Relevant bibliographies by topics / D-enantiomer

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  1. Journal articles
  2. Dissertations / Theses
  3. Book chapters
  4. Conference papers

Academic literature on the topic 'D-enantiomer'

Author: Grafiati
Published: 4 June 2021
Last updated: 16 February 2022

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Journal articles on the topic "D-enantiomer"

1

Zhou, Juan, Qiao Chen, Li-lan Wang, Yong-hua Wang, and Ying-zi Fu. "Chiral Discrimination of Tryptophan Enantiomers via (1R, 2R)-2-Amino-1, 2-Diphenyl Ethanol Modified Interface." International Journal of Electrochemistry 2011 (2011): 1–6. http://dx.doi.org/10.4061/2011/502364.

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The paper reported that a simple chiral selective interface constructed by (1R, 2R)-2-amino-1, 2-diphenyl ethanol had been developed to discriminate tryptophan enantiomers. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used for the characteristic analysis of the electrode. The results indicated that the interface showed stable and sensitive property to determine the tryptophan enantiomers. Moreover, it exhibited the better stereoselectivity for L-tryptophan than that for D-tryptophan. The discrimination characteristics of the chiral selective interface for discriminating tryptophan enantiomers, including the response time, the effect of tryptophan enantiomers concentration, and the stability, were investigated in detail. In addition, the chiral selective interface was used to determine the enantiomeric composition of L- and D-tryptophan enantiomer mixtures by measuring the relative change of the peak current as well as in pure enantiomeric solutions. These results suggested that the chiral selective interface has the potential for enantiomeric discrimination of tryptophan enantiomers.
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Bystrická, Zuzana, and Jozef Lehotay. "In Vitro Investigation of D- and Lenantiomer Synergistic Efects of Some Amino Acids." Nova Biotechnologica et Chimica 15, no. 1 (June 1, 2016): 47–54. http://dx.doi.org/10.1515/nbec-2016-0005.

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Abstract D-amino acids can arise from endogenous microbial flora, from ingestion with the diet or from spontaneous racemization of L-amino acids during ageing. In this work, the behavior of methionine, homocysteine and cysteine enantiomers was investigated in human serum in vitro during 0-72 h at incubation temperature 37°C. The separation of enantiomers was realized in two dimensional on-line system (the connection of an achiral column Purospher RP-18 endcapped and a chiral column Chirobiotic TAG). This system allowed simultaneous monitoring all tested amino acids and their enantiomers. The possible effect D-enantiomer on the behavior of its L-enantiomer (the synergistic effect) was evaluated during incubation time. The first results have showed that no synergistic effect of D-enantiomer on its Lisomer has been observed in our experimental conditions in vitro.
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Ge, Huilin, Min Zhou, Daizhu Lv, Mingyue Wang, Cunzhu Dong, Yao Wan, Zhenshan Zhang, and Suru Wang. "New Insight Regarding the Relationship Between Enantioselective Toxicity Difference and Enantiomeric Toxicity Interaction from Chiral Ionic Liquids." International Journal of Molecular Sciences 20, no. 24 (December 6, 2019): 6163. http://dx.doi.org/10.3390/ijms20246163.

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Chirality is an important property of molecules. The study of biological activity and toxicity of chiral molecules has important theoretical and practical significance for toxicology, pharmacology, and environmental science. The toxicological significance of chiral ionic liquids (ILs) has not been well revealed. In the present study, the enantiomeric joint toxicities of four pairs of chiral ILs 1-alkyl-3-methylimidazolium lactate to Allivibrio fischeri were systematically investigated by using a comprehensive approach including the co-toxicity coefficient (CTC) integrated with confidence interval (CI) method (CTCICI), concentration-response curve (CRC), and isobole analysis. The direct equipartition ray (EquRay) design was used to design five binary mixtures of enantiomers according to molar ratios of 1:5, 2:4, 3:3, 4:2, and 5:1. The toxicities of chiral ILs and their mixtures were determined using the microplate toxicity analysis (MTA) method. Concentration addition (CA) and independent action (IA) were used as the additive reference models to construct the predicted CRC and isobole of mixtures. On the whole, there was an enantioselective toxicity difference between [BMIM]D-Lac and [BMIM]L-Lac, and [HMIM]D-Lac and [HMIM]L-Lac, while no enantioselective toxicity difference was observed for [EMIM]D-Lac and [EMIM]L-Lac, and [OMIM]D-Lac and [OMIM]L-Lac. Thereinto, the enantiomer mixtures of [BMIM]D-Lac and [BMIM]L-Lac, and [HMIM]D-Lac and [HMIM]L-Lac presented antagonistic action, and the enantiomer mixtures of [EMIM]D-Lac and [EMIM]L-Lac, and [OMIM]D-Lac and [OMIM]L-Lac overall presented additive action. Moreover, the greatest antagonistic toxicity interaction occurred at the equimolar ratio of enantiomers. Based on these results, we proposed two hypotheses, (1) chiral molecules with enantioselective toxicity difference tended to produce toxicity interactions, (2) the highest or lowest toxicity was usually at the equimolar ratio and its adjacent ratio for the enantiomer mixture. These hypotheses will need to be further validated by other enantiomer mixtures.
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Šaman, David, Martina Wimmerová, and Zdeněk Wimmer. "Synthesis and Structure Assignment of 2-(4-Methoxybenzyl)cyclohexyl β-D-Galactopyranoside Stereoisomers." Collection of Czechoslovak Chemical Communications 71, no. 8 (2006): 1186–98. http://dx.doi.org/10.1135/cccc20061186.

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Several promoters were used in the Koenigs-Knorr synthesis of the title alkyl β-D-galactopyranosides, both in their diastereoisomeric forms (5a/5b and 6a/6b), resulting from the synthesis performed with the respective racemic cis and trans isomers of 2-(4-methoxybenzyl)cyclohexan-1-ol, and in their enantiomerically pure forms 5a and 6a, starting only from the (1S,2S)- and (1S,2R)-enantiomers of 2-(4-methoxybenzyl)cyclohexan-1-ol. The aim of the study was to find convenient modification(s) of the Koenigs-Knorr synthesis of alkyl β-D-galactopyranosides from more hindered and more complex 2-substituted cycloalkanols. Separation of the diastereoisomeric compounds using HPLC on a chiral Nucleodex-β-OH column was used to obtain small quantities of all possibly existing enantiomerically pure products for unambiguous structure assignment by NMR analysis. The (1S,2S)- and (1S,2R)- enantiomers of 2-(4-methoxybenzyl)cyclohexan-1-ol (1a and 2a) were prepared by a reduction of 2-(4-methoxybenzyl)cyclohexan-1-one with Saccharomyces cerevisiae in enantiomeric purities: ee = 98.5% ((1S,2S)-enantiomer (1a)), and ee ≥ 99% ((1S,2R)-enantiomer (2a)).
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Gao, Jingyao, Haoyang Zhang, Chen Ye, Qilong Yuan, Kuan Chee, Weitao Su, Aimin Yu, et al. "Electrochemical Enantiomer Recognition Based on sp3-to-sp2 Converted Regenerative Graphene/Diamond Electrode." Nanomaterials 8, no. 12 (December 14, 2018): 1050. http://dx.doi.org/10.3390/nano8121050.

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It is of great significance to distinguish enantiomers due to their different, even completely opposite biological, physiological and pharmacological activities compared to those with different stereochemistry. A sp3-to-sp2 converted highly stable and regenerative graphene/diamond electrode (G/D) was proposed as an enantiomer recognition platform after a simple β-cyclodextrin (β-CD) drop casting process. The proposed enantiomer recognition sensor has been successfully used for d and l-phenylalanine recognition. In addition, the G/D electrode can be simply regenerated by half-minute sonication due to the strong interfacial bonding between graphene and diamond. Therefore, the proposed G/D electrode showed significant potential as a reusable sensing platform for enantiomer recognition.
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Ciceri, Samuele, Patrizia Ferraboschi, Paride Grisenti, Shahrzad Reza Elahi, Carlo Castellano, Matteo Mori, and Fiorella Meneghetti. "(S)-Pramipexole and Its Enantiomer, Dexpramipexole: A New Chemoenzymatic Synthesis and Crystallographic Investigation of Key Enantiomeric Intermediates." Catalysts 10, no. 8 (August 16, 2020): 941. http://dx.doi.org/10.3390/catal10080941.

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A new chemoenzymatic method has been developed for the synthesis of (S)- and (R)-N-(6-hydroxy-4,5,6,7-tetrahydrobenzo[d]thiazol-2-yl) acetamide, two key synthons for the preparation of (S)-pramipexole, an anti-Parkinson drug, and its enantiomer dexpramipexole, which is currently under investigation for the treatment of eosinophil-associated disorders. These two building blocks have been obtained in good yields and high enantiomeric excess (30% and >98% ee for the R-enantiomer, and 31% and >99% ee for the S- one) through a careful optimization of the reaction conditions, starting from the corresponding racemic mixture and using two consecutive irreversible transesterifications, catalyzed by Candida antarctica lipase type A. Single crystal X-ray analysis has been carried out to unambiguously define the stereochemistry of the two enantiomers, and to explore in depth their three-dimensional features.
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Chanotiya, Chandan S., and Anju Yadav. "Natural Variability in Enantiomeric Composition of Bioactive Chiral Terpenoids in the Essential Oil of Solidago Canadensis L. from Uttarakhand, India." Natural Product Communications 3, no. 2 (February 2008): 1934578X0800300. http://dx.doi.org/10.1177/1934578x0800300232.

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The natural variability in the enantiomeric distribution of biologically active chiral terpenoids in Solidago canadensis L. essential oil from Kumaon was evaluated by enantioselective capillary GC, capillary GC, and GC-MS. Germacrene D, a sesquiterpene hydrocarbon, was noticed as the major compound, contributing 56.7%, 75.5% and 69.7% to the samples, while other constituents with variable compositions were limonene (0.2 to 12.5%), bornyl acetate (2.1 to 2.9%), δ-elemene (2.4 to 3.2), β-elemene (1.3 to 1.8%), and elemol (1.4 to 2.6%). The enantiomeric excess has been determined for germacrene D with (+)-enantiomer (>41.8% to >47%) dominating over the (-)-enantiomer in all the samples. Furthermore, there has been above 95% enantiomeric excess for ( R)-(+)-limonene (>95.1% to >99%), whereas moderate to low excess for (1 R)-(+)-α-pinene (>47.9%), and (1 S)-(-)-β-pinene (>30.3%) was established. Notably, only (-)-bornyl acetate was found as a single enantiomer with >99% enantiomeric excess. However, for all the identified chiral terpenoids, the enantiomeric distribution varied within only a narrow range in all the samples.
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Bennett, L. Lee, Paula W. Allan, Gussie Arnett, Y. Fulmer Shealy, Donna S. Shewach, William S. Mason, Isabelle Fourel, and William B. Parker. "Metabolism in Human Cells of the d and l Enantiomers of the Carbocyclic Analog of 2′-Deoxyguanosine: Substrate Activity with Deoxycytidine Kinase, Mitochondrial Deoxyguanosine Kinase, and 5′-Nucleotidase." Antimicrobial Agents and Chemotherapy 42, no. 5 (May 1, 1998): 1045–51. http://dx.doi.org/10.1128/aac.42.5.1045.

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ABSTRACT The carbocyclic analog of 2′-deoxyguanosine (CdG) has broad-spectrum antiviral activity. Because of recent observations with other nucleoside analogs that biological activity may be associated thel enantiomer rather than, as expected, with thed enantiomer, we have studied the metabolism of both enantiomers of CdG to identify the enzymes responsible for the phosphorylation of CdG in noninfected and virally infected human and duck cells. We have examined the enantiomers as substrates for each of the cellular enzymes known to catalyze phosphorylation of deoxyguanosine. Both enantiomers of CdG were substrates for deoxycytidine kinase (EC 2.7.1.74) from MOLT-4 cells, 5′-nucleotidase (EC 3.1.3.5) from HEp-2 cells, and mitochondrial deoxyguanosine kinase (EC 2.7.1.113) from human platelets and CEM cells. For both deoxycytidine kinase and mitochondrial deoxyguanosine kinase, thel enantiomer was the better substrate. Even though thed enantiomer was the preferred substrate with 5′-nucleotidase, the rate of phosphorylation of the lenantiomer was substantial. The phosphorylation of d-CdG in MRC-5 cells was greatly stimulated by infection with human cytomegalovirus. The fact that the phosphorylation of d-CdG was stimulated by mycophenolic acid and was not affected by deoxycytidine suggested that 5′-nucleotidase was the enzyme primarily responsible for its metabolism in virally infected cells.d-CdG was extensively phosphorylated in duck hepatocytes, and its phosphorylation was not affected by infection with duck hepatitis B virus. These results are of importance in understanding the mode of action of d-CdG and related analogs and in the design of new biologically active analogs.
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MÜller, Markus D., and Hans-Paul Bosshardt. "Enantiomer Resolution and Assay of Propionic Acid-Derived Herbicides in Formulations by Using Chiral Liquid Chromatography and Achiral Gas Chromatography." Journal of AOAC INTERNATIONAL 71, no. 3 (May 1, 1988): 614–17. http://dx.doi.org/10.1093/jaoac/71.3.614.

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Abstract Enantiomers of 6 propionic acid-derived herbicides in the form of their esters were resolved using liquid chromatography with a chiral column. Free acids are converted to methyl esters by means of a BF3- catalyzed reaction. Chromatographic resolutions for 6 of 8 herbicides investigated were in the range of 2 to 4. The method was applied for the simultaneous determination of mecoprop and 2,4-D content and individual mecoprop enantiomers in 2 formulations containing racemic and R-mecoprop in mixture with 2,4-D. Precision and accuracy of content determination was comparable to standard methods, and enantiomer contents were in good agreement with declared values. The enantiomers of dichlorprop and mecoprop were also resolved as diastereomeric menthyl esters by achiral high resolution gas chromatography (HRGC). HRGC data on enantiomer composition were in good agreement with those from the LC method and other data
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Li, Yan Liang, Zhong Zhen Liu, Yu Fen Huang, Lan Wei, Lian Xi Huang, Shao Hai Yang, and Zhi Xiang Fang. "Biphasic Enantioselective Partitioning of R,S-Omeprazole Enantiomers Using Chiral Extraction." Advanced Materials Research 1030-1032 (September 2014): 2334–39. http://dx.doi.org/10.4028/www.scientific.net/amr.1030-1032.2334.

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Enantioselective partitioning of racemic omeprazole enantiomers was studied using a biphasic recognition chiral extraction system. Hydrophilic hydroxypropyl-ڂ-cyclodextrin in aqueous phase and hydrophobic D-tartaric acid hexyl ester in organic phase as chiral selectors which preferentially recognize (R)-omeprazole enantiomer and (S)-omeprazole enantiomer, respectively. Different experimental variable parameters could affect the chiral extraction efficiency. The largest distribution coefficientskS,kRand separation factorځwere obtained at concentrations o f 0.1 mol/L HP-ڂ-CD and 0.2 mol/L D-tartaric acid hexyl ester, which were 47.38, 58.65 and 1.24, respectively.kRis always larger thankSwhen using different kinds of tartaric acid derivatives as chiral selectors in organic phase. The present study also reveal the mechanism of biphasic recognition chiral extraction forR,S-omeprazole enantiomers.
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Dissertations / Theses on the topic "D-enantiomer"

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Zreika, Sami. "Etude de l'impact de la protéine antimicrobienne humaine hCAP18/LL-37 sur le cancer du sein." Thesis, Tours, 2011. http://www.theses.fr/2011TOUR4052.

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Le peptide hCAP18/LL-37, une partie de la défense immunitaire innée, a maintenant été reconnu comme multifonctionnelle pour les cellules eucaryotes. Nos études démontrent sa contribution au développement du cancer, montrant qu'il est surexprimé dans la plupart des tumeurs mammaires humaines, active la signalisation la famille de ERBB et augmente le potentiel métastatique des cellules cancéreuses du sein. Notre comparaison des deux lignées du cancer du sein n'a pas révélé de récepteurs communs, mais une structure peptidique identiques mais de chiralité différente est pré requis pour le peptide dans toutes ses activités. Nous émettons l'hypothèse que LL-37 active indirectement des récepteurs transmembranaires en se liant à la membrane cellulaire. Des peptides tronqués dérivés de LL-37 inhibent ses activités et peuvent aider à concevoir une future thérapie anticancéreuse
The peptide hCAP18/LL-37, part of the innate immune defense, has now been recognized as multifunctional for eukaryotic cells. Our studies demonstrate its contribution to cancer development, showing that it is overexpressed in most human breast tumors, activates ERBB signaling and increases the metastatic potential of breast cancer cells. Our comparison on two breast cancer lines did not reveal any common receptors but identical structural prerequisites for the peptide in all its activities. We hypothesize that LL-37 indirectly activates transmembrane receptors by attaching to the cellular membrane. Truncated derivatives inhibit its activities and may help to design a future anticancer therapy
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Kwok, Hoi-shan, and 郭凱珊. "The comparison of biological properties of L- and D-enantiomeric antimicrobial peptides." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2014. http://hdl.handle.net/10722/206507.

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Antibiotics have been used widely for the treatment of bacterial infections for over half a century. However, the emergence of resistance to antibiotics has aroused public health concern, leading to the development of antimicrobial peptides (AMPs) as potential alternative therapeutic agents against bacterial infections. AMPs are naturally found in many species and have important roles in our innate immune defense systems. AMPs are usually cationic amphipathic peptides with membrane destabilizing property. They have a relatively broad spectrum of antimicrobial activity and pathogens are less likely to develop resistance against AMPs. The major challenge of using AMPs as therapeutic agents is their toxicity towards mammalian cells. The biological stability of AMPs to protease in human body is another concern. To address the latter problem, instead of the naturally occur L-enantiomers, Denantiomeric AMPs were introduced to enhance their stability. This study aimed to test the hypothesis that the D-enantiomeric AMPs are more resistant than the Lenantiomeric AMPs against proteolytic degradation. Three pairs of synthetic D-/LAMPs (D-LAO160-P13/LAO160-P12; D-LAO160-H/LAO160-H; and D-LAK-120-HP13/LAK-120-HP13) were employed to test for their stability when treated with trypsin, serum and gastric fluid, and the samples were analyzed by high performance liquid chromatography (HPLC). Generally, all the D-enantiomeric AMPs were found to be resistant towards proteolysis. Besides, to compare the cytotoxicity of D-/LAMPs, MTT and LDH assays of the D/L-LAK120-HP13 pair were carried out on two different cell lines, A549 cells (human lung adenocarcinoma epithelial cells) and RAW264.7 cells (mouse macrophage cells). Significant difference in cytotoxicity of D-LAK120-HP13 and LAK120-HP13 on RAW264.7 cells were obtained from MTT assay, but not in LDH assays or on A549 cells. Further analysis has to be done to validate the findings obtained from this research.
published_or_final_version
Pharmacology and Pharmacy
Master
Master of Medical Sciences
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Fraunholz, Thomas [Verfasser], and R. H. W. [Akademischer Betreuer] Hoppe. "Transport at Interfaces in Lipid Membranes and Enantiomer Separation / Thomas Fraunholz. Betreuer: R. H. W. Hoppe." Augsburg : Universität Augsburg, 2015. http://d-nb.info/1077705638/34.

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Combs, Carolyn C., Erin L. Hankins, Cara L. Copeland, Stacy D. Brown, and Brooks B. Pond. "Quantitative Determination of D- and L- Enantiomers of Methylphenidate in Brain Tissue by Liquid Chromatography-Mass Spectrometry." Digital Commons @ East Tennessee State University, 2013. https://doi.org/10.1002/bmc.2975.

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Methylphenidate, a psychostimulant used for the treatment of attention deficit hyperactivity disorder and narcolepsy, is administered as a 50:50 racemic mixture, despite the fact that d‐methylphenidate has been shown to have greater pharmacologic activity. This paper presents a validated LC‐MS/MS approach to separation and quantification of methylphenidate enantiomers using a vancomycin column and triethylammonium acetate to enhance the chiral separation. The method is applicable to the monitoring of these enantiomers in mouse brain, with a limit of detection of 0.5 ng/mL and a lower limit of quantification of 7.5 ng/mL.
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Allen, Jeremy Thomas. "Uptake of D- and L-amino acid enantiomers by protoscoleces and secondary hydatid cysts of Echinococcus granulosus (Cestoda)." Thesis, Keele University, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.334748.

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Peters, Haley T., Stacy D. Brown, Brooks Pond, and Lauren G. Strange. "Quantitative Determination of D- and L- Enantiomers of Methylphenidate in Placenta and Fetal Brain Tissue by Liquid Chromatography-Mass Spectrometry." Digital Commons @ East Tennessee State University, 2013. https://dc.etsu.edu/etsu-works/5282.

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Dunkelmann, Tina Verfasser], Dieter [Gutachter] [Willbold, and Karl-Josef [Gutachter] Langen. "Evaluation von D-enantiomeren Peptiden als mögliche Wirkstoffkandidaten in einem Alzheimer-Mausmodell / Tina Dunkelmann ; Gutachter: Dieter Willbold, Karl-Josef Langen." Düsseldorf : Universitäts- und Landesbibliothek der Heinrich-Heine-Universität Düsseldorf, 2016. http://d-nb.info/1121745709/34.

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Jiang, Nan Verfasser], and Dieter [Akademischer Betreuer] [Willbold. "Preclinical pharmacokinetics and cerebral distribution of D-enantiomeric peptides for the treatment of Alzheimer’s disease / Nan Jiang ; Betreuer: Dieter Willbold." Düsseldorf : Universitäts- und Landesbibliothek der Heinrich-Heine-Universität Düsseldorf, 2018. http://d-nb.info/1150918845/34.

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Jiang, Nan [Verfasser], and Dieter [Akademischer Betreuer] Willbold. "Preclinical pharmacokinetics and cerebral distribution of D-enantiomeric peptides for the treatment of Alzheimer’s disease / Nan Jiang ; Betreuer: Dieter Willbold." Düsseldorf : Universitäts- und Landesbibliothek der Heinrich-Heine-Universität Düsseldorf, 2018. http://d-nb.info/1150918845/34.

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Dunkelmann, Tina [Verfasser], Dieter [Gutachter] Willbold, and Karl-Josef [Gutachter] Langen. "Evaluation von D-enantiomeren Peptiden als mögliche Wirkstoffkandidaten in einem Alzheimer-Mausmodell / Tina Dunkelmann ; Gutachter: Dieter Willbold, Karl-Josef Langen." Düsseldorf : Universitäts- und Landesbibliothek der Heinrich-Heine-Universität Düsseldorf, 2016. http://d-nb.info/1121745709/34.

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Book chapters on the topic "D-enantiomer"

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Chen, Chien-Ming, and Chi-Fu Yen. "Designing a Column-Switching High-Performance Liquid Chromatograph System for Enantiomeric Separation of Mouse Urinary D,L-Lactate." In Bio-Science and Bio-Technology, 69–75. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-642-10616-3_10.

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Yamamoto, Toshiharu, and Susumu Ohtani. "Estimation of Chronological Age from the Racemization Rate of l- and d-Aspartic Acid: How to Completely Separate Enantiomers from Dentin." In Methods in Molecular Biology, 265–72. Totowa, NJ: Humana Press, 2011. http://dx.doi.org/10.1007/978-1-61779-331-8_17.

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Morrow, Gary W. "The Terpenoid Pathway: Products from Mevalonic Acid and Deoxyxylulose Phosphate." In Bioorganic Synthesis. Oxford University Press, 2016. http://dx.doi.org/10.1093/oso/9780199860531.003.0007.

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It was Otto Wallach (1847– 1931) who first coined the term “terpene” and made the observation that many plant-derived essential oils had chemical structures whose composition was based on multiples of a basic five-carbon unit. His work with turpentine and the organic products derived from it was consistent with earlier studies of natural rubber which had shown that its thermal decomposition released “isoprene” (2-methyl-1,3-butadiene) as the principal product. This led eventually to the formulation of the so-called biogenetic isoprene rule of Leopold Ruzicka (1887–1976) in 1953 which stated that “the carbon skeleton of the terpenes is composed of isoprene units linked in regular or irregular arrangement.” As it turns out, biosynthetic pathways to terpenes are found in nearly all organisms, producing a remarkable variety of different structural types, as we will soon see. In fact, something in excess of over 25,000 different terpenes with a wide variety of biological functions have been isolated from the plant kingdom over the years. Interestingly, while many terpenes are simple achiral compounds, others are chiral as can be seen in the case of α-pinene in Fig. 4.1. But unlike the naturally occurring L-amino acids and D-carbohydrates, different organisms may produce the same terpene product but in different enantiomeric forms. For example, limonene is formed by more than 300 plants, with the (+)-(R) enantiomer being the most widespread form as the major constituent of citrus peel essential oils (orange oil). As the most abundant of all terpenes, its pleasant citrus fragrance and flavor have led to its worldwide use in the food and fragrance industries and also as a botanical insecticide. A number of plants produce both enantiomers of limonene, while others produce only the (−)-(S)-enantiomer which possesses a strong pine smell reminiscent of turpentine. This obviously speaks to the chirality and enantioselectivity of our own olfactory receptor sites which can readily distinguish between the two enantiomers, thus signaling a different odor response in each case.
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Taber, Douglass F. "C-N Ring Construction: The Zakarian Synthesis of (-)-Rhazinilam." In Organic Synthesis. Oxford University Press, 2013. http://dx.doi.org/10.1093/oso/9780199965724.003.0055.

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William D. Wulff of Michigan State University developed (J. Am. Chem. Soc. 2010, 132, 13100; Org. Lett. 2010, 12, 4908) a general enantio- and diastereocontrolled route from an imine 1 to the aziridine 3. Craig W. Lindsley of Vanderbilt University established (Org. Lett. 2010, 12, 3276) a complementary approach (not illustrated). Joseph P. Konopelski of the University of California, Santa Cruz, designed (J. Am. Chem. Soc. 2010, 132, 11379) a practical and inexpensive flow apparatus for the cyclization of 4 to the β-lactam 5. Manas K. Ghorai of the Indian Institute of Technology, Kanpur, showed (J. Org. Chem. 2010, 75, 6173) that an aziridine 6 could be opened with malonate to give the γ-lactam 8. John P. Wolfe of the University of Michigan devised (J. Am. Chem. Soc. 2010, 132, 12157) a Pd catalyst for the enantioselective cyclization of 9 to 11. Sherry R. Chemler of the State University of New York at Buffalo observed (Angew. Chem. Int. Ed. 2010, 49, 6365) that the cyclization of 12 to 14 proceeded with high diastereoselectivity. Glenn M. Sammis of the University of British Columbia devised (Synlett 2010, 3035) conditions for the radical cyclization of 15 to 16. Jeffrey S. Johnson of the University of North Carolina observed (J. Am. Chem. Soc. 2010, 132, 9688) that the opening of racemic 17 with 18 could be effected with high ee. The residual 17 was highly enriched in the nonreactive enantiomer. Kevin D. Moeller of Washington University found (Org. Lett . 2010, 12, 5174) that the n -BuLi catalyzed cyclization of 20 set the quaternary center of 21 with high relative control. Yujiro Hayashi of the Tokyo University of Science, using the diphenyl prolinol TMS ether that he developed as an organocatalyst, designed (Org. Lett. 2010, 12, 4588) the sequential four-component coupling of 22, 23, benzaldehyde imine, and allyl silane to give 24 with high relative and absolute stereocontrol. Derrick L. J. Clive of the University of Alberta showed (J. Org. Chem. 2010, 75, 5223) that 25, prepared in enantiomerically pure form from serine, participated smoothly in the Claisen rearrangement, to deliver 27.
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Taber, Douglass. "The Takayama Synthesis of (-)-Cernuine." In Organic Synthesis. Oxford University Press, 2011. http://dx.doi.org/10.1093/oso/9780199764549.003.0094.

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(-)-Cernuine 3 falls in the subset of the Lycopodium alkaloids that feature a bicyclic aminal core. There had not been a total synthesis of this class of alkaloids until the recent (Organic Lett. 2008, 10, 1987) work of Hiromitsu Takayama of Chiba University. The key step in this synthesis was a diastereoselective intramolecular reductive amination, converting 1 to 2. As is apparent from the 3-D projection, (-)-cernuine 3 has a tricyclic trans-anti-trans aminal core, with an appended six-membered ring, both branches of which are axial on the core. While the branch that is part of the aminal could be expected to equilibrate, the other branch had to be deliberately installed. The synthesis began with (+)-citronellal 4, each enantiomer of which is commercially available in bulk. After protection and ozonolysis, the first singly-aminated stereogenic center was installed by enantioselective, and therefore diastereoselective, addition of 5 to the azodicarboxylate 6, mediated by the organocatalyst 7. Reductive cleavage of the N-N bond followed by acetal methanolysis converted 8 to 9. Ionization followed by allyl silane addition then delivered 11, having the requisite axial alkyl branch. The next two tasks were the assembly of the second of the four rings of 3, and the construction of the second single-aminated stereogenic center. The ring was assembled by deprotection of 11 followed by acylation with acryloyl chloride, to give 12. Grubbs cyclization followed by hydrogenation then led to 13. Homologation of 13 to the aldehyde 14 set the stage for condensation with the camphor-derived tertiary amine 15, following the protocol developed by Kobayashi. Sequential imine formation, aza-Cope rearrangement, and hydrolysis led to 1 in 94% de. One could envision reduction of the lactam carbonyl of 1 to an aldehyde equivalent, that would then, under acidic conditions, condense to form the desired aminal 2. This approach was, however, not successful. As an alternative, conditions were developed to convert 1 to the amidine 16. Reduction then proceeded with the expected high diastereocontrol, to give the cis 1,3-fused aminal 2. This was not isolated, but was directly acylated with acryloyl chloride, to 17.
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6

Taber, Douglass F. "Enantioselective Synthesis of Alcohols and Amines: The Doi Synthesis of Apratoxin C." In Organic Synthesis. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780190646165.003.0034.

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Hiromitsu Takayama of Chiba University used (Org. Lett. 2014, 16, 5000) the Itsuno-Corey protocol to reduce the enone 1 to the allylic alcohol 2. Peiming Gu of Ningxia University developed (Org. Lett. 2014, 16, 5339) a Cu catalyst that cyclized the pro­chiral 3 to 4 in high ee. Xiaoming Feng of Sichuan University effected (Org. Lett. 2014, 16, 3938) enantioselective Baeyer–Villiger oxidation of the racemic cyclopentanone 5, converting one enantiomer to the δ-lactone 6. The velocity of catalytic osmylation is often limited by slow turnover of the interme­diate osmate ester. Koichi Narasaka, then at the University of Tokyo, showed (Chem. Lett. 1988, 1721) that the efficiency of the transformation was improved by the addi­tion of stoichiometric phenyl boronic acid. Kilian Muñiz, now at ICIQ Tarragona, established (Chem. Eur. J. 2005, 11, 3951) that this acceleration also worked with Sharpless asymmetric dihydroxylation. D. Christopher Braddock of Imperial College London took advantage (Chem. Commun. 2014, 50, 13725) of these observations, converting myrcene 7 selectively to the cyclic boronate 8. Michael P. Doyle of the University of Maryland developed (J. Org. Chem. 2014, 79, 12185) a Rh catalyst for the ene reaction of 9 with 10 to give 11. Adriaan J. Minnaard of the University of Groningen devised (Chem. Eur. J. 2014, 20, 14250) a Cu cata­lyst that mediated the face selective addition of 13 to 12, establishing the oxygenated quaternary center of 14. Tomonori Misaki and Takashi Sugimura of the University of Hyogo used (Chem. Lett. 2014, 43, 1826) Michael addition of 15 to 16 to construct the oxygenated quaternary center of 17. Jon C. Antilla of the University of South Florida assembled (Chem. Commun. 2014, 50, 14187) the δ-lactone 20 by adding the diene 19 to the α-keto ester 18. Zhiyong Wang of the University of Science and Technology of China reported (Org. Lett. 2014, 16, 3564) related results. Jonathan A. Ellman of Yale University achieved (Angew. Chem. Int. Ed. 2014, 53, 11329) substantial enantioselectivity in the addition of thioacetic acid 22 to the nitroalkene 21 to give 23. Subhash P. Chavan of the National Chemistry Laboratory prepared (Tetrahedron Lett. 2014, 55, 5905) the allylic amine 25 by reduction of the aziridine 24.
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7

Taber, Douglass F. "Arrays of Stereogenic Centers: The Yadav Synthesis of Nhatrangin A." In Organic Synthesis. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780190646165.003.0040.

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Miquel Costas of the Universitat de Girona developed (J. Am. Chem. Soc. 2013, 135, 14871) an iron catalyst for the enantioselective epoxidation of the Z-ester 1 to 2. Although the α-chloro aldehyde derived from 3 epimerized under the reaction conditions, Robert Britton of Simon Fraser University showed (Org. Lett. 2013, 15, 3554) that the subsequent aldol condensation with 4 favored one enantiomer, leading to 5 in high ee. Other selective aldol condensations of 4 (not illustrated) have been reported by Zorona Ferjancic and Radomir N. Saicic of the University of Belgrade (Eur. J. Org. Chem. 2013, 5555) and by Tomoya Machinami of Meisei University (Synlett 2013, 24, 1501). Motomu Kanai of the University of Tokyo condensed (Org. Lett. 2013, 15, 4130) D-arabinose 6 with diallyl amine and the alkyne 7 to give the amine 8 as a mixture of diastereomers. Naoya Kumagai and Masakatsu Shibasaki of the Institute of Microbial Chemistry combined (Angew. Chem. Int. Ed. 2013, 52, 7310) 9 and 10 to prepare the α-chiral amine 11. Tomoya Miura and Masahiro Murakami of Kyoto University used (J. Am. Chem. Soc. 2013, 135, 11497) an Ir catalyst to migrate the alkene of 13 to the E allyl boro­nate, that then added to 12 to give 14. Gong Chen of Pennsylvania State University alkylated (J. Am. Chem. Soc. 2013, 135, 12135) the β-H of 15 with 16 to give selec­tively the diastereomer 17. Geoffrey W. Coates of Cornell University devised (J. Am. Chem. Soc. 2013, 135, 10930) catalysts for the carbonylation of the epoxide 18 to either regioisomer of the β-lactone 19. Yujiro Hayashi of Tohoku University combined (Chem. Lett. 2013, 42, 1294) the inexpensive succinaldehyde 20 and ethyl glyoxylate 21 to give the versatile aldehyde 22. Nuno Maulide of the Max-Planck-Institut für Kohlenforschung Mülheim effected (J. Am. Chem. Soc. 2013, 135, 14968) Claisen rearrangement of 23 to give, after reduc­tion and hydrolysis, the aldehyde 24. Stephen G. Davies of the University of Oxford reported (Chem. Commun. 2013, 49, 7037) a related Claisen rearrangement (not illustrated). Ying-Chun Chen of Sichuan University devised (Org. Lett. 2013, 15, 4786) the cascade combination of 25 and 26 to give 27.
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8

Taber, Douglass F. "The Fürstner Synthesis of Amphidinolide F." In Organic Synthesis. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780190646165.003.0090.

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The amphidinolides, having zero, one, or (as exemplified by amphidinolide F 3) two tetrahydrofuran rings, have shown interesting antineoplastic activity. It is a tribute to his development of robust Mo catalysts for alkyne metathesis that Alois Fürstner of the Max-Planck-Institut für Kohlenforschung Mülheim could with confidence design (Angew. Chem. Int. Ed. 2013, 52, 9534) a route to 3 that relied on the ring-closing metathesis of 1 to 2 very late in the synthesis. Three components were prepared for the assembly of 1. Julia had already reported (J. Organomet. Chem. 1989, 379, 201) the preparation of the E bromodiene 5 from the sulfone 4. The alcohol 7 was available by the opening of the enantiomerically-pure epoxide 6 with propynyl lithium, followed by oxidation following the Pagenkopf pro­tocol. Amino alcohol-directed addition of the organozinc derived from 5 to the alde­hyde from oxidation of 7 completed the assembly of 8. Addition of the enantiomer 10 of the Marshall butynyl reagent to 9 followed by protection, oxidation to 11, and addition of, conveniently, the other Marshall enan­tiomer 12 led to the protected diol 13. Silylcupration–methylation of the free alkyne set the stage for selective desilylation and methylation of the other alkyne. Iodination then completed the trisubstituted alkene of 14. Methylation of the crystalline lactone 15, readily prepared from D-glutamic acid, led to a mixture of diastereomers. Deprotonation of that product followed by an aque­ous quench delivered 16. Reduction followed by reaction with the phosphorane 17 gave the unsaturated ester, that cyclized with TBAF to the crystalline 18. The last ste­reogenic center of 22 was established by proline-mediated aldol condensation of the aldehyde 19 with the ketone 20. To assemble the three fragments, the ketone of 21 was converted to the enol triflate and thence to the alkenyl stannane. Saponification gave the free acid 22, that was acti­vated, then esterified with the alcohol 18. Coupling of the stannane with the iodide 14 followed by removal of the TES group led to the desired diyne 1. It is noteworthy that the Mo metathesis catalyst is stable enough to tolerate the free alcohol of 1 in the cyclization to 2.
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9

Taber, Douglass F. "C–N Ring Construction: The Weinreb Synthesis of Myrioneurinol." In Organic Synthesis. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780190646165.003.0055.

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Terminal epoxides such as 1 are readily available in high enantiomeric excess. Christopher D. Bray of Queen Mary University of London observed (Tetrahedron Lett. 2014, 55, 5890) clean inversion in the conversion of 1 to the aziridine 3 with the reagent 2. Yong-Chun Luo and Peng-Fei Xu of Lanzhou University opened (Org. Lett. 2014, 16, 4896) the activated cyclopropane 4 with benzyl azide, then heated the adduct to expel N2, leading to the azetidine 5. Zhenming Du of Roche Shanghai and Michelangelo Scalone of Roche Basel devel­oped (Org. Process Res. Dev. 2014, 18, 1702) practical conditions for the asymmetric hydrogenation of 6 to the pyrrolidine 7. Young Ho Rhee of the Pohang University of Science and Technology showed (Chem. Eur. J. 2014, 20, 16391) that depending on the diol protecting group, addition of allyl silane to 8 could lead to either the cis product 9 or the trans diastereomer (not illustrated). Ohyun Kwon of UCLA used (J. Am. Chem. Soc. 2014, 136, 11890) an organocatalyst to add the racemic allene 10 to 11 to give 12 in high ee. Tom Livinghouse of Montana State University cyclized (Angew. Chem. Int. Ed. 2014, 53, 14352) the hydrazine 13 into an intermediate organozinc species that was then coupled with allyl bromide to give 14. Yonggang Chen of Merck Process and Xumu Zhang of Rutgers University devised (Angew. Chem. Int. Ed. 2014, 53, 12761) practical conditions for the reduction of 15 to the piperidine 16. Teck-Peng Loh of the Nanyang Technological University and the University of Science and Technology of China effected (Chem. Commun. 2014, 50, 8324) asymmetric phenylation of biomass-derived 17 to give an intermediate that was oxidatively rearranged, then reduced to 18. Robert R. Knowles of Princeton University showed (J. Am. Chem. Soc. 2014, 136, 12217) that the cyclization of 19 to 20 proceeded with high diastereoselectivity. Maria J. Alves of the Universidade do Minho osmylated (Synlett 2014, 25, 1751) the adduct from the Diels–Alder cycload­dition of 22 to 21 to give 23 in high ee.
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Conference papers on the topic "D-enantiomer"

1

Chen, Chien-Ming, Yih-Chiao Tsai, Takeshi Fukushima, Kazuhiro Imai, and Jen-Ai Lee. "Enantiomeric determination of D-, L-lactate in diabetic rat urine using a column-switching HPLC." In SPIE Proceedings, edited by Jose F. Lopez, Chenggen Quan, Fook Siong Chau, Francisco V. Fernandez, Jose Maria Lopez-Villegas, Anand Asundi, Brian Stephen Wong, Jose M. de la Rosa, and Chwee Teck Lim. SPIE, 2005. http://dx.doi.org/10.1117/12.621955.

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