. Stereoisomers can have different degrees of efficacy or even opposing effects when interacting with a target protein. Stereochemistry is a molecular property difficult to represent in 2D-QSAR as it is an inherently three-dimensional phenomenon. A major drawback of most proposed descriptors for 3D-QSAR that encode stereochemistry is that they require a heuristic for defining all stereocenters and rank-ordering its substituents. Here we propose a novel 3D-QSAR descriptor termed Enantioselective Molecular ASymmetry (EMAS that is capable of distinguishing between enantiomers in the absence of such heuristics. The descriptor aims to measure the deviation from an overall symmetric shape of the molecule. A radial-distribution function (RDF determines a signed volume of tetrahedrons of all triplets of atoms and the molecule center. The descriptor can be enriched with atom-centric properties such as partial charge. This descriptor showed good predictability when tested with a dataset of thirty-one steroids commonly used to benchmark stereochemistry descriptors (r2 = 0.89, q2 = 0.78. Additionally, EMAS improved enrichment of 4.38 versus 3.94 without EMAS in a simulated virtual high-throughput screening (vHTS for inhibitors and substrates of cytochrome P450 (PUBCHEM AID891.

  16. 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.

  17. 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

  18. 80 aastat tagasi : Jaanuar 1928 / Mati Märtin

    Index Scriptorium Estoniae

    Märtin, Mati

    2008-01-01

    Muusikasündmustest 80 aastat tagasi: Noorte Meeste Kristliku Ühing andis loengkontserte, Tallinna Kaarli kirikus tuli ettekandele A.Dvoraki "Stabat Mater" (juhatas Johannes Paulsen, esinesid Jekeli lauluselts, Estonia sümfooniaorkester ja solistid Olga Torokoff-Tiedeberg, J. Badendiesk-Inger, Arnold Vissmann ja Karl Viitol), trükist ilmus Johannes Jürgensoni (Juhan Jürme) "12 vaimulikku laulu" (kirjastajaks Tallinna Kaarli Lauluselts), 50. surma-aastapäeva puhul meenutati kirikumuusikut Johann August Hagenit, meenutati Keila muusikameest Jakob Maabergi

  19. Synthesis, characterisation, stereochemistry and antimicrobial ...

    Indian Academy of Sciences (India)

    Benzodiazepines are bicyclic heterocyclic compounds having benzene .... ods using the program SHELXS-9712b,c with E's ≥ 1.2. An E-map ..... were inverted and incubated for 24-48 h at 37◦C. After ... sured its diameter using microscope.

  20. Interaction of nogalamycin and analogs with DNA and other biopolymers

    Energy Technology Data Exchange (ETDEWEB)

    Krueger, W C [Univ. of Minnesota, Minneapolis; Pschigoda, L M; Schpok, S L.F.; Moscowitz, A.; McGovren, J P; Neta, P; Merritt, M V; Li, L H

    1981-01-01

    The interaction with calf thymus DNA of the anthracycline antibiotics, nogalamycin and its analogs, was studied by electronic absorption, circular dichroism (CD), thermal denaturation, solvent partition and pulse radiolysis techniques. The Scatchard, thermal denaturation (..delta..T/sub m/), difference circular dichroism (..delta..CD) and solvent partition binding parameters gave the same order of relative binding on a given lot of DNA, but some parameters were DNA-lot-dependent. In general, molecules containing the sugar moiety nogalose at C-7 or those having the natural or dis stereochemistry of nogalamycin at C-7 bound more strongly to DNA than did the molecules lacking nogalose or those with the opposite configuration at C-7 (con stereochemistry). This stereochemical-binding correlation differs from that found for adriamycin which has the con stereochemistry, but which binds strongly to DNA. Scatchard binding parameters could not be obtained from the pulse radiolysis or solvent partition techniques because of solubility difficulties.

  1. Electron-impact and pyrolytic eliminations from 4-tert-butylcyclohexyl xanthates

    International Nuclear Information System (INIS)

    Eadon, G.; Jefson, M.

    1976-01-01

    The stereochemistry of electron--impact induced xanthic acid elimination reactions was assessed by mass spectrographic studies of cis and trans deuterated 4-tert-butylcyclohexyl xanthates and their derivatives. Cis elimination was observed to be about 30 times as facile as trans elimination in the axial xanthate reaction. In the equatorial ester derivative reactions, the cis elimination was found to be slightly preferred. The electron-impact induced elimination results were compared with pyrolytic elimination results for the xanthates; and similar stereochemistry was observed for each type of elimination

  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. Elagu noor kino! / Andres Maimik

    Index Scriptorium Estoniae

    Maimik, Andres, 1970-

    2007-01-01

    Käesoleva TMK numbriga kaasas olevast DVDst "Valik eesti tudengifilme", mis tutvustab tudengite lühifilme (ilmus Kinobussi eestvõttel) : T. Toom "Tuul", B. Demidova "Roosa kleit ja nahksed püksid", K. Sarv "2pic", R. Merivoo "Mis värvi on armastus", R. Mandri "Annaliisa", E. Vasli "Nagu ikka", M. Oja "Rain Terrain" ("Varjude maa"), J. Matjus "Suvine dokumentaal", L. Kuusk, R. Võsa, M. Monko, H. Melesk "Eestimaa. Revisited", Johnson ja Johnson (I. Köster ja T. Talve) "Mõrv striptiisi ajal"

  4. Kultuuriajakiri levitab kümmet tudengifilmi / Toomas Teder

    Index Scriptorium Estoniae

    Teder, Toomas

    2007-01-01

    Kinobussi eestvõttel ilmus koos TMK aprilli-numbriga DVD "Valik eesti tudengifilme", mis tutvustab tudengite lühifilme: T. Toom "Tuul", B. Demidova "Roosa kleit ja nahksed püksid", K. Sarv "2pic", R. Merivoo "Mis värvi on armastus", R. Mandri "Annaliisa", E. Vasli "Nagu ikka", M. Oja "Rain Terrain" ("Varjude maa"), J. Matjus "Suvine dokumentaal", L. Kuusk, R. Võsa, M. Monko, H. Melesk "Eestimaa. Revisited", Johnson ja Johnson (I. Köster ja T. Talve) "Mõrv striptiisi ajal"

  5. "Hariduse ja kasvatuse sõnaraamat"

    Directory of Open Access Journals (Sweden)

    Helin Puksand

    2014-11-01

    Full Text Available 2014. aastal ilmus viiekeelne "Hariduse ja kasvatuse sõnaraamat", milles on 4850 mõistet paljudelt hariduse ja kasvatuse aladelt: kasvatus ja areng, alusharidus, põhi- ja keskharidus, kutse- ja kõrgharidus, huviharidus, eripedagoogika, andragoogika, sotsiaalpedagoogika, didaktika, koolikorraldus, kasvatusteaduslik uurimistöö, pedagoogika ajalugu jne. Iga mõiste kohta on esitatud eesti, inglise, saksa, soome ja vene termin ning enamasti ka seletus. "Hariduse ja kasvatuse sõnaraamat" on mõeldud kõigile haridustöötajaile ja haridusvaldkonnast huvitatuile.

  6. 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

  7. 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

  8. EFEKTIVITAS PEMBELAJARAN STEREOKIMIA BERBASIS VISUALISASI 3D MOLEKUL UNTUK MENINGKATKAN KEMAMPUAN SPASIAL

    Directory of Open Access Journals (Sweden)

    M. Setyarini

    2017-02-01

      Abstract: The purpose of this study is to investigate the effectiveness of stereochemistry learning programs based on 3D visualization of molecules using the open source chemical drawing softwares, Avogadro, and animation of chirality to improve spatial ability of teacher candidates. This study used a quasi-experimental control group pretest-posttest design. The research instrument consisted of 25 multiple choice questions along with the reasons elaboration, composed based on three major indicator dimensions of spatial ability. The research was conducted at a LPTK in Lampung Province, in the first semester of Academic Year 2014/2015. The subjects consisted of control class and experimental class, each of which consisted of 30 students. The results showed that the average post-test scores of spatial ability of students learning stereochemistry based on 3D visualization of molecules was significantly higher than the group of students learning using molymood media. The effectiveness of the program was shown by the increase in N-gain in the medium category and effect size (d in high category for the three main dimensions of spatial ability.   Key words: stereochemistry, 3D visualization, spatial ability, open-source software

  9. Stereoselective synthesis of an active metabolite of the potent PI3 kinase inhibitor PKI-179.

    Science.gov (United States)

    Chen, Zecheng; Venkatesan, Aranapakam M; Dos Santos, Osvaldo; Delos Santos, Efren; Dehnhardt, Christoph M; Ayral-Kaloustian, Semiramis; Ashcroft, Joseph; McDonald, Leonard A; Mansour, Tarek S

    2010-03-05

    The synthesis and stereochemical determination of 1-(4-(4-((1R,5R,6R)-6-hydroxy-3-oxa-8-azabicyclo[3.2.1]octan-8-yl)-6-morpholino-1,3,5-triazin-2-yl)phenyl)-3-(pyridin-4-yl)urea (2), an active metabolite of the potent PI3 kinase inhibitor PKI-179 (1), is described. Stereospecific hydroboration of the double bond of 2,5-dihydro-1H-pyrrole 8 gave the 2,3-trans alcohol 9 exclusively. The configuration of the 3-hydroxyl group in 9 was inverted by an oxidation and stereoselective reduction sequence to give the corresponding 2,3-cis isomer 23. Both exo (21) and endo (27) isomers of the metabolite 2 were prepared via a practical synthetic route from 9 and 23, respectively, and the stereochemistry of 2 was determined to be endo. The endo isomer (27) was separated into two enantiomers 28 and 29 by chiral HPLC. Compound 2 was found to be enantiomerically pure and identical to the enantiomer 28. The absolute stereochemistry of the enantiomer 28 was determined by Mosher's method, thus establishing the stereochemistry of the active metabolite 2.

  10. Inversion of Configuration at the Phosphorus Nucleophile in the Diastereoselective and Enantioselective Synthesis of P-Stereogenic syn-Phosphiranes from Chiral Epoxides.

    Science.gov (United States)

    Muldoon, Jake A; Varga, Balázs R; Deegan, Meaghan M; Chapp, Timothy W; Eördögh, Ádám M; Hughes, Russell P; Glueck, David S; Moore, Curtis E; Rheingold, Arnold L

    2018-04-23

    Nucleophilic substitution results in inversion of configuration at the electrophilic carbon center (S N 2) or racemization (S N 1). The stereochemistry of the nucleophile is rarely considered, but phosphines, which have a high barrier to pyramidal inversion, attack electrophiles with retention of configuration at P. Surprisingly, cyclization of bifunctional secondary phosphine alkyl tosylates proceeded under mild conditions with inversion of configuration at the nucleophile to yield P-stereogenic syn-phosphiranes. DFT studies suggested that the novel stereochemistry results from acid-promoted tosylate dissociation to yield an intermediate phosphenium-bridged cation, which undergoes syn-selective cyclization. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Chiral relay: a novel strategy for the control and amplification of enantioselectivity in chiral Lewis acid promoted reactions.

    Science.gov (United States)

    Corminboeuf, Olivier; Quaranta, Laura; Renaud, Philippe; Liu, Mei; Jasperse, Craig P; Sibi, Mukund P

    2003-01-03

    Chiral Lewis acid catalysis has emerged as one of the premiere method to control stereochemistry. Much effort has gone into the design of superior ligands with increasing steric extension to shield distant reactive sites. We report here an alternative and complementary approach based on a "chiral relay". This strategy focuses on the improved design of achiral templates which may relay and amplify the stereochemistry from ligands. The essence of this strategy is that the chiral Lewis acid would effectively convert an achiral template into a chiral non-racemic template. This approach combines the advantages of enantioselective catalysis (substoichiometric amount of the chiral inducer) with the ones of chiral auxiliary control (efficient and predictable stereocontrol).

  12. A rapid alternative to X-ray crystallography for chiral determination: case studies of vibrational circular dichroism (VCD) to advance drug discovery projects.

    Science.gov (United States)

    Wesolowski, Steven S; Pivonka, Don E

    2013-07-15

    The absolute stereochemistry of chiral drugs is usually established via X-ray crystallography. However, vibrational circular dichroism (VCD) spectroscopy coupled with quantum mechanics simulations offers a rapid alternative to crystallography and is readily applied to both crystalline and non-crystalline samples. VCD is an effective complement to X-ray analysis of drug candidates, and it can be used as a high-throughput means of assessing absolute stereochemistry at all phases of the discovery process (hundreds of assignments per year). The practical implementation (or fee-for-service outsourcing) of VCD and selected case studies are illustrated with an emphasis on providing utility and impact to pharmaceutical discovery programs. Copyright © 2013 Elsevier Ltd. All rights reserved.

  13. Stereochemical studies of acyclic isoprenoids-XII. Lipids of methanogenic bacteria and possible contributions to sediments

    Science.gov (United States)

    Risatti, J.B.; Rowland, S.J.; Yon, D.A.; Maxwell, J.R.

    1984-01-01

    Abundant volatile lipids of Methanobacterium thermoautotrophicum and Methanosarcina barkeri include isoprenoid hydrocarbons (??? C30), and C15, C20 and C25 isoprenoid alcohols. M. barkeri contains 2,6,10,15,19-pentamethyleicosane, whose relative stereochemistry is the same as found in marine sediments, indicating that it is a marker of methanogenic activity. The C20, C30 and C25 alkenes in M. thermoautotrophicum also have a preferred sterochemistry; the latter have the 2,6,10,14,18-pentamethyleicosanyl skeleton, suggesting that the alkane in marine sediments may derive from methanogens. The stereochemistry of squalane in a marine sediment is also compatible with an origin in methanogens; in contrast, the stereochemistry of pristane in M. thermoautotrophicum indicates a fossil fuel contaminant origin, suggesting that this and certain other alkanes reported in archaebacteria might also be of contaminant origin. There is, therefore, little evidence at present that the pristane in immature marine sediments originates in methanogens. The C15 and C20 saturated alcohols in M. thermoautotrophicum have mainly the all-R configuration. If this is generally true for methanogens, the C20 alcohol in the Messel shale may originate mainly from methanogens, whereas that in the Green River shale may originate mainly from photosynthetic organisms. ?? 1984.

  14. The effect of maturation on the configuration of pristane in sediments and petroleum

    Science.gov (United States)

    Patience, R. L.; Rowland, S. J.; Maxwell, J. R.

    1978-01-01

    The absolute stereochemistry of pristane in a sample of contemporary marine zooplankton, Messel shale (Germany) and Djatibarang (Java) crude has been determined by gas chromatographic methods. The relative stereochemistry in Irati shale (Brazil), Green River (U.S.) crude, Halibut (Australia) crude has also been determined, and confirmed for a sample of the Green River shale. The stereoisomer distributions indicate a loss of stereospecificity of the phytol-derived 6(R), 10(S) pristane with increasing geological maturation. For example, the least mature geological sample, the Eocene Messel shale, contains solely the 6(R), 10(S) isomer, whereas a mature sample, Djatibarange crude, contains 50% of the 6(R), 10(S) isomer and 25% of each of the 6(R), 10(R) and 6(S), 10(S) isomers.

  15. 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...

  16. 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...

  17. Bottom-up elucidation of glycosidic bond stereochemistry

    DEFF Research Database (Denmark)

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

    2017-01-01

    a particular challenge. Here, we show that "memory" of anomeric configuration is retained following gas-phase glycosidic bond fragmentation during tandem mass spectrometry (MS(2)). These findings allow for integration of MS(2) with ion mobility spectrometry (IM-MS(2)) and lead to a strategy to distinguish α...

  18. Stereochemistry of substitution at trico-ordinate phosphorus

    DEFF Research Database (Denmark)

    Nielsen, John; Dahl, Otto

    1984-01-01

    A series of reactions of ring-substituted 1,3,2-dioxaphospholanes, 1,3,2-oxazaphospholanes, 1,2-oxaphospholes, and phosphetanes bearing the leaving groups Cl, OR, or NR2 on phosphorus, with the nucleophiles HCl, MeO-, MeOH, PhOH, Me2NH, Et2NH, and [CH 2]5NH have been studied. N.m.r. signals (1H...

  19. Antiviral agents of plant origin. III. Scopadulin, a novel tetracyclic diterpene from Scoparia dulcis L.

    Science.gov (United States)

    Hayashi, T; Kawasaki, M; Miwa, Y; Taga, T; Morita, N

    1990-04-01

    The structure and stereochemistry of scopadulin, a novel aphidicolane-type diterpene isolated from Scoparia dulcis L. have been established from spectral data and single-crystal X-ray analysis of its acetone solvate.

  20. Enantioselective conjugate addition of hydroxylamines to pyrazolidinone acrylamides.

    Science.gov (United States)

    Sibi, M P; Liu, M

    2001-12-27

    Chiral relay templates provide amplification of selectivity in conjugate addition reactions. Reversal of stereochemistry of the product isoxazolidinones has also been demonstrated by a simple change of the Lewis acid. [reaction: see text

  1. SHORT COMMUNICATION SYNTHESIS AND PRELIMINARY ...

    African Journals Online (AJOL)

    a

    2006 Chemical Society of Ethiopia ... 1Department of Chemistry, School of Pure & Applied Sciences, The University of the South. Pacific, Post ... bonding and stereochemistry [1-3], whereas their semicarbazones analogs received much less.

  2. Uudised : Bachi muusikaga ooper Helsingis. Shakespeare ja Marlowe ooperis. Lordist ilmus esimene raamat

    Index Scriptorium Estoniae

    2006-01-01

    Helsingis Aleksandri teatris esietendunud J.S. Bachi muusika põhjal loodud ooperist "Herakles". Vadstena lossiteatris juuli lõpul esietendunud Tommy Anderssoni nüüdisooperist "William". Sven Pahajoki raamatust tänavu Soomele eurovisioonivõidu toonud rockansamblist Lordi

  3. 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)

  4. 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

  5. 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...

  6. Diazo compounds in the chemistry of fullerenes

    International Nuclear Information System (INIS)

    Tuktarov, Airat R; Dzhemilev, Usein M

    2010-01-01

    Experimental and theoretical data on the reactions of different diazo compounds (diazomethane, its derivatives, cyclic diazo compounds and diazocarbonyl compounds) with fullerenes are summarized. The structures and stereochemistry of cycloadducts formed in these reactions are considered.

  7. Diazo compounds in the chemistry of fullerenes

    Science.gov (United States)

    Tuktarov, Airat R.; Dzhemilev, Usein M.

    2010-09-01

    Experimental and theoretical data on the reactions of different diazo compounds (diazomethane, its derivatives, cyclic diazo compounds and diazocarbonyl compounds) with fullerenes are summarized. The structures and stereochemistry of cycloadducts formed in these reactions are considered.

  8. Diazo compounds in the chemistry of fullerenes

    Energy Technology Data Exchange (ETDEWEB)

    Tuktarov, Airat R; Dzhemilev, Usein M [Institute of Petrochemistry and Catalysis, Russian Academy of Sciences, Ufa (Russian Federation)

    2010-09-14

    Experimental and theoretical data on the reactions of different diazo compounds (diazomethane, its derivatives, cyclic diazo compounds and diazocarbonyl compounds) with fullerenes are summarized. The structures and stereochemistry of cycloadducts formed in these reactions are considered.

  9. 2------------------------------~~~---------RESONANCE--Isep-te-mber-1-9-9-9

    Indian Academy of Sciences (India)

    and so did an aura of self-confidence and independent thinking. The latter ... by inventing the coordination theory - a theory that truly liberated stereochemistry from all prevalent shackles into ... Experimental verification and silencing critics took ...

  10. 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 ...

  11. 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.; DeSouza, L; 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...

  12. Nascent VLDL from liver perfusions of cynomolgus monkeys are preferentially enriched in RRR- compared with SRR-alpha-tocopherol: Studies using deuterated tocopherols

    International Nuclear Information System (INIS)

    Traber, M.G.; Rudel, L.L.; Burton, G.W.; Hughes, L.; Ingold, K.U.; Kayden, H.J.

    1990-01-01

    The transport and secretion of vitamin E in lipoproteins have been studied in cynomolgus monkeys fed tocopherols labeled with different amounts of deuterium. The animals were fed a single dose of vitamin E containing 60 mumol of each 2R,4'R,8'R-alpha-(5,7-(C2H3)2)tocopheryl acetate (d6-RRR-alpha-tocopheryl acetate; alpha-tocopherol with natural stereochemistry), 2S,4'R,8'R-alpha-5-(C2H3)tocopheryl acetate (d3-SRR-alpha-tocopheryl acetate; alpha-tocopherol with unnatural stereochemistry), and 2R,4'R,8'R-gamma-(3,4-2H)tocopherol (d2-RRR-gamma-tocopherol; gamma-tocopherol with natural stereochemistry). Chylomicrons, as well as the other plasma lipoproteins, contained equal concentrations of all three tocopherols at the earliest time points after feeding suggesting that all three tocopherols were absorbed equally. At later times plasma lipoproteins became preferentially enriched in d6-RRR-alpha-tocopherol. This is likely to be due to hepatic secretion of VLDL (very low density lipoproteins) and other lipoproteins, which were enriched in d6-RRR-alpha-tocopherol, as demonstrated in the lipoproteins isolated from perfused livers that had been obtained 24 h following the administration of the deuterated tocopherols. Taken together these data demonstrate that the liver, not the intestine, is the likely site of discrimination between tocopherol isomers and that the liver secretes nascent lipoproteins preferentially enriched in d6-RRR-alpha-tocopherol

  13. 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 ...

  14. Guajadial: an unusual meroterpenoid from guava leaves Psidium guajava.

    Science.gov (United States)

    Yang, Xiao-Long; Hsieh, Kun-Lung; Liu, Ji-Kai

    2007-11-22

    Guajadial (1), a novel caryophyllene-based meroterpenoid, was isolated from the Leaves of Psidium guajava (guava). The structure and relative stereochemistry of guajadial (1) were elucidated by extensive spectroscopic analysis. A possible biosynthetic pathway for 1 was proposed.

  15. 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.

  16. Stereochemical errors and their implications for molecular dynamics simulations

    Directory of Open Access Journals (Sweden)

    Freddolino Peter L

    2011-05-01

    Full Text Available Abstract Background Biological molecules are often asymmetric with respect to stereochemistry, and correct stereochemistry is essential to their function. Molecular dynamics simulations of biomolecules have increasingly become an integral part of biophysical research. However, stereochemical errors in biomolecular structures can have a dramatic impact on the results of simulations. Results Here we illustrate the effects that chirality and peptide bond configuration flips may have on the secondary structure of proteins throughout a simulation. We also analyze the most common sources of stereochemical errors in biomolecular structures and present software tools to identify, correct, and prevent stereochemical errors in molecular dynamics simulations of biomolecules. Conclusions Use of the tools presented here should become a standard step in the preparation of biomolecular simulations and in the generation of predicted structural models for proteins and nucleic acids.

  17. 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

  18. Reactions of charged and neutral recoil particles following nuclear transformations. Progress report No. 10

    International Nuclear Information System (INIS)

    Ache, H.J.

    1976-09-01

    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; and chemistry of positronium

  19. 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

    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...

  20. 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 ...

  1. 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 ...

  2. 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.

  3. Novofumigatonin, a New Orthoester Meroterpenoid from Aspergillus novofumigatus

    DEFF Research Database (Denmark)

    Rank, Christian; Phipps, Richard Kerry; Harris, Pernille

    2008-01-01

    Novofumigatonin (1), a new metabolite, has been isolated from Aspergillus novofumigatus. The structure and relative stereochemistry were determined from HR ESI MS, one- and two-dimensional NMR, and single-crystal X-ray analysis. The absolute configuration was assigned using vibrational circular...

  4. 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...

  5. 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...

  6. 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...

  7. 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.

  8. 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

  9. Dynamics of molecular stereochemistry via oriented molecule scattering

    International Nuclear Information System (INIS)

    Parker, D.H.; Jalink, H.; Stolte, S.

    1987-01-01

    Crossed-beam reactive scattering experiments employing electrostatic hexapole fields to control the initial collision geometry of chemical reactions are described. New results are presented on the reactions of oriented NO with ozone and oriented N 2 O with Ba. Preliminary results are also given for the oriented CH 3 F + Ca* → CaF* + CH 3 reaction. Recent technical advances in state selection and product detection are detailed. They discuss the effects of rotational coupling and nonzero impact parameters in changing the molecular precollisions orientation selected by the hexapole fields to a different in-collision orientation at the moment of impact with the reaction partner. Uncoupling of l doubling in N 2 O at strong orientation fields is demonstrated via the observed reactive anisotropy. Steric effects are found to govern many aspects of the reactions investigated thus far. Strong correlations are observed of the reactivity, product recoil, and rotational angular momentum distributions with the collisional orientation. These correlations ultimately provide information on the anisotropic part of the reaction potential energy surface. They conclude with a brief outline of possible future directions in oriented molecule scattering

  10. 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.

  11. Characterization of a unique tomaymycin-d(CICGAATTCICG)2 adduct containing two drug molecules per duplex by NMR, fluorescence, and molecular modeling studies

    International Nuclear Information System (INIS)

    Boyd, F.L.; Stewart, D.; Hurley, L.H.; Remers, W.A.; Barkley, M.D.

    1990-01-01

    Tomaymycin is a member of the pyrrolo[1,4]benzodiazepine [P(1,4)B] antitumor antibiotic group. This antibiotic is proposed to react with the exocyclic 2-amino group (N2) of guanine to form a covalent adduct that lies snugly within the minor groove of DNA. While DNA-footprinting experiments using methidiumpropyl-EDTA have revealed the favored bonding sequences for tomaymycin and related drugs on DNA, the stereochemistry at the covalent bonding site (C-11) and orientation in the minor groove were not established by these experiments. In previous studies using a combined fluorescence, high-field NMR, and molecular modeling approach, the authors have shown that for tomaymycin there are two diastereomeric species (11R and 11S) on both calf thymus DNA and d(ATGCAT) 2 . Although they were able to infer the identify of the two species on d(ATGCAT) 2 , definitive experimental evidence was lacking. They have designed and synthesized a self-complementary 12-mer [d(CICGAATTCICG) 2 ] based on the Dickerson dodecamer [d(CGCGAATTCGCG) 2 ] that bonds identically two tomaymycin molecules, each having a defined orientation and stereochemistry. The results presented in this study together with previous investigations show that the orientation of the drug molecule in the minor groove, and stereochemistry at the covalent linkage site, is dependent upon both the flanking sequence and drug structure. This conclusion mandates caution be used in rationalizing the biochemical and and biological effects of P(1,4)B bonding to DNA until precise structural information is established

  12. 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...

  13. 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.

  14. 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...

  15. Stereospecific control of peptide gas-phase ion chemistry with cis and trans cyclo ornithine residues

    Czech Academy of Sciences Publication Activity Database

    Marek, Aleš; Nguyen, H. T. H.; Brož, Břetislav; Tureček, F.

    2018-01-01

    Roč. 53, č. 2 (2018), s. 124-137 ISSN 1076-5174 Institutional support: RVO:61388963 Keywords : cis and trans isomers * cyclo ornithine * peptide dissociations * peptide ion structures * stereochemistry Subject RIV: CB - Analytical Chemistry, Separation OBOR OECD: Analytical chemistry Impact factor: 2.422, year: 2016

  16. 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...

  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. 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...

  19. 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.

  20. 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, ...

  1. Synthesis and physicochemical properties of glycolipids bearing oligosaccharide headgroups; Origoto wo shinsuiki tosuru toshishitsu no gose to butsusei

    Energy Technology Data Exchange (ETDEWEB)

    Minamikawa, H [National Institute of Materials and Chemical Research, Tsukuba (Japan)

    1999-12-22

    Glycolipids, amphiphiles that bear oligosaccharides their hydrophilic, are of importance both scientifically and technically. This review describes recent advances in our understanding of the molecular correlations in phase behavior of aqueous glycolipids. In the first part, we discuss how headgroup stereochemistry affects the phase behavior of glycolipids both two- and three- dimensional systems. In the second part, we discuss effects of alkyl chain structure behavior of phytanyl-chained glycolipid/water systems Physical properties of glycolipid/water systems strongly depend on the inter-headgroup interactions that is related to factors such as stereochemistry (conformation) and size of headgroups, type of sugar residues involved, alkyl chain structure, etc. Thus. apart from the conventional concept like [hydrophilic/lipophilic balance], explicit accounts of headgroup interactions are crucial to control a particular glycolipid/water system concerned. This makes contrast to the conventional amphiphile/water systems where the inter-headgroup interaction are in most cases simply repulsive. (author)

  2. 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

  3. Relative stability of radicals derived from artemisinin: A semiempirical and DFT study

    Science.gov (United States)

    Arantes, C.; de Araujo, M. T.; Taranto, A. G.; de M. Carneiro, J. W.

    The semiempirical AM1 and PM3 methods, as well as the density functional (DFT/B3LYP) approach using the 6-31g(d) basis set, were employed to calculate the relative stability of intermediate radicals derived from artemisinin, a sesquiterpene lactone having an endoperoxide bridge that is essential for its antimalarial activity. The compounds studied have their nonperoxidic oxygen atom of the trioxane ring and/or the carbonyl group replaced by a CH2 unit. Relative stabilities were calculated by means of isodesmic equations using artemisinin as reference. It was found that replacement of oxygen atoms decreases the relative stability of the anionic radical intermediates. In contrast, for compounds with inverted stereochemistry the intermediate radicals were found to be more stable than those with the artemisinin-like stereochemistry. These relative stabilities may modulate the antimalarial potency. Radicals centered on carbon are always more stable than the corresponding radicals centered on oxygen.

  4. 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)

  5. Structural information on the coordination compounds formed by manganese(II), cobalt(II), nickel(II), zinc(II), cadmium(II) and mercury(II) thiocyanates with 4-cyanopyridine N-oxide from their magnetic moments, electronic and infrared spectra

    Science.gov (United States)

    Ahuja, I. S.; Yadava, C. L.; Singh, Raghuvir

    1982-05-01

    Coordination compounds formed by the interaction of 4-cyanopyridine. N-oxide (4-CPO), a potentially bidentate ligand, with manganese(II), cobalt(II), nickel(II), zinc(II), cadmium(II) and rnercury(II) thiocyanates have been prepared and characterized from their elemental analyses, magnetic susceptibilities, electronic and infrared spectral studies down to 200 cm -1 in the solid state. The compounds isolated are: Mn(4-CPO) 2(NCS) 2, Co(4-CPO) 2(NCS) 2,Ni(4-CPO) 2(NCS) 2,Zn(4-CPO) 2(NCS) 2, Cd(4-CPO)(NCS) 2 and Hg(4-CPO) 2(SCN) 2. It is shown that 4-CPO acts as a terminal N-oxide oxygen bonded monodentate ligand in all the metal(II) thiocyanate complexes studied. Tentative stereochemistries of the complexes in the solid state are discussed. The ligand field parameters 10 Dq, B, β and λ calculated for the manganese(II), cobalt(II) and nickel(II) complexes are consistent with their proposed stereochemistries.

  6. Stereochemical insignificance discovered in Acinetobacter baumannii quorum sensing.

    Directory of Open Access Journals (Sweden)

    Amanda L Garner

    Full Text Available Stereochemistry is a key aspect of molecular recognition for biological systems. As such, receptors and enzymes are often highly stereospecific, only recognizing one stereoisomer of a ligand. Recently, the quorum sensing signaling molecules used by the nosocomial opportunistic pathogen, Acinetobacter baumannii, were identified, and the primary signaling molecule isolated from this species was N-(3-hydroxydodecanoyl-L-homoserine lactone. A plethora of bacterial species have been demonstrated to utilize 3-hydroxy-acylhomoserine lactone autoinducers, and in virtually all cases, the (R-stereoisomer was identified as the natural ligand and exhibited greater autoinducer activity than the corresponding (S-stereoisomer. Using chemical synthesis and biochemical assays, we have uncovered a case of stereochemical insignificance in A. baumannii and provide a unique example where stereochemistry appears nonessential for acylhomoserine lactone-mediated quorum sensing signaling. Based on previously reported phylogenetic studies, we suggest that A. baumannii has evolutionarily adopted this unique, yet promiscuous quorum sensing system to ensure its survival, particularly in the presence of other proteobacteria.

  7. The effect of interesterification on the bioavailability of fatty acids in structured lipids.

    Science.gov (United States)

    Farfán, M; Villalón, M J; Ortíz, M E; Nieto, S; Bouchon, P

    2013-08-15

    Fatty acid (FA) profile is a critical factor in the nutritional properties of fats, but, stereochemistry may also play a fundamental role in the rate and extent to which FAs are absorbed and become available. To better understand this phenomenon, we evaluated the bioavailability of FAs in linseed-oil and palm-stearin blends compared to their interesterified mix, using a sn-1,3 stereospecific lipase, to determine if there was any difference in terms of FA availability when using this technology. Test meals were fed through an intragastric feeding tube on Sprague-Dawley male rats after 18 h fasting. Postprandial blood samples were collected after meal or physiological serum (control) administration and the FA profile of plasma lipids was determined. Results showed that modification of the melting profile through interesterification, without altering the bioavailability determined by sn-2 stereochemistry, could delay lipid absorption at the beginning, but had no effect on total lipid absorption. Copyright © 2013. Published by Elsevier Ltd.

  8. Synthesis and properties of highly branched Jatropha curcas L. oil derivatives

    NARCIS (Netherlands)

    Daniel, Louis; Ardiyanti, Agnes R.; Schuur, Boelo; Manurung, Robert; Broekhuis, Antonius A.; Heeres, Hero J.

    The synthesis and properties of a number of novel branched Jatropha curcas L. oil (JO) derivatives containing vicinal di-ester units in the fatty acid chains are reported. Both the length (acetyl vs. hexanoyl) and the stereochemistry of the vicinal di-ester units (cis vs. trans) were varied. The

  9. 2001 Chemistry N abel Prize

    Indian Academy of Sciences (India)

    a biological process, led to his discovery of microbes, his resolu- tion of sodium ... (Nobel Laureates 1975, stereochemistry of enzymatic and or- ganic reactions), C J ... companies nowadays have to make sure that both enantiomers of a drug are ... Generally, chemical synthesis of asymmetric compounds results in racemic ...

  10. 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

  11. 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.

  12. Conformation analysis of oligomeric flavanoids

    Science.gov (United States)

    Jan P. Steynberg; E. Vincent Brandt; Daneel Ferreira; Carin A. Helfer; Wayne L. Mattice; Dominika Gornik; Richard W. Hemingway

    1995-01-01

    The profisetinidins are the most important polyflavanoids of commerce, making up the major constituents of wattle and quebracho tannins. Within the dimeric profisetinidins, substantial complexity exists because of stereo-, regio, rotational and conformational isomers. Definition of the stereochemistry of the upper and lower flavan units, the location of the...

  13. 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.…

  14. Stereochemical preference of yeast epoxide hydrolase for the O-axial C3 epimers of 1-oxaspiro[2.5] octanes

    NARCIS (Netherlands)

    Weijers, C.A.G.M.; Koenst, P.; Franssen, M.C.R.; Sudhölter, E.J.R.

    2007-01-01

    The 1-oxaspiro[2.5]octane moiety is a common motif in many biologically active spiroepoxide compounds. Stereochemistry plays an important role in the action of these spiroepoxides, since the O-axial C3 epimers are predominantly responsible for biological activity. In view of this, the reactivity of

  15. Learning Organic Chemistry Through Natural Products

    Indian Academy of Sciences (India)

    SERIES I ARTICLE. Learning Organic Chemistry. Through Natural Products. 2. Determination of Absolute Stereochemistry. N R Krishnaswamy was initiated into the world of natural products by T R. Seshadri at University of. Delhi and has carried on the glorious traditions of his mentor. He has taught at Bangalore University,.

  16. 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 ...

  17. 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.

  18. 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 ...

  19. Conformational analysis of oligomeric flavanoids

    Science.gov (United States)

    Jan P. Steynberg; E. Vincent Brandt; Daneel Ferreira; Carin A. Helfer; Wayne L. Mattice; Dominika Gornik; Richard W. Hemingway

    1995-01-01

    The profisetinidins are the most important polyflavanoids of commerce, making up the major constituents of wattle and quebracho tannins. Even within the dimeric profisetinidins, substantial complexity exists because of stereo-, regio-, rotational and conformational isomers. Definition of the stereochemistry of the upper and lower flavan units, the location of the...

  20. 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: ...

  1. Synthesis and pharmacological characterization at glutamate receptors of the four enantiopure isomers of tricholomic acid

    DEFF Research Database (Denmark)

    Pinto, Andrea; Conti, Paola; De Amici, Marco

    2008-01-01

    of the studied amino acids reflect the relationship between the activity/selectivity and the stereochemistry of the two stereogenic centers: while the (2 S,5' S) stereoisomer is an agonist at the AMPA and KA receptors, its (2 R,5' R) enantiomer interacts selectively with the NMDA receptors; the (2 S,5' R...

  2. 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

  3. 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…

  4. An efficient synthesis of (7S,10R)-2-bromo-5,6,7,8,9,10-hexahydro-7,10-epiminocyclohepta[b]indole: application in the preparation and structural confirmation of a potent 5-HT6 antagonist

    DEFF Research Database (Denmark)

    Isherwood, Matthew; Guzzo, Peter R.; Henderson, Alan J.

    2012-01-01

    precipitation from n-hexane. The absolute stereochemistry of 7a was determined by X-ray crystallography and the structure was confirmed as (7S,10R)-tert-butyl 2-bromo-5,6,7,8,9,10-hexahydro-7,10-epiminocyclohepta[b]indole-11-carboxylate. Removal of the chiral auxiliary under basic conditions afforded...

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

    Indian Academy of Sciences (India)

    IAS Admin

    While many features, like the phenanthrene-type of fusion of the three ... thought to contain the original ring A of abietic acid, retaining the. 'nuclear methyl .... Thinking that the anhydride he had obtained by the action of heat on the C-11 acid ...

  6. 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...

  7. 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)

  8. 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.

  9. Resonance – Journal of Science Education | News

    Indian Academy of Sciences (India)

    Interconversion of Fischer and Zig-Zag Projections - Learning Stereochemistry with the Help of Hands · Syed R Hussaini · More Details Fulltext PDF. pp 355-362 Classroom. Motion of a Tiny Tool Thrown by an Astronaut towards another Astronaut inside a Spinning Space Vehicle in a State of Free Fall Revisited · S N Maitra.

  10. 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 ...

  11. Resonance – Journal of Science Education | News

    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.

  12. Technetium(I) complexes Tc(CO)3BrL2 (L = phosphine, pyridine, isocyanide)

    International Nuclear Information System (INIS)

    Lorenz, B.; Findeisen, M.; Olk, B.; Schmidt, K.

    1988-01-01

    Technetium pentacarbonyl bromide reacts with π-acceptor ligands L (L = phosphine, pyridine, isocyanide) to form disubstituted compounds of the type Tc(CO) 3 BrL 2 . The stereochemistry of the complexes was established by infrared and 1 H-NMR measurement. Chemical shifts and the half-widths of the 99 Tc-NMR signals are discussed. (author)

  13. Flexible synthetic routes to poison-frog alkaloids of the 5,8-disubstituted indolizidine-class I: synthesis of common lactam chiral building blocks and application to the synthesis of (--203A, (--205A, and (--219F

    Directory of Open Access Journals (Sweden)

    Spande Thomas F

    2007-09-01

    Full Text Available Abstract Background The 5,8-disubstituted indolizidines are the largest class of poison-frog alkaloids found in anuran skin, and are of considerable interest because of their inhibitory effects on the neuronal nicotinic acetylcholine receptors. Many synthetic strategies for the construction of this nucleus have been reported: however, a flexible route has not been reported to date. Results Synthesis of lactam chiral building blocks for the flexible synthesis of the title alkaloids has been achieved using a Michael-type conjugate addition reaction to a chiral cyclic enamine ester as the key step in constructing the trisubstituted piperidine ring system. To demonstrate the usefulness of these chiral building blocks, syntheses of (--203A, (--205A from 1, and (--219F from 2 have been achieved. Conclusion The total synthesis of (--203A, (--205A, and (--219F was achieved, and the absolute stereochemistry of natural 203A was determined to be 5S, 8R, 9S. In addition, the relative stereochemistry of natural 219F was determined.

  14. Biologically Important Eremophilane Sesquiterpenes from Alaska Cedar Heartwood Essential Oil and Their Semi-Synthetic Derivatives

    Directory of Open Access Journals (Sweden)

    Joe J. Karchesy

    2011-06-01

    Full Text Available The essential oil of Alaska cedar heartwood is known to contain compounds which contribute to the remarkable durability of this species. While previous research has identified several compounds, a complete description of this oil has not been undertaken. In this research a profile of the oil is given in which the major components are identified by GC, isolation and spectroscopic techniques. The major components of the steam distilled essential oil were identified as nootkatin, nootkatone, valencene, nootaktene, carvacrol, methyl carvacrol, nootkatol (2, and eremophil-1(10,11-dien-13-ol (3. The last two compounds were isolated for the first time from Alaska cedar in this research. The absolute stereochemistry at C-2 of nootkatol was shown to have the (S configuration using the Mosher ester method. Assignment of stereochemistry for valencene-13-ol (3 was established by synthesis from valencene (6. Finally, two related sesquiterpenoids were synthesized from nootkatone and valencene. These sesquiterpenoids were nootkatone-1,10-11,12-diepoxide (5 and valencene-13-aldehyde (4, respectively.

  15. Biologically important eremophilane sesquiterpenes from alaska cedar heartwood essential oil and their semi-synthetic derivatives.

    Science.gov (United States)

    Khasawneh, Mohammad A; Xiong, Yeping; Peralta-Cruz, Javier; Karchesy, Joe J

    2011-06-08

    The essential oil of Alaska cedar heartwood is known to contain compounds which contribute to the remarkable durability of this species. While previous research has identified several compounds, a complete description of this oil has not been undertaken. In this research a profile of the oil is given in which the major components are identified by GC, isolation and spectroscopic techniques. The major components of the steam distilled essential oil were identified as nootkatin, nootkatone, valencene, nootaktene, carvacrol, methyl carvacrol, nootkatol (2), and eremophil-1(10),11-dien-13-ol (3). The last two compounds were isolated for the first time from Alaska cedar in this research. The absolute stereochemistry at C-2 of nootkatol was shown to have the (S) configuration using the Mosher ester method. Assignment of stereochemistry for valencene-13-ol (3) was established by synthesis from valencene (6). Finally, two related sesquiterpenoids were synthesized from nootkatone and valencene. These sesquiterpenoids were nootkatone-1,10-11,12-diepoxide (5) and valencene-13-aldehyde (4), respectively.

  16. Synthesis and spectroscopic stereospecificity assay of the deuterated quinolizidine alkaloids (2S)-[2H]- and (2R)-[2H]-sparteine

    International Nuclear Information System (INIS)

    Ebner, T.; Meese, C.O.; Rebell, J.

    1989-01-01

    Borohydride reduction of the (+)-1,2-dehydrosparteinium salts proceeds almost exclusively from the Si side, yielding, respectively, the stereoselectively (2S)(β)-deuterated (-)-sparteine and the (2R)(α)-deuterated (-)-sparteine. Stereo-chemistry and isotopic purity of the deuterium label (≥98%) are established unequivocally by 1 H, 2 H and 13 C NMR spectroscopy. (author)

  17. 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

  18. Further sesquiterpenoids and phenolics from Taraxacum officinale.

    Science.gov (United States)

    Kisiel, W; Barszcz, B

    2000-06-01

    Five germacrane- and guaiane-type sesquiterpene lactones, including two previously described taraxinic acid derivatives, were isolated from the roots of Taraxacum officinale, together with benzyl glucoside, dihydroconiferin, syringin and dihydrosyringin. The other three lactones were identified as 11beta, 13-dihydrolactucin, ixerin D and ainslioside. Moreover, the stereochemistry at C-11 in dihydrotaraxinic acid was assigned.

  19. Total assignment of 1 H and 13 C NMR of Cordiachrome C, a terpenoid benzoquinone from Cordia trichotoma

    International Nuclear Information System (INIS)

    Alencar, Jane Eire; Pessoa, Otilia Deusdenia Loiola; Lemos, Tlema Leda Gomes de; Silveira, Edilberto Rocha; Braz Filho, Raimundo

    1999-01-01

    1 D and 2 D NMR techniques were applied for establishing of the complete assignment of hydrogen and carbon-13 NMR of cordiachrome C. Th results were also used to confirm 1 H NMR data already published, as well as to define the relative stereochemistry, which has not been completely established for cordiachrome C, previously isolated from C. millenii

  20. Synthesis and spectroscopic stereospecificity assay of the deuterated quinolizidine alkaloids (2S)-( sup 2 H)- and (2R)-( sup 2 H)-sparteine

    Energy Technology Data Exchange (ETDEWEB)

    Ebner, T.; Meese, C.O. (Fischer-Bosch Inst. fuer Klinische Pharmakologie, Stuttgart (Germany, F.R.)); Rebell, J. (Stuttgart Univ. (Germany, F.R.). Inst. fuer Organische Chemie); Fischer, P. (Stuttgart Univ. (Germany, F.R.). Inst. fuer Organische Chemie Fischer-Bosch Inst. fuer Klinische Pharmakologie, Stuttgart (Germany, F.R.))

    1989-04-01

    Borohydride reduction of the (+)-1,2-dehydrosparteinium salts proceeds almost exclusively from the Si side, yielding, respectively, the stereoselectively (2S)({beta})-deuterated (-)-sparteine and the (2R)({alpha})-deuterated (-)-sparteine. Stereo-chemistry and isotopic purity of the deuterium label ({>=}98%) are established unequivocally by {sup 1}H, {sup 2}H and {sup 13}C NMR spectroscopy. (author).

  1. 57Fe quadrupole splitting and isomer shift in various oxyhemoglobins: study using Mössbauer spectroscopy

    International Nuclear Information System (INIS)

    Oshtrakh, M. I.; Berkovsky, A. L.; Kumar, A.; Kundu, S.; Vinogradov, A. V.; Konstantinova, T. S.; Semionkin, V. A.

    2010-01-01

    A comparative study of normal human, rabbit and pig oxyhemoglobins and oxyhemoglobin from patients with chronic myeloleukemia and multiple myeloma using Mössbauer spectroscopy with a high velocity resolution demonstrated small variations of the 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.

  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. Form Follows Function: Designer Chemistry at the 52nd Bürgenstock Conference.

    Science.gov (United States)

    Heretsch, Philipp

    2017-07-24

    The 52nd Bürgenstock Conference on Stereochemistry took place from April 30-May 4, 2017, and showed how chemistry and design go hand-in-hand (as reflected in the image of the Bauhausarchiv in Berlin). In this Conference Report, Philipp Heretsch outlines the program. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. 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.

  5. 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.

  6. Total assignment of {sup 1} H and {sup 13} C NMR of Cordiachrome C, a terpenoid benzoquinone from Cordia trichotoma

    Energy Technology Data Exchange (ETDEWEB)

    Alencar, Jane Eire; Pessoa, Otilia Deusdenia Loiola; Lemos, Tlema Leda Gomes de; Silveira, Edilberto Rocha [Ceara Univ., Fortaleza, CE (Brazil). Dept. de Quimica Organica e Inorganica; Braz Filho, Raimundo [Universidade Estadual do Norte Fluminense (UENF), Campos dos Goytacazes, RJ (Brazil). Setor de Quimica de Produtos Naturais

    1999-05-01

    1 D and 2 D NMR techniques were applied for establishing of the complete assignment of hydrogen and carbon-13 NMR of cordiachrome C. Th results were also used to confirm {sup 1} H NMR data already published, as well as to define the relative stereochemistry, which has not been completely established for cordiachrome C, previously isolated from C. millenii.

  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. Identification of a sex pheromone of the chrysanthemum lace bug Corythucha marmorata (Hemiptera: Tingidae).

    Science.gov (United States)

    Watanabe, Kisaki; Shimizu, Nobuhiro

    2017-08-04

    Although the nymphs of Corythucha marmorata form clusters on the undersides of host plant leaves, as frequently observed for Hemiptera, the adults are scattered in the vicinity of the nymph population. By investigating the biological activities of volatile secretions from the adult, we found that the secretions activated male mounting behaviour. A chemical analysis revealed that borneol was a common component of the secretions from both sexes. The absolute configuration of the natural product was the (+)-enantiomer of borneol and the optical isomer was undetectable. Although (+)-borneol showed significant sex pheromone activity against males, the antipode (-)-borneol also induced sex pheromone activity, albeit only slightly. Males may not have a strict identification mechanism based on stereochemistry. To verify the origin of this sex pheromone, we analysed the components of the essential oil of the leaves of Solidago canadensis L. (Compositae: Asteraceae), a host plant; bornyl acetate was detected to be a major component. The plant-produced bornyl acetate had different stereochemistry from the sex pheromone. The results suggested that the adults do not utilise the secondary metabolites of plants but biosynthesise this sex pheromone themselves. This is the first report on sex pheromone identification in Tingidae.

  9. Complete Analysis of a Biologically Active Tetrapeptide: A Project Utilizing Thin-Layer Chromatography and Tandem Quadrupole Mass Spectrometry

    Science.gov (United States)

    Lefevre, Joseph W.; Dodsworth, David W.

    2000-04-01

    The biologically active tetrapeptide d-Ala-Gly-l-Phe-d-Leu ([des-Tyr1-d-Ala2-d-Leu5]enkephalin) was analyzed for its amino acid content and stereochemistry by normal and reversed-phase thin-layer chromatography (TLC), and its sequence was determined by tandem quadrupole mass spectrometry. The project involved sequential N-dansylation of a portion of the tetrapeptide, hydrolysis, isolation, and identification of the N-terminal amino acid as dansyl-alanine by comparison with standards using normal-phase TLC. A second portion of the tetrapeptide was hydrolyzed and the resulting four free amino acids were converted to their corresponding dansyl derivatives and purified by preparative normal-phase TLC. The three dansyl amino acids not identified previously were identified by TLC. The stereochemistry of each was determined by comparison with dansyl-dl-amino acid standards using reversed-phase TLC in the presence of ß-cyclodextrin, a chiral mobile phase additive. Finally, the correct amino acid sequence was determined by tandem quadrupole mass spectrometry. This project gives students valuable experience in microscale synthesis, both normal and reversed-phase TLC, stereochemical analysis, and mass spectrometry.

  10. 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

  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. 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.

  13. Mosher Amides: Determining the Absolute Stereochemistry of Optically-Active Amines

    Science.gov (United States)

    Allen, Damian A.; Tomaso, Anthony E., Jr.; Priest, Owen P.; Hindson, David F.; Hurlburt, Jamie L.

    2008-01-01

    The use of chiral reagents for the derivatization of optically-active amines and alcohols for the purpose of determining their enantiomeric purity or absolute configuration is a tool used by many chemists. Among the techniques used, Mosher's amide and Mosher's ester analyses are among the most reliable and one of the most often used. Despite this,…

  14. New isomalabaricane triterpenes from the marine sponge Stelletta globostellata that induce morphological changes in rat fibroblasts.

    Science.gov (United States)

    Oku, N; Matsunaga, S; Wada, S i; Watabe, S; Fusetani, N

    2000-02-01

    Three new isomalabaricane triterpenes, 29-hydroxystelliferin D (2), 3-epi-29-hydroxystelliferin E (3), and 3-epi-29-hydroxystelliferin A (4), were isolated from the marine sponge Stelletta globostellata. Their structures, including absolute stereochemistry, were determined on the basis of spectral data and chemical methods. Rat fibroblasts treated with 0.2 microM of 2-4 exhibited unusual morphological characteristics, followed by death in 5 days.

  15. Mechanistic, Mutational, and Structural Evaluation of a Taxus Phenylalanine Aminomutase

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Lei; Wanninayake, Udayanga; Strom, Susan; Geiger, James; Walker, Kevin D. (MSU)

    2014-10-02

    The structure of a phenylalanine aminomutase (TcPAM) from Taxus canadensis has been determined at 2.4 {angstrom} resolution. The active site of the TcPAM contains the signature 4-methylidene-1H-imidazol-5(4H)-one prosthesis, observed in all catalysts of the class I lyase-like family. This catalyst isomerizes (S)-{alpha}-phenylalanine to the (R)-{beta}-isomer by exchange of the NH{sub 2}/H pair. The stereochemistry of the TcPAM reaction product is opposite of the (S)-{beta}-tyrosine made by the mechanistically related tyrosine aminomutase (SgTAM) from Streptomyces globisporus. Since TcPAM and SgTAM share similar tertiary- and quaternary-structures and have several highly conserved aliphatic residues positioned analogously in their active sites for substrate recognition, the divergent product stereochemistries of these catalysts likely cannot be explained by differences in active site architecture. The active site of the TcPAM structure also is in complex with (E)-cinnamate; the latter functions as both a substrate and an intermediate. To account for the distinct (3R)-{beta}-amino acid stereochemistry catalyzed by TcPAM, the cinnamate skeleton must rotate the C{sub 1}-C{sub {alpha}} and C{sub ipso}-C{sub {beta}} bonds 180{sup o} in the active site prior to exchange and rebinding of the NH{sub 2}/H pair to the cinnamate, an event that is not required for the corresponding acrylate intermediate in the SgTAM reaction. Moreover, the aromatic ring of the intermediate makes only one direct hydrophobic interaction with Leu-104. A L104A mutant of TcPAM demonstrated an 1.5-fold increase in k{sub cat} and a decrease in K{sub M} values for sterically demanding 3'-methyl-{alpha}-phenylalanine and styryl-{alpha}-alanine substrates, compared to the kinetic parameters for TcPAM. These parameters did not change significantly for the mutant with 4'-methyl-{alpha}-phenylalanine compared to those for TcPAM.

  16. 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"

  17. Determinação por RMN das configurações relativas e conformações de alcalóides oxindólicos isolados de Uncaria guianensis

    Directory of Open Access Journals (Sweden)

    Carbonezi Carlos Alberto

    2004-01-01

    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.

  18. 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)

  19. 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.

  20. Selective electrocatalytic oxidation of sorbitol to fructose and sorbose.

    Science.gov (United States)

    Kwon, Youngkook; de Jong, Ed; van der Waal, Jan Kees; Koper, Marc T M

    2015-03-01

    A new electrocatalytic method for the selective electrochemical oxidation of sorbitol to fructose and sorbose is demonstrated by using a platinum electrode promoted by p-block metal atoms. By the studying a range of C4, C5 and C6 polyols, it is found that the promoter interferes with the stereochemistry of the polyol and thereby modifies its reactivity. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. 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.

  2. 13C NMR and stereochestry of 1-β-phenylethylcyclohexanol derivatives obtained by synthesis

    International Nuclear Information System (INIS)

    Antunes, O.A.C.; Braz Filho, R.

    1986-01-01

    1-β-Phenylethylcyclohexanol derivatives substituted in position 2 have been synthesized and analysed by 13 C-NMR spectroscopy. Their stereochemistry have been considered as cis (hydroxyl in C-1 and substituent in C-2) which is in agreement with the pertinent literature. Derivatives obtained were 2-β-phenylethyl-2-allycyclohexanol, 1-β-phenylethyl-2-methylcyclohexanol, 7a-β-phenylethylperhy-drobenzo (b) furan, and 1-β-phenylethyl-2-β-hydroxyethylcyclohexanol. (author) [pt

  3. Glutathiolactaldehyde as a probe of the overall stereochemical course of glyoxalase-I catalyzed reactions

    International Nuclear Information System (INIS)

    Brush, E.J.; Kozarich, J.W.

    1986-01-01

    The overall stereochemical course of the reactions catalyzed by glyoxalase-I (GX-I) has remained elusive as the substrates are equilibrium mixtures of rapidly interconverting diastereomeric thiohemiacetals. However, with the discovery of inverse substrate processing by Kozarich and coworkers, it is possible to design GX-I substrate analogs that are intrinsically more stable than the thiohemiacetals. Hence, Chari and Kozarich reported that glutathiohydroxyacetone (GHA, GSCH 2 COCH 2 OH) undergoes GX-I catalyzed exchange of the pro-S hydroxymethyl proton with solvent deuterium. Their data suggest that GX-I processes a single diastereomeric thiohemiacetal, and are consistent with a cis-enediol intermediate. To test this hypothesis and to follow the overall stereochemistry on a single substrate, they have prepared glutathiolactaldehyde (GLA, GSCH 2 CHOHCHO) as a potential inverse substrate. Human erythrocyte GX-I catalyzes the isomerization of GLA to GHA as evidenced by UV and NMR spectra of the product. Solvent deuterium is incorporated into the hydroxymethyl position, and NMR data suggest that incorporation is stereospecific. Furthermore, 50% of the expected amount of GHA is produced indicating that only one diastereomer of GLA is processed by GX-I. Identification of the absolute stereochemistry of the substrate diastereomer will lead to a clarification of the overall stereochemical and mechanistic course of GX-I catalyzed reactions

  4. Identification and Actions of a Novel Third Maresin Conjugate in Tissue Regeneration: MCTR3.

    Directory of Open Access Journals (Sweden)

    Jesmond Dalli

    Full Text Available Maresin conjugates in tissue regeneration (MCTR are a new family of evolutionarily conserved chemical signals that orchestrate host responses to promote tissue regeneration and resolution of infections. Herein, we identified the novel MCTR3 and established rank order potencies and matched the stereochemistries of MCTR1, MCTR2 and MCTR3 using material prepared by total organic synthesis and mediators isolated from both mouse and human systems. MCTR3 was produced from endogenous substrate by E. coli activated human macrophages and identified in sepsis patients. Each of the three synthetic MCTR dose-dependently (1-100 nM accelerated tissue regeneration in planaria by 0.6-0.9 days. When administered at the onset or peak of inflammation, each of the MCTR promoted resolution of E. coli infections in mice. They increased bacterial phagocytosis by exudate leukocytes (~15-50%, limited neutrophil infiltration (~20-50%, promoted efferocytosis (~30% and reduced eicosanoids. MCTR1 and MCTR2 upregulated human neutrophil and macrophage phagocytic responses where MCTR3 also proved to possess potent actions. These results establish the complete stereochemistry and rank order potencies for MCTR1, MCTR2 and MCTR3 that provide novel resolution moduli in regulating host responses to clear infections and promote tissue regeneration.

  5. Synthesis, characterization and ion- exchange study of poly[(2,4-dihydroxy benzophenone)butylene] resin and its poly chelates with transition metals

    International Nuclear Information System (INIS)

    Joshi, J. D.; Patel, N.B.; Patel, S. D.

    2006-01-01

    The polymeric ligand poly[(2,4-dihydroxy benzophenone)butylene] H(DHBP-BD) forms 1 :2 metal-ligand complexes with Ni(ll), Co(ll), Cu(ll) and Zn(ll). The polymeric ligand and its poly chelates were characterized on the basis of elemental analyses, magnetic susceptibilities, IR-spectroscopy, UV-visible spectra, NMR, thermogravimetric analyses. The molecular weight of resin was determined using number average molecular weight (M n ) by vapour pressure osmometry method. The stereochemistry in case of the Cu(ll) poly chelate is square-planar, tetrahedral for Zn(ll) and octahedral for Ni(ll) and Co(ll). The stereochemistry in each chelate is proposed on the basis of magnetic susceptibilities and electronic spectra. The IR spectra show that the bidentate ligand coordinates through the oxygen atom of the carbonyl and phenolic group with replacement of hydrogen by metal ions, respectively. All the chelates are paramagnetic in nature except the Zn(ll) chelate which is diamagnetic. The ion-exchange study of the prepared resin was checked by batch equilibration method with selected metal ions [Cu(ll), Ni(ll), Fe(lll) and UO 2 2+( VI)] at varying electrolyte concentration, pH and time. It is found that, resin can be used as an ion-exchanger

  6. Mechanistic basis for high stereoselectivity and broad substrate scope in the (salen)Co(III)-catalyzed hydrolytic kinetic resolution.

    Science.gov (United States)

    Ford, David D; Nielsen, Lars P C; Zuend, Stephan J; Musgrave, Charles B; Jacobsen, Eric N

    2013-10-16

    In the (salen)Co(III)-catalyzed hydrolytic kinetic resolution (HKR) of terminal epoxides, the rate- and stereoselectivity-determining epoxide ring-opening step occurs by a cooperative bimetallic mechanism with one Co(III) complex acting as a Lewis acid and another serving to deliver the hydroxide nucleophile. In this paper, we analyze the basis for the extraordinarily high stereoselectivity and broad substrate scope observed in the HKR. We demonstrate that the stereochemistry of each of the two (salen)Co(III) complexes in the rate-determining transition structure is important for productive catalysis: a measurable rate of hydrolysis occurs only if the absolute stereochemistry of each of these (salen)Co(III) complexes is the same. Experimental and computational studies provide strong evidence that stereochemical communication in the HKR is mediated by the stepped conformation of the salen ligand, and not the shape of the chiral diamine backbone of the ligand. A detailed computational analysis reveals that the epoxide binds the Lewis acidic Co(III) complex in a well-defined geometry imposed by stereoelectronic rather than steric effects. This insight serves as the basis of a complete stereochemical and transition structure model that sheds light on the reasons for the broad substrate generality of the HKR.

  7. Imino Diels-Alder-Based Construction of a Piperidine A-Ring Unit for Total Synthesis of the Marine Hepatotoxin Cylindrospermopsin.

    Science.gov (United States)

    Heintzelman, Geoffrey R.; Weinreb, Steven M.; Parvez, Masood

    1996-07-12

    The synthesis of a piperidine A-ring precursor to the alkaloid cylindrospermopsin (1) is described. The initial approach to the A-ring precursor focused on the imino Diels-Alder reaction of diene 8 with ethyl (N-tosylimino)acetate (9) to form the cycloadduct 10 as a single stereoisomer. However, all attempts to convert ester 10 to a requisite diene such as 5 were unsuccessful. An alternative strategy involved the Diels-Alder cycloaddition of N-tosylimine 9 with oxygenated diene 19 under either thermal or Lewis acid-catalyzed conditions to produce a mixture of cis and trans enones 20 and 21. Although the undesired cis-enone 20 was the major product under all reaction conditions, it could be converted to the desired trans enone 21 by acid-catalyzed isomerization. Copper-mediated conjugate addition of vinylmagnesium bromide to cis-enone 20 followed by stereoselective ketone reduction with L-Selectride produced alcohol 23, whose structure was confirmed by X-ray crystallography. Similarly, trans-enone 21 was converted to alcohol 25 whose structure and stereochemistry were also established by X-ray analysis. Alcohol 25 was then protected as the silyl ether 26, which was hydroborated at the terminal olefin to produce primary alcohol ester 28having the stereochemistry and functionality needed for cylindrospermopsin.

  8. Proton transfers in the Strecker reaction revealed by DFT calculations

    Directory of Open Access Journals (Sweden)

    Shinichi Yamabe

    2014-08-01

    Full Text Available The Strecker reaction of acetaldehyde, NH3, and HCN to afford alanine was studied by DFT calculations for the first time, which involves two reaction stages. In the first reaction stage, the aminonitrile was formed. The rate-determining step is the deprotonation of the NH3+ group in MeCH(OH-NH3+ to form 1-aminoethanol, which occurs with an activation energy barrier (ΔE≠ of 9.6 kcal/mol. The stereochemistry (R or S of the aminonitrile product is determined at the NH3 addition step to the carbonyl carbon of the aldehyde. While the addition of CN− to the carbon atom of the protonated imine 7 appears to scramble the stereochemistry, the water cluster above the imine plane reinforces the CN− to attack the imine group below the plane. The enforcement hinders the scrambling. In the second stage, the aminonitrile transforms to alanine, where an amide Me-CH(NH2-C(=O-NH2 is the key intermediate. The rate-determining step is the hydrolysis of the cyano group of N(amino-protonated aminonitrile which occurs with an ΔE≠ value of 34.7 kcal/mol. In the Strecker reaction, the proton transfer along the hydrogen bonds plays a crucial role.

  9. 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.

  10. Impact of Secondary Interactions in Asymmetric Catalysis

    OpenAIRE

    Frölander, Anders

    2007-01-01

    This thesis deals with secondary interactions in asymmetric catalysis and their impact on the outcome of catalytic reactions. The first part revolves around the metal-catalyzed asymmetric allylic alkylation reaction and how interactions within the catalyst affect the stereochemistry. An OH–Pd hydrogen bond in Pd(0)–π-olefin complexes of hydroxy-containing oxazoline ligands was identified by density functional theory computations and helped to rationalize the contrasting results obtained emplo...

  11. Highly enantio- and diastereoselective reactions of γ-substituted butenolides through direct vinylogous conjugate additions

    KAUST Repository

    Zhang, Wen; Tan, Davin; Lee, Richmond; Tong, Guanghu; Chen, Wenchao; Qi, Baojian; Huang, Kuo-Wei; Tan, Choonhong; Jiang, Zhiyong

    2012-01-01

    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.

  12. 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.

  13. A facile regioselective synthesis of novel spiroacenaphthene pyrroloisoquinolines through 1,3-dipolar cycloaddition reactions

    International Nuclear Information System (INIS)

    Sarrafi, Yaghoub; Asghari, Asieh; Sadatshahabi, Marzieh; Hamzehloueian, Mahshid; Alimohammadi, Kamal

    2013-01-01

    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)

  14. Synthesis of Enantiomerically Pure 6-Substituted-Piperazine-2-Acetic Acid Esters as Intermediates for Library Production.

    Science.gov (United States)

    Chamakuri, Srinivas; Jain, Prashi; Guduru, Shiva Krishna Reddy; Arney, Joseph Winston; MacKenzie, Kevin; Santini, Conrad; Young, Damian W

    2018-05-11

    Amino acids from the chiral pool have been used to produce a 24-member branch of 2,6-disubstituted piperazine scaffolds suitable for use in compound library production. Each scaffold was obtained as a single absolute stereoisomer in multi-gram quantities. Stereochemistry was confirmed by 2D NMR protocols and enantiomeric purity was determined by chiral HPLC. The scaffolds are intended for use as intermediates in parallel synthesis of small-molecule libraries.

  15. 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.

  16. 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)

  17. 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

  18. Effect of sequence and stereochemistry reversal on p53 peptide mimicry.

    Directory of Open Access Journals (Sweden)

    Alessio Atzori

    Full Text Available Peptidomimetics effective in modulating protein-protein interactions and resistant to proteolysis have potential in therapeutic applications. An appealing yet underperforming peptidomimetic strategy is to employ D-amino acids and reversed sequences to mimic a lead peptide conformation, either separately or as the combined retro-inverso peptide. In this work, we examine the conformations of inverse, reverse and retro-inverso peptides of p53(15-29 using implicit solvent molecular dynamics simulation and circular dichroism spectroscopy. In order to obtain converged ensembles for the peptides, we find enhanced sampling is required via the replica exchange molecular dynamics method. From these replica exchange simulations, the D-peptide analogues of p53(15-29 result in a predominantly left-handed helical conformation. When the parent sequence is reversed sequence as either the L-peptide and D-peptide, these peptides display a greater helical propensity, feature reflected by NMR and CD studies in TFE/water solvent. The simulations also indicate that, while approximately similar orientations of the side-chains are possible by the peptide analogues, their ability to mimic the parent peptide is severely compromised by backbone orientation (for D-amino acids and side-chain orientation (for reversed sequences. A retro-inverso peptide is disadvantaged as a mimic in both aspects, and further chemical modification is required to enable this concept to be used fruitfully in peptidomimetic design. The replica exchange molecular simulation approach adopted here, with its ability to provide detailed conformational insights into modified peptides, has potential as a tool to guide structure-based design of new improved peptidomimetics.

  19. Chirality Made Simple: A 1 - and 2-Dimensional Introduction to Stereochemistry

    Science.gov (United States)

    Gawley, Robert E.

    2005-01-01

    The introduction of chirality in one and two dimensions, along with the concepts of internal and external reflection, can be combined with concepts familiar to all students. Once familiar with 1-Dimensional and 2-Dimensional chirality, the same concepts can be extended to 3-Dimensional and by projecting 3-D back to two, it is possible to interpret…

  20. 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.

  1. 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

  2. Isotope chirality in long-armed multifunctional organosilicon ("Cephalopod") molecules.

    Science.gov (United States)

    Barabás, Béla; Kurdi, Róbert; Zucchi, Claudia; Pályi, Gyula

    2018-07-01

    Long-armed multifunctional organosilicon molecules display self-replicating and self-perfecting behavior in asymmetric autocatalysis (Soai reaction). Two representatives of this class were studied by statistical methods aiming at determination of probabilities of natural abundance chiral isotopomers. The results, reported here, show an astonishing richness of possibilities of the formation of chiral isotopically substituted derivatives. This feature could serve as a model for the evolution of biological chirality in prebiotic and early biotic stereochemistry. © 2018 Wiley Periodicals, Inc.

  3. Haenamindole, an unusual diketopiperazine derivative from a marine-derived Penicillium sp. KCB12F005.

    Science.gov (United States)

    Kim, Jong Won; Ko, Sung-Kyun; Son, Sangkeun; Shin, Kee-Sun; Ryoo, In-Ja; Hong, Young-Soo; Oh, Hyuncheol; Hwang, Bang Yeon; Hirota, Hiroshi; Takahashi, Shunji; Kim, Bo Yeon; Osada, Hiroyuki; Jang, Jae-Hyuk; Ahn, Jong Seog

    2015-11-15

    During the chemical investigation of marine-derived fungus, an unusual diketopiperazine (DKP) alkaloid, haenamindole (1), was isolated from a culture of the marine-derived fungus Penicillium sp. KCB12F005. The structure of 1, which possesses benzyl-hydroxypiperazindione and phenyl-pyrimidoindole rings system in the molecule, was elucidated by analysis of NMR and MS data. The stereochemistry of 1 was determined by ROESY and advanced Marfey's method. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Dictyosphaeric acids A and B: new decalactones from an undescribed Penicillium sp. obtained from the alga Dictyosphaeria versluyii.

    Science.gov (United States)

    Bugni, Tim S; Janso, Jeffrey E; Williamson, R Thomas; Feng, Xidong; Bernan, Valerie S; Greenstein, Michael; Carter, Guy T; Maiese, William M; Ireland, Chris M

    2004-08-01

    Fungal isolate F01V25 was obtained from the alga Dictyosphaeria versluyii collected near Dravuni, Fiji, in 2001 and represented a previously undescribed Penicillium sp. Fermentation of isolate F01V25 resulted in the production of two new polyketides, dictyosphaeric acids A and B, along with the known anthraquinone carviolin. The relative stereochemistry of dictyosphaeric acids A and B was determined using the J-based configuration analysis method in conjunction with ROE and NOE correlations.

  5. Synthesis and pharmacological evaluation of the individual stereoisomers of 3- [methyl(1,2,3,4-tetrahydro-2-naphthalenyl)amino]-1-indanone, a potent mast cell stabilising agent

    OpenAIRE

    WALSH, JOHN JARLATH

    2011-01-01

    PUBLISHED Each stereoisomer of 3-[methyl(1,2,3,4-tetrahydro-2-naphthalenyl)amino]-1-indanone, 1a-d, was prepared and evaluated in vitro for its ability to prevent mediator release induced by different degranulating agents from rodent mast cells and also in vivo against passive cutaneous anaphylaxis. The manner in which the stereoisomers prevented direct membrane activation was found to be highly dependent on the stereochemistry of the individual isomers. Stereoisomer 1b was the most active...

  6. The DFT-DVM theoretical study of the differences of quadrupole splitting and the iron electronic structure for the rough heme models for {alpha}- and {beta}-subunits in deoxyhemoglobin and for deoxymyoglobin

    Energy Technology Data Exchange (ETDEWEB)

    Yuryeva, E. I. [Institute of Solid State Chemistry of the Ural Branch of the Russian Academy of Sciences (Russian Federation); Oshtrakh, M. I., E-mail: oshtrakh@mail.utnet.ru [Ural State Technical University-UPI, Faculty of Physical Techniques and Devices for Quality Control (Russian Federation)

    2008-01-15

    Quantum chemical calculations of the iron electron structure and {sup 57}Fe quadrupole splitting were made by density functional theory and X{alpha} discrete variation method for the rough heme models for {alpha}- and {beta}-subunits in deoxyhemoglobin and for deoxymyoglobin accounting stereochemical differences of the active sites in native proteins. The calculations revealed differences of quadrupole splitting temperature dependences for three models indicating sensitivity of quadrupole splitting and Fe(II) electronic structure to small variations of iron stereochemistry.

  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. Structural and kinetic insights into binding and incorporation of L-nucleotide analogs by a Y-family DNA polymerase

    OpenAIRE

    Gaur, Vineet; Vyas, Rajan; Fowler, Jason D.; Efthimiopoulos, Georgia; Feng, Joy Y.; Suo, Zucai

    2014-01-01

    Considering that all natural nucleotides (D-dNTPs) and the building blocks (D-dNMPs) of DNA chains possess D-stereochemistry, DNA polymerases and reverse transcriptases (RTs) likely possess strongD-stereoselectivity by preferably binding and incorporating D-dNTPs over unnatural L-dNTPs during DNA synthesis. Surprisingly, a structural basis for the discrimination against L-dNTPs by DNA polymerases or RTs has not been established although L-deoxycytidine analogs (lamivudine and emtricitabine) a...

  9. 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.

  10. Diastereo- and regioselective addition of thioamide dianions to imines and aziridines: synthesis of N-thioacyl-1,2-diamines and N-thioacyl-1,3-diamines.

    Science.gov (United States)

    Shibahara, Fumitoshi; Kobayashi, Shun-ichiro; Maruyama, Toshifumi; Murai, Toshiaki

    2013-01-02

    Addition reactions of thioamide dianions that were derived from N-arylmethyl thioamides to imines and aziridines were carried out. The reactions of imines gave the addition products of N-thioacyl-1,2-diamines in a highly diastereoselective manner in good-to-excellent yields. The diastereomeric purity of these N-thioacyl-1,2-diamines could be enriched by simple recrystallization. The reduction of N-thioacyl-1,2-diamines with LiAlH(4) gave their corresponding 1,2-diamines in moderate-to-good yields with retention of their stereochemistry. The oxidative-desulfurization/cyclization of an N-thioacyl-1,2-diamine in CuCl(2)/O(2) and I(2)/pyridine systems gave the cyclized product in moderate yield and the trans isomer was obtained as the sole product. On the other hand, a similar cyclization reaction with antiformin (aq. NaClO) as an oxidant gave the cis isomer as the major product. The reactions of N-tosylaziridines gave the addition products of N-thioacyl-1,3-diamines with low diastereoselectivity but high regioselectivity and in good-to-excellent yields. The use of AlMe(3) as an additive improved the efficiency and regioselectivity of the reaction. The stereochemistry of the obtained products was determined by X-ray diffraction. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Sequence-Dependent Diastereospecific and Diastereodivergent Crosslinking of DNA by Decarbamoylmitomycin C.

    Science.gov (United States)

    Aguilar, William; Paz, Manuel M; Vargas, Anayatzinc; Clement, Cristina C; Cheng, Shu-Yuan; Champeil, Elise

    2018-04-20

    Mitomycin C (MC), a potent antitumor drug, and decarbamoylmitomycin C (DMC), a derivative lacking the carbamoyl group, form highly cytotoxic DNA interstrand crosslinks. The major interstrand crosslink formed by DMC is the C1'' epimer of the major crosslink formed by MC. The molecular basis for the stereochemical configuration exhibited by DMC was investigated using biomimetic synthesis. The formation of DNA-DNA crosslinks by DMC is diastereospecific and diastereodivergent: Only the 1''S-diastereomer of the initially formed monoadduct can form crosslinks at GpC sequences, and only the 1''R-diastereomer of the monoadduct can form crosslinks at CpG sequences. We also show that CpG and GpC sequences react with divergent diastereoselectivity in the first alkylation step: 1"S stereochemistry is favored at GpC sequences and 1''R stereochemistry is favored at CpG sequences. Therefore, the first alkylation step results, at each sequence, in the selective formation of the diastereomer able to generate an interstrand DNA-DNA crosslink after the "second arm" alkylation. Examination of the known DNA adduct pattern obtained after treatment of cancer cell cultures with DMC indicates that the GpC sequence is the major target for the formation of DNA-DNA crosslinks in vivo by this drug. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. 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.

  13. Michael additions of thiocompounds to {alpha}, {beta}-unsaturated carbonyl compounds in aqueous media: stereoselectivity with unambiguous characterization by NMR

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, Queli Aparecida Rodrigues de; Pereira, Maria Luiza de Oliveira; Coelho, Ricardo Bezerra; Kaiser, Carlos Roland; Jones Junior, Joel; Silva, Flavia Martins da [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Inst. de Quimica. Dept. de Quimica Organica]. E-mail: soa@iq.ufrj.br; Carvalho, Erika Martins de [Instituto de Tecnologia em Farmacos (Far-Manguinhos), Rio de Janeiro, RJ (Brazil)

    2008-07-01

    The reactions of crotonaldehyde (8) with thiophenol (2) and benzalacetone (10) with ethane-1,2- dithiol (11) yield Michael addition products. The reactions of thiophenol (2) with (R)-carvone (13) and (S)-perillaldehyde (15) lead to (2S,3R,5S)-5-isopropenyl-2-methyl-3-(phenylthio)cyclohexanone (14) and (1R,2R,4S)-4-isopropenyl-2-(phenylthio)cyclohexanecarbaldehyde (16), respectively. An unambiguous elucidation of the stereochemistry of 14 and 16 by NMR is also presented. (author)

  14. New Meroterpenoids from the Endophytic Fungus Aspergillus flavipes AIL8 Derived from the Mangrove Plant Acanthus ilicifolius

    Directory of Open Access Journals (Sweden)

    Zhi-Qiang Bai

    2015-01-01

    Full Text Available Four new meroterpenoids (2–5, along with three known analogues (1, 6, and 7 were isolated from mangrove plant Acanthus ilicifolius derived endophytic fungus Aspergillus flavipes. The structures of these compounds were elucidated by NMR and MS analysis, the configurations were assigned by CD data, and the stereochemistry of 1 was confirmed by X-ray crystallography analysis. A possible biogenetic pathway of compounds 1–7 was also proposed. All compounds were evaluated for antibacterial and cytotoxic activities.

  15. New alkaloids of the sarpagine group from Rauvolfia serpentina hairy root culture.

    Science.gov (United States)

    Sheludko, Yuri; Gerasimenko, Irina; Kolshorn, Heinz; Stöckigt, Joachim

    2002-07-01

    Three new monoterpenoid indole alkaloids, 19(S),20(R)-dihydroperaksine (1), 19(S),20(R)-dihydroperaksine-17-al (2), and 10-hydroxy-19(S),20(R)-dihydroperaksine (3), along with 16 known alkaloids 4-19 were isolated from hairy root culture of Rauvolfia serpentina, and their structures were elucidated by 1D and 2D NMR analyses. Taking into account the stereochemistry of the new alkaloids and results of preliminary enzymatical studies, the putative biosynthetical relationships between the novel alkaloids are discussed.

  16. A practical deca-gram scale ring expansion of (R)-(-)-carvone to (R)-(+)-3-methyl-6-isopropenyl-cyclohept-3-enone-1.

    Science.gov (United States)

    Alves, Leandro de C; Desiderá, André L; de Oliveira, Kleber T; Newton, Sean; Ley, Steven V; Brocksom, Timothy J

    2015-07-28

    A route to enantiopure (R)-(+)-3-methyl-6-isopropenyl-cyclohept-3-enone-1, an intermediate for terpenoids, has been developed and includes a highly chemo- and regioselective Tiffeneau-Demjanov reaction. Starting from readily available (R)-(-)-carvone, this robust sequence is available on a deca-gram scale and uses flow chemistry for the initial epoxidation reaction. The stereochemistry of the addition of two nucleophiles to the carbonyl group of (R)-(-)-carvone has been determined by X-ray diffraction studies and chemical correlation.

  17. 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.

  18. JICST Factual Database(2)

    Science.gov (United States)

    Araki, Keisuke

    The computer programme, which builds atom-bond connection tables from nomenclatures, is developed. Chemical substances with their nomenclature and varieties of trivial names or experimental code numbers are inputted. The chemical structures of the database are stereospecifically stored and are able to be searched and displayed according to stereochemistry. Source data are from laws and regulations of Japan, RTECS of US and so on. The database plays a central role within the integrated fact database service of JICST and makes interrelational retrieval possible.

  19. Crystal and molecular structure of 8-acetoxy-7-aza-6-ethoxycarbonyl-7-formyl-3,4-dihydroxy-3,4-O-isopropylidene-2-oxabicyclo [3.30]octane

    International Nuclear Information System (INIS)

    Holzapfel, C.W.; Koekemoer, J.M.; Kruger, G.J.; Van Dyk, M.S.

    1985-01-01

    The structure and stereochemistry of the title compound, a 11-deoxy-11-azaprostaglandin synthon, has been determined by single-crystal X-ray diffraction methods. The dioxolane and aza-rings are cis-fused on the same side to the central furanose ring. Both the ethoxycarbonyl group on C(5) and the acetoxy-group on C(6) have a β-configuration. The conformation of the solid state structure is compared with that in chloroform solution, as evidenced by 1 H n.m.r. studies

  20. Complex chemistry

    International Nuclear Information System (INIS)

    Kim, Bong Gon; Kim, Jae Sang; Kim, Jin Eun; Lee, Boo Yeon

    2006-06-01

    This book introduces complex chemistry with ten chapters, which include development of complex chemistry on history coordination theory and Warner's coordination theory and new development of complex chemistry, nomenclature on complex with conception and define, chemical formula on coordination compound, symbol of stereochemistry, stereo structure and isomerism, electron structure and bond theory on complex, structure of complex like NMR and XAFS, balance and reaction on solution, an organo-metallic chemistry, biology inorganic chemistry, material chemistry of complex, design of complex and calculation chemistry.

  1. Aspergilones A and B, two benzylazaphilones with an unprecedented carbon skeleton from the gorgonian-derived fungus Aspergillus sp.

    KAUST Repository

    Shao, Chang Lun; Wang, Chang Yun; Wei, Mei Yan; Gu, Yu Cheng; She, Zhi Gang; Qian, Pei Yuan; Lin, Yong Cheng

    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.

  2. Introduction to magnetochemistry

    CERN Document Server

    Earnshaw, Alan

    2013-01-01

    Introduction to Magnetochemistry provides an introduction to the more important aspects of magnetochemistry. The measurement of magnetic moment has been one of the most consistently useful to coordination chemists. For teaching purposes it provides a simple method of illustrating the ideas of electronic structure, and in research it can provide fundamental information about the bonding and stereochemistry of complexes. The book contains six chapters covering topics such as free atoms and ions, transition metal complexes, crystal field theory, second and third row transition metal complexes, a

  3. A Short Synthetic Route to the Calystegine Alkaloids

    DEFF Research Database (Denmark)

    Skaanderup, Philip Robert; Madsen, Robert

    2003-01-01

    An efficient strategy is described for the synthesis of enantiopure calystegine alkaloids. The key step employs a zinc-mediated fragmentation of benzyl-protected methyl 6-iodo-glycosides followed by in situ formation of the benzyl imine and Barbier-type allylation with zinc, magnesium, or indium...... metal. Stereochemistry in the pivotal allylation is controlled by the choice of the metal. The functionalized 1,8-nonadienes, thus formed, are converted into cycloheptenes by ring-closing metathesis. Regioselective hydroboration and oxidation give the corresponding cycloheptanones, which are deprotected...

  4. Nomenclature on an inorganic compound

    International Nuclear Information System (INIS)

    1998-10-01

    This book contains eleven chapters : which mention nomenclature of an inorganic compound with introduction and general principle on nomenclature of compound. It gives the description of grammar for nomenclature such as brackets, diagonal line, asterisk, and affix, element, atom and groups of atom, chemical formula, naming by stoichiometry, solid, neutral molecule compound, ion, a substituent, radical and name of salt, oxo acid and anion on introduction and definition of oxo acid, coordination compound like symbol of stereochemistry , boron and hydrogen compound and related compound.

  5. Spectroscopy and chemistry of uranium IV

    International Nuclear Information System (INIS)

    Folcher, G.; Rigny, P.

    1980-06-01

    Different fundamental research papers on uranium IV are presented, some were never edited. Molecular spectroscopy was used for identification and structural study of uranium IV in aqueous or organic solutions. The fields studied are: coordination, stereochemistry, electronic structure and chemical properties. For interpretation of results some studies were made with solid compounds or with thorium compounds or thorium complexes. Knowledge of actinides chemistry is improved, uranium and thorium being models for 5 f ions, extractive chemistry is better understood and new applications are possible [fr

  6. Cyclization of 1,2:3,4-di-O-isopropylidene-α-D-galacto-1,6-hexodialdo-1,5-pyranose acylhydrazone and semicarbazone

    OpenAIRE

    Martins Alho, Miriam Amelia; Baggio, Ricardo Fortunato; D'accorso, Norma Beatriz

    2015-01-01

    Cyclization of 1,2:3,4-di-O-isopropylidene-α-D-galacto-1,6-hexodialdo-1,5-pyranose benzoylhydrazone using acetylating mixtures led us to the corresponding (2R)- and (2S)-5- phenyl-1,3,4-oxadiazoline derivatives. The same conditions applied to the semicarbazone produced the 5-methyl-1,3,4-oxadiazoline derivative as the main compound, which is formed with acetylating mixtures even at room temperature. X-Ray analysis and NMR techniques were used to determine the stereochemistry of the new asymme...

  7. 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)

  8. Molecular structure studies by 3D imaging of fast ion beams

    International Nuclear Information System (INIS)

    Kanter, E.P.; Vager, Z.; Both, G.; Cooney, P.J.; Faibis, A.; Koenig, W.; Zabransky, B.J.; Zajfman, D.

    1986-01-01

    The use of the Coulomb-explosion technique combined with a radically new multi-particle detector, extremely thin film targets, and low-excitation ion source has enabled, for the first time, direct measurements of the complete stereochemistry of complex polyatomic molecular ions. We outline the methods used and present results for protonated acetylene (C 2 H 3 + ) and the methane cation (CH 4 + ) as examples. We demonstrate the techniques by which these methods can be generalized to determine directly vibrational motions in polyatomic molecules. 24 refs., 4 figs

  9. 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)

  10. The Features of Moessbauer Spectra of Hemoglobins: Approximation by Superposition of Quadrupole Doublets or by Quadrupole Splitting Distribution?

    International Nuclear Information System (INIS)

    Oshtrakh, M. I.; Semionkin, V. A.

    2004-01-01

    Moessbauer spectra of hemoglobins have some features in the range of liquid nitrogen temperature: a non-Lorentzian asymmetric line shape for oxyhemoglobins and symmetric Lorentzian line shape for deoxyhemoglobins. A comparison of the approximation of the hemoglobin Moessbauer spectra by a superposition of two quadrupole doublets and by a distribution of the quadrupole splitting demonstrates that a superposition of two quadrupole doublets is more reliable and may reflect the non-equivalent iron electronic structure and the stereochemistry in the α- and β-subunits of hemoglobin tetramers.

  11. Synthesis, Properties and Stereochemistry of 2-Halo-1,2λ5-oxaphosphetanes

    Directory of Open Access Journals (Sweden)

    Anastasy O. Kolodiazhna

    2016-10-01

    Full Text Available Results of research into four-membered 2-halo-1,2λ5-oxaphosphetane phosphorus(V-heterocycles are presented. The preparation of 2-halo-1,2λ5-oxaphosphetanes by reaction of P-haloylides with carbonyl compounds is described. The mechanism of asynchronous [2+2]-сycloaddition of ylides to aldehydes was proposed on the base of low-temperature NMR investigations. 2-Halo-1,2λ5-oxaphosphetanes were isolated as individual compounds and their structures were confirmed by 1Н-, 13C-, 19F- and 31Р-NMR spectra. These compounds are convenient reagents for preparing of various organic and organophosphorus compounds hardly available by other methods. Chemical and physical properties of the 2-halo-1,2λ5-oxaphosphetanes are reviewed. The 2-chloro-1,2λ5-oxaphosphetanes, rearrange with formation of 2-chloroalkyl-phosphonates or convert into trans-phosphorylated alkenes depending on the substituents at the α-carbon atom. Prospective synthetic applications of 2-halo-1,2λ5-oxaphosphetanes are analyzed. The 2-halo-1,2λ5-oxaphosphetanes may be easily converted to various alkenylphosphonates: allyl- or vinylphosphonates, phosphorus ketenes, thioketenes, ketenimines.

  12. Structure, stereochemistry and synthesis of a variety of physiologically active plant phenols

    Energy Technology Data Exchange (ETDEWEB)

    Van Heerden, F R

    1980-01-01

    The medicinal use of various Leguminosae species by the local population led to a phytochemical study of the bark of Dalbergia nitidula, Dalbergia melanoxylon and wood of Acacia fasciculifera. Rotenoid glycoside and three new carbon bonded isoflavone glycosides were isolated from the bark of D. nitidula. The rotenoid glycoside was characterized by means of acid and enzymatic hydrolysis and its absolute configuration was determined with reference to CD comparisons. A kinetic study was done to determine the relative toxidities of the rotenoid glycoside and its aglicone. The identity and the coupling positions of the sugars was confirmed by a C-NMR investigation of the rotenoid and isoflavane glycosides. The structure of heminitidulan, a complex isoflavane from D. nitidula, was confirmed by complete synthesis. Trans- and cis-clovamide, amides made up of L-DOPA and trans- and cis-caffeic acid respectively, and four new analogous deoxyclovamides are present in the bark of D. melanoxylon. For the first time optically pure trans clovamide was obtained by direct synthesis. C-NMR and CD confirmed differentiation between trans- and cisclovamide. The therapeutic value of L-DOPA for Parkinson's Disease implies possible physiological activity for the clovamide. As well as a number of known flavonoids and peltoginoids, a tetracyclic flavonoid (peltoginoid), fasciculiferin, was found in the wood of A. fasciculifera. Although peltoginoids with a D-ring in a fully reduced or oxidised state are known, this is the first natural peltoginoid with the D-ring in an intermediate oxidation state. Fasciculiferol, till now an unknown metabolyte from A. fasciculifera, is a new member of a rare group of natural products that are generally cytotoxic. The relatively drastic reaction conditions necessary for carbocation formation from peltoginol in comparison to the analogous flavon-3, 4-diols, is attributed to steric factors which arise from the rigid conformation of the B-ring of peltoginol.

  13. 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

  14. Luminescent chiral ionic Ir(III) complexes: Synthesis and photophysical properties

    Energy Technology Data Exchange (ETDEWEB)

    Ricciardi, Loredana, E-mail: loredana.ricciardi@unical.it [CNR NANOTEC-Istituto di Nanotecnologia U.O.S. Cosenza, 87036 Arcavacata di Rende (CS) (Italy); La Deda, Massimo; Ionescu, Andreea; Godbert, Nicolas; Aiello, Iolinda; Ghedini, Mauro [MAT-INLAB (Laboratorio di Materiali Molecolari Inorganici), LASCAMM and CR INSTM, Unità INSTM della Calabria, Dipartimento di Chimica e Tecnologie Chimiche, Università della Calabria, 87036 Arcavacata di Rende (CS) (Italy); Fusè, Marco, E-mail: marco.fuse@unimi.it [Dipartimento di Scienze Farmaceutiche, Università di Milano, Via Golgi 19, 20133 Milano (Italy); Rimoldi, Isabella; Cesarotti, Edoardo [Dipartimento di Scienze Farmaceutiche, Università di Milano, Via Golgi 19, 20133 Milano (Italy)

    2016-02-15

    Three homologous series of luminescent octahedral ionic Ir(III) complexes (1–12) with a dual stereogenic center of general formula {sup Δ,Λ} {sup (R,S)}[(ppy){sub 2}Ir(R-campy)]X, where ppy=2-phenylpyridine, R-campy=2-methyl-5,6,7,8-tetrahydroquinolin-8-amine (Me-campy) or 8-amino-5,6,7,8-tetrahydroquinolines (H-campy) and as counterions X{sup −}=Cl{sup −} or CH{sub 3}COO{sup −} have been synthesized and characterized. The NMR characterization of each complex highlighted the diastereoisomeric purity and the absolute configuration has been confirmed by Electronic Circular Dichroism spectroscopy. The absorption and the luminescence properties of the compounds in solution and in solid state have been investigated by UV–vis, steady-state emission and time-correlated single-photon counting spectroscopy. The obtained results from the 12 compounds highlight the difficult to correlate photophysical properties in solution to the stereochemistry, while excited states decay studies of the solid state samples indicate a correlation between photophysics and packing mode which is affected by the different stereochemistry. - Highlights: • Luminescent chiral ionic Ir(III) complexes have been synthesized and characterized. • Presence in the same structure of two stereogenic centers. • Use of camphorsulfonate as resolving anion to obtain enantiomerically pure samples. • Stereoisomers produce aggregates with different emitting properties. • Lifetimes from solid samples show the presence of AIPE.

  15. Mechanistic studies of ethylene biosynthesis in higher plants

    International Nuclear Information System (INIS)

    McGeehan, G.M.

    1986-01-01

    Ethylene is a plant hormone that elicits a wide variety of responses in plant tissue. Among these responses are the hastening of abscission, ripening and senescence. In 1979 it was discovered that 1-amino-1-cyclopropane carboxylic acid is the immediate biosynthetic precursor to ethylene. Given the obvious economic significance of ethylene production the authors concentrated their studies on the conversion of ACC to ethylene. They delved into mechanistic aspects of ACC oxidation and they studied potential inhibitors of ethylene forming enzyme (EFE). They synthesized various analogs of ACC and found that EFE shows good stereodiscrimination among alkyl substituted ACC analogs with the 1R, 2S stereoisomer being processed nine times faster than the 1S, 2R isomer in the MeACC series. They also synthesized 2-cyclopropyl ACC which is a good competitive inhibitor of EFE. This compound also causes time dependent loss of EFE activity leading us to believe it is an irreversible inhibitor of ethylene formation. The synthesis of these analogs has also allowed them to develop a spectroscopic technique to assign the relative stereochemistry of alkyl groups. 13 C NMR allows them to assign the alkyl stereochemistry based upon gamma-shielding effects on the carbonyl resonance. Lastly, they measured kinetic isotope effects on the oxidation of ACC in vivo and in vitro and found that ACC is oxidized by a rate-determining 1-electron removal from nitrogen in close accord with mechanisms for the oxidation of other alkyl amines

  16. Application of positive mode atmospheric chemical ionisation to distinguish epimeric oleanolic and ursolic acids.

    Science.gov (United States)

    Townley, Chloe; Brettell, Rhea C; Bowen, Richard D; Gallagher, Richard T; Martin, William H C

    2015-01-01

    A new and more reliable method is reported for distinguishing the equatorial and axial epimers of oleanolic and ursolic acids and related triterpenoids based primarily on the relative abundance of the [M+H](+) and [M+-H(2)O](+) signals in their positive mode atmospheric pressure chemical ionisation mass spectra. The rate of elimination of water, which is the principal primary fragmentation of protonated oleanolic and ursolic acids, depends systematically on the stereochemistry of the hydroxyl group in the 3 position. For the b-epimer, in which the 3-hydroxyl substituent is in an equatorial position,[M+-H(2)O](+) is the base peak. In contrast, for the α-epimer, where the 3-hydroxyl group is axial, [M + H](+) is the base peak. This trend, which is general for a range of derivatives of oleanolic and ursolic acids, including the corresponding methyl esters, allows epimeric triterpenoids in these series to be securely differentiated. Confirmatory information is available from the collision-induced dissociation of the [M+-H(2)O](+) primary fragment ions, which follow different pathways for the species derived from axial and equatorial epimers of oleanolic and ursolic acids. These two pieces of independent spectral information permit the stereochemistry of epimeric oleanolic and ursolic acids (and selected derivatives) to be assigned with confidence without relying either on chromatographic retention times or referring to the spectra or other properties of authentic samples of these triterpenoids.

  17. Interaction of model aryl- and alkyl-boronic acids and 1,2-diols in aqueous solution.

    Science.gov (United States)

    Marinaro, William A; Prankerd, Richard; Kinnari, Kaisa; Stella, Valentino J

    2015-04-01

    The goal of this work was to quantitate ester formation between alkyl and aryl boronic acids and vicinal-diols or 1,2-diols in aqueous solution. As used here, 1,2-diols includes polyols with one or more 1,2-diol pairs. Multiple techniques were used including apparent pKa shifts of the boronic acids using UV spectrophotometry (for aryl acids) and titration (for aryl and alkyl acids). Isothermal microcalorimetry was also used, with all reactions being enthalpically favored. For all the acids and 1,2-diols and the conditions studied, evidence only supported 1:1 ester formation. All the esters formed were found to be significantly more acidic, as Lewis acids, by 3-3.5 pKa units than the corresponding nonesterified boronic acid. The equilibrium constants for ester formation increased with increasing number of 1,2-diol pairs but stereochemistry may also play a role as sorbitol with five possible 1,2-diol pairs and five isomers (taking into account the stereochemistry of the alcohol groups) was twice as efficient at ester formation compared with mannitol, also with five possible 1,2-diol pairs but only three isomers. Alkyl boronic acids formed esters to a greater extent than aryl acids. Although some quantitative differences were seen between the various techniques used, rank ordering of the structure/reactivity was consistent. Formulation implications of ester formation between boronic acids and 1,2-diols are discussed. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.

  18. Difluorothromboxane A2 and stereoisomers: Stable derivatives of thromboxane A2 with differential effects on platelets and blood vessels

    International Nuclear Information System (INIS)

    Morinelli, T.A.; Okwu, A.K.; Mais, D.E.; Halushka, P.V.; John, V.; Chen, Chienkuang; Fried, J.

    1989-01-01

    The present study reports on the selective effects on human platelets and canine saphenous veins of four stable difluorinated analogues and thromboxane A 2 (TXA 2 ), in which the characteristic 2,6-dioxa[3.1.1]bicycloheptane structure of TXA 2 has been retained. The four compounds differ in their stereochemistry of the 5,6 double bond and/or the 15-hydroxyl group. Only 10,10-difluoro-TXA 2 (compound I) with the natural stereochemistry of TXA 2 was an agonist in both platelets and canine saphenous veins. (15R)-10,10-Difluoro-TXA 2 (compound II), (5E)-10,10-difluoro-TXA 2 (compound III), and (5E,15R)-10,10-difluoro-TXA 2 (compound IV) were antagonists of platelet aggregation stimulated by compound I. However, compounds II, III, and IV stimulated contraction of canine saphenous veins. All four compounds could displace the TXA 2 /prostaglandin H 2 antagonist 9,11-dimethylmethano-11,12-methano-16-(3- 125 I-4-hydroxyphenyl)-13,14-dihydro-13-aza-15αβ-ω-tetranor-TXA 2 from its platelet receptor. These results support the existence of two subtypes of TXA 2 /prostaglandin H 2 receptors and emphasize the importance of the stereochemical requirements of these TXA 2 analogues for interaction with these receptors. These stable fluorinated TXA 2 analogues should prove useful tools for the further characterization of these and other TXA 2 /prostaglandin H 2 receptors

  19. Cis–Trans Configuration of Coumaric Acid Acylation Affects the Spectral and Colorimetric Properties of Anthocyanins

    Directory of Open Access Journals (Sweden)

    Gregory T. Sigurdson

    2018-03-01

    Full Text Available The color expression of anthocyanins can be affected by a variety of environmental factors and structural characteristics. Anthocyanin acylation (type and number of acids is known to be key, but the influence of acyl isomers (with unique stereochemistries remains to be explored. The objective of this study was to investigate the effects of cis–trans configuration of the acylating group on the spectral and colorimetric properties of anthocyanins. Petunidin-3-rutinoside-5-glucoside (Pt-3-rut-5-glu and Delphinidin-3-rutinoside-5-glucoside (Dp-3-rut-5-glu and their cis and trans coumaroylated derivatives were isolated from black goji and eggplant, diluted in pH 1–9 buffers, and analyzed spectrophotometrically (380–700 nm and colorimetrically (CIELAB during 72 h of storage (25 °C, dark. The stereochemistry of the acylating group strongly impacted the spectra, color, and stability of the Dp and Pt anthocyanins. Cis acylated pigments exhibited the greatest λmax in all pH, as much as 66 nm greater than their trans counterparts, showing bluer hues. Cis acylation seemed to reduce hydration across pH, increasing color intensity, while trans acylation generally improved color retention over time. Dp-3-cis-p-cou-rut-5-glu exhibited blue hues even in pH 5 (C*ab = 10, hab = 256° where anthocyanins are typically colorless. Cis or trans double bond configurations of the acylating group affected anthocyanin spectral and stability properties.

  20. (5S,6R-5-Methyl-6-phenyl-4-propyl-1,3,4-oxadiazinane-2-thione

    Directory of Open Access Journals (Sweden)

    Joshua L. Kocher

    2009-06-01

    Full Text Available The title molecule, C13H18N2OS, is an oxadiazinanthione derived from (1R,2S-norephedrine. There are two molecules in the asymmetric. Both adopt roughly half-chair conformations; however, the 5-position carbon orients out of opposite faces of the oxadiazinanthiones plane in the two molecules. In the crystal structure, they are oriented as a dimer linked by a pair of N—H...S hydrogen bonds. The absolute configuration has been established from anomalous dispersion and confirms the known stereochemistry based on the synthetic procedure.

  1. Synthesis and Transformations of di-endo-3-Aminobicyclo-[2.2.2]oct-5-ene-2-carboxylic Acid Derivatives

    Directory of Open Access Journals (Sweden)

    Márta Palkó

    2011-09-01

    Full Text Available all-endo-3-amino-5-hydroxybicyclo[2.2.2]octane-2-carboxylic acid (13 and all-endo-5-amino-6-(hydroxymethylbicyclo[2.2.2]octan-2-ol (10 were prepared via dihydro-1,3-oxazine or g-lactone intermediates by the stereoselective functionalization of an N-protected derivative of endo-3-aminobicyclo[2.2.2]oct-5-ene-2-carboxylic acid (2. Ring closure of b-amino ester 4 resulted in tricyclic pyrimidinones 15 and 16. The structures, stereochemistry and relative configurations of the synthesized compounds were determined by IR and NMR.

  2. 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.

  3. 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)

  4. mmpdb: An Open-Source Matched Molecular Pair Platform for Large Multiproperty Data Sets.

    Science.gov (United States)

    Dalke, Andrew; Hert, Jérôme; Kramer, Christian

    2018-05-29

    Matched molecular pair analysis (MMPA) enables the automated and systematic compilation of medicinal chemistry rules from compound/property data sets. Here we present mmpdb, an open-source matched molecular pair (MMP) platform to create, compile, store, retrieve, and use MMP rules. mmpdb is suitable for the large data sets typically found in pharmaceutical and agrochemical companies and provides new algorithms for fragment canonicalization and stereochemistry handling. The platform is written in Python and based on the RDKit toolkit. It is freely available from https://github.com/rdkit/mmpdb .

  5. 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)

  6. Profisetinidins: the first synthesis of tetraflavenoids: bi- and triflavenoids with terminal diolfunction. Profisetinidiene: die eerste sintese van tetraflavanoiede: bi- en triflavanoiede met terminale diolfunksie

    Energy Technology Data Exchange (ETDEWEB)

    Young, D A

    1984-01-01

    Chemists in the flavenoid field rely heavily on spectroscopic methods for unravelling complex flavenoid structures. The most powerful of these techniques - ultrahigh resolution /sup 1/H and /sup 13/C nmr spectroscopy - have certain inherent shortcomings especially at the tetraflavenoid level, owing to the obnormal high temperature requirements (>200/sup 0/C) to induce rapid rotation around the various interflavenoidbands and consequently sharply defined spectra. This problems have stressed the need for synthetic access to oligomeric tannins. In this study the coupling sequence and the stereochemistry of tetraflavenoids is determined via synthesis.

  7. Enantioselective Copper-Catalyzed Carboetherification of Unactivated Alkenes**

    Science.gov (United States)

    Bovino, Michael T.; Liwosz, Timothy W.; Kendel, Nicole E.; Miller, Yan; Tyminska, Nina

    2014-01-01

    Chiral saturated oxygen heterocycles are important components of bioactive compounds. Cyclization of alcohols onto pendant alkenes is a direct route to their synthesis, but few catalytic enantioselective methods enabling cyclization onto unactivated alkenes exist. Herein is reported a highly efficient copper-catalyzed cyclization of γ-unsaturated pentenols that terminates in C-C bond formation, a net alkene carboetherification. Both intra- and intermolecular C-C bond formations are demonstrated, yielding functionalized chiral tetrahydrofurans as well as fused-ring and bridged-ring oxabicyclic products. Transition state calculations support a cis-oxycupration stereochemistry-determining step. PMID:24798697

  8. 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)

  9. Synthesis and pharmacological evaluation of the individual stereoisomers of 3-[methyl(1,2,3,4-tetrahydro-2-naphthalenyl)amino]-1-indanone, a potent mast cell stabilising agent.

    Science.gov (United States)

    Byrne, Adam J; Barlow, James W; Walsh, John J

    2011-02-15

    Each stereoisomer of 3-[methyl(1,2,3,4-tetrahydro-2-naphthalenyl)amino]-1-indanone, 1a-d, was prepared and evaluated in vitro for its ability to prevent mediator release induced by different degranulating agents from rodent mast cells and also in vivo against passive cutaneous anaphylaxis. The manner in which the stereoisomers prevented direct membrane activation was found to be highly dependent on the stereochemistry of the individual isomers. Stereoisomer 1b was the most active isomer in vivo, exhibiting superior activity to disodium cromoglycate. Copyright © 2010 Elsevier Ltd. All rights reserved.

  10. 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)

  11. 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

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

    DEFF Research Database (Denmark)

    Nielsen, Thomas Eiland

    2009-01-01

    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...... 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...

  13. 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

    Synthetic analogues of the cell-wall lipid monomycoloyl glycerol (MMG) are promising as next-generation vaccine adjuvants. In the present study, the thermotropic phase behaviour of an array of synthetic MMG analogues was examined using simultaneous small- and wide-angle X-ray scattering under...... 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...

  14. N-(2-Carboxyethyl-2,5-dideoxy-2,5-imino-d-mannonic acid [(3R,4R,5R-1-(2-carboxyethyl-3,4-dihydroxy-5-hydroxymethyl-l-proline

    Directory of Open Access Journals (Sweden)

    David S. Edgeley

    2012-10-01

    Full Text Available The absolute stereochemistry of the title compound, C9H15NO7, was determined from the use of d-glucuronolactone as the starting material. The compound crystallizes as the zwitterion. The five-membered ring adopts an envelope conformation with the –CH2OH-substituted C atom forming the flap. An intramolecular N—H...O hydrogen-bond occurs. In the crystal, the compound exists as a three-dimensional O—H...O intermolecular hydrogen-bonded network with each molecule acting as a donor and acceptor for four hydrogen bonds.

  15. Resolução do ibuprofeno: um projeto para disciplina de química orgânica experimental

    Directory of Open Access Journals (Sweden)

    Adriano L. Romero

    2012-01-01

    Full Text Available 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-(--α-methylbenzylamine with (±-ibuprofen; separation and determination of absolute configuration of amides by ¹H NMR spectroscopy and GC analysis, and hydrolysis of amides to obtain (+- and (--ibuprofen.

  16. The synthesis of 8-β-[(methylsulfinyl-[18O])-methyl]-6-propylergoline

    International Nuclear Information System (INIS)

    Wheeler, W.J.

    1987-01-01

    The synthesis of 18 O-labeled 8-Β-[(methylsulfinyl)-methyl]-6-propyl-ergoline(pergolide-[ 18 O]-sulfoxide) of undetermined stereochemistry by the reaction of 8-Β-(methylthiomethyl)-6-propyl-ergoline (pergolide) with bis-(4-methoxyphenyl)-selen-[ 18 O]-oxide in acetic acid is described. Although the yields were low and the incorporation of 18 O was not high, this procedure represents a convenient method for the preparation of 18 O-labeled sulfoxides of pergolide and other sulfides present in compounds for which the usual methods are inappropriate. (author)

  17. Investigating the Structure-Activity Relationship of the Insecticidal Natural Product Rocaglamide.

    Science.gov (United States)

    Hall, Roger G; Bruce, Ian; Cooke, Nigel G; Diorazio, Louis J; Cederbaum, Fredrik; Dobler, Markus R; Irving, Ed

    2017-12-01

    The natural product Rocaglamide (1), isolated from the tree Aglaia elliptifolia, is a compelling but also challenging lead structure for crop protection. In laboratory assays, the natural product shows highly interesting insecticidal activity against chewing pests and beetles, but also phytotoxicity on some crop plants. Multi-step syntheses with control of stereochemistry were required to probe the structure-activity relationship (SAR), and seek simplified analogues. After a significant research effort, just two areas of the molecule were identified which allow modification whilst maintaining activity, as will be highlighted in this paper.

  18. Liquid phase hot atom chemistry: At crossroads

    International Nuclear Information System (INIS)

    Rack, E.P.; Veterans Administration Medical Center, Omaha, NE

    1981-01-01

    The state of current research in liquid phase hot atom chemistry is discussed. Four classes of experimental approaches are high-lighted. These include 1) primary physical data for (n,γ)-activated 128 I, (I.T.)-activated 130 I and effects on chemical reactivity; 2) the density-variation technique involving iodine reactions with saturated and unsaturated hydrocarbons; 3) stereochemistry experiments on chlorocarbon molecules with single and multiple chiral centers; and 4) experiments employing dilute aqueous solutions of halogenerated biomolecules in the ice state, exposed to neutron irradiation. (orig.) [de

  19. Resolution of ibuprofen: a project for an experimental organic chemistry course

    International Nuclear Information System (INIS)

    Romero, Adriano L.; Baptistella, Lucia H.B.; Coelho, Fernando; Imamura, Paulo M.

    2012-01-01

    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)-(-)-α-methylbenzylamine with (+-)-ibuprofen; separation and determination of absolute configuration of amides by 1 H NMR spectroscopy and GC analysis, and hydrolysis of amides to obtain (+)- and (-)-ibuprofen. (author)

  20. N- and C-alkylation of seven-membered iminosugars generates potent glucocerebrosidase inhibitors and F508del-CFTR correctors.

    Science.gov (United States)

    Désiré, J; Mondon, M; Fontelle, N; Nakagawa, S; Hirokami, Y; Adachi, I; Iwaki, R; Fleet, G W J; Alonzi, D S; Twigg, G; Butters, T D; Bertrand, J; Cendret, V; Becq, F; Norez, C; Marrot, J; Kato, A; Blériot, Y

    2014-11-28

    The glycosidase inhibitory properties of synthetic C-alkyl and N-alkyl six-membered iminosugars have been extensively studied leading to therapeutic candidates. The related seven-membered iminocyclitols have been less examined despite the report of promising structures. Using an in house ring enlargement/C-alkylation as well as cross-metathesis methodologies as the key steps, we have undertaken the synthesis and biological evaluation of a library of fourteen 2C- and eight N-alkyl tetrahydroxylated azepanes starting from an easily available glucopyranose-derived azidolactol. Four, six, nine and twelve carbon atom alkyl chains have been introduced. The study of two distinct D-gluco and L-ido stereochemistries for the tetrol pattern as well as R and S configurations for the C-2 carbon bearing the C-alkyl chain is reported. We observed that C-alkylation of the L-ido tetrahydroxylated azepane converts it from an α-L-fucosidase to a β-glucosidase and β-galactosidase inhibitor while N-alkylation of the D-gluco iminosugar significantly improves its inhibition profile leading to potent β-glucosidase, β-galactosidase, α-L-rhamnosidase and β-glucuronidase inhibitors whatever the stereochemistry of the alkyl chain. Interestingly, the N-alkyl chain length usually parallels the azepane inhibitor potency as exemplified by the identification of a potent glucocerebrosidase inhibitor (Ki 1 μM) bearing a twelve carbon atom chain. Additionally, several C-alkyl azepanes demonstrated promising F508del-CFTR correction unlike the parent tetrahydroxyazepanes. None of the C-alkyl and N-alkyl azepanes did inhibit ER α-glucosidases I or II.

  1. Stereodivergent Synthesis of 1,3-Syn-Polyol Natural Product for Stereochemical-Based Structure Activity Relationship Studies

    Science.gov (United States)

    Zheng, Jiamin

    The 1,3-syn-diol functionality is very common in many natural products. An important class containing this moiety are the 1,3-syn-polyol/pyranone natural products, which have been isolated from a variety of plant sources, and possess biological activities like plant growth inhibition as well as antifeedant, antifungal, antibacterial, and antitumor properties. The feature of this class is a 6-membered lactone where the lactoe oxygen is part of a 1,3-syn-diol motif. To pursue the 1,3-syn-polyol/pyranone natural products, an iterative hydration of polyene strategy was utilized to provide the 1,3- syn-diol functionality, and asymmetric synthetic strategies were explored to form the requisite stereochemistry. The versatility of the asymmetric approach was demonstrated in the synthesis of eupatorium pyranone and also in an ongoing project aimed at the synthesis of SIA7248. As an outgrowth of our work on the total syntheses of 1,3-syn -polyol natural products inspired a stereo-divergent synthesis of 1,3-syn-polyol natural products and their analogs for stereochemical-based structure-activity relationship (SSAR) studies. To identify the key structural factors important for the anticancer activity of the 1,3-syn-polyol/pyranones, a stereo-divergent 16-member library of pyranone/polyol congeners was designed, synthesized and tested with variations in both stereochemistry and numbers of polyol repeat units. Having access to stereochemical isomers of the biologically active natural products allowed us to design experiments that help illustrate their mechanisms of action.

  2. Influence of major structural features of tocopherols and tocotrienols on their omega-oxidation by tocopherol-omega-hydroxylase.

    Science.gov (United States)

    Sontag, Timothy J; Parker, Robert S

    2007-05-01

    Human cytochrome P450 4F2 (CYP4F2) catalyzes the initial omega-hydroxylation reaction in the metabolism of tocopherols and tocotrienols to carboxychromanols and is, to date, the only enzyme shown to metabolize vitamin E. The objective of this study was to characterize this activity, particularly the influence of key features of tocochromanol substrate structure. The influence of the number and positions of methyl groups on the chromanol ring, and of stereochemistry and saturation of the side chain, were explored using HepG2 cultures and microsomal reaction systems. Human liver microsomes and microsomes selectively expressing recombinant human CYP4F2 exhibited substrate activity patterns similar to those of HepG2 cells. Although activity was strongly associated with substrate accumulation by cells or microsomes, substantial differences in specific activities between substrates remained under conditions of similar microsomal membrane substrate concentration. Methylation at C5 of the chromanol ring was associated with markedly low activity. Tocotrienols exhibited much higher Vmax values than their tocopherol counterparts. Side chain stereochemistry had no effect on omega-hydroxylation of alpha-tocopherol (alpha-TOH) by any system. Kinetic analysis of microsomal CYP4F2 activity revealed Michaelis-Menten kinetics for alpha-TOH but allosteric cooperativity for other vitamers, especially tocotrienols. Additionally, alpha-TOH was a positive effector of omega-hydroxylation of other vitamers. These results indicate that CYP4F2-mediated tocopherol-omega-hydroxylation is a central feature underlying the different biological half-lives, and therefore biopotencies, of the tocopherols and tocotrienols.

  3. Synthesis, Properties and Stereochemistry of 2-Halo-1,2λ⁵-oxaphosphetanes.

    Science.gov (United States)

    Kolodiazhna, Anastasy O; Kolodiazhnyi, Oleg I

    2016-10-17

    Results of research into four-membered 2-halo-1,2λ⁵-oxaphosphetane phosphorus(V)-heterocycles are presented. The preparation of 2-halo-1,2λ⁵-oxaphosphetanes by reaction of P- haloylides with carbonyl compounds is described. The mechanism of asynchronous [2+2]-сycloaddition of ylides to aldehydes was proposed on the base of low-temperature NMR investigations. 2-Halo-1,2λ⁵-oxaphosphetanes were isolated as individual compounds and their structures were confirmed by ¹Н-, 13 C-, 19 F- and 31 Р-NMR spectra. These compounds are convenient reagents for preparing of various organic and organophosphorus compounds hardly available by other methods. Chemical and physical properties of the 2-halo-1,2λ⁵-oxaphosphetanes are reviewed. The 2-chloro-1,2λ⁵-oxaphosphetanes, rearrange with formation of 2-chloroalkyl-phosphonates or convert into trans -phosphorylated alkenes depending on the substituents at the α-carbon atom. Prospective synthetic applications of 2-halo-1,2λ⁵-oxaphosphetanes are analyzed. The 2-halo-1,2λ⁵-oxaphosphetanes may be easily converted to various alkenylphosphonates: allyl- or vinylphosphonates, phosphorus ketenes, thioketenes, ketenimines.

  4. Regio- and stereochemistry of 1,3-dipolar cycloaddition of nitrile oxides to alkenes

    International Nuclear Information System (INIS)

    Litvinovskaya, Raisa P; Khripach, Vladimir A

    2001-01-01

    The published data on the chemistry of intermolecular 1,3-dipolar cycloaddition of nitrile oxides to different types of alkene derivatives are systematised. Various aspects of stereo- and regiochemistry of this reaction are considered. The bibliography includes 182 references.

  5. 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.

  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. Stereochemistry Balances Cell Permeability and Solubility in the Naturally Derived Phepropeptin Cyclic Peptides.

    Science.gov (United States)

    Schwochert, Joshua; Lao, Yongtong; Pye, Cameron R; Naylor, Matthew R; Desai, Prashant V; Gonzalez Valcarcel, Isabel C; Barrett, Jaclyn A; Sawada, Geri; Blanco, Maria-Jesus; Lokey, R Scott

    2016-08-11

    Cyclic peptide (CP) natural products provide useful model systems for mapping "beyond-Rule-of-5" (bRo5) space. We identified the phepropeptins as natural product CPs with potential cell permeability. Synthesis of the phepropeptins and epimeric analogues revealed much more rapid cellular permeability for the natural stereochemical pattern. Despite being more cell permeable, the natural compounds exhibited similar aqueous solubility as the corresponding epimers, a phenomenon explained by solvent-dependent conformational flexibility among the natural compounds. When analyzing the polarity of the solution structures we found that neither the number of hydrogen bonds nor the total polar surface area accurately represents the solvation energies of the high and low dielectric conformations. This work adds to a growing number of natural CPs whose solvent-dependent conformational behavior allows for a balance between aqueous solubility and cell permeability, highlighting structural flexibility as an important consideration in the design of molecules in bRo5 chemical space.

  8. The structure, stereochemistry and synthesis of a variety of physiologically active plant phenols

    International Nuclear Information System (INIS)

    Van Heerden, F.R.

    1980-03-01

    The medicinal use of various Leguminosae species by the local population led to a phytochemical study of the bark of Dalbergia nitidula, Dalbergia melanoxylon and wood of Acacia fasciculifera. Rotenoid glycoside and three new carbon bonded isoflavone glycosides were isolated from the bark of D. nitidula. The rotenoid glycoside was characterized by means of acid and enzymatic hydrolysis and its absolute configuration was determined with reference to CD comparisons. A kinetic study was done to determine the relative toxidities of the rotenoid glycoside and its aglicone. The identity and the coupling positions of the sugars was confirmed by a C-NMR investigation of the rotenoid and isoflavane glycosides. The structure of heminitidulan, a complex isoflavane from D. nitidula, was confirmed by complete synthesis. Trans- and cis-clovamide, amides made up of L-DOPA and trans- and cis-caffeic acid respectively, and four new analogous deoxyclovamides are present in the bark of D. melanoxylon. For the first time optically pure trans clovamide was obtained by direct synthesis. C-NMR and CD confirmed differentiation between trans- and cisclovamide. The therapeutic value of L-DOPA for Parkinson's Disease implies possible physiological activity for the clovamide. As well as a number of known flavonoids and peltoginoids, a tetracyclic flavonoid (peltoginoid), fasciculiferin, was found in the wood of A. fasciculifera. Although peltoginoids with a D-ring in a fully reduced or oxidised state are known, this is the first natural peltoginoid with the D-ring in an intermediate oxidation state. Fasciculiferol, till now an unknown metabolyte from A. fasciculifera, is a new member of a rare group of natural products that are generally cytotoxic. The relatively drastic reaction conditions necessary for carbocation formation from peltoginol in comparison to the analogous flavon-3, 4-diols, is attributed to steric factors which arise from the rigid conformation of the B-ring of peltoginol

  9. Crystal Structure and Hydrogen Bonding Study of (10E-2,2-Dimethyl-3,4-dihydro-2H-benzo[g]chromene-5,10-dione 10-Oxime Derived From a-Lapachone

    Directory of Open Access Journals (Sweden)

    Lorenzo C. Visentin

    2011-01-01

    Full Text Available The compound (10E-2,2-dimethyl-3,4-dihydro-2H-benzo[g]chromene-5,10-dione-10-oxime (1 was synthesized from a-lapachone and hydroxylamine chloride in alkaline medium. Single-crystals suitable for X-ray diffraction measurements were grown from an ethanol solution, and the crystal structure of the title molecule is reported for the first time. The title molecule was also characterized by 1H- and 13C-NMR in CDCl3 solution, FTIR and MS. The crystal structure of 1 shows an E stereochemistry and dimers formed through classical hydrogen bonds.

  10. Total synthesis and biological investigation of (-)-promysalin.

    Science.gov (United States)

    Steele, Andrew D; Knouse, Kyle W; Keohane, Colleen E; Wuest, William M

    2015-06-17

    Compounds that specifically target pathogenic bacteria are greatly needed, and identifying the method by which they act would provide new avenues of treatment. Herein we report the concise, high-yielding total synthesis (eight steps, 35% yield) of promysalin, a natural product that displays antivirulence phenotypes against pathogenic bacteria. Guided by bioinformatics, four diastereomers were synthesized, and the relative and absolute stereochemistries were confirmed by spectral and biological analysis. Finally, we show for the first time that promysalin displays two antivirulence phenotypes: the dispersion of mature biofilms and the inhibition of pyoverdine production, hinting at a unique pathogenic-specific mechanism of action.

  11. Preparation and study of dialkyl nitroxide radicals

    International Nuclear Information System (INIS)

    Chenavas, P.

    1969-01-01

    These radicals are obtained by oxidation of N-hydroxy-imides with lead tetracetate or p-nitro-perbenzoic acid. These imides are prepared by heating dicarboxylic acids anhydrides with benzyloxy-amine followed by catalytic hydrogenation of N-benzyloxy-imides so obtained. Two series of radicals have mainly been studied, the first concerning five-membered cyclic imides, the second six-membered cyclic imides, these molecules having methyls substituents or no on the carbon ring. N. M. R. spectra of some O-benzyl-imides have been analysed. These different results have made it possible to study the conformation and stereochemistry of these imides. (author) [fr

  12. Alkynes as Allylmetal Equivalents in Redox-Triggered C–C Couplings to Primary Alcohols: (Z)-Homoallylic Alcohols via Ruthenium-Catalyzed Propargyl C–H Oxidative Addition

    Science.gov (United States)

    2015-01-01

    The cationic ruthenium catalyst generated upon the acid–base reaction of H2Ru(CO)(PPh3)3 and 2,4,6-(2-Pr)3PhSO3H promotes the redox-triggered C–C coupling of 2-alkynes and primary alcohols to form (Z)-homoallylic alcohols with good to complete control of olefin geometry. Deuterium labeling studies, which reveal roughly equal isotopic compositions at the allylic and distal vinylic positions, along with other data, corroborate a catalytic mechanism involving ruthenium(0)-mediated allene–aldehyde oxidative coupling to form a transient oxaruthenacycle, an event that ultimately defines (Z)-olefin stereochemistry. PMID:25075434

  13. Structural aspects of some hydrobenzofuran neolignans; Aspectos estruturais de algumas neolignanas hidrobenzofuranicas

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, Massayoshi, E-mail: myoshida@iq.usp.br [Universidade de Sao Paulo (IQ/USP), SP (Brazil). Inst. de Quimica; Centro de Biotecnologia da Amazonia, Manaus, AM (Brazil)

    2012-07-01

    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)

  14. Steviamine, a new class of indolizidine alkaloid [(1R,2S,3R,5R,8aR-3-hydroxymethyl-5-methyloctahydroindolizine-1,2-diol hydrobromide

    Directory of Open Access Journals (Sweden)

    Amber L. Thompson

    2009-11-01

    Full Text Available X-ray crystallographic analysis of the title hydrobromide salt, C10H20N+·Br−, of (1R,2S,3R,5R,8aR-3-hydroxymethyl-5-methyloctahydroindolizine-1,2-diol defines the absolute and relative stereochemistry at the five chiral centres in steviamine, a new class of polyhydroxylated indolizidine alkaloid isolated from Stevia rebaudiana (Asteraceae leaves. In the crystal structure, molecules are linked by intermolecular O—H...Br and N—H...Br hydrogen bonds, forming double chains around the twofold screw axes along the b-axis direction. Intramolecular O—H...O interactions occur.

  15. Chemical constituents from branches of Maytenus gonoclada (Celastraceae) and evaluation of antimicrobial activity

    International Nuclear Information System (INIS)

    Silva, Fernando C.; Duarte, Lucienir P.; Silva, Gracia D.F.; Vieira Filho, Sidney A.; Lula, Ivana S.; Takahashi, Jacqueline A.; Sallum, William S.T.

    2011-01-01

    Six pentacyclic triterpenes were isolated from branches of Maytenus gonoclada (Celastraceae) and all NMR data of a new compound 3-oxo-12α,29-dihydroxyfriedelane are herein reported. The stereochemistry of the new friedelane was established by bidimensional NMR (HSQC, HMBC and NOESY) data, and its molecular weight confirmed by ESI mass spectrometry. Antimicrobial activity assays using the method of disk diffusion and macrodilution were carried out against the bacteria Escherichia coli, Citrobacter freundii, and Bacillus cereus, and against the fungi Candida albicans. The triterpene 3-oxo-12α-hydroxyfriedelane showed positive result against C. albicans. (author)

  16. Chemical constituents from branches of Maytenus gonoclada (Celastraceae) and evaluation of antimicrobial activity

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Fernando C.; Duarte, Lucienir P.; Silva, Gracia D.F.; Vieira Filho, Sidney A.; Lula, Ivana S., E-mail: lucienir@ufmg.b [Universidade Federal de Minas Gerais (DQ/UFMG), Belo Horizonte (Brazil). Dept. de Quimica. Nucleo de Estudos de Plantas Medicinais; Takahashi, Jacqueline A.; Sallum, William S.T. [Universidade Federal de Ouro Preto (UFOP), MG (Brazil). Escola de Farmacia

    2011-07-01

    Six pentacyclic triterpenes were isolated from branches of Maytenus gonoclada (Celastraceae) and all NMR data of a new compound 3-oxo-12{alpha},29-dihydroxyfriedelane are herein reported. The stereochemistry of the new friedelane was established by bidimensional NMR (HSQC, HMBC and NOESY) data, and its molecular weight confirmed by ESI mass spectrometry. Antimicrobial activity assays using the method of disk diffusion and macrodilution were carried out against the bacteria Escherichia coli, Citrobacter freundii, and Bacillus cereus, and against the fungi Candida albicans. The triterpene 3-oxo-12{alpha}-hydroxyfriedelane showed positive result against C. albicans. (author)

  17. 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.)

  18. Alisiaquinones and alisiaquinol, dual inhibitors of Plasmodium falciparum enzyme targets from a New Caledonian deep water sponge.

    Science.gov (United States)

    Desoubzdanne, Denis; Marcourt, Laurence; Raux, Roselyne; Chevalley, Séverine; Dorin, Dominique; Doerig, Christian; Valentin, Alexis; Ausseil, Frédéric; Debitus, Cécile

    2008-07-01

    Four new meroterpenes, alisiaquinones A-C (1-3) and alisiaquinol (4), were isolated from a New Caledonian deep water sponge. Their structures and relative stereochemistry were elucidated by spectroscopic data analysis. They are related to xestoquinone, but showed unusual substitution on a tetrahydrofuran junction. They displayed micromolar range activity on two enzymatic targets of importance for the control of malaria, the plasmodial kinase Pfnek-1 and a protein farnesyl transferase, as well as on different chloroquine-sensitive and -resistant strains of Plasmodium falciparum. Alisiaquinone C displayed a submicromolar activity on P. falciparum and a competitive selectivity index on the different plasmodial strains.

  19. 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.

  20. 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)

  1. 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.

  2. 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

  3. 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)

  4. 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.

  5. 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.

  6. Structural variety in solvated lanthanoid (III) halide complexes

    International Nuclear Information System (INIS)

    Deacon, G.B; Feng, T.; Scott, N.M.; Junk, P.C.; James Cook University, Townsville, QLD; Meyer, G.; Skelton, B.W.; White, A.H.

    2000-01-01

    Treatment of lanthanum metal with CH 2 Br 2 or CH 2 I 2 in tetrahydrofuran (thf) under ultrasound conditions yields the corresponding [LaX 3 (thf) 4 ] (X Br, I) complexes in good yield. Recrystallization of [LaBr 3 (thf) 4 ] from 1,2-dimethoxyethane (dme) or bis(2-methoxyethyl) ether (dig-lyme) generates [LaBr 2 (μ-Br)(dme) 2 ] 2 and [LaBr 2 (dig-lyme) 2 ][LaBr 4 (diglyme)]. Treatment of lanthanoid metals with hexachloroethane in dme yields [LnCl 3 (dme) 2 ] (Ln = La, Nd, Er or Yb) and in acetonitrile [YbCl 2 (MeCN) 5 ] 2 [YbCl 3 (MeCN)(-Cl) 2 YbCl 3 (MeCN)]. The reaction of Yb metal pieces with 1,2-dibromoethane in thf and dme gave single crystals of [YbBr 3 (thf) 3 ] and [YbBr 3 (dme) 2 ], respectively. The X-ray determined structure of [LaBr 3 (thf) 4 ] shows a seven-coordinate monomer with pentagonal-bipyramidal stereochemistry and apical bromide ligands. For [YbBr 3 (thf) 3 ], a monomeric structure with mer-octahedral stereochemistry is observed. In [LaBr 2 (μ-Br)(dme) 2 ] 2 , two eight-coordinate La centres are linked by two bridging bromides. The dme ligands have a trans relationship to each other, and cis terminal bromides are transoid to the bridging bromides with dodecahedral stereochemistry for La. By contrast, the 1: 1.5 diglyme adduct is found to be ionic [LaBr 2 (diglyme) 2 ][LaBr 4 (diglyme)], with an eight-coordinate bicapped trigonal-prismatic lanthanum cation and a seven-coordinate pentagonal-bipyramidal lanthanum anion. In the cation, the bromide ligands are cis to each other, and in the anion, two bromides are equatorial and two are axial. In [YbBr 3 (dme) 2 ], [YbCl 3 (dme) 2 ] and [ErCl 3 (dme) 2 ], a seven-coordinate pentagonal-bipyramidal arrangement exists with apical halogen ligands. Far-infrared data, and in particular the absence of absorptions attributable to I(La-Cl ter ), suggest that [LaCl 3 (dme)] is polymeric with six bridging chlorides per lanthanum. For [YbCl 2 (MeCN) 5 ] 2 [YbCl 3 (MeCN)(-Cl) 2 YbCl 3 -(MeCN)], a remarkable

  7. Differences in anti-malarial activity of 4-aminoalcohol quinoline enantiomers and investigation of the presumed underlying mechanism of action

    Directory of Open Access Journals (Sweden)

    Mullié Catherine

    2012-03-01

    Full Text Available Abstract Background A better anti-malarial efficiency and lower neurotoxicity have been reported for mefloquine (MQ (+- enantiomer. However, the importance of stereoselectivity remains poorly understood as the anti-malarial activity of pure enantiomer MQ analogues has never been described. Building on these observations, a series of enantiopure 4-aminoalcohol quinoline derivatives has previously been synthesized to optimize the efficiency and reduce possible adverse effects. Their in vitro activity on Plasmodium falciparum W2 and 3D7 strains is reported here along with their inhibition of β-haematin formation and peroxidative degradation of haemin, two possible mechanisms of action of anti-malarial drugs. Results The (S-enantiomers of this series of 4-aminoalcohol quinoline derivatives were found to be at least as effective as both chloroquine (CQ and MQ. The derivative with a 5-carbon side-chain length was the more efficient on both P. falciparum strains. (R -enantiomers displayed an activity decreased by 2 to 15-fold as compared to their (S counterparts. The inhibition of β-haematin formation was significantly stronger with all tested compounds than with MQ, irrespective of the stereochemistry. Similarly, the inhibition of haemin peroxidation was significantly higher for both (S and (R-enantiomers of derivatives with a side-chain length of five or six carbons than for MQ and CQ. Conclusions The prominence of stereochemistry in the anti-malarial activity of 4-aminoalcohol quinoline derivatives is confirmed. The inhibition of β-haematin formation and haemin peroxidation can be put forward as presumed mechanisms of action but do not account for the stereoselectivity of action witnessed in vitro.

  8. A New Aggreceride analogue and a peltogynoid isolated from the stem bark of Entada abyssinica (Fabaceae).

    Science.gov (United States)

    Melong, Raduis; Kapche, Deccaux G F W; Feussia, Michel T; Laatsch, Hartmut

    2014-10-01

    A new monoglyceride, l',26'-bis-[(S)-2,3-dihydroxypropyl] hexacosanedioate (1a) and the new peltogynoid, entadanin (3), along with eight known compounds, were isolated from the stem bark of Entada abyssinica (Fabaceae). The structures of the new compounds were determined by detailed analyses of 1D and 2D NMR spectra, in combination with high-resolution mass spectrometry data, and by comparison with related data from the literature. The stereochemistry of la was derived by comparison of the optical rotation with reference data. Peltogynoids have been reported previously from other Fabaceae, however this is the first report ofa peltogynoid from the genus Entada.

  9. Cytotoxic and antibacterial dihydrochalcones from Piper aduncum.

    Science.gov (United States)

    Orjala, J; Wright, A D; Behrends, H; Folkers, G; Sticher, O; Rüegger, H; Rali, T

    1994-01-01

    Bioactivity-guided fractionation of a CH2Cl2 extract from the leaves of Piper aduncum afforded three new dihydrochalcones, piperaduncins A [3], B [4], and C [5], as well as two known dihydrochalcones, 2',6'-dihydroxy-4'-methoxydihydrochalcone [1] and 2',6',4-trihydroxy-4'-methoxydihydrochalcone [2] (asebogenin), together with sakuranetin, anodendroic acid methyl ester, and the carotenoid lutein. The structures of the isolates were elucidated by spectroscopic methods, mainly 1D- and 2D nmr spectroscopy. The proposed stereochemistry for compound 4 was deduced by NOESY spectroscopy and the corresponding energy minimum was established by molecular modelling calculations and translated into a 3D structure.

  10. Radioimmunoassay for the citrus bitter principle, naringin, and related flavonoid-7-O-neohesperidosides

    International Nuclear Information System (INIS)

    Jourdan, P.S.; Weiler, E.W.; Mansell, R.L.

    1982-01-01

    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-[ 125 I] as immunotracer. (orig.)

  11. Chemo- and Enantioselective Intramolecular Silver-Catalyzed Aziridinations.

    Science.gov (United States)

    Ju, Minsoo; Weatherly, Cale D; Guzei, Ilia A; Schomaker, Jennifer M

    2017-08-07

    Asymmetric nitrene-transfer reactions are a powerful tool for the preparation of enantioenriched amine building blocks. Reported herein are chemo- and enantioselective silver-catalyzed aminations which transform di- and trisubstituted homoallylic carbamates into [4.1.0]-carbamate-tethered aziridines in good yields and with ee values of up to 92 %. The effects of the substrate, silver counteranion, ligand, solvent, and temperature on both the chemoselectivity and ee value were explored. Stereochemical models were proposed to rationalize the observed absolute stereochemistry of the aziridines, which undergo nucleophilic ring opening to yield enantioenriched amines with no erosion in stereochemical integrity. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Vibrational Raman optical activity of ketose monosaccharides

    Science.gov (United States)

    Bell, Alasdair F.; Hecht, Lutz; Barron, Laurence D.

    1995-07-01

    The vibrational Raman optical activity (ROA) spectra of the four ketose sugars D-fructose, L-sorbose, D-tagatose and D-psicose in aqueous solution, which have been measured in backscattering in the range ≈250-1500 cm -1, are reported. These results are combined with those from a previous ROA study of aldose and pentose sugars in an attempt to establish new vibrational assignments and to verify old ones. The high information content of these spectra provides a new perspective on all the central features of monosaccharide stereochemistry including dominant anomeric configuration, ring conformation, exocyclic CH 2OH group conformation and relative disposition of the hydroxyl groups around the ring.

  13. Potential cancer chemopreventive agents from Arbutus unedo.

    Science.gov (United States)

    Carcache-Blanco, Esperanza J; Cuendet, Muriel; Park, Eun Jung; Su, Bao-Ning; Rivero-Cruz, J Fausto; Farnsworth, Norman R; Pezzuto, John M; Douglas Kinghorn, A

    2006-04-01

    A phytochemical study of the petroleum ether and ethyl acetate extracts of the entire plant of Arbutus unedo led to the isolation of a new sterol, 7beta-hydroxystigmast-4-en-3-one (1), and nine known compounds of the flavan, steroid, and terpenoid types. The structure of 1 was determined by spectroscopic data interpretation in combination with molecular modeling calculations. The absolute stereochemistry of C-7 was assigned as S for compound 1 based on the obtained CD spectral data. Activity in the JB6 cell transformation assay was found for pomolic acid 3-acetate (4). All isolates obtained were evaluated in a cyclooxygenase-2 (COX-2) inhibition assay.

  14. Novel bioactive dibenzocycloctadiene lignans from Schisandra neglecta

    Energy Technology Data Exchange (ETDEWEB)

    Xue-Mei, Gao; De-Yun, Niu; Chun-Yang, Menga and others, E-mail: huqiufena@aliyun.com, E-mail: xwl@mail.kib.ac.cn [Key Laboratory of Ethnic Medicine Resource Chemistry, Yunnan University of Nationalities, State Ethnic Affairs Commission and Ministry of Education (China)

    2013-12-01

    Four new dibenzocyclooctadiene lignans, neglectalignans A-D (1-4), together with nineteen known compounds (5-23) were isolated from the stems of Schisandra neglecta. Their structures and stereochemistries were elucidated by spectroscopic methods, including 1D-, 2D-nuclear magnetic resonance (NMR) and high-resolution electrospray ionization mass spectrometry (HR-ESI-MS) techniques. Compounds 1-4 were evaluated for their anti-HIV activities and cytotoxicities. The results revealed that compounds 1-4 showed moderate anti-HIV-1 activities with therapeutic index (TI) values above 61.7, 22.6, 57.7, and 27.9, respectively, and weak cytotoxic activities for some selected cell lines. (author)

  15. Structure and conformational analysis of spiroketals from 6-O-methyl-9(E-hydroxyiminoerythronolide A

    Directory of Open Access Journals (Sweden)

    Ana Čikoš

    2015-08-01

    Full Text Available Three novel spiroketals were prepared by a one-pot transformation of 6-O-methyl-9(E-hydroxyiminoerythronolide A. We present the formation of a [4.5]spiroketal moiety within the macrolide lactone ring, but also the unexpected formation of a 10-C=11-C double bond and spontaneous change of stereochemistry at position 8-C. As a result, a thermodynamically stable structure was obtained. The structures of two new diastereomeric, unsaturated spiroketals, their configurations and conformations, were determined by means of NMR spectroscopy and molecular modelling. The reaction kinetics and mechanistic aspects of this transformation are discussed. These rearrangements provide a facile synthesis of novel macrolide scaffolds.

  16. Enantioselective copper-catalyzed carboetherification of unactivated alkenes.

    Science.gov (United States)

    Bovino, Michael T; Liwosz, Timothy W; Kendel, Nicole E; Miller, Yan; Tyminska, Nina; Zurek, Eva; Chemler, Sherry R

    2014-06-16

    Chiral saturated oxygen heterocycles are important components of bioactive compounds. Cyclization of alcohols onto pendant alkenes is a direct route to their synthesis, but few catalytic enantioselective methods enabling cyclization onto unactivated alkenes exist. Herein reported is a highly efficient copper-catalyzed cyclization of γ-unsaturated pentenols which terminates in C-C bond formation, a net alkene carboetherification. Both intra- and intermolecular C-C bond formations are demonstrated, thus yielding functionalized chiral tetrahydrofurans as well as fused-ring and bridged-ring oxabicyclic products. Transition-state calculations support a cis-oxycupration stereochemistry-determining step. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Lanthanide tris(β-diketonates) as useful probes for chirality determination of biological amino alcohols in vibrational circular dichroism: ligand to ligand chirality transfer in lanthanide coordination sphere.

    Science.gov (United States)

    Miyake, Hiroyuki; Terada, Keiko; Tsukube, Hiroshi

    2014-06-01

    A series of lanthanide tris(β-diketonates) functioned as useful chirality probes in the vibrational circular dichroism (VCD) characterization of biological amino alcohols. Various chiral amino alcohols induced intense VCD signals upon ternary complexation with racemic lanthanide tris(β-diketonates). The VCD signals observed around 1500 cm(-1) (β-diketonate IR absorption region) correlated well with the stereochemistry and enantiomeric purity of the targeted amino alcohol, while the corresponding monoalcohol, monoamine, and diol substrates induced very weak VCD signals. The high-coordination number and dynamic property of the lanthanide complex offer an effective chirality VCD probing of biological substrates. © 2014 Wiley Periodicals, Inc.

  18. Diastereoisomers of 2-benzyl-2, 3-dihydro-2-(1H-inden-2-yl)-1H-inden-1-ol: potential anti-inflammatory agents.

    Science.gov (United States)

    Sheridan, Helen; Walsh, John J; Cogan, Carina; Jordan, Michael; McCabe, Tom; Passante, Egle; Frankish, Neil H

    2009-10-15

    The synthesis and biological activity of the novel diastereoisomers of 2-benzyl-2,3-dihydro-2-(1H-inden-2-yl)-1H-inden-1-ol is reported. The 2,2-coupled indane dimers were synthesised by coupling of the silyl enol ether of 1-indanone with the dimethyl ketal of 2-indanone. The coupled product was directly alkylated to give the racemic ketone which was reduced to the diastereoisomeric alcohols. The alcohols were separated and their relative stereochemistry was established by X-ray crystallography. These molecules demonstrate significant anti-inflammatory activity in vivo and in vitro and may represent a new class of anti-inflammatory agent.

  19. 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.

  20. Total Synthesis of (-)-Salvinorin A.

    Science.gov (United States)

    Line, Nathan J; Burns, Aaron C; Butler, Sean C; Casbohm, Jerry; Forsyth, Craig J

    2016-12-12

    Salvinorin A (1) is natural hallucinogen that binds the human κ-opioid receptor. A total synthesis has been developed that parlays the stereochemistry of l-(+)-tartaric acid into that of (-)-1 via an unprecedented allylic dithiane intramolecular Diels-Alder reaction to obtain the trans-decalin scaffold. Tsuji allylation set the C9 quaternary center and a late-stage stereoselective chiral ligand-assisted addition of a 3-titanium furan upon a C12 aldehyde/C17 methyl ester established the furanyl lactone moiety. The tartrate diol was finally converted into the C1,C2 keto-acetate. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Synthesis, physico-chemical characterization and biological activity of copper(ii and nickel(ii complexes with l-benzoyl-2-methylbenzimidazole derivatives

    Directory of Open Access Journals (Sweden)

    Podunavac-Kuzmanović Sanja O.

    2002-01-01

    Full Text Available Chlorides of copper(II and nickel(ll react with 1-benzoyl-2-methylbenzimidazole or 1-(4-chlorobenzoyl-2-methylbenzimidazole to give complexes of the type [M(LnCln(H20∙Cln (M = Cu or Ni; L = (1-benzoyl-2-methylbenzimidazole or 1-(4-chlorobenzoyl-2-methylbenzimidazole; n=O, 1 or 2. The complexes were synthesized and characterized by elemental analysis, molar conductivity magnetic susceptibility measurements and IR spectra. These studies suggest that all the complexes possess an octahedral stereochemistry. The antibacterial activity of (1-benzoyl-2-methylbenzimidazole or 1-(4-chlorobenzoyl-2-methylbenzimidazole and their complexes was evaluated against Escherichia coli and Bacillus sp.

  2. 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.

  3. Mechanism and Stereochemistry of Polyketide Chain Elongation and Methyl Group Epimerization in Polyether Biosynthesis.

    Science.gov (United States)

    Xie, Xinqiang; Garg, Ashish; Khosla, Chaitan; Cane, David E

    2017-03-01

    The polyketide synthases responsible for the biosynthesis of the polyether antibiotics nanchangmycin (1) and salinomycin (4) harbor a number of redox-inactive ketoreductase (KR 0 ) domains that are implicated in the generation of C2-epimerized (2S)-2-methyl-3-ketoacyl-ACP intermediates. Evidence that the natural substrate for the polyether KR 0 domains is, as predicted, a (2R)-2-methyl-3-ketoacyl-ACP intermediate, came from a newly developed coupled ketosynthase (KS)-ketoreductase (KR) assay that established that the decarboxylative condensation of methylmalonyl-CoA with S-propionyl-N-acetylcysteamine catalyzed by the Nan[KS1][AT1] didomain from module 1 of the nanchangmycin synthase generates exclusively the corresponding (2R)-2-methyl-3-ketopentanoyl-ACP (7a) product. In tandem equilibrium isotope exchange experiments, incubation of [2- 2 H]-(2R,3S)-2-methyl-3-hydroxypentanoyl-ACP (6a) with redox-active, epimerase-inactive EryKR6 from module 6 of the 6-deoxyerythronolide B synthase and catalytic quantities of NADP + in the presence of redox-inactive, recombinant NanKR1 0 or NanKR5 0 , from modules 1 and 5 of the nanchangmycin synthase, or recombinant SalKR7 0 from module 7 of the salinomycin synthase, resulted in first-order, time-dependent washout of deuterium from 6a. Control experiments confirmed that this washout was due to KR 0 -catalyzed isotope exchange of the reversibly generated, transiently formed oxidation product [2- 2 H]-(2R)-2-methyl-3-ketopentanoyl-ACP (7a), consistent with the proposed epimerase activity of each of the KR 0 domains. Although they belong to the superfamily of short chain dehydrogenase-reductases, the epimerase-active KR 0 domains from polyether synthases lack one or both residues of the conserved Tyr-Ser dyad that has previously been implicated in KR-catalyzed epimerizations.

  4. 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.

  5. 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.

  6. 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

  7. X-ray crystallographic studies on novel natural products from marine animals

    International Nuclear Information System (INIS)

    Choudhary, M.I.; Clardy, J.C.

    1991-01-01

    This chapter starts with an analysis to illustrate the utility of X-ray diffraction. The X-ray diffraction experiment is particularly suitable for structure elucidation of naturally occurring compounds, especially those that are structurally novel or have a great deal of stereochemistry. Marine plants and animals constitute a prodigious source of new and structurally complex secondary metabolites. Their unique structural features also provide strong incentives for further structural, synthetic and biosynthetic investigations. Organic compounds isolated from various marine animals in relatively small quantities, where structural work by conventional spectroscopic techniques did not lead to ambiguous structures, are investigated and the structures were finally determined through single-crystal X-ray diffraction measurements. (A.S.) 20 refs.; 5 figs

  8. Insight into the stereospecificity of short-chain thermus thermophilus alcohol dehydrogenase showing pro-S hydride transfer and prelog enantioselectivity.

    Science.gov (United States)

    Pennacchio, Angela; Giordano, Assunta; Esposito, Luciana; Langella, Emma; Rossi, Mosè; Raia, Carlo A

    2010-04-01

    The stereochemistry of the hydride transfer in reactions catalyzed by NAD(H)-dependent alcohol dehydrogenase from Thermus thermophilus HB27 was determined by means of (1)H-NMR spectroscopy. The enzyme transfers the pro-S hydrogen of [4R-(2)H]NADH and exhibits Prelog specificity. Enzyme-substrate docking calculations provided structural details about the enantioselectivity of this thermophilic enzyme. These results give additional insights into the diverse active site architectures of the largely versatile short-chain dehydrogenase superfamily enzymes. A feasible protocol for the synthesis of [4R-(2)H]NADH with high yield was also set up by enzymatic oxidation of 2-propanol-d(8) catalyzed by Bacillus stearothermophilus alcohol dehydrogenase.

  9. Synthesis of allocolchicinoids: a 50 year journey

    International Nuclear Information System (INIS)

    Sitnikov, N S; Fedorov, A Yu

    2013-01-01

    Published data on the stereo- and enantioselective synthesis of allocolchicinoids, which are of interest as antitumour agents, are summarized. The stereochemistry of these compounds is described. Two key approaches to their preparation are considered, namely, the synthesis from natural colchicine and total synthesis from commercially available reagents. Various total syntheses of N-acetylcolchicinol are performed using biaryl oxidative and reductive coupling, cyclopropanation–ring expansion and Nicholas reaction. The synthetic routes to allocolchicine are based on Diels–Alder cycloaddition, combination of metathesis and Diels–Alder reaction and direct catalytic CH-arylation. Analogues of the colchicine site ligands incorporating heteroaromatic rings are briefly considered; their structural features and methods of synthesis are discussed. The bibliography includes 144 references.

  10. Rauvolfianine, a new antimycobacterial glyceroglycolipid and other constituents from Rauvolfia caffra. Sond (Apocynaceae).

    Science.gov (United States)

    Ebeh Messanga, Robert; Dominique Serge, Ngono Bikobo; Abouem A Zintchem, Auguste; Norbert, Mbabi Nyemeck Ii; Esther Del Florence, Moni Ndedi; Patrick Hervé, Betote Diboué; Maximilienne Ascension, Nyegue; Alex De Théodore, Atchadé; Dieudonné Emmanuel, Pegnyemb; Christian G, Bochet; Koert, Ulrich

    2017-08-16

    The chemical investigation of the extract of the dried leaves of Rauvolfia caffra (Sond) (synonym Rauvolfia macrophylla) (Apocynaceae) led to isolation of a new glycoside derivative, rauvolfianine (1) as well as six known compounds: oleanolic acid (2), sitosterol-3-O-β-D-glucopyranoside (3), betulinic acid (4), vellosimine (5), sarpagine (6) and D-fructofuranosyl-β-(2→1)-α-D-glucopyranoside (7). Compounds 1, 2, 3, 4 and 7 were evaluated for antitubercular activity. Compounds 1 and 2 were the most active (MIC = 7.8125 and 31.25 μg/mL) towards the Isoniazid resistant strain of Mycobacterium tuberculosis AC45. Their structures and relative stereochemistry were elucidated by spectroscopic methods.

  11. Photoredox-Catalyzed Stereoselective Conversion of Alkynes into Tetrasubstituted Trifluoromethylated Alkenes.

    Science.gov (United States)

    Tomita, Ren; Koike, Takashi; Akita, Munetaka

    2015-10-26

    A regio- and stereoselective synthesis of trifluoromethylated alkenes bearing four different substituents has been developed. Stereocontrolled sulfonyloxytrifluoromethylation of unsymmetric internal alkynes with an electrophilic CF3 reagent, namely the triflate salt of the Yagupol'skii-Umemoto reagent, in the presence of an Ir photoredox catalyst under visible-light irradiation afforded trifluoromethylalkenyl triflates with well-predictable stereochemistry resulting from anti addition of the trifluoromethyl and triflate groups. Subsequent palladium-catalyzed cross-couplings led to tetrasubstituted trifluoromethylated alkenes in a highly stereoselective manner. The present method is the first example of a facile one-pot synthesis of tetrasubstituted trifluoromethylated alkenes from simple alkynes. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Stereocontrol of Methyl Methacrylate during Photoinduced Nitroxide-Mediated Polymerization in the Presence of Photosensitive Alkoxyamine

    Directory of Open Access Journals (Sweden)

    Juahui Su

    2016-01-01

    Full Text Available Photosensitive alkoxyamine 2,2,6,6-tetramethyl-1-(1-phenylethoxypiperidin-4-yl quinoline-2-carboxylate (PE-TEMPO-Q was synthesized. Photochemical properties of PE-TEMPO-Q were studied to develop photoinduced nitroxide-mediated polymerization of methyl methacrylate (MMA. Rapid and facile polymerization at ambient temperature with PE-TEMPO-Q as an initiator was confirmed to proceed in a controlled mechanism based on the linear growth in molecular weight combined with relative narrow polydispersity index (1.4–1.8 of the resulting polymers. The stereochemistry of obtained polymers was also investigated, and the syndiotacticity slightly increased compared with the typical photopolymerization. Dual-controlled photopolymerization of MMA was achieved in the presence of synthesized alkoxyamine.

  13. Antioxidant activity of extracts and condensed tannins from Maytenus ilicifolia Mart. ex Reiss

    International Nuclear Information System (INIS)

    Pessuto, Monica Bordin; Costa, Isis Casemiro da; Souza, Angelita Boldieri de; Nicoli, Fernanda Michely; Mello, Joao Carlos Palazzo de; Petereit, Frank; Luftmann, Heinrich

    2009-01-01

    Maytenus ilicifolia Mart. ex Reiss. Maytenus ilicifolia (Celastraceae) is a native plant of South America and popularly known as 'espinheira-santa'. The aim of this study was to evaluate the antioxidant capacity of extracts and isolated compounds from this plant. The antioxidant activity of the crude and semipurified extracts and isolated compounds was evaluated through DPPH-radical and phosphomolybdenum-complex assays. By both methods, the ethyl-acetate fraction demonstrated better antioxidant capacity compared with vitamin C and trolox. In the compounds, the higher the number of hydroxyls, the greater the antioxidant activity. In addition, stereochemistry influenced antioxidant activity, i.e., compounds with 2 R,3 R showed greater activity than those with 2 R,3 S. (author)

  14. Antioxidant activity of extracts and condensed tannins from Maytenus ilicifolia Mart. ex Reiss; Atividade antioxidante de extratos e taninos condensados das folhas de Maytenus ilicifolia Mart. ex Reiss

    Energy Technology Data Exchange (ETDEWEB)

    Pessuto, Monica Bordin; Costa, Isis Casemiro da; Souza, Angelita Boldieri de; Nicoli, Fernanda Michely; Mello, Joao Carlos Palazzo de [Universidade Estadual de Maringa (UEM), PR (Brazil). Dept. de Farmacia e Farmacologia]. E-mail: mello@uem.br; Petereit, Frank [Westfaelische Wilhelms-Universitaet, Muenster (Germany). Inst. for Pharmaceutical Biology and Phytochemistry; Luftmann, Heinrich [Westfaelische Wilhelms-Universitaet, Muenster (Germany). Inst. for Organic Chemistry

    2009-07-01

    Maytenus ilicifolia Mart. ex Reiss. Maytenus ilicifolia (Celastraceae) is a native plant of South America and popularly known as 'espinheira-santa'. The aim of this study was to evaluate the antioxidant capacity of extracts and isolated compounds from this plant. The antioxidant activity of the crude and semipurified extracts and isolated compounds was evaluated through DPPH-radical and phosphomolybdenum-complex assays. By both methods, the ethyl-acetate fraction demonstrated better antioxidant capacity compared with vitamin C and trolox. In the compounds, the higher the number of hydroxyls, the greater the antioxidant activity. In addition, stereochemistry influenced antioxidant activity, i.e., compounds with 2 R,3 R showed greater activity than those with 2 R,3 S. (author)

  15. Chirality of Modern Antidepressants: An Overview

    Directory of Open Access Journals (Sweden)

    Monica Budău

    2017-12-01

    Full Text Available The majority of modern antidepressants (selective serotonin reuptake inhibitors and selective serotonin and norepinephrine reuptake inhibitors have one or two centers of asymmetry in their structure; resulting in the formation of enantiomers which may exhibit different pharmacodynamic and pharmacokinetic properties. Recent developments in drug stereochemistry has led to understanding the role of chirality in modern therapy correlated with increased knowledge regarding the molecular structure of specific drug targets and towards the possible advantages of using pure enantiomers instead of racemic mixtures. The current review deals with chiral antidepressant drugs; presenting examples of stereoselectivity in the pharmacological actions of certain antidepressants and their metabolites and emphasizing the differences between pharmacological actions of the racemates and pure enantiomers.

  16. 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.

  17. 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.

  18. 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

  19. 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.

  20. 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.

  1. Chiral Analysis of Pesticides and Drugs of Environmental Concern: Biodegradation and Enantiomeric Fraction

    Directory of Open Access Journals (Sweden)

    Alexandra S. Maia

    2017-09-01

    Full Text Available The importance of stereochemistry for medicinal chemistry and pharmacology is well recognized and the dissimilar behavior of enantiomers is fully documented. Regarding the environment, the significance is equivalent since enantiomers of chiral organic pollutants can also differ in biodegradation processes and fate, as well as in ecotoxicity. This review comprises designed biodegradation studies of several chiral drugs and pesticides followed by enantioselective analytical methodologies to accurately measure the enantiomeric fraction (EF. The enantioselective monitoring of microcosms and laboratory-scale experiments with different environmental matrices is herein reported. Thus, this review focuses on the importance of evaluating the EF variation during biodegradation studies of chiral pharmaceuticals, drugs of abuse, and agrochemicals and has implications for the understanding of the environmental fate of chiral pollutants.

  2. Structure and Absolute Configuration of 20β-Hydroxyprednisolone, a Biotransformed Product of Predinisolone by the Marine Endophytic Fungus Penicilium lapidosum

    Directory of Open Access Journals (Sweden)

    Sadia Sultan

    2014-09-01

    Full Text Available The anti-inflammatory drug predinisolone (1 was reduced to 20β-hydroxyprednisolone (2 by the marine endophytic fungus Penicilium lapidosum isolated from an alga. The structural elucidation of 2 was achieved by 1D- and 2D-NMR, MS, IR data. Although, 2 is a known compound previously obtained through microbial transformation, the data provided failed to prove the C20 stereochemistry. To solve this issue, DFT and TD-DFT calculations have been carried out at the B3LYP/6–31+G (d,p level of theory in gas and solvent phase. The absolute configuration of C20 was eventually assigned by combining experimental and calculated electronic circular dichroism spectra and 3JHH chemical coupling constants.

  3. Synthesis, Formulation, and Adjuvanticity of Monodesmosidic Saponins with Olenanolic Acid, Hederagenin and Gypsogenin Aglycones, and some C-28 Ester Derivatives

    DEFF Research Database (Denmark)

    Greatrex, Ben W.; Daines, Alison M.; Hook, Sarah

    2015-01-01

    In an attempt to discover a new synthetic vaccine adjuvant, the glycosylation of hederagenin, gypsogenin, and oleanolic acid acceptors with di- and trisaccharide donors to generate a range of mimics of natural product QS-21 was carried out. The saponins were formulated with phosphatidylcholine...... of cholesterol and phospholipid, the choline ester derivatives produced nanocrystalline rods or helical micelles. The effects of modifying sugar stereochemistry and the aglycone on the immunostimulatory effects of the saponins was then evaluated using the activation markers MHC class II and CD86 in murine bone...... marrow dendritic cells. The most active saponin, 3-O-(Manp(13)Glcp)hederagenin, was stimulatory at high concentrations in cell culture, but this did not translate to strong responses in vivo....

  4. New phenyl derivatives from endophytic fungus Aspergillus flavipes AIL8 derived of mangrove plant Acanthus ilicifolius.

    Science.gov (United States)

    Bai, Zhi-Qiang; Lin, Xiuping; Wang, Yizhu; Wang, Junfeng; Zhou, Xuefeng; Yang, Bin; Liu, Juan; Yang, Xianwen; Wang, Yi; Liu, Yonghong

    2014-06-01

    Two new aromatic butyrolactones, flavipesins A (1) and B (2), two new natural products (3 and 4), and a known phenyl dioxolanone (5) were isolated from marine-derived endophytic fungus Aspergillus flavipes. The structures of compounds 1-5 were elucidated by 1D- and 2D-NMR and MS analysis, the absolute configurations were assigned by optical rotation and CD data, and the stereochemistry of 1 was determined by X-ray crystallography analysis. 1 demonstrated lower MIC values against Staphylococcus aureus (8.0 μg/mL) and Bacillus subtillis (0.25 μg/mL). 1 also showed the unique antibiofilm activity of penetration through the biofilm matrix and kills live bacteria inside mature S. aureus biofilm. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. Stereocontrolled dopamine receptor binding and subtype selectivity of clebopride analogues synthesized from aspartic acid.

    Science.gov (United States)

    Einsiedel, Jürgen; Weber, Klaus; Thomas, Christoph; Lehmann, Thomas; Hübner, Harald; Gmeiner, Peter

    2003-10-06

    Employing the achiral 4-aminopiperidine derivative clebopride as a lead compound, chiral analogues were developed displaying dopamine receptor binding profiles that proved to be strongly dependent on the stereochemistry. Compared to the D1 receptor, the test compounds showed high selectivity for the D2-like subtypes including D2(long), D2(short), D3 and D4. The highest D4 and D3 affinities were observed for the cis-3-amino-4-methylpyrrolidines 3e and the enantiomer ent3e resulting in K(i) values of 0.23 and 1.8 nM, respectively. The benzamides of type 3 and 5 were synthesized in enantiopure form starting from (S)-aspartic acid and its unnatural optical antipode.

  6. Activity coefficients of CaCl2 in (maltose + water) and (lactose + water) mixtures at 298.15 K

    International Nuclear Information System (INIS)

    Zhuo Kelei; Liu Hongxun; Zhang Honghao; Liu Yaohui; Wang Jianji

    2008-01-01

    Activity coefficients of CaCl 2 in disaccharide {(maltose, lactose) + water} mixtures at 298.15 K were determined by cell potentials. The molalities of CaCl 2 ranged from about 0.01 mol . kg -1 to 0.20 mol . kg -1 , the mass fractions of maltose from 0.05 to 0.25, and those of lactose from 0.025 to 0.125. The cell potentials were analyzed by using the Debye-Hueckel extended equation and the Pitzer equation. The activity coefficients obtained from the two theoretical models are in good agreement with each other. Gibbs free energy interaction parameters (g ES ) and salting constants (k S ) were also obtained. These were discussed in terms of the stereo-chemistry of saccharide molecules and the structural interaction model

  7. 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 much...... more electron-withdrawing when positioned equatorially rather than axially. In contrast, little difference in electronic effects was observed from apolar groups as a result of epimerization. These observations were believed to be caused by differences in charge-dipole interactions and were used...... to explain why stereoisomeric glycosides hydrolyze with different rates. The conformational changes of hydroxylated piperidines and related compounds as a function of pH were likewise explained from the different substituent effects of axial and equatorial OH groups....

  8. Investigating the nature of palladium chain-walking in the enantioselective redox-relay Heck reaction of alkenyl alcohols.

    Science.gov (United States)

    Hilton, Margaret J; Xu, Li-Ping; Norrby, Per-Ola; Wu, Yun-Dong; Wiest, Olaf; Sigman, Matthew S

    2014-12-19

    The mechanism of the redox-relay Heck reaction was investigated using deuterium-labeled substrates. Results support a pathway through a low energy palladium-alkyl intermediate that immediately precedes product formation, ruling out a tautomerization mechanism. DFT calculations of the relevant transition structures at the M06/LAN2DZ+f/6-31+G* level of theory show that the former pathway is favored by 5.8 kcal/mol. Palladium chain-walking toward the alcohol, following successive β-hydride eliminations and migratory insertions, is also supported in this study. The stereochemistry of deuterium labels is determined, lending support that the catalyst remains bound to the substrate during the relay process and that both cis- and trans-alkenes form from β-hydride elimination.

  9. Erosion of stereochemical control with increasing nucleophilicity: O-glycosylation at the diffusion limit.

    Science.gov (United States)

    Beaver, Matthew G; Woerpel, K A

    2010-02-19

    Nucleophilic substitution reactions of 2-deoxyglycosyl donors indicated that the reactivity of the oxygen nucleophile has a significant impact on stereoselectivity. Employing ethanol as the nucleophile resulted in a 1:1 (alpha:beta) ratio of diastereomers under S(N)1-like reaction conditions. Stereoselective formation of the 2-deoxy-alpha-O-glycoside was only observed when weaker nucleophiles, such as trifluoroethanol, were employed. The lack of stereoselectivity observed in reactions of common oxygen nucleophiles can be attributed to reaction rates of the stereochemistry-determining step that approach the diffusion limit. In this scenario, both faces of the prochiral oxocarbenium ion are subject to nucleophilic addition to afford a statistical mixture of diastereomeric products. Control experiments confirmed that all nucleophilic substitution reactions were performed under kinetic control.

  10. Structures and biological activities of azaphilones produced by Penicillium sp. KCB11A109 from a ginseng field.

    Science.gov (United States)

    Son, Sangkeun; Ko, Sung-Kyun; Kim, Jong Won; Lee, Jae Kyoung; Jang, Mina; Ryoo, In-Ja; Hwang, Gwi Ja; Kwon, Min Cheol; Shin, Kee-Sun; Futamura, Yushi; Hong, Young-Soo; Oh, Hyuncheol; Kim, Bo Yeon; Ueki, Masashi; Takahashi, Shunji; Osada, Hiroyuki; Jang, Jae-Hyuk; Ahn, Jong Seog

    2016-02-01

    Twelve metabolites, including five highly oxygenated azaphilones, geumsanols A-E, along with seven known analogues were isolated from Penicillium sp. KCB11A109, a fungus derived from a ginseng field. Their structures were assigned by spectroscopic means (NMR and MS), and stereochemistries were determined by extensive spectroscopic analyses ((1)H-(1)H coupling constants, NOESY, and HETLOC) and chemical derivatizations (modified Mosher's method and acetonide formation). The isolates were evaluated for their anticancer, antimicrobial, antimalarial activities, and phenotypic effects in zebrafish development. Of these compounds possessing no pyranoquinone core, only geumsanol E exhibited cytotoxic activities and toxic effects on zebrafish embryos, suggesting that a double bond at C-11 and C-12 is important for biological activity. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Silver and gold in the Protein Data Bank.

    Science.gov (United States)

    Carugo, Oliviero

    2017-10-01

    The structural features of the silver and gold sites in protein crystal structures extracted from the Protein Data Bank have been investigated. It is observed that both cations have nearly always low oxidations states (+1) and low coordination numbers, adopt standard stereochemistries, and interact preferentially (particularly gold) with sulfur donor atoms of cysteine and methionine side-chains. Interestingly, gold cation have been very often refined with occupancy minor than 1.0 and are very often "naked", in the sense that no donor atoms are sufficiently close to the metal cation. This apparently strange observation points out towards the need to develop specific and efficient validation tools for these elements when they are coordinated to proteins. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. A practical synthesis of a gamma-secretase inhibitor.

    Science.gov (United States)

    Scott, Jeremy P; Lieberman, David R; Beureux, Olivier M; Brands, Karel M J; Davies, Antony J; Gibson, Andrew W; Hammond, Deborah C; McWilliams, Chris J; Stewart, Gavin W; Wilson, Robert D; Dolling, Ulf-H

    2007-05-25

    A practical and scaleable synthesis of the gamma-secretase inhibitor 1 is reported. The inhibitor consists of a central trisubstituted cyclohexane core with appended propionic acid, 2,5-difluorophenyl, and 4-chlorophenylsulfonyl moieties. Two alternative synthetic strategies, proceeding by way of a common disubstituted cyclohexanone derivative 5, were studied. In the preferred route, conjugate reduction of acrylonitrile derivative 4 with L-Selectride configures the desired relative stereochemistry of the cyclohexane core with >99.9:0.1 dr. A second strategy, based on catalyst-controlled hydrogenation of racemic cyclohexene derivative 2, is more convergent but less diastereoselective (up to 75:25 dr). The common cyclohexanone intermediate 5 was constructed by a regioselective Diels-Alder condensation of a 1,1-disubstituted vinyl sulfone 6 with 2-trimethylsiloxybutadiene.

  13. Chiral nanophotonics chiral optical properties of plasmonic systems

    CERN Document Server

    Schäferling, Martin

    2017-01-01

    This book describes the physics behind the optical properties of plasmonic nanostructures focusing on chiral aspects. It explains in detail how the geometry determines chiral near-fields and how to tailor their shape and strength. Electromagnetic fields with strong optical chirality interact strongly with chiral molecules and, therefore, can be used for enhancing the sensitivity of chiroptical spectroscopy techniques. Besides a short review of the latest results in the field of plasmonically enhanced enantiomer discrimination, this book introduces the concept of chiral plasmonic near-field sources for enhanced chiroptical spectroscopy. The discussion of the fundamental properties of these light sources provides the theoretical basis for further optimizations and is of interest for researchers at the intersection of nano-optics, plasmonics and stereochemistry. .

  14. Benzo(a)pyrene-7,8-dihydrodiol 9,10-oxide adenosine and deoxyadenosine adducts: structure and stereochemistry.

    Science.gov (United States)

    Jeffrey, A M; Grzeskowiak, K; Weinstein, I B; Nakanishi, K; Roller, P; Harvey, R G

    1979-12-14

    The structure and absolute stereoconfigurations of four adenosine adducts with (+/-)-7 alpha,8 beta-dihydroxy-9 beta, 10 beta-epoxy-7,8,9,10-tetrahydrobenzo(a)pyrene (BPDE) and their deoxyadenosine analogs have been determined. They result from both cis and trans addition of the N6 amino group of ademine to the 10 position of both enantiomers of BDPE. This was determined from studies of the nuclear magnetic resonance spectra, mass spectra, and circular dichroism spectra, as well as from their pKa values and chemical reactivities.

  15. Further studies on 4-hydroxy-3-methoxyphenylglycol oxidation in humans: effect of pool expansion and stereochemistry

    Energy Technology Data Exchange (ETDEWEB)

    Mardh, G.

    1983-08-01

    The in vivo oxidation of the norepinephrine metabolite 4-hydroxy-3-methoxyphenylglycol (HMPG) to 4-hydroxy-3-methoxymandelic acid was studied in man with two different doses of deuterium-labeled HMPG and a tracer dose of (/sup 14/C)HMPG. HMPG oxidation appeared to be dose-dependent with an oxidation of 62-70% for doses below or equal to 2.2 mumol. With the use of a capillary column coated with an optically active phase (Chirasil-Val) and gas chromatography mass-spectrometry the human urinary excretions of the two stereoisomers of deuterium-labelled HMPG (free + conjugates) were found to be equal.

  16. Synthesis, stereochemistry, crystal structure, docking study and biological evaluation of some new N-benzylpiperidin-4-ones

    Science.gov (United States)

    Ponnuswamy, S.; Kayalvizhi, R.; Sethuvasan, S.; Sugumar, P.; Ponnuswamy, M. N.

    2018-03-01

    Two new N-benzylpiperidin-4-ones 3 and 4 have been synthesized and characterized using IR, 1D and 2D NMR spectral studies. The NMR data of N-benzylpiperidin-4-ones 3 and 4 reveal that the compounds prefer to exist in chair conformation with equatorial orientation of the bulky substituents and the single crystal X-ray structure of compound 4 also reveals a similar conformation in solid state. Furthermore, the antimicrobial studies carried out for the compounds 1-4 indicate moderate activities with the selected strains. The antioxidant potency of 3 is superior whereas 4 exhibits moderate activity when compared to that of standard drug. The results of molecular docking studies with the AmpC β-lactamase enzyme indicate that compound 3 shows better docking score and binding energy than the co-crystal ligand.

  17. Asymmetric Synthesis of P-Chiral Diphosphines. Steric Effects on the Palladium-Complex-Promoted Asymmetric Diels-Alder Reaction between a Dimethylphenylphosphole and (E/Z)-Methyl-Substituted Diphenylvinylphosphines.

    Science.gov (United States)

    Aw, Beng-Hwee; Hor, T. S. Andy; Selvaratnam, S.; Mok, K. F.; White, Andrew J. P.; Williams, David J.; Rees, Nicholas H.; McFarlane, William; Leung, Pak-Hing

    1997-05-07

    The organopalladium complex containing ortho-metalated (S)-(1-(dimethylamino)ethyl)naphthalene as the chiral auxiliary has been used successfully to promote the asymmetric [4+2] Diels-Alder reactions between 1-phenyl-3,4-dimethylphosphole and the following coordinated dienophiles: (a) diphenylvinylphosphine; (b) (E)-diphenyl-1-propenylphosphine; (c) (Z)-diphenyl-1-propenylphosphine. Reaction a generates three carbon and one phosphorus stereogenic centers while reactions b and c each produce four carbon and one phosphorus chiral centers. In dichloromethane, all three reactions proceeded smoothly at room temperature giving the corresponding rigid diphosphines in high yields. Under similar reaction conditions, the reaction times observed for reactions a-c are 2, 3, and 50 h, respectively. Two-dimensional ROESY NMR studies confirmed that the prolonged reaction time required for reaction c is due to several major repulsive interactions between the chiral naphthylamine auxiliary and the (Z)-methyl-substituted vinylphosphine in the transition state. Nevertheless, all three reactions gave the corresponding rigid diphosphine in high yields. The absolute stereochemistries of the three bidentate phosphine ligands that were produced from the cycloaddition reactions have been assigned by 2D ROESY NMR spectroscopy. These diphosphines are powerful sequesterers of group 8 metals although they are highly air-sensitive in the free ligand form. The coordination chemistry and the absolute stereochemistry of the optically active complex [1alpha,4alpha,5alpha(S),6alpha(S),7R]-dichloro[5-(diphenylphosphino)-2,3,6-trimethy-7-phenyl-7-phosphabicyclo[2.2.1]-hept-2-ene-P(5)(),P(7)()]palladium(II) has been studied by single-crystal X-ray analysis. Crystal structure data: C(27)H(28)Cl(2)P(2)Pd, M(r) = 591.7; triclinic; space group P1; a = 8.643(3), b = 9.044(6), c = 9.058(4) Å; alpha = 102.75(4) degrees, beta = 108.59(2) degrees, gamma = 97.82(3) degrees; V = 638.0(5) Å(3); Z = 1; R(1) = 0.036.

  18. Nuclear Medicine Program progress report for quarter ending June 30, 1993

    Energy Technology Data Exchange (ETDEWEB)

    Knapp, F.F. Jr.; Ambrose, K.R.; Beets, A.L.; Callahan, A.P.; Hsieh, B.T.; McPherson, D.W.; Mirzadeh, S.; Lambert, C.R.

    1993-07-01

    The ``IQNP`` agent is an antagonist for the cholinergic-muscarinic receptor. Since the IQNP molecule has two asymmetric centers and either cis or trans isomerism of the vinyl iodide, there are eight possible isomeric combinations. In this report, the systematic synthesis, purification and animal testing of several isomers of radioiodinated ``IQNP`` are reported. A dramatic and unexpected relation between the absolute configuration at the two asymmetric centers and the stereochemistry of the vinyl iodide on receptor specificity was observed. The E-(R)(R) isomer shows specific and significant localization (per cent dose/gram at 6 hours) in receptor-rich cerebral structures (i.e. Cortex = 1.38 + 0.31; Striatum = 1.22 + 0.20) and low uptake in tissues rich in the M{sub 2} subtype (Heart = 0.10; Cerebellum = 0.04). In contrast, the E-(R)(S) isomer shows very low receptor-specific uptake (Cortex = 0.04; Striatum = 0.02), demonstrating the importance of absolute configuration at the acetate center. An unexpected and important observation is that the stereochemistry of the vinyl iodine appears to affect receptor subtype specificity, since the Z-(R,S)(R) isomer shows much higher uptake in the heart (0.56 + 0.12) and cerebellum (0.17 + 0.04). Studies are now in progress to confirm these exciting results in vitro. Progress has also continued during this period with several collaborative programs. The first large-scale clinical tungsten-188/rhenium-188 generator prototype (500 mCi) was fabricated and supplied to the Center for Molecular Medicine and Immunology (CMMI), in Newark, New Jersey, for Phase I clinical trials of rhenium-188-labeled anti CEA antibodies for patient treatment. Collaborative studies are also continuing in conjunction with the Nuclear Medicine Department at the University of Massachusetts where a generator is in use to compare the biological properties of {open_quotes}direct{close_quotes} and {open_quotes}indirect{close_quotes} labeled antibodies.

  19. Structure Activity Relationships of N-linked and Diglycosylated Glucosamine-Based Antitumor Glycerolipids

    Directory of Open Access Journals (Sweden)

    Makanjuola Ogunsina

    2013-12-01

    Full Text Available 1-O-Hexadecyl-2-O-methyl-3-O-(2'-amino-2'-deoxy-β-D-glucopyranosyl-sn-glycerol (1 was previously reported to show potent in vitro antitumor activity on a range of cancer cell lines derived from breast, pancreas and prostate cancer. This compound was not toxic to mice and was inactive against breast tumor xenografts in mice. This inactivity was attributed to hydrolysis of the glycosidic linkage by glycosidases. Here three N-linked (glycosylamide analogs 2–4, one triazole-linked analog 5 of 1 as well as two diglycosylated analogs 6 and 7 with different stereochemistry at the C2-position of the glycerol moiety were synthesized and their antitumor activity against breast (JIMT-1, BT-474, MDA-MB-231, pancreas (MiaPaCa2 and prostrate (DU145, PC3 cancer cell lines was determined. The diglycosylated analogs 1-O-hexadecyl-2(R-, 3-O-di-(2'-amino-2'-deoxy-β-D-glucopyranosyl-sn-glycerol (7 and the 1:1 diastereomeric mixture of 1-O-hexadecyl-2(R/S, 3-O-di-(2'-amino-2'-deoxy-β-D-glucopyranosyl-sn-glycerol (6 showed the most potent cytotoxic activity at CC50 values of 17.5 µM against PC3 cell lines. The replacement of the O-glycosidic linkage by a glycosylamide or a glycosyltriazole linkage showed little or no activity at highest concentration tested (30 µM, whereas the replacement of the glycerol moiety by triazole resulted in CC50 values in the range of 20 to 30 µM. In conclusion, the replacement of the O-glycosidic linkage by an N-glycosidic linkage or triazole-linkage resulted in about a two to three fold loss in activity, whereas the replacement of the methoxy group on the glycerol backbone by a second glucosamine moiety did not improve the activity. The stereochemistry at the C2-position of the glycero backbone has minimal effect on the anticancer activities of these diglycosylated analogs.

  20. π-Bond Screening in Benzonorbornadienes: The Role of 7-Substituents in Governing the Facial Selectivity for the Diels-Alder Reaction of Benzonorbornadienes with 3,6-Di(2-pyridyl-s-Tetrazine

    Directory of Open Access Journals (Sweden)

    Peter A. Harrison

    2001-03-01

    Full Text Available Benzonorbornadiene 21, 7-spirocyclopropylbenzonorbornadiene 23, 7,7-dimethylbenzonorbornadiene 25, and 7-spirocyclopentylbenzonorbornadiene 27 have been reacted with 3,6-di(2-pyridyl-s-tetrazine (rate: 21>23>25=27 to form symmetrical 4,5-dihydropyridazines which are stable towards fragmentation but rearrange with varying facility to their 1,4 isomers. The facial selectivity of attack on the π-bond changes from exo-attack for 21 and 23 to endo-attack for 25 and 27. The 7-spirocyclopropyl benzonorbornadiene 23 typically forms a mixture of dihydropyridazines with exo-stereochemistry, which undergo further stereochemical isomerisation to an exo-fused product upon acetylation (acetyl chloride in hot pyridine. Oxidation with DDQ of the dihydropyridazines individually or as mixtures gives the corresponding fused 3,6-di(2-pyridylpyridazines.

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