Academic literature on the topic 'Lactones – Synthèse'
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Journal articles on the topic "Lactones – Synthèse"
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Caille, Jean Claude, Michel Farnier, Roger Guilard, André Aubry, and Claude Lecomte. "Sur une nouvelle méthode de synthèse de δ-lactones cyclopenténiques." Canadian Journal of Chemistry 64, no. 4 (April 1, 1986): 831–36. http://dx.doi.org/10.1139/v86-136.
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Synthesis of two cyclopentenic δ-lactones, 1,3,4,4a,5,6-hexahydrocyclopenta[c]pyran-1-one and its analogue possessing a cyclopentenyl group bonded to the carbon atom 4a is described, starting from the cyclopentanone or cyclopentylidene cyclopentanone. The remarkable reactivity of the tosylhydrazones allows transformation of these compounds into substituted cyclopentenes, which lead to δ-lactones by cyclization. The conditions of cyclization depend on the nature of the cyclopentanone. The structure of the two δ-lactones is established by 1H and 13C nmr data, mass spectrometry, and, in one case, by X-ray analysis.
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Ulrich, Ricky L. "Quorum Quenching: Enzymatic Disruption of N-Acylhomoserine Lactone-Mediated Bacterial Communication in Burkholderia thailandensis." Applied and Environmental Microbiology 70, no. 10 (October 2004): 6173–80. http://dx.doi.org/10.1128/aem.70.10.6173-6180.2004.
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ABSTRACT Many species of gram-negative bacteria communicate by synthesizing, secreting, and responding to N-acylhomoserine lactones (AHLs), a mechanism termed quorum sensing. Several investigations have characterized numerous AHL-degrading enzymes (AiiA lactonases) encoded by environmental isolates of Bacillus spp. The Burkholderia thailandensis quorum system is comprised of at least three AHL synthases (AHSs) and five transcriptional regulators belonging to the LuxIR class of proteins. Expression of the Bacillus anthracis (Ames strain) AiiA lactonase in B. thailandensis completely abolished the accumulation of N-decanoylhomoserine lactone (C10-HSL) and N-octanoylhomoserine lactone (C8-HSL), reduced N-hexanoylhomoserine lactone (C6-HSL) levels, altered both swarming and twitching motility, caused a significant increase in generation time, and affected carbon metabolism. In contrast, heterologous expression of the Bacillus cereus strain A24 AiiA lactonase in B. thailandensis reduced the concentrations of C6-HSL, C8-HSL, and C10-HSL to nondetectable levels; altered both swarming and twitching motility; and caused fluctuations in carbon utilization. Individual disruption of the B. thailandensis AHSs, specifically disruption of the btaI1 and btaI3 genes, which encode the proteins that direct the synthesis of C8-HSL and C6-HSL, respectively, caused the hyper-beta-hemolysis of sheep erythrocytes on blood agar plates. In contrast, AHL cleavage in B. thailandensis by the Bacillus AiiA lactonases failed to enhance beta-hemolytic activity. The results of this study demonstrate that heterologous expression of Bacillus sp. AiiA lactonases in B. thailandensis reduced AHL accumulation, affected both swarming and twitching motility, increased generation time, altered substrate utilization, and prevented the beta-hemolysis of sheep erythrocytes.
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Xu, Yuquan, Patricia Espinosa-Artiles, Vivien Schubert, Ya-ming Xu, Wei Zhang, Min Lin, A. A. Leslie Gunatilaka, Roderich Süssmuth, and István Molnár. "Characterization of the Biosynthetic Genes for 10,11-Dehydrocurvularin, a Heat Shock Response-Modulating Anticancer Fungal Polyketide from Aspergillus terreus." Applied and Environmental Microbiology 79, no. 6 (January 18, 2013): 2038–47. http://dx.doi.org/10.1128/aem.03334-12.
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ABSTRACT10,11-Dehydrocurvularin is a prevalent fungal phytotoxin with heat shock response and immune-modulatory activities. It features a dihydroxyphenylacetic acid lactone polyketide framework with structural similarities to resorcylic acid lactones like radicicol or zearalenone. A genomic locus was identified from the dehydrocurvularin producer strainAspergillus terreusAH-02-30-F7 to reveal genes encoding a pair of iterative polyketide synthases (A. terreusCURS1 [AtCURS1] and AtCURS2) that are predicted to collaborate in the biosynthesis of 10,11-dehydrocurvularin. Additional genes in this locus encode putative proteins that may be involved in the export of the compound from the cell and in the transcriptional regulation of the cluster. 10,11-Dehydrocurvularin biosynthesis was reconstituted inSaccharomyces cerevisiaeby heterologous expression of the polyketide synthases. Bioinformatic analysis of the highly reducing polyketide synthase AtCURS1 and the nonreducing polyketide synthase AtCURS2 highlights crucial biosynthetic programming differences compared to similar synthases involved in resorcylic acid lactone biosynthesis. These differences lead to the synthesis of a predicted tetraketide starter unit that forms part of the 12-membered lactone ring of dehydrocurvularin, as opposed to the penta- or hexaketide starters in the 14-membered rings of resorcylic acid lactones. TetraketideN-acetylcysteamine thioester analogues of the starter unit were shown to support the biosynthesis of dehydrocurvularin and its analogues, with yeast expressing AtCURS2 alone. Differential programming of the product template domain of the nonreducing polyketide synthase AtCURS2 results in an aldol condensation with a different regiospecificity than that of resorcylic acid lactones, yielding the dihydroxyphenylacetic acid scaffold characterized by an S-type cyclization pattern atypical for fungal polyketides.
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Ibrahimi, Sanae, Gilles Sauvé, Joslyn Yelle, and El Mokhtar Essassi. "Synthèse racémique et énantiosélective d’énol-lactones et leur évaluation comme inhibiteurs de la protéase du VIH-1." Comptes Rendus Chimie 8, no. 1 (January 2005): 75–83. http://dx.doi.org/10.1016/j.crci.2004.08.002.
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Hanzelka, Brian L., Matthew R. Parsek, Dale L. Val, Paul V. Dunlap, John E. Cronan, and E. P. Greenberg. "Acylhomoserine Lactone Synthase Activity of the Vibrio fischeri AinS Protein." Journal of Bacteriology 181, no. 18 (September 15, 1999): 5766–70. http://dx.doi.org/10.1128/jb.181.18.5766-5770.1999.
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ABSTRACT Acylhomoserine lactones, which serve as quorum-sensing signals in gram-negative bacteria, are produced by members of the LuxI family of synthases. LuxI is a Vibrio fischeri enzyme that catalyzes the synthesis of N-(3-oxohexanoyl)-l-homoserine lactone from an acyl-acyl carrier protein andS-adenosylmethionine. Another V. fischeri gene,ainS, directs the synthesis ofN-octanoylhomoserine lactone. The AinS protein shows no significant sequence similarity with LuxI family members, but it does show sequence similarity with the Vibrio harveyi LuxM protein. The luxM gene is required for the synthesis ofN-(3-hydroxybutyryl)-l-homoserine lactone. To gain insights about whether AinS and LuxM represent a second family of acylhomoserine lactone synthases, we have purified AinS as a maltose-binding protein (MBP) fusion protein. The purified MBP-AinS fusion protein catalyzed the synthesis ofN-octanoylhomoserine lactone fromS-adenosylmethionine and either octanoyl-acyl carrier protein or, to a lesser extent, octanoyl coenzyme A. With the exception that octanoyl coenzyme A served as an acyl substrate for the MBP-AinS fusion protein, the substrates for and reaction kinetics of the MBP-AinS fusion protein were similar to those of the several LuxI family members previously studied. We conclude that AinS is an acylhomoserine lactone synthase and that it represents a second family of such enzymes.
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Dancewicz, Katarzyna, Antoni Szumny, Czesław Wawrzeńczyk, and Beata Gabryś. "Repellent and Antifeedant Activities of Citral-Derived Lactones against the Peach Potato Aphid." International Journal of Molecular Sciences 21, no. 21 (October 28, 2020): 8029. http://dx.doi.org/10.3390/ijms21218029.
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Citral is well known for its antimicrobial, antifungal, and insecticidal activities. Natural sesquiterpene α-methylenelactones also exhibit a broad spectrum of biological activities. The aim of the study was to explore the effect of structural changes to citral molecules on citral behavior-modifying activity towards Myzus persicae. Specifically, the effects of the introduction of a γ-lactone moiety and methylene groups in α and γ positions of the lactone ring were investigated. The lactones were obtained in five-step (saturated lactone and γ-methylenelactone) or six-step (α-methylenelactone and α,γ-dimethylenelactone) syntheses from citral. The synthetic procedures and physical and spectral data of the lactones are presented. The settling behavior of freely moving aphids in choice and no-choice situations was monitored. The probing behavior of tethered M. persicae using the Electrical Penetration Graph (EPG) technique was also analyzed. Citral appeared a strong repellent and pre-ingestive and ingestive probing deterrent to M. persicae. The incorporation of a lactone moiety caused the loss of the repellent activity. α-Methylenelactone inhibited aphid settling and probing activities at pre-ingestive and ingestive phases. The saturated γ-lactone and α,γ-dimethylenelactone were the settling post-ingestive deterrents to M. persicae, which did not affect aphid probing activity. γ-Methylenelactone did not affect aphid behavior.
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Miyazawa, Takeshi, Brendan J. Fitzgerald, and Adrian T. Keatinge-Clay. "Preparative production of an enantiomeric pair by engineered polyketide synthases." Chemical Communications 57, no. 70 (2021): 8762–65. http://dx.doi.org/10.1039/d1cc03073f.
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Modules from the pikromycin synthase were recombined into engineered synthases that furnish an enantiomeric pair of 2-stereocenter triketide lactones at >99% ee with yields up to 0.39 g per liter of E. coli K207-3 in shake flasks.
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Sakagami, Yukari, Naoki Kondo, Yuki Sawayama, Hiroyuki Yamakoshi, and Seiichi Nakamura. "Total Syntheses of Marrubiin and Related Labdane Diterpene Lactones." Molecules 25, no. 7 (April 1, 2020): 1610. http://dx.doi.org/10.3390/molecules25071610.
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Total syntheses of the labdane diterpene lactones marrubiin, marrulibacetal, desertine, marrulibacetal A, marrubasch F, cyllenine C, marrulanic acid, and marrulactone are described. The trans-decalin moiety of these molecules was constructed in a stereoselective manner by a Pauson-Khand reaction, and the resultant cyclopentenone was oxidatively cleaved for formation of the lactone ring. Elongation of the side chain at C9 was achieved by an epoxide-opening reaction with a variety of nucleophiles, and the functional group manipulations completed the syntheses of these natural products. Stereochemistries of desertine could be established by the transformations.
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Hong, Hui, Yuhui Sun, Yongjun Zhou, Emily Stephens, Markiyan Samborskyy, and Peter F. Leadlay. "Evidence for an iterative module in chain elongation on the azalomycin polyketide synthase." Beilstein Journal of Organic Chemistry 12 (October 11, 2016): 2164–72. http://dx.doi.org/10.3762/bjoc.12.206.
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The assembly-line synthases that produce bacterial polyketide natural products follow a modular paradigm in which each round of chain extension is catalysed by a different set or module of enzymes. Examples of deviation from this paradigm, in which a module catalyses either multiple extensions or none are of interest from both a mechanistic and an evolutionary viewpoint. We present evidence that in the biosynthesis of the 36-membered macrocyclic aminopolyol lactones (marginolactones) azalomycin and kanchanamycin, isolated respectively from Streptomyces malaysiensis DSM4137 and Streptomyces olivaceus Tü4018, the first extension module catalyses both the first and second cycles of polyketide chain extension. To confirm the integrity of the azl gene cluster, it was cloned intact on a bacterial artificial chromosome and transplanted into the heterologous host strain Streptomyces lividans, which does not possess the genes for marginolactone production. When furnished with 4-guanidinobutyramide, a specific precursor of the azalomycin starter unit, the recombinant S. lividans produced azalomycin, showing that the polyketide synthase genes in the sequenced cluster are sufficient to accomplish formation of the full-length polyketide chain. This provides strong support for module iteration in the azalomycin and kanchanamycin biosynthetic pathways. In contrast, re-sequencing of the gene cluster for biosynthesis of the polyketide β-lactone ebelactone in Streptomyces aburaviensis has shown that, contrary to a recently-published proposal, the ebelactone polyketide synthase faithfully follows the colinear modular paradigm.
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Gamage, Akshamal Mihiranga, Guanghou Shui, Markus R. Wenk, and Kim Lee Chua. "N-Octanoylhomoserine lactone signalling mediated by the BpsI–BpsR quorum sensing system plays a major role in biofilm formation of Burkholderia pseudomallei." Microbiology 157, no. 4 (April 1, 2011): 1176–86. http://dx.doi.org/10.1099/mic.0.046540-0.
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The genome of Burkholderia pseudomallei encodes three acylhomoserine lactone (AHL) quorum sensing systems, each comprising an AHL synthase and a signal receptor/regulator. The BpsI–BpsR system produces N-octanoylhomoserine lactone (C8HL) and is positively auto-regulated by its AHL product. The products of the remaining two systems have not been identified. In this study, tandem MS was used to identify and quantify the AHL species produced by three clinical B. pseudomallei isolates – KHW, K96243 and H11 – three isogenic KHW mutants that each contain a null mutation in an AHL synthase gene, and recombinant Escherichia coli heterologously expressing each of the three B. pseudomallei AHL synthase genes. BpsI synthesized predominantly C8HL, which accounted for more than 95 % of the extracellular AHLs produced in stationary-phase KHW cultures. The major products of BpsI2 and BpsI3 were N-(3-hydroxy-octanoyl)homoserine lactone (OHC8HL) and N-(3-hydroxy-decanoyl)homoserine lactone, respectively, and their corresponding transcriptional regulators, BpsR2 and BpsR3, were capable of driving reporter gene expression in the presence of these cognate lactones. Formation of biofilm by B. pseudomallei KHW was severely impaired in mutants lacking either BpsI or BpsR but could be restored to near wild-type levels by exogenous C8HL. BpsI2 was not required, and BpsI3 was partially required for biofilm formation. Unlike the bpsI mutant, biofilm formation in the bpsI3 mutant could not be restored to wild-type levels in the presence of OHC8HL, the product of BpsI3. C8HL and OHC8HL had opposite effects on biofilm formation; exogenous C8HL enhanced biofilm formation in both the bpsI3 mutant and wild-type KHW while exogenous OHC8HL suppressed the formation of biofilm in the same strains. We propose that exogenous OHC8HL antagonizes biofilm formation in B. pseudomallei, possibly by competing with endogenous C8HL for binding to BpsR.
Dissertations / Theses on the topic "Lactones – Synthèse"
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Rabiller, Christine. "Nouvelles voies de synthèse de lactones bioactives." Nancy 1, 1994. http://www.theses.fr/1994NAN10339.
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La synthèse enantiospécifique de lactones bioactives, inhibitrices d'une part de l'hmgcoa réductase, et d'autre part des lipases pancréatiques a été entreprise. Dans une première partie, l'accès facile et rapide à des composés de structure didesoxy-2-4-hexopyranose, chiron clé pour la synthèse d'inhibiteurs de la biosynthèse du cholestérol, a été réalisé par transformation stéréospécifique du 1,6-anhydro-beta-d-glucopyranose obtenu par pyrolyse dans de bonnes conditions qui ont été mises au point dans ce travail. Dans la deuxième partie, l'application des méthodes de création de liaison carbone-carbone en c-2 et en c-6 sur un dérivé du glucose, a permis d'ouvrir deux nouvelles voies pour la préparation d'intermédiaires clés de la synthèse de la valilactone, le tetrahydrolipstatine et la tetrahydroexterastine, composes d'intérêt pharmacologique pour le traitement de l'obésité
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Lakhrissi, Mohammed. "Dichloromethylenation de lactones et d'esters : synthèse et réactivité." Nancy 1, 1993. http://www.theses.fr/1993NAN10176.
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La dichloromethylenation des lactones et d'esters a été mise au point par l'utilisation d'un nouveau système de réactifs: triphenylphosphine-tetrachlorure de carbone. Ce système permet de transformer les lactones en présence des groupements o-benzyl, o-methylmethylether et d'esters encombres comme les pivaloyles et 4-phenylbenzoyles. Les nouvelles conditions que nous avons mises au point permettent la transformation des lactones -1,4; 1,5 et des acétates. Le motif dichloromethylene se prête bien à des transformations chimiques telles que la réduction, la chloration, la coupure oxydante ainsi que la cyclopropanation
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Harmange, Jean-Christophe. "Synthèse totale énantiosélective d'acétogénines d'Annonacées (gamma-lactones monotétrahydroguraniques)." Paris 11, 1992. http://www.theses.fr/1992PA114840.
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Archambaud, Sylvie. "Recherches en série des bréfeldines A et C : synthèse totale de la (+)-bréfeldine C." Nantes, 2004. http://www.theses.fr/2004NANT2038.
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Les bréfeldines A et C (BFA et BFC) sont deux lactones macrocycliques isolées en 1958 d'un champignon phytopathogène Penicillium decumbens. La BFA possède de nombreuses propriétés biologiques. Elle inhibe en particulier le transport des protéines du réticulum endoplasmique vers l'appareil de Golgi selon un mécanisme d'action original qui pourrait ouvrir une nouvelle voie de recherche pour la conception de médicaments. La recherche d'analogues structuraux de la BFA qui conserveraient la même activité en étant moins toxique s'avère nécessaire. La BFC (précurseur biologique de la BFA), pourrait constituer un bon candidat de départ pour cette recherche. Ce mémoire décrit une nouvelle synthèse totale de la (+)-BFC, potentiellement transposable à la synthèse de la (+)-BFA et à celle d'analogues structuraux. Nous avons préparé la (+)-BFC en 19 étapes avec un rendement global de 2,9 %. L'application de la stratégie de synthèse en série de la BFA est en cours de réalisationBrefeldins A and B (BFA and BFC) are two macrocyclic lactones first isolated from Penicillium decumbens in 1958. Early studies showed that BFA exhibits a wide range of biological activities including the inhibition of proteins transport from the endoplasmic reticulum to the Golgi apparatus. BFA acts in a specific and unusual manner that could inspired new conceptions for drug design. The utility of BFA is hampered however by its toxicity so that the synthesis of active, but less toxic, analogues, is highly desirable. Toward this end, BFC (BFA bioprecursor) was first designed as a good candidate. We report herein a novel total synthesis of naturally occurring (+)-BFC that could be next applied to the synthesis of (+)-BFA and to a large variety of analogues. Our 19 steps synthesis features anhydride desymmetrisation, Suzuki cross-coupling and diastereoselective addition reaction of an organometallic species as key steps. Application of this strategy to BFA is now in progress
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Fouque, Elie. "Synthèse itérative de lactones α, β-ethyléniques à cycle moyen : hydrolyse enzymatique de lactones saturées." Paris 11, 1989. http://www.theses.fr/1989PA112246.
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Dans ce mémoire de thèse, nous proposons une nouvelle voie d'accès aux lactones alpha, bêta-éthyléniques à cycle moyen par une méthode d'agrandissement de cycle, qui, utilisée de façon récurrente permet à chaque itération d'incorporer dans le squelette laconique un atome de carbone porteur ou non d'un substituant. Dans le premier chapitre, après un exposé concernant la préparation des éthers d'énols triméthylsilyliques de lactones, nous étudions la réaction de ces énoxysilanes avec trois chlorocarbénoïdes différents. Les adduits cyclopropaniques ainsi obtenus, conduisent thermiquement aux lactones alpha, bêta-éthyléniques d'agrandissement de cycle. A l'aide de cette méthode, nous avons préparé avec des rendements satisfaisants des lactones alpha, bêta éthyléniques non substituées, méthylées ou fluorées en alpha, de taille comprise entre 7 et 10 maillons. Dans le second chapitre, nous étudions les propriétés spectroscopiques ainsi que quelques propriétés chimiques de ces lactones insaturées à cycle moyen. Nous mettons en évidence les différences importantes existant entre les composés de stéréochimie E et Z. Par hydrogénation catalytique en phase hétérogène, nous préparons les lactones saturées correspondantes, réalisant ainsi la dernière étape de la séquence et rendant la méthode itérative. Dans le troisième chapitre, nous présentons une nouvelle méthode de préparation des lactones à cycle moyen optiquement actives méthylées en alpha de l'atome d'oxygène, par dédoublement cinétique catalysée par des hydrolases. En utilisant l'estérase de foie de porc (PLE) ou l'estérase de foie de cheval (HLE) sous forme de leur extrait acétonique, en milieu aqueux, l'hydrolyse de ces alkanolides procède de façon hautement énantiosélective. Ainsi le (S)-(+) octanolide-7, le (S)-(+)-nonanolide-8 et le (S)-(+)-décanolide-9 ((S)-(+)-phoracantholide I) ont été isolés avec un bon rendement et un excès énantiomérique supérieur à 95%In this thesis, we report a new method for the preparation of alpha,beta-ethylenic medium ring lactones involving a ring enlargement method which can be used in an iterative way allowing, at each iteration, the incorporation of a carbon atom, substituted or not, in the lactonic skeleton. In the first chapter, is reported the preparation of trimethylsilyl enol ethers of lactones, then the reaction of these enoxysilanes with three different chlorocarbenoids. The cyclopropane adducts so obtained, are thermally transformed into alpha, beta-ethylenic ring expanded lactones. By this way we have prepared in satisfactory yields alpha unsubstituted, alpha methylated or alpha fluorinated 7 to 10 membered alpha,beta-ethylenic lactones. In the second chapter, we study spectroscopic and chemical properties of these unsaturated medium ring lactones. We outline large differences between E and Z isomers. By catalytic heterogeneous hydrogenation we prepare the corresponding saturated compounds, allowing thus the last step of this iterative method. In the third chapter, we present a new method for the preparation of optically active medium ring lactones, methylated in the alpha position of the oxygen atom, by an hydrolase-catalyzed kinetic resolution. Using pig liver esterase (PLE) or horse liver esterase (HLE) (acetone powder), in aqueous phase the hydrolysis is performed with a high enantioselectivity. Thus, (S)-(+)-7- octanolide, (S)-(+)-8-nonanolide and (S)-(+)-9-decanolide ((S)-(+)-phoracantholide I) have been isolated in good yield and enantiomeric excess (over 95%)
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Carrière, Anne. "Cyclisations tandem de radicaux alpha-alcoxycarbonyle, alpha-carbamoyle et alpha-carbonyle : application à la synthèse de composés bicycliques." Aix-Marseille 3, 1994. http://www.theses.fr/1994AIX30084.
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La cyclisation de radicaux alpha-alcoxycarbonyle permet l'obtention de lactones. De meme, la cyclisation de radicaux alpha-carbamoyle et alpha-carbonyle conduit a des lactames et des cycloalcanones. Notre but etait de preparer des composes bicycliques via une cyclisation tandem de ces intermediaires radicalaires. Pour atteindre cet objectif, nous avons utilise diverses methodologies de production de ces radicaux a partir de precurseurs varies. La cyclisation oxydante d'esters allyliques actives ne permet d'obtenir ni des 2-oxo-3-oxa-bicyclo3. 1. 0hexanes ni des 2-oxo-3-oxa-bicyclo3. 3. 0octanes. La formation de 2-oxo-3-oxa-bicyclo3. 1. 0hexanes et de leurs analogues azotes a pu etre effectuee par la reduction d'alpha-dichloroesters ou amides avec cucl. Nous avons montre que l'enchainement d'une cyclisation radicalaire 5-exo avec la cyclopropanation d'un enolate de cuivre peut etre realisee sous ces conditions experimentales. Les memes composes peuvent etre prepares en deux etapes en utilisant, dans la deuxieme etape, de l'iodure de samarium comme agent reducteur. Le rearrangement de vinylcyclopropanes catalyse par le radical phenylthiyle conduit a des 2-oxo-3-oxa-bicyclo3. 3. 0octanes et a leurs analogues azotes. Les rendements et la chimioselectivite sont controles par la regio- et la stereoselectivite de la premiere cyclisation radicalaire. Les produits majoritaires sont des bicycles accoles a jonction cis, toutefois des bicycles a jonction trans ont ete isoles et caracterises. Nous avons montre que sous ces conditions experimentales, les cyclisations conduisant a des gamma-lactones et des gamma-lactames a partir de radicaux alpha-alcoxycarbonyle et alpha-carbamoyle stabilises ne sont pas reversibles. Le rearrangement de vinylcyclopropylcetones conduit a des bicyclo3. 2. 1octanones comme produit majoritaire, sauf dans le cas ou le radical alpha-carbonyle s'additionne sur une double liaison portant deux groupes methyle sur le carbone terminal
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Bos, Maxence. "Synthèse de [gamma]-lactones polyfonctionnelles chirales par catalyse énantiosélective." Thesis, Reims, 2015. http://www.theses.fr/2015REIMS017.
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La mise au point de méthodologies de synthèse permettant d’obtenir des substances énantiopures présentant une diversité structurale importante est une préoccupation majeure de la chimie contemporaine. L’efficacité de ces approches doit être désormais évaluée au regard de critères tel que la pureté optique et l’analyse de l’impact écologique des processus mis en jeu. Au cours de ce travail nous avons développé de nouvelles méthodologies permettant d’accéder à des γ-lactones polyfonctionnelles chirales. La 5-hydroxyfuran-2(5H)-one, petite molécule bio-sourcée, a servi d’élément clé pour la construction du cycle γ-lactone. Dans une première approche, des γ-lactones chirales possédant une grande diversité structurale ont été obtenues par une séquence réactionnelle « one pot ». Une première étape de catalyse organique a permis d’activer le transfert énantiosélectif d’acides boroniques sur la 5-hydroxyfuran-2(5H)-one ; l’adduit chiral obtenu a ensuite été engagé dans une réaction de Passerini pour construire le cycle lactone. Dans une deuxième partie, nous avons mis au point des réactions d’alkylation de γ-lactones, catalytiques et énantiosélectives, pour la formation de γ-lactones possédant un centre quaternaire. L’utilisation de complexes du palladium et de l’iridium a permis d’effectuer des réactions d’Alkylation Allylique Asymétrique avec un très bon contrôle de l’induction asymétrique. Le squelette carboné des lactones obtenues par AAA a permis d’effectuer une fonctionnalisation inédite d’hétérocycles aromatiques par des réactions sigmatropiques [3,3]. Enfin des réactions d’alkylations énantiosélectives induites par un catalyseur organique ont été évaluéesThe development of new synthetic pathway leading to enantiopure compounds with significant structural diversity is an ongoing challenge in many fields of chemistry. The efficiency of these processes has to be evaluated, not only in term of quantitative criteria, such as yields and/or optical purities of obtained compounds, but also by analyzing the environmental impact of the different processes involved. In this work, we sought to develop new methodologies for the synthesis of polyfunctional chiral γ-lactones. The 5-hydroxyfuran-2(5H)-one, a bio-based molecule, was used as a platform to the construction of the γ-lactone ring. In the first part of our work, a variety of chiral γ-lactone displaying a great structural diversity were obtained by a one-pot sequential reaction. First, a step of enantioselective organocatalysis allowed the activation for the transfer of boronic acids on the hydroxyfuran-2(5H)-one; then the chiral adduct formed was engaged in a Passerini reaction leading to the construction of the lactone ring. In a second part, our efforts focused then on the development of catalytic asymmetric alkylation reactions leading to the construction of γ-lactones bearing an all-carbon quaternary stereocenter. Asymmetric allylic reactions were carried out with a very good control of the selectivity of the reaction by the use of palladium and iridium complexes catalysts. Theses lactones bearing an [1,5]-diene scaffold were then engaged in a sigmatropic [3,3] reaction opening a path for a new approach to the functionalization of aromatic heterocycles. Finally, the use of organic enantioselective catalysis was envisioned for the creation of all-quaternary stereocenters
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Le, Lamer Anne-Cécile. "α-méthylène-γ-lactones lichéniques : extraction, isolement et synthèse d'analogues." Rennes 1, 2006. http://www.theses.fr/2006REN1S092.
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Les lichens constituent une source de composés originaux peu explorés pour leurs potentialités thérapeutiques, notamment anticancéreuses. L’acide protolichestérinique (APL) issu de Cetraria islandica a été retenu pour mener notre étude. Après l’isolement de cette alpha-méthylène-gamma-lactone et de ses dérivés par chromatographies, le développement de méthodologies originales pour l’extraction, la purification et la synthèse de dérivés de l’APL a été entrepris. Une chimiothèque d’alpha-méthylène-gamma-lactones a ainsi été synthétisée via l’introduction d’un support fluoré dans une séquence réactionnelle. L’activité cytotoxique des produits obtenus sur des lignées de mélanome a permis de confirmer l’importance de ce motif. Ces composés originaux méritent enfin d’être étudiés sous un aspect chimiotaxonomique. Des extractions en parallèle ont été réalisées afin de cribler rapidement 24 lichens et des techniques de détection et de purification sélectives de ces dérivés sont proposées. Une stratégie de piégeage et de relargage sur support fluoré a notamment permis d’isoler l’APL de façon originale.
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Cheaib, Rouba. "Les carboxymethyl glycosides lactones : synthèse et application à l'imagerie membranaire." Lyon, INSA, 2008. http://theses.insa-lyon.fr/publication/2008ISAL0056/these.pdf.
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La carboxyméthyl 3,4,6-tri-O-acétyl-α-D-glucopyranoside 2-0-lactone, préparée à partir de l'isomaltulose, est un bon "donneur de glycoside" pour la synthèse de composés ciblés soit pour leur intérêt biologique soit pour leurs propriétés physico-chimiques potentielles tels que des pseudo-oligosaccharides, pseudo-glycoaminoacides, et pseudo-glycolipides. Dans ce contexte, de nouvelles stratégies de synthèse ont été mise au point pour l'obtention de ces lactones construites sur des systèmes mono- et disaccharidiques avec des groupements protecteurs variés. D'autre part, la fonctionnalisation de la position 2 sélectivement libérée après ouverture de cette lactone par des agentrs nucléophiles, a été effectuée pour la synthèse de systèmes multifonctionnels. Une application de cette stratégie a aussi été étudiée pour la synthèse de produits amphiphiles pour la conception de sondes membranaires hydrosolubles pour l'imagerie membranaire par microscopie optique non linéaireThe carboxymethyl 3,4,6-tri-O-acétyl-α-D-glucopyranoside 2-0-lactone,, prepared starting from isomaltulose, has shown to be a good “glycoside donor” for the synthesis of compounds targeted either for their biological interest or for their potential physicochemical properties such as pseudo-oligosaccharides, pseudo-glycoaminoacids, and pseudo-glycolipids. New strategies of synthesis for obtaining carboxymethyl glycoside lactones based on mono- and disaccharidic systems with varied protective groups are now presented. In addition, the fonctionnalisation of position 2 selectively released after opening of these lactones by nucleophilic agents allowed the synthesis of multifunctionnalised systems. An application of this strategy was also studied for the synthesis of amphiphilic products for the design of water-soluble membrane probes for the membrane imagery by non linear optical microscopy
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Escudier, Jean-Marc. "Synthèse de composés polyoxygènes optiquement actifs : application aux polyols "1,3" et "1,2,3"." Toulouse 3, 1992. http://www.theses.fr/1992TOU30066.
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Le travail concerne la mise au point d'une methode de synthese de composes polyoxygenes optiquement actifs, comportant des enchainements de fonctions hydroxyle de type-1,3 ou -1,2,3. Les precurseurs communs retenus pour la synthese de ces composes sont des epoxyhydroxyesters obtenus par addition diastereoselective d'enolates d'esters a des epoxyaldehydes optiquement actifs. L'etude de la condensation aldolique et l'optimisation des conditions de reaction, nous ont permis de porter pour cetains exemples la diastereoselectivite a 13/1; les differences observees selon les substrats sont discutees. La reduction totale des epoxyhydroxyesters conduit de facon regiospecifique aux polyols de type-1,3 dont la fonctionnalisation aboutit a un analogue de la lactone mevinique (inhibiteur de l'hmgcoa reductase, enzyme impliquee dans la biosynthese du cholesterol. Nous avons par la suite mis au point une reaction intramoleculaire stereospecifique de lactonisation des epoxyhydroxyesters de tertiobutyle, qui donne acces aux composes polyhydroxyles de type-1,2,3 (sous forme d'hydroxybutyrolactones). La reduction des lactones procure des 2-desoxyhexoses analogues de sucres intervenant dans la synthese de produits antitumoraux ou antiviraux (de type azt). Par ailleurs, la conversion des lactones en amides par la methode de weinreb, permet une fonctionnalisation par des equivalents d'acyle et ouvre une voie de synthese rapide a l'acide 3-desoxy-d-arabinoheptulosonique (intermediaire de la biosynthese des acides amines aromatiques chez les vegetaux). La methode developpee autorise un controle de la configuration des divers centres chiraux au cours de chaque etape, lui conferant ainsi une grande souplesse en synthese
Books on the topic "Lactones – Synthèse"
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Rehders, Frank. Aufbau enantiomerenreiner [beta]-Hydroxy-[gamma]-lactone [Beta-Hydroxy-gamma-lactone] durch Homoaldol-Reaktion: Synthese von 2,6-Didesoxyhexonsäuren und Dihydroxyethylen-dipeptidisosteren. [S.l.]: [s.n.], 1991.
Find full textBook chapters on the topic "Lactones – Synthèse"
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Schomburg, Dietmar, and Dörte Stephan. "Lactose synthase." In Enzyme Handbook 12, 209–13. Berlin, Heidelberg: Springer Berlin Heidelberg, 1996. http://dx.doi.org/10.1007/978-3-642-61117-9_35.
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Reddy, M. Venkat Ram, Herbert C. Brown, and P. Veeraraghavan Ramachandran. "Syntheses of Chiral Lactones via Asymmetric Allylboration." In ACS Symposium Series, 220–34. Washington, DC: American Chemical Society, 2001. http://dx.doi.org/10.1021/bk-2001-0783.ch016.
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Harcken, Christian, Thilo Berkenbusch, Stefan Braukmüller, Andreas Umland, Konrad Siegel, Felix Görth, Frank von der Ohe, and Reinhard Brückner. "Stereoselective Syntheses of γ-Lactones and γ-Alkylidene- Butenolides." In Current Trends in Organic Synthesis, 153–61. Boston, MA: Springer US, 1999. http://dx.doi.org/10.1007/978-1-4615-4801-0_19.
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Shin, Daniel, and Rajesh Nagarajan. "Enzymatic Assays to Investigate Acyl-Homoserine Lactone Autoinducer Synthases." In Methods in Molecular Biology, 161–76. New York, NY: Springer New York, 2017. http://dx.doi.org/10.1007/978-1-4939-7309-5_13.
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"Acyl-homoserine-lactone synthase." In Class 2 Transferases, 140–51. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-540-85697-9_26.
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Mardones, Lorena, and Marcelo Villagrán. "Lactose Synthesis." In Lactose and Lactose Derivatives. IntechOpen, 2020. http://dx.doi.org/10.5772/intechopen.91399.
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This chapter is related to lactose synthesis, its chemistry, regulation, and differences between species, especially in cattle. Lactose synthesis takes place in the Golgi apparatus of mammary epithelial cells (MEC) by the lactose synthase (LS) enzyme complex from two precursors, glucose and UDP-galactose. The enzyme complex is formed by galactosyltransferase, and it is associated with α-lactalbumin. Importantly, the lactose secreted determines the volume of milk produced, due to its osmotic properties. Milk contains 5% lactose and 80% water, percentages that remain constant during lactation in the different mammalian species. The low variation in milk lactose content indicates that lactose synthesis remains constant throughout the period of lactation and that is highly conserved in all mammals. Lactose synthesis is initiated during the first third of the pregnancy, increasing after birth and placenta removal. Different glucose transporters have been involved in mammary glucose uptake, mainly facilitative glucose transporters GLUT1, GLUT8, and GLUT12 and sodium-glucose transporter SGLT1, with more or less participation depending on mammal species.
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Wills, Martin. "Organoiron chemistry 2: iron acyl and 1r-ally1tricarbonyliron lactone chemistry." In Transition Metals in Organic Synthesis, 99–131. Oxford University PressOxford, 1997. http://dx.doi.org/10.1093/oso/9780198558460.003.0004.
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Abstract Two classes of organoiron chemistry will be described in this chapter. The first part concerns the synthesis and applications of acyl derivatives of the enantiomerically pure chiral auxiliary [(C5H5)Fe(CO)(PPh3)]. Such complexes may be elaborated through a variety of synthetic transformations with invariably high diastereoselectivity. Removal of the acyl group furnishes enantiomerically enriched or pure products. The second class of organoiron reagents featured in this chapter are iron tricarbonyl ir-allyl complexes. These have been employed as intermediates in general methods for the synthesis of lactones and lactams and have been applied to a number of total syntheses of complex natural products.
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Taber, Douglass. "Total Synthesis by Alkene Metathesis: Amphidinolide X (Urpí/Vilarrasa), Dactylolide (Jennings), Cytotrienin A (Hayashi), Lepadin B (Charette), Blumiolide C (Altmann)." In Organic Synthesis. Oxford University Press, 2011. http://dx.doi.org/10.1093/oso/9780199764549.003.0031.
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To assemble the framework of the cytotoxic macrolide Amphidinolide X 3, Fèlix Urpí and Jaume Vilarrasa of the Universitat de Barcelona devised (Organic Lett. 2008, 10, 5191) the ring-closing metathesis of the alkenyl silane 1. No Ru catalyst was effective, but the Schrock Mo catalyst worked well. In the course of a synthesis of (-)-Dactylolide 6, Michael P. Jennings of the University of Alabama offered (J. Org. Chem. 2008, 73, 5965) a timely reminder of the particular reactivity of allylic alcohols in ring-closing metathesis. The cyclization of 4 to 5 proceeded smoothly, but attempted ring closing of the corresponding bis silyl ether failed. Polyenes such as ( + )-Cytotrienin A 8 are notoriously unstable. It is remarkable that Yujiro Hayashi of the Tokyo University of Science could (Angew. Chem. Int. Ed. 2008, 47, 6657) assemble the triene of 8 by the ring-closing metathesis of the highly functionalized precursor 7. Bicyclo [2.2.2] structures such as 9 are readily available by the addition of, in this case, methyl acrylate to an enantiomerically-pure 2-methylated dihydropyridine. André B. Charette of the Université de Montréal found (J. Am. Chem. Soc. 2008, 130, 13873) that 9 responded well to ring-opening/ring-closing metathesis, to give the octahydroquinoline 10. Functional group manipulation converted 10 into the Clavelina alkaloid ( + )-Lepadin B 11. The construction of trisubstituted alkenes by ring-closing metathesis can be difficult, and medium rings with their transannular strain are notoriously challenging to form. Nevertheless, Karl-Heinz Altmann of the ETH Zürich was able (Angew. Chem. Int. Ed. 2008, 47, 10081), using the H2 catalyst, to cyclize 12 to cyclononene 13, the precursor to the Xenia lactone ( + )-Blumiolide C 14. It is noteworthy that these fi ve syntheses used four different metathesis catalysts in the key alkene forming step. For the cyclization of 7, the use of the Grubbs first generation catalyst G1, that couples terminal alkenes but tends not to interact with internal alkenes, was probably critical to success.
Reports on the topic "Lactones – Synthèse"
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Yedidia, I., H. Senderowitz, and A. O. Charkowski. Small molecule cocktails designed to impair virulence targets in soft rot Erwinias. Israel: United States-Israel Binational Agricultural Research and Development Fund, 2020. http://dx.doi.org/10.32747/2020.8134165.bard.
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Chemical signaling between beneficial or pathogenic bacteria and plants is a central factor in determining the outcome of plant-microbe interactions. Pectobacterium and Dickeya (soft rot Erwinias) are the major cause of soft rot, stem rot, and blackleg formed on potato and ornamentals, currently with no effective control. Our major aim was to establish and study specific bacterial genes/proteins as targets for anti-virulence compounds, by combining drug design tools and bioinformatics with experimental work. The approach allowed us to identify and test compounds (small molecules) that specifically interfere with the activities of these targets, by this impairing bacterial virulence. Two main targets were selected within the frame of the BARD project. The first is the ATP-binding cassette (ABC) transporters and methyl-accepting chemotaxis proteins (MCP) that have been characterized here for the first time in Pectobacteriaceae, and the second is the quorum sensing (QS) machinery of Pectobacterium with its major proteins and in particular, the AHL synthase ExpI that was identified as the preferred target for inhibition. Both systems are strongly associated with bacterial virulence and survival in planta. We found that Pectobacteriaceae, namely Dickeya and Pectobacterium, encode more ABC transporters and MCP in their genomes, compared to other bacteria in the order. For MCP, soft rot Pectobacteriaceae not only contain more than 30 MCP genes per strain, but also have more diverse ligand binding domains than other species in the Enterobacteriales. These findings suggest that both ABC transporters and MCP are important for soft rot Pectobacteriaceae pathogenicity. We now have a selection of mutants in these proteins that may be further explored to understand their direct involvement in virulence. In parallel, we studied the QS central proteins in pectobacteria, the signaling molecule N-acyl-homoserine lactone synthase, ExpI, and the response regulator ExpR, and established their phylogenetic relations within plant pathogenic Gram negative bacteria. Next, these proteins were used for virtual screening of millions of compounds in order to discover new compounds with potential to interfere with the QS machinery. Several natural compounds were tested for their interference with virulence related traits in Pectobacterium and their capability to minimize soft rot infections. Our findings using microcalorimetric binding studies have established for the first time direct interaction between the protein ExpI and two natural ligands, the plant hormone salicylic acid and the volatile compound carvacrol. These results supported a model by which plants interfere with bacterial communication through interkingdom signaling. The collaborative project yielded two research papers and a comprehensive review, which included new computational and bioinformatics data, in Annu. Rev. Phytopathol., the highest ranked journal in phytopathology. Additional two papers are in preparation. In order to transform the fundamental knowledge that have been gained during this collaborative BARD project into agricultural practice, to control soft rot bacteria, we have submitted a continual project.