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Peluso P, Chankvetadze B. Recognition in the Domain of Molecular Chirality: From Noncovalent Interactions to Separation of Enantiomers. Chem Rev 2022; 122:13235-13400. [PMID: 35917234 DOI: 10.1021/acs.chemrev.1c00846] [Citation(s) in RCA: 57] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
It is not a coincidence that both chirality and noncovalent interactions are ubiquitous in nature and synthetic molecular systems. Noncovalent interactivity between chiral molecules underlies enantioselective recognition as a fundamental phenomenon regulating life and human activities. Thus, noncovalent interactions represent the narrative thread of a fascinating story which goes across several disciplines of medical, chemical, physical, biological, and other natural sciences. This review has been conceived with the awareness that a modern attitude toward molecular chirality and its consequences needs to be founded on multidisciplinary approaches to disclose the molecular basis of essential enantioselective phenomena in the domain of chemical, physical, and life sciences. With the primary aim of discussing this topic in an integrated way, a comprehensive pool of rational and systematic multidisciplinary information is provided, which concerns the fundamentals of chirality, a description of noncovalent interactions, and their implications in enantioselective processes occurring in different contexts. A specific focus is devoted to enantioselection in chromatography and electromigration techniques because of their unique feature as "multistep" processes. A second motivation for writing this review is to make a clear statement about the state of the art, the tools we have at our disposal, and what is still missing to fully understand the mechanisms underlying enantioselective recognition.
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Affiliation(s)
- Paola Peluso
- Istituto di Chimica Biomolecolare ICB, CNR, Sede secondaria di Sassari, Traversa La Crucca 3, Regione Baldinca, Li Punti, I-07100 Sassari, Italy
| | - Bezhan Chankvetadze
- Institute of Physical and Analytical Chemistry, School of Exact and Natural Sciences, Tbilisi State University, Chavchavadze Avenue 3, 0179 Tbilisi, Georgia
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2
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Dahmer J, Marangon P, Adolpho LO, Reis FL, Maldaner G, Burrow RA, Mostardeiro MA, Dalcol II, Morel AF. Alkaloids from the stem barks of Scutia buxifolia Reissek (Rhamnaceae): Structures and antimicrobial evaluation. PHYTOCHEMISTRY 2022; 196:113071. [PMID: 35032919 DOI: 10.1016/j.phytochem.2021.113071] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 11/29/2021] [Accepted: 12/21/2021] [Indexed: 06/14/2023]
Abstract
A reinvestigation of the chemical constituents of the stem barks of Scutia buxifolia, a member of the Rhamnaceae, resulted, along with the known alkaloids scutianine C and scutianene L, in the isolation of three undescribed diastereoisomeric alkaloids - scutianine N, 27-epi-scutianine N and 3, 4, 7-tri-epi-scutianine N -, one undescribed non macrocyclic alkaloid - scutianine Q - and a neutral compound -scutianene M. Their structures were determined using extensive NMR techniques and HRMS. The absolute configurations of the stereogenic centers of the three diastereoisomeric alkaloids have been assigned by gas chromatography employing modified cyclodextrins as chiral stationary phases. Scutianine Q had its structure and stereochemistry defined by single crystal X-ray crystallographic analysis. All tested compounds showed good to moderate antibacterial activity (MICs between 1.56 and 100 μg mL-1) when evaluated in vitro against a panel of Gram-positive and Gram-negative bacteria. Some stereochemistry-activity relationships have been identified for the antibacterial activity of diastereoisomeric alkaloids against the Gram-negative bacteria Enterobacter aerogenes. The alkaloid 27-epi-scutianine N was as active as the standard antibiotic chloramphenicol (MIC = 1.56 μg mL-1), while scutianine N and 3,4,27-tris-epi-Scutianine N were inactive (>100 μg mL-1).
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Affiliation(s)
- Janice Dahmer
- Universidade Federal de Santa Maria, Departamento de Química, CEP, 97105-900, Santa Maria, RS, Brazil
| | - Patricia Marangon
- Universidade Federal de Santa Maria, Departamento de Química, CEP, 97105-900, Santa Maria, RS, Brazil
| | - Luciana O Adolpho
- Programa de Pós-Graduação em Farmacologia, Universidade Federal de Santa Maria (UFSM), Santa Maria, RS 97105-900, Brazil
| | - Frederico L Reis
- Universidade Federal de Santa Maria, Departamento de Química, CEP, 97105-900, Santa Maria, RS, Brazil
| | - Graciela Maldaner
- Universidade Federal de Santa Maria, Departamento de Química, CEP, 97105-900, Santa Maria, RS, Brazil
| | - Robert A Burrow
- Universidade Federal de Santa Maria, Departamento de Química, CEP, 97105-900, Santa Maria, RS, Brazil
| | - Marco A Mostardeiro
- Universidade Federal de Santa Maria, Departamento de Química, CEP, 97105-900, Santa Maria, RS, Brazil
| | - Ionara I Dalcol
- Universidade Federal de Santa Maria, Departamento de Química, CEP, 97105-900, Santa Maria, RS, Brazil; Programa de Pós-Graduação em Farmacologia, Universidade Federal de Santa Maria (UFSM), Santa Maria, RS 97105-900, Brazil.
| | - Ademir F Morel
- Universidade Federal de Santa Maria, Departamento de Química, CEP, 97105-900, Santa Maria, RS, Brazil.
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Absolute Configuration of Aliphatic Hydrocarbon Enantiomers Identified by Gas Chromatography: Theorized Application for Isoprenoid Alkanes and the Search of Molecular Biosignatures on Mars. Symmetry (Basel) 2022. [DOI: 10.3390/sym14020326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Acyclic saturated hydrocarbon enantiomers were resolved by gas chromatography using a β-cyclodextrin-based chiral stationary phase. The stereospecific synthesis of single enantiomers of 4-methyloctane allowed to assign the absolute stereochemical configuration to the resolved enantiomers. Data show that the (S)-4-methyloctane shows higher chromatographic retention as compared to the (R)-4-methyloctane due to stronger van der Waals interactions with the β-cyclodextrin chiral selector. This introductive research presents future prospects for the separation of stereoisomers of larger branched hydrocarbons. We discuss the importance of chiral hydrocarbons, more precisely the stereochemistry of the isoprenoid alkanes pristane and phytane, as potential biosignatures stable on geological timescales. The origins of pristane and phytane in Earth sediments are presented, and we detail the implications for the search of extinct or extant life on Mars. The data presented here will help to systematically investigate the chirality of hydrocarbon enantiomers in biological and nonbiological samples and in samples to be analyzed by the ESA’s ExoMars rover to trace the chiral precursors of life in 2023.
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Płotka JM, Simeonov V, Morrison C, Biziuk M, Namieśnik J. Capillary gas chromatography using a γ-cyclodextrin for enantiomeric separation of methylamphetamine, its precursors and chloro intermediates after optimization of the derivatization reaction. J Chromatogr A 2014; 1347:146-56. [DOI: 10.1016/j.chroma.2014.04.062] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2014] [Revised: 04/15/2014] [Accepted: 04/20/2014] [Indexed: 11/29/2022]
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5
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Meinert C, Meierhenrich UJ. Derivatization and Multidimensional Gas-Chromatographic Resolution of α-Alkyl and α-Dialkyl Amino Acid Enantiomers. Chempluschem 2014. [DOI: 10.1002/cplu.201300328] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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6
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Pažitná A, Špánik I. Enantiomeric distribution of major chiral volatile organic compounds in juniper-flavored distillates. J Sep Sci 2014; 37:398-403. [DOI: 10.1002/jssc.201301151] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2013] [Revised: 12/02/2013] [Accepted: 12/03/2013] [Indexed: 11/10/2022]
Affiliation(s)
- Alexandra Pažitná
- Institute of Analytical Chemistry; Faculty of Chemical and Food Technology; Slovak University of Technology; Bratislava Slovak Republic
| | - Ivan Špánik
- Institute of Analytical Chemistry; Faculty of Chemical and Food Technology; Slovak University of Technology; Bratislava Slovak Republic
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Schurig V, Kreidler D. Gas-chromatographic enantioseparation of unfunctionalized chiral hydrocarbons: an overview. Methods Mol Biol 2013; 970:45-67. [PMID: 23283770 DOI: 10.1007/978-1-62703-263-6_3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Analytical gas-chromatographic enantioseparations of unfunctionalized chiral hydrocarbons (cycloalkanes and alkanes) on modified cyclodextrins with high-resolution capillary columns are reviewed. Due to the lack of functional groups of the hydrocarbons, enantiorecognition in the presence of cyclodextrins is ascribed to weak van der Waals forces. Thermodynamic parameters of enantiorecognition between four chiral alkanes and octakis(6-O-methyl-2,3-di-O-pentyl)-γ-cyclodextrin (Lipodex G) have been determined. The possible role of molecular inclusion is indicated by the complete loss of enantioselectivity when the cyclodextrins are replaced by the corresponding linear dextrins. The substitution pattern and cavity size of the modified cyclodextrins have a pronounced effect on the degree of enantiorecognition observed. On mixed binary cyclodextrin stationary phases, all C7 and C8 chiral alkanes possessing one stereogenic center can be enantioseparated simultaneously. The methodology has been used to determine enantiomeric excesses, ee, of alkanes formed by the enantioselective catalytic hydrogenation of prochiral alkenes. The novel online coupling of enantioselective gas chromatography with proton nuclear magnetic resonance spectroscopy is demonstrated for 2,4-dimethylhexane and Lipodex G.
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Affiliation(s)
- Volker Schurig
- Institute of Organic Chemistry, University of Tübingen, Tübingen, Germany.
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8
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Petzold K, Klemm D, Stein A, Günther W. Synthesis and NMR characterization of regiocontrolled starch alkyl ethers. Des Monomers Polym 2012. [DOI: 10.1163/156855502760408099] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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9
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Maldaner G, Marangon P, Ilha V, Caro MSB, Burrow RA, Dalcol II, Morel AF. Cyclopeptide alkaloids from Scutia buxifolia Reiss. PHYTOCHEMISTRY 2011; 72:804-809. [PMID: 21420695 DOI: 10.1016/j.phytochem.2011.02.019] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2010] [Revised: 02/12/2011] [Accepted: 02/21/2011] [Indexed: 05/30/2023]
Abstract
Scutianene E (1), 3,4,28-tris-epi-scutiaene E (2), 28-epi-scutianene E (3) and scutianene L (4), four neutral cyclopeptide alkaloids, were isolated from Scutia buxifolia Reiss, together with four known cyclopeptide alkaloids, scutianines B, C, D and E. Scutianenes 1-3 are diastereoisomeric compounds, with 3-hydroxyleucine as a β-hydroxy amino acid unit, which is connected to the styryl fragment via an ether bridge, β-phenylserine, as a common ring-bonded amino acid residue. Attached to the amino group of β-hydroxyamino acid is a side chain [trans-CH=CH-Ph]. The structures of the peptides were elucidated by means of spectroscopic analysis, including extensive 2D NMR studies. The stereochemistry for the diastereomeric 3,4,28-tris-epi-scutiaene E and 28-epi-scutianene E was confirmed by X-ray diffraction analysis of their O-acetyl derivatives.
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Affiliation(s)
- Graciela Maldaner
- Departamento de Química (NPPN), Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
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10
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Kühnle M, Kreidler D, Holtin K, Czesla H, Schuler P, Schurig V, Albert K. Online coupling of enantioselective capillary gas chromatography with proton nuclear magnetic resonance spectroscopy. Chirality 2010; 22:808-12. [PMID: 20803744 DOI: 10.1002/chir.20840] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The hyphenation of enantioselective capillary gas chromatography and mass spectrometry is not always sufficient to distinguish between structural isomers, thus requiring peak identification by NMR spectroscopy. Here the first online coupling of enantioselective capillary gas chromatography with proton nuclear resonance spectroscopy is described for the unfunctionalized chiral alkane 2,4-dimethylhexane resolved on octakis(6-O-methyl-2,3-di-O-pentyl)-gamma-cyclodextrin at 60 degrees C. NMR allows constitutional and configurational isomers (diastereomers and enantiomers) to be distinguished. Enantiomers display identical spectra at different retention times, which enable an indirect identification of these unfunctionalized alkanes. The presented method is still at an early development stage, and will require instrumental optimization in the future.
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Affiliation(s)
- Maximilian Kühnle
- Institute of Organic Chemistry, University of Tübingen, Tübingen D-72076, Germany
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11
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Morel AF, Maldaner G, Ilha V. Cyclopeptide alkaloids from higher plants. THE ALKALOIDS. CHEMISTRY AND BIOLOGY 2009; 67:79-141. [PMID: 19827366 DOI: 10.1016/s1099-4831(09)06702-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Affiliation(s)
- Ademir Farias Morel
- Departamento de Química, NPPN, Universidade Federal de Santa Maria, Rio Grande do Sul, Brazil.
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12
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Sicoli G, Kreidler D, Czesla H, Hopf H, Schurig V. Gas chromatographic enantioseparation of unfunctionalized chiral alkanes: A challenge in separation science (overview, state of the art, and perspectives). Chirality 2009; 21:183-98. [DOI: 10.1002/chir.20638] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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13
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Cravotto G, Palmisano G, Panza L, Tagliapietra S. Synthesis of Selectively Permodified γ–Cyclodextrins. A New Set of Chiral Stationary Phases in Capillary GC. J Carbohydr Chem 2008. [DOI: 10.1080/07328300008544147] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- Giancarlo Cravotto
- a Dipartimento di Scienza e Tecnologia del Farmaco , Via Giuria 9, 10125 Torino, Italy
- b Dipartimento di Scienze Chimiche, Fisiche e Matematiche , Università degli Studi dell'Insubria , Via Lucini 3, 22100 Como, Italy
- c Dipartimento di Scienze Chimiche, Alimentari , Farmaceutiche e Farmacologiche , Viale Ferrucci 33, 28100 Novara, Italy
- d Dipartimento di Scienza e Tecnologia del Farmaco , Via Giuria 9, 10125 Torino, Italy
| | - Giovanni Palmisano
- a Dipartimento di Scienza e Tecnologia del Farmaco , Via Giuria 9, 10125 Torino, Italy
- b Dipartimento di Scienze Chimiche, Fisiche e Matematiche , Università degli Studi dell'Insubria , Via Lucini 3, 22100 Como, Italy
- c Dipartimento di Scienze Chimiche, Alimentari , Farmaceutiche e Farmacologiche , Viale Ferrucci 33, 28100 Novara, Italy
- d Dipartimento di Scienza e Tecnologia del Farmaco , Via Giuria 9, 10125 Torino, Italy
| | - Luigi Panza
- a Dipartimento di Scienza e Tecnologia del Farmaco , Via Giuria 9, 10125 Torino, Italy
- b Dipartimento di Scienze Chimiche, Fisiche e Matematiche , Università degli Studi dell'Insubria , Via Lucini 3, 22100 Como, Italy
- c Dipartimento di Scienze Chimiche, Alimentari , Farmaceutiche e Farmacologiche , Viale Ferrucci 33, 28100 Novara, Italy
- d Dipartimento di Scienza e Tecnologia del Farmaco , Via Giuria 9, 10125 Torino, Italy
| | - Silvia Tagliapietra
- a Dipartimento di Scienza e Tecnologia del Farmaco , Via Giuria 9, 10125 Torino, Italy
- b Dipartimento di Scienze Chimiche, Fisiche e Matematiche , Università degli Studi dell'Insubria , Via Lucini 3, 22100 Como, Italy
- c Dipartimento di Scienze Chimiche, Alimentari , Farmaceutiche e Farmacologiche , Viale Ferrucci 33, 28100 Novara, Italy
- d Dipartimento di Scienza e Tecnologia del Farmaco , Via Giuria 9, 10125 Torino, Italy
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14
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Wang DX, Abdul M. Separation of Enantiomers of a Chiral Lactone on Sol-Gel Gas Chromatography Capillary Columns of Poly(methydrosiloxane) Stationary Phase with Pendant Permethylated β-Cyclodextrin. CHINESE JOURNAL OF ANALYTICAL CHEMISTRY 2007. [DOI: 10.1016/s1872-2040(07)60039-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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15
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Dias GCD, Gressler V, Hoenzel SCSM, Silva UF, Dalcol II, Morel AF. Constituents of the roots of Melochia chamaedrys. PHYTOCHEMISTRY 2007; 68:668-72. [PMID: 17169385 DOI: 10.1016/j.phytochem.2006.11.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2006] [Revised: 09/11/2006] [Accepted: 11/03/2006] [Indexed: 05/13/2023]
Abstract
The cyclic peptide alkaloid, chamaedrine, was isolated from the roots of Melochia chamaedris (Sterculiaceae), along with four known cyclic peptide alkaloids (adouetine X, frangulaline, scutianine B and scutianine C), and waltherione A, parasorbic acid, propacine, and (-)-epicatequine. Their structures were elucidated on the basis of spectroscopic analysis, especially by 2D NMR ((1)H-(1)H-COSY, NOESY, HMQC, HMBC).
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Affiliation(s)
- G C D Dias
- Departamento de Química, NPPN, Universidade Federal de Santa Maria, 97045-100 Santa Maria, RS, Brazil
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16
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Ulland S, Ian E, Borg-Karlson AK, Mustaparta H. Discrimination between enantiomers of linalool by olfactory receptor neurons in the cabbage moth Mamestra brassicae (L.). Chem Senses 2006; 31:325-34. [PMID: 16495438 DOI: 10.1093/chemse/bjj036] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Plants emit complex blends of volatiles, including chiral compounds that might be detected by vertebrates and invertebrates. Insects are ideal model organisms for studying the underlying receptor neuron mechanisms involved in olfactory discrimination of enantiomers. In the present study, we have employed two-column gas chromatography linked to recordings from single olfactory receptor neurons of Mamestra brassicae, in which separation of volatiles in a polar and a chiral column was performed. We here present the response properties of olfactory receptor neurons tuned to linalool. The narrow tuning of these receptor neurons was demonstrated by their strong responses to (R)-(-)-linalool, the weaker responses to the (+)-enantiomer as well as a few structurally related compounds, and no responses to the other numerous plant released volatiles. The enantioselectivity was verified by parallel dose-response curves, that of (R)-(-)-linalool shifted 1 log unit to the left of the (S)-(+)-linalool curve. A complete overlap of the temporal response pattern was found when comparing the responses of the same strength. Analysis of the spike amplitude and waveform indicated that the responses to the two enantiomers originated from the same neuron.
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Affiliation(s)
- Stig Ulland
- Neuroscience Unit, Department of Biology, Norwegian University of Science and Technology, NO-7489 Trondheim, Norway.
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17
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Wolf C, Hochmuth DH, A. König W, Roussel C. Influence of Substituents on the Rotational Energy Barrier of Axially Chiral Biphenyls, II. ACTA ACUST UNITED AC 2006. [DOI: 10.1002/jlac.199619960310] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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18
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Morel AF, Maldaner G, Ilha V, Missau F, Silva UF, Dalcol II. Cyclopeptide alkaloids from Scutia buxifolia Reiss and their antimicrobial activity. PHYTOCHEMISTRY 2005; 66:2571-6. [PMID: 16226284 DOI: 10.1016/j.phytochem.2005.08.016] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2005] [Revised: 07/19/2005] [Accepted: 08/26/2005] [Indexed: 05/04/2023]
Abstract
The present study reports a cyclopeptide alkaloid, scutianine M, isolated from the methanolic root bark extract of Scutia buxifolia Reiss (Rhamnaceae) along with six known compounds, scutianines-B, -C, -D, -E, -F, and scutianene D. Its structure was established on the basis of spectroscopic analyses, including application of 2D NMR spectroscopic techniques. As part of a study of the bioactive compounds of medicinal plants from southern Brazil, we also compared the antimicrobial activity of the isolated compounds towards Gram (+), Gram (-) bacteria, and yeasts.
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Affiliation(s)
- Ademir F Morel
- Departamento de Química (NPPN), Universidade Federal de Santa Maria, 97105-900 Santa Maria, RS, Brazil.
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Liang M, Qi M, Zhang C, Fu R. Peralkylated-β-cyclodextrin used as gas chromatographic stationary phase prepared by sol–gel technology for capillary column. J Chromatogr A 2004; 1059:111-9. [PMID: 15628131 DOI: 10.1016/j.chroma.2004.10.019] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
For the first time, three peralkylated-beta-cyclodextrins (beta-CD), permethylated-beta-CD, perethylated-beta-CD and perpentylated-beta-CD, were coated onto the fused-silica capillary by sol-gel method with simplicity and rapidity. Multiple steps in conventional column preparation technology were avoided. Also, these new columns demonstrated many inherent advantages, the main being the outstanding thermal stability (up to 300 degrees C), high number of theoretical plates, excellent column-to-column and run-to-run reproducibility, and pronounced selectivity for positional isomers and enantiomers. Using n-tridecane as a test reagent (k = 4.18), an efficiency value of 3520 theoretical plates/m was obtained on a sol-gel perpentylated-beta-CD capillary column (15 m x 0.25 mm I.D.). On the basis of the results, we proposed that the peralkylated-beta-CD, which has no terminal hydroxyl group, is encapsulated in the sol-gel network and the whole matrix is chemically bonded to the surface of the fused-silica tubing.
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Affiliation(s)
- Minmin Liang
- Department of Chemistry, School of Science, Beijing Institute of Technology, Beijing 100081, PR China.
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Unusual and Novel C11H16Hydrocarbons from the Southern Australian Brown AlgaDictyopteris acrostichoides(Phaeophyceae). Helv Chim Acta 2004. [DOI: 10.1002/hlca.19920750309] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Bajgrowicz JA, Frank I, Fráter G, Hennig M. Synthesis and Structure Elucidation of a New Potent Sandalwood-Oil Substitute. Helv Chim Acta 2004. [DOI: 10.1002/hlca.19980810545] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Giacomelli SR, Maldaner G, Gonzaga WA, Garcia CM, da Silva UF, Dalcol II, Morel AF. Cyclic peptide alkaloids from the bark of Discaria americana. PHYTOCHEMISTRY 2004; 65:933-937. [PMID: 15081298 DOI: 10.1016/j.phytochem.2004.02.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2003] [Revised: 12/11/2003] [Indexed: 05/24/2023]
Abstract
The isolation and structure determination of cyclic peptide alkaloids, discarine-M and discarine-N, along with seven known cyclic peptide alkaloids, adouetine-Y', franganine, frangulanine, discarines-A, -B, -C, and -D from the root bark of Discaria americana are described. Structures were determined spectroscopically, especially using 2D NMR spectroscopic analysis. The crude methanol extract, the basic ether extract, and the alkaloids 6 and 7 also weakly inhibited growth of gram-negative and gram-positive bacteria.
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Affiliation(s)
- Sandro R Giacomelli
- Departamento de Química, Universidade Federal de Santa Maria, 97105-900 Santa Maria RS, Brazil
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Meierhenrich UJ, Nguyen MJ, Barbier B, Brack A, Thiemann WHP. Gas chromatographic separation of saturated aliphatic hydrocarbon enantiomers on permethylated beta-cyclodextrin. Chirality 2004; 15 Suppl:S13-6. [PMID: 12884370 DOI: 10.1002/chir.10269] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Enantiomers of chiral aliphatic hydrocarbons are generally difficult to separate because they lack functional groups to be derivatized in order to generate diastereomers. The systematic and quantitative separation of a series of branched hydrocarbon enantiomers using a chiral cyclodextrin stationary phase and a cryostat-controlled gas chromatograph is described. The use of a cryogenic system allows the improvement of separations for various chiral aliphatic hydrocarbons. The molecular cyclodextrin-based mechanism of the achieved enantiomeric separations is discussed briefly. Possible applications of this analytical technique are summarized, with special emphasis on the planned enantiomeric separation experiment on a cometary nucleus.
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Albrow V, Biswas K, Crane A, Chaplin N, Easun T, Gladiali S, Lygo B, Woodward S. Synthesis of an octahydro-1,1′-binaphthyl thioether ligand and comparison with unhydrogenated binaphthyl analogues. ACTA ACUST UNITED AC 2003. [DOI: 10.1016/s0957-4166(03)00583-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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25
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Tooker JF, Koenig WA, Hanks LM. Altered host plant volatiles are proxies for sex pheromones in the gall wasp Antistrophus rufus. Proc Natl Acad Sci U S A 2002; 99:15486-91. [PMID: 12438683 PMCID: PMC137743 DOI: 10.1073/pnas.252626799] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We describe a previously uncharacterized function for changes in plant chemistry induced by phytophagous insects: to provide cues for mate location. Larvae of the gall wasp Antistrophus rufus Gillette (Hymenoptera: Cynipidae) feed within inconspicuous galls inside the flowering stems of the prairie perennials Silphium laciniatum L. and Silphium terebinthinaceum Jacquin (Asteraceae). Adult male A. rufus emerge before females and are challenged with locating mates that are sequestered within dead plant stems that occur in a matrix of dead vegetation. Allozyme studies revealed complete reproductive isolation between wasp subpopulations in the two plant species. In laboratory bioassays, males responded only to their natal plant species, antennating the stem surface. Males from S. laciniatum also responded to hexane extracts of S. laciniatum stems, and extracts contained much higher concentrations of monoterpenes (alpha-pinene, beta-pinene, and camphene) than did S. terebinthinaceum. Ratios of "+" and "-" enantiomers of alpha- and beta-pinene approximated 50:50 for nongalled S. laciniatum stems but strongly differed from 50:50 in galled stems, with "+" and "-" enantiomers strongly dominant in different plants. In bioassays, male wasps from S. laciniatum responded to a synthetic blend of the monoterpenes in enantiomeric ratios characteristic of galled stems. Male A. rufus rely entirely on olfaction to locate females within stems in a complex prairie habitat, and gall wasps themselves apparently influence the plant to modify ratios of monoterpene enantiomers. These plant volatiles serve as a signal for males, acting as a sex pheromone proxy for females concealed within plant tissues.
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Affiliation(s)
- John F Tooker
- Department of Entomology, University of Illinois at Urbana-Champaign, 61801, USA
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Morel AF, Araujo CA, da Silva UF, Hoelzel SCSM, Záchia R, Bastos NR. Antibacterial cyclopeptide alkaloids from the bark of Condalia buxifolia. PHYTOCHEMISTRY 2002; 61:561-566. [PMID: 12409023 DOI: 10.1016/s0031-9422(02)00287-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The cyclopeptide alkaloid, named condaline-A, was isolated from the root bark of Condalia buxifolia Reissek (Rhamnaceae), along with the known compounds adouetine-Y', scutianine-B, and scutianine-C. Their structures were determined by spectroscopic analyses, with their antibacterial activities being evaluated by use of a direct bioautography method.
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Affiliation(s)
- Ademir F Morel
- Departamento de Química, Universidade Federal de Santa Maria, RS, Santa Maria, Brazil.
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27
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Bicchi C, Brunelli C, Cravotto G, Rubiolo P, Galli M. Cyclodextrin derivatives in GC separation of racemates of different volatility Part XVIII: 2-methyl-3-acetyl- and 2-acetyl-3-methyl-6-O-t-hexyldimethylsilyl-γ-cyclodextrin derivatives. J Sep Sci 2002. [DOI: 10.1002/1615-9314(20020201)25:3<125::aid-jssc125>3.0.co;2-w] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Meierhenrich UJ, Thiemann WH, Goesmann F, Roll R, Rosenbauer H. Enantiomer separation of hydrocarbons in preparation for ROSETTA's "chirality-experiment". Chirality 2001; 13:454-7. [PMID: 11466768 DOI: 10.1002/chir.1061] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Until now the favored method for separating racemic pairs of underivatized alcohols, diols, and phenylsubstituted amines has been gas chromatography on cyclodextrin phases. However, certain enantiomers of saturated chiral hydrocarbons could not be resolved in this way because they lack the functional groups necessary to undergo "intensive" diastereomeric interactions with the cyclodextrins. The present study describes a gas-chromatographic technique for resolution of saturated aliphatic hydrocarbons into their enantiomers and presents a brief discussion of the possible applications. The (enantiomer) separations were performed in preparation for the Cometary Sampling and Composition Experiment on board the cometary lander RoLand, part of ESA's cornerstone mission ROSETTA. This experiment has been designed to investigate the hypotheses that biomolecular asymmetry has an interstellar origin and to separate and identify a wide range of organic enantiomers in situ on the surface of a comet's nucleus.
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Abstract
The four stereoisomers of chalcogran 1 ((2RS,SRS)-2-ethyl-1,6-di-oxaspiro[4.4]nonane), the principal component of the aggregation pheromone of the bark beetle pityogenes chalcographus, are prone to interconversion at the spiro center (C5). During diastereo- and enantioselective dynamic gas chromatography (DGC), epimerization of 1 gives rise to two independent interconversion peak profiles, each featuring a plateau between the peaks of the interconverting epimers. To determine the rate constants of epimerization by dynamic gas chromatography (DGC), equations to simulate the complex elution profiles were derived, using the theoretical plate model and the stochastic model of the chromatographic process. The Eyring activation parameters of the experimental interconversion profiles, between 70 and 120 C in the presence of the chiral stationary phase (CSP) Chirasil-beta-Dex, were then determined by computer-aided simulation with the aid of the new program Chrom-Win: (2R,5R)-1: deltaG(++) (298.15 K) = 108.0 +/-0.5 kJ mol(-1), deltaH(++) = 47.1+/-0.2 kJ mol(-1), deltaS(++) = -204+/-6 JK(-1) mol(-1): (2R,5S)-1: deltaG(++) (298.15 K) = 108.5+/-0.5 kJ mol(-1), deltaH(++) = 45.8+/-0.2 kJ mol(-1), deltaS(++) = -210 +/-6 J K mol(-1); (2S,5S)-1: deltaG(++) (298.15 K)= 108.1+/-0.5 kJ mol(-1), deltaH(++) = 49.3+/-0.3 kJ mol(-1), deltaS(++) = -197+/-8 J K(-1) mol(-1); (2S,5R)-1: deltaG(++) (298.15 K)=108.6+/-0.5 kJ mol(-1), deltaH(++) = 48.0+/-0.3 kJ mol(-1), deltaS(++) = -203+/-8 J K(-1) mol(-1). The thermodynamic Gibbs free energy of the E/Z equilibrium of the epimers was determined by the stopped-flow multidimensional gas chromatographic technique: deltaG(E/Z) (298.15 K)= -0.5 kJ mol(-1), deltaH(E/Z) = 1.4 kJ mol(-1) and deltaS(E/Z) = 6.3 J K(-1) mol(-1). An interconversion pathway proceeding through ring-opening and formation of a zwitterion and an enol ether/alcohol intermediate of 1 is proposed.
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Affiliation(s)
- O Trapp
- Institut für Organische Chemie, Universität Tübingen, Germany
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33
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Russell WK, Russell DH, Busby MB, Kolberg A, Li S, Maynard DK, Sanchez-Vindas S, Zhu W, Vigh G. Artifact-free matrix-assisted laser desorption ionization time-of-flight mass spectra of tert.-butyldimethylsilyl ether derivatives of cyclodextrins used for the synthesis of single-isomer, chiral resolving agents for capillary electrophoresis. J Chromatogr A 2001; 914:325-30. [PMID: 11358227 DOI: 10.1016/s0021-9673(00)01264-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Artifact-free, high-resolution matrix-assisted laser desorption ionization (MALDI) time-of-flight mass spectra have been obtained for the labile, single-isomer, tert.-butyldimethylsilyl ether derivatives of alpha-, beta- and gamma-cyclodextrins by optimizing the MALDI sample preparation method. 2,5-Dihydroxybenzoic acid, a 3:1 mixture of 2,5-dihydroxybenzoic acid and 1-hydroxyisoquinoline, and 2,4,6-trihydroxyacetophenone were investigated as MALDI matrices with methanol and acetonitrile as matrix solvents. Partial-to-complete loss of the tert.-butyldimethylsilyl groups was observed when the commonly used 2,5-dihydroxybenzoic acid was the MALDI matrix and/or methanol was the solvent, both with and without trifluoroacetic acid as additive. Loss of the labile tert.-butyldimethylsilyl groups was avoided with 2,4,6-trihydroxyacetophenone as MALDI matrix and acetonitrile as matrix solvent. Good ion intensities were achieved for the (M+Na)+ and (M+K)+ quasimolecular ions in the positive-ion mode. Minor byproducts were observed in some of the samples and the information was used to aid the optimization of the synthetic work.
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Affiliation(s)
- W K Russell
- Department of Chemistry, Texas A&M University, College Station 77842-3012, USA
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34
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Börner C, König WA, Woodward S. Enone structure as a probe to Lewis acid carbonyl binding in copper-catalysed asymmetric conjugate addition. Tetrahedron Lett 2001. [DOI: 10.1016/s0040-4039(00)01940-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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35
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Wazynska M, Temeriusz A, Chmurski K, Bilewicz R, Jurczak J. Synthesis and monolayer behavior of amphiphilic per(2,3-di-O-alkyl)-α- and β-cyclodextrins and hexakis(6-deoxy-6-thio-2,3-di-O-pentyl)-α-cyclodextrin at an air–water interface. Tetrahedron Lett 2000. [DOI: 10.1016/s0040-4039(00)01628-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Graebner IB, Mostardeiro MA, Ethur EM, Burrow RA, Dessoy EC, Morel AF. Diterpenoids from Humirianthera ampla. PHYTOCHEMISTRY 2000; 53:955-959. [PMID: 10820811 DOI: 10.1016/s0031-9422(99)00585-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Two diterpenoids, humirianthol and acrenol, as well as the known annonalide, were isolated from Humirianthera ampla. Humirianthol and acrenol were determined by 1D and 2D NMR spectroscopic techniques to be 3 beta,20:14 beta,16-diepoxy-3 alpha, 15 alpha-dihydroxy-7-pimaren-19,6 beta-olide and 3 beta,20-epoxy-3 alpha,15,16-trihydroxy-7-pimaren-19,6 beta-olide, respectively.
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Affiliation(s)
- I B Graebner
- Departamento de Química (NPPN), Universidade Federal de Santa Maria, RS, Brazil
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Morel AF, Flach A, Zanatta N, Ethur EM, Mostardeiro MA, Gehrke IT. A new cyclopeptide alkaloid from the bark of waltheria douradinha. Tetrahedron Lett 1999. [DOI: 10.1016/s0040-4039(99)01821-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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38
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Dessoy MA, Moreira JDJ, Ethur EM, Dessoy ECM, Morel AF. Heptakis(6-O-ethyl-2,3-O-pentyl)-β-cyclodextrin: A New Chiral Stationary Phases for Capillary GC. ACTA ACUST UNITED AC 1999. [DOI: 10.1002/(sici)1521-4168(19990401)22:4<242::aid-jhrc242>3.0.co;2-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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39
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Bicchi C, Cravotto G, D'amato A, Rubiolo P, Galli A, Galli M. Cyclodextrin derivatives in gas chromatographic separation of racemates with different volatility. Part XV: 6-O-t-butyldimethylsilyl- versus 6-O-t-hexyldimethylsilyl-? and -? derivatives. ACTA ACUST UNITED AC 1999. [DOI: 10.1002/(sici)1520-667x(1999)11:7<487::aid-mcs1>3.0.co;2-b] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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40
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Moreira JJ, Pereira CS, Ethur EM, Machado EC, Morel AF, König WA. Volatile Constituents Composition ofBlepharocalyx salicifoliusLeaf Oil. JOURNAL OF ESSENTIAL OIL RESEARCH 1999. [DOI: 10.1080/10412905.1999.9701067] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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41
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Bouwmeester HJ, Gershenzon J, Konings MC, Croteau R. Biosynthesis of the monoterpenes limonene and carvone in the fruit of caraway. I. Demonstration Of enzyme activities and their changes with development. PLANT PHYSIOLOGY 1998; 117:901-12. [PMID: 9662532 PMCID: PMC34944 DOI: 10.1104/pp.117.3.901] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/1997] [Accepted: 03/27/1998] [Indexed: 05/19/2023]
Abstract
The biosynthesis of the monoterpenes limonene and carvone in the fruit of caraway (Carum carvi L.) proceeds from geranyl diphosphate via a three-step pathway. First, geranyl diphosphate is cyclized to (+)-limonene by a monoterpene synthase. Second, this intermediate is stored in the essential oil ducts without further metabolism or is converted by limonene-6-hydroxylase to (+)-trans-carveol. Third, (+)-trans-carveol is oxidized by a dehydrogenase to (+)-carvone. To investigate the regulation of monoterpene formation in caraway, we measured the time course of limonene and carvone accumulation during fruit development and compared it with monoterpene biosynthesis from [U-14C]Suc and the changes in the activities of the three enzymes. The activities of the enzymes explain the profiles of monoterpene accumulation quite well, with limonene-6-hydroxylase playing a pivotal role in controlling the nature of the end product. In the youngest stages, when limonene-6-hydroxylase is undetectable, only limonene was accumulating in appreciable levels. The appearance of limonene-6-hydroxylase correlates closely with the onset of carvone accumulation. At later stages of fruit development, the activities of all three enzymes declined to low levels. Although this correlates closely with a decrease in monoterpene accumulation, the latter may also be the result of competition with other pathways for substrate.
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42
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Miranda E, Sánchez F, Sanz J, Jiménez MI, Martínez-Castro I. 2,3-Di-O-pentyl-6-O-tert-butyldimethylsilyl-β-cyclodextrin as a Chiral Stationary Phase in Capillary Gas Chromatography. ACTA ACUST UNITED AC 1998. [DOI: 10.1002/(sici)1521-4168(19980401)21:4<225::aid-jhrc225>3.0.co;2-z] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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43
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Franke S, Meyer C, Specht M, König WA, Francke W. Chloro-bis-propyl Ethers in the Elbe River - Isomeric Distribution and Enantioselective Degradation. ACTA ACUST UNITED AC 1998. [DOI: 10.1002/(sici)1521-4168(19980201)21:2<113::aid-jhrc113>3.0.co;2-m] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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44
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Benick� E, Tak�?ov� D, Krup?�k J, Ska?�ni I, Onuska F, Terry K. Gas chromatographic separation of PCB atropisomers on cyclodextrin stationary phases. Chirality 1998. [DOI: 10.1002/(sici)1520-636x(1998)10:6<540::aid-chir7>3.0.co;2-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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45
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46
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Luithle JEA, Pietruszka J. Synthesis of Enantiomerically Pure Cyclopropyl Boronic Esters. ACTA ACUST UNITED AC 1997. [DOI: 10.1002/jlac.199719971118] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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47
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Zhang HB, Ling Y, Fu RN, Wen YX, Gu JL. A new gas chromatographic stationary phase: Polysiloxane with β-cyclodextrin side chain for the separation of chiral and positional isomers. Chromatographia 1997. [DOI: 10.1007/bf02490928] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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48
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König WA, Fricke C, Saritas Y, Momeni B, Hohenfeld G. Adulteration or natural variability? enantioselective gas chromatography in purity control of essential oils. ACTA ACUST UNITED AC 1997. [DOI: 10.1002/jhrc.1240200202] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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49
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Agosti D, Austin C, G�k�en OA, K�nig WA, Morgan ED, Scott ED, Wehner R. (S)-2-Methyl-1-hexanol, characteristic mandibular gland substance of ants of theCataglyphis bicolor group. CHEMOECOLOGY 1996. [DOI: 10.1007/bf01240638] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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50
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Icheln D, Gehrcke B, Piprek Y, Mischnick P, König WA, Dessoy MA, Morel AF. Migration of secondary tert-butyldimethylsilyl groups in cyclomalto-heptaose and -octaose derivatives. Carbohydr Res 1996; 280:237-50. [PMID: 8593638 DOI: 10.1016/0008-6215(95)00322-3] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
When 2,6-di-O-tert-butyldimethylsilylated cyclomalto-oligosaccharides (cyclodextrins) are treated with allyl or methyl iodide and NaH in dry tetrahydrofuran, O-2-->O-3 migration of the secondary 2-O-tert-butyldimethylsilyl groups occurs, leading to 2-O-alk(en)yl-3,6-di-O-tert-butyldimethylsilyl-cyclodextrin derivatives. The detection and identification of the reaction step during which migration occurred is described and possible mechanisms of migration are discussed.
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Affiliation(s)
- D Icheln
- Institut für Organische Chemie, Universität Hamburg, Germany
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