Dissertations / Theses on the topic 'Indolizidine'
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Nelson, A. "Synthesis of bioactive indolizidine alkaloids." Thesis, Queen's University Belfast, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.421009.
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Padmanabhan, Padma. "Biosynthetic studies on the indolizidine alkaloid cyclizidine." Thesis, University of Cambridge, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.304387.
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Mitchell, Douglas. "Synthetic studies towards pyrrolizidine and indolizidine alkaloids." Thesis, Sheffield Hallam University, 1992. http://shura.shu.ac.uk/20067/.
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This project was concerned with the synthesis of the pyrrolizidine alkaloids supinidine, trachelanthamidine and isoretronecanol and also synthetic studies towards the indolizidine alkaloid 251D. In all cases, the synthesis began from a cheap, readily-available, simple amino acid, in this case glutamic acid, and proceeded to a suitable monocyclic intermediate which could then undergo an intramolecular Horner-Wittig cyclisation reaction to form the required bicyclic core structure. Subsequent modification reactions then led in the pyrrolizidine series to penultimate precursors of the target alkaloids supinidine, trachelanthamidine and isoretronecanol, and in the indolizidine series to a bicyclic intermediate in the synthesis towards the toxin 251D. The intramolecular Horner-Wittig cyclisation reaction was found to proceed with retention of chirality, thus leading to the enantiospecific synthesis of the pyrrolizidine alkaloids. The use of alternative monocyclic intermediates in the intramolecular Horner-Wittig cyclisation reaction, thus leading to other pyrrolizidine alkaloids is also discussed. One of the major problems encountered in this project was the solubility of the unprotected monocyclic amide intermediates, and this was overcome by the use of N-benzyl and N- carbobenzyloxy protecting groups; in the indolizidine synthesis where the unprotected monocyclic amides were necessary, the reaction work-up for these intermediates usually required continuous solvent extraction. Another major problem was the instability of the bicyclic amide intermediates and some of the monocyclic intermediates,As well as covering a comprehensive background of each class of alkaloid, this report also contains an in-depth discussion of the key intramolecular Horner-Wittig cyclisation reaction and suggestions for its use in the possible synthesis of other classes of alkaloids.
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St-Denis, Yves. "Studies toward the synthesis of hydroxylated indolizidine alkaloids." Thesis, McGill University, 1991. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=70343.
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The formation of the indolizidine ring system was studied. First, the intramolecular electrophilic cyclisation of substituted allylsilanes, vinylsilanes and enol ethers was attempted. Reactions with the allylsilane moiety indeed gave the desired ring system, whereas the vinylsilanes failed to give any cyclisation product. In order to easily introduce oxygen functionalities in the rings, enol ether cyclisations were also attempted but did not produce the expected bicyclic systems.Secondly, the intramolecular nucleophilic cyclisation of free amines bearing suitable leaving groups was attempted, providing an easy method for the formation of the indolizidine system, with an interesting entry into the synthesis of biologically active polyhydroxylated alkaloids Swainsonine and Castanospermine. The synthesis of these two natural compounds, as well as some of their analogues, using the successful nucleophilic methodology was attempted.
Finally, the regioselective and stereoselective introduction of hydroxyl groups into the pyrrolidine ring system was studied in order to prepare mono- and di-hydroxylated pyrrolidines for the synthesis of the aforementioned natural products.
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Kefalas, Panagiotis. "Synthèse d'une indolizidine hydroxylée, analogue de la castanospermine." Paris 11, 1988. http://www.theses.fr/1988PA112340.
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Les alcaloïdes indolizidiniques polyhydroxylés comme la swainsonine et la castanospermine ont une activité remarquable vis-à-vis des glycosidases. Nous nous étions fixés comme but, la synthèse de la castanospermine et de ses épimères. Cet alcaloïde a une activité contre le virus du SIDA in vitro et également contre le virus de la grippe. Ces propriétés biologiques permettraient d'envisager une utilisation comme insecticide. Vu la ressemblance de cet alcaloïde et les sucres, il paraît évident d'utiliser des carbohydrates comme produits du départ. Le D-glucose présente une configuration convenable pour les centres C-6, C-7 et C-8 de l'alcaloïde. Dans une première approche de synthèse, nous avons étudié la formation du noyau à cinq chaînons du système indolizidinique en appliquant la chimie des α-aminonitriles sur l'aldéhyde O-1,2-isopropylidène l-α-D-xylo-pentodialdo-furanose-1,4 –issu du D-glucose - de deux façons: soit par formation de l'a-aminonitrile, N-benzylé suivie de l'introduction des carbones C-2 et C-3 par réaction de Grignard sur le nitrile et cyclisation, soit par préparation de l’a-aminonitrile portant les carbones C-2 et C-3 substitués sur la fonction amine et cyclisation. Les difficultés rencontrées au cours de cette voie nous ont contraints à l'abandonner. Dans une deuxième approche, nous avons étudié la formation du noyau indolizidinique polyhydroxylé à partir des dérivés du D-glucose, du D-xylose et du D-arabinose. On introduit les carbones C-1, C-2 et C-3 et l'oxygène en C-1 sous forme d'éther d'énol par réaction de Wittig. Ensuite, on forme une oxazine-1,2-dihydro-3, 6-2H éthoxy-4 par réaction d'hétéro-Diels-Alder avec un diénophile portant la fonction nitroso. Le dérivé du glucose ne répond pas aux conditions requises pour la suite de la synthèse à cause de la sensibilité du noyau furannique au milieu basique de la réaction de Wittig. Les dérivés du D-xylose et du D·arabinose ne portant pas le noyau furannique permettent la poursuite de cette voie. La cyclisation de l'azote de l’oxazine sur le tosylate en position terminale de la chaine d'arabinose fournit un produit bicyclique portant un hydroxyle libre en β de l'azote. En série xylose une réaction concurrentielle de l'hydroxyle secondaire en a du tosylate fournit aussi l'époxyde; cette différence de comportement est due à des effets stériques. La réduction de la double liaison et de la liaison N-O de l’oxazine en série arabinose donnent un δ-aminoalcool. Nous avons tenté trois méthodes de cyclisation déshydratante de cet aminoalcool en utilisant : i) le système PPh₃; NEt₃; CCI4 ii) le complexe de rhodium RhH (PPh₃)₄ iii) le réactif combiné, diéthylazodicarboxylate-triphénylphosphine (réaction de Mitsunobu). Seule la réaction de Mitsunobu a pu fournir le squelette du produit final en série arabinose, la méthode n'ayant pu aboutir pour des raisons stériques quand elle était appliquée au dérivé bicyclique du xylose. On obtient un seul isomère, la(1R,6R,7R,8R,8aS)-éthoxy-1,hydroxy6;O-7,8 isopropylidène, octahydroindolizidine. La réaction de Mitsunobu s'avère stéréosélective puisque l'hydroxyle libre secondaire du noyau à six n'intervient pas à la réactionSeveral attempts for the synthesis of the indolizidinic alkaloid (1S,6S,7R,8R,8aR)-1,6,7,8 tetrahydroxy-octahydroindolizine (castanospermine), a glucosidase inhibitor and of its epimers are described. The general synthetic approach was undertaken starting from sugars that have an established configuration on the carbon atoms corresponding to the C-6, C-7 and C-8 centres of the indolizidinic ring. Ln a first synthetic route we have studied the formation of the alkaloid five-member ring, through the application of α-aminonitrile chemistry on the aldehyde 1,2-O-isopropylidene-α-D-xylo-pentodialdo-1,4-furanose prepared from D-(+)-Glucose; either by formation of the N-benzyl,α-aminonitrile, followed by the introduction of C-2 and C-3 and cyclization, or by the synthesis of the α-aminonitrile carrying C-2 and C-3 substituted on the amine function and ring closure. The difficulties met during this route obliged us to abandon. In a second approach we have studied the formation of the polyhydroxylated indolizidinic ring starting from D-Glucose, D-Xylose and D-Arabinose derivatives; we introduce C-1, C-2 and C-3 and the oxygen on C-1 in the form of an enol ether, by Wittig reaction. Then we form a 1,2-oxazine-3,6- dihydro-2H; 4 ethoxy by Diels-Alder reaction with a dienophile carrying the nitroso function. The glucose derivative does not meet the requirements for the continuation of the synthesis, due to the sensitivity of the furan ring in the basic medium of the Wittig reaction. Cyclization of the oxazine on the tosylated sugar frame supplies a bicyclic product. Reduction of the double bond and the N-O bond of the arabinose series derivative give a δ-aminoalcohol which leads to the (1S,6S,7R,8R,8aS),1-ethoxy,6-hydroxy;7,8-O- isopropylidene octahydroindolizine(ie. A close analog of castanospermine) by dehydrative cyclization. (Mitsunobu reaction). The same reaction sequence could not be used on the bicyclic xylose derivative; the Mitsunobu reaction being inappropriate for steric reasons
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Agarwal, Sameer. "Transition Metal-Mediated Syntheses of Yohimbane and Indolizidine Alkaloids." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2005. http://nbn-resolving.de/urn:nbn:de:swb:14-1119360417222-39155.
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Polycyclic nitrogen containing heterocycles form the basic skeleton of numerous alkaloids and physiologically active drugs. Alloyohimbane was obtained from 3,4-dihydro-â-carboline using an iron-mediated [2+2+1] cycloaddition as the key-step. The bis-TMS-diyne was conveniently obtained by the C-alkylation of 3,4-dihydro-â-carboline followed by N-alkylation. Demetalation of the iron-complex followed by hydrogenation, E-ring expansion, and reduction provided alloyohimbane, a structurally and biologically interesting substance, via a linear eight-step sequence in 7% overall yield based on 3,4-dihydro-â-carboline. Another sequence provided (±)-alloyohimbane and (±)-3-epi-alloyohimbane in nine steps. The pyrrole unit occurs in a variety of naturally occurring compounds, pharmaceutical products and polymers. A novel two-step procedure for the synthesis of pyrroles by addition of a propargyl Grignard reagent to a Schiff base and subsequent silver(I)-promoted oxidative cyclization of the resulting homopropargylamine has been developed. The generality of this reaction was proven by the synthesis of a broad variety of substituted pyrroles using silver(I)-promoted cyclization. A three-step synthesis of (±)-harmicine, a natural product isolated from the Malaysian plant Kopsia griffithii having strong anti-leishmania activity, from 3,4-dihydro-â-carboline is achieved by addition of 3-trimethylsilylpropargyl Grignard reagent, Ag(I)-promoted oxidative cyclization to a pyrrole, and chemoselective hydrogenation of pyrrole ring. Total synthesis of anti-tumor active crispine A and biologically active 1,2,3,5,6,10b-hexahydropyrrolo[2,1-a]isoquinoline have been achieved in three steps using silver(I)-promoted oxidative cyclization as key step.
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Kondakal, Vishnu. "The attempted synthesis of indolizidine and pyrrolizidine natural products." Thesis, University of Huddersfield, 2013. http://eprints.hud.ac.uk/id/eprint/19281/.
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Aza-sugars are naturally occurring polyhydroxylated alkaloids in which the ring oxygen is replaced by nitrogen. They are reported to have a wide range of biological properties, most importantly as glycosidase inhibitors; these glycosidases play a key role in various diseases like HIV, cancer and lysosomal storage disorders. This thesis will describe an approach to the synthesis of analogues and precursors of azasugar natural products in the indolizidine (for example castanospermine) and pyrrolizidine (for example hyacinthacine) using cyclopropenones and cyclic imines as key intermediates. This thesis contains work that is an extension of the work pioneered by Eicher and Heimgartner and followed by our group for the reaction of cyclic imines with diphenylcyclopropenone. The methodology was extended towards the synthesis of more complex bicyclic heterocycles like indolizidine and pyrrolizidine aza-sugars and is summarised by the following Scheme. In this thesis, cyclopropenones other than diphenylcyclopropenone were used. This work also extended the range of cyclic imines that can be reacted by using for the first time, the parent aldimines, polyhydroxylated cyclic aldimines synthesised from sugars and other substituted cyclic imines. The reactions gave bicyclic products but always with an extra oxygen at the bridge head postion (X= OH) via aerial oxidation of the initial product (X= H).
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Szeto, Peter. "Recent development in indolizidine alkaloids : a synthesis of (-)-slaframine." Thesis, University of Bristol, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.294850.
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Kefalas, Panagiotis. "Synthèse asymétrique d'une indolizidine hydroxylée, analogue de la castanospermine." Grenoble 2 : ANRT, 1988. http://catalogue.bnf.fr/ark:/12148/cb37614731r.
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Farrant, Elizabeth. "A novel approach to the synthesis of polyhydroxylated indolizidine alkaloids." Thesis, University of Reading, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.360718.
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Cuthbertson, James D. "New routes to indolizidine alkaloids : the total synthesis of (-)-grandisine B." Thesis, University of York, 2011. http://etheses.whiterose.ac.uk/1970/.
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The plant family Elaeocarpaceae has been the source of a plethora of structurally related alkaloids isolated over the last 50 years. This Thesis describes our synthetic approaches to (−)-grandisine B I, a bioactive indolizidine alkaloid isolated from Elaocarpus grandis in 2005. An overview of alkaloids isolated from the family Elaeocarpaceae is provided and preliminary studies into the synthesis of grandisine B I are described (Chapters 1 and 2). Novel routes to bicyclic lactams II and isoquinuclidinone frameworks III have been developed using aqueous ammonia in a one-pot amination/cyclisation sequence (Chapters 3 and 4). The scope of the developed methodology was initially demonstrated with a concise synthesis of the alkaloid (−)-mearsine V. A biomimetic synthesis of (±)-grandisine B I, using the alkaloid grandisine D IV as a synthetic precursor, is then described in Chapter 5. The development of a formic acid mediated alkyne/acetal cyclisation for the synthesis of heterocyclic scaffolds is also reported. The scope and limitations of the methodology are discussed and applications of the methodology in the synthesis of (−)-grandisine B I and structurally related Elaeocarpus alkaloids are described (Chapter 6).
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Fox, Martin Edward. "Intramolecular cycloaddition reactions of nitrones and hydroxylamines." Thesis, University of Cambridge, 1992. https://www.repository.cam.ac.uk/handle/1810/272243.
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Santarem, Marco. "Synthèse diastéréosélective d’alcaloïdes tricycliques : la (+)-géphyrotoxine et les myrmicarines (-) 217, (+)-215A et (-)-215B." Paris 6, 2010. http://www.theses.fr/2010PA066738.
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Le motif pyrrolidinique est présent dans un grand nombre de composés naturels et (ou) biologiquement actifs. Les stratégies de synthèse stéréosélective de pyrrolidines sont nombreuses, mais il existe très peu de méthodologies permettant d’accéder à des pyrrolidines cis 2,5-disubstituées fonctionnalisées et énantiopures. Au cours de ce travail, nous avons effectué la synthèse totalement diastéréosélective d’une pyrrolidine cis 2,5-disubstituée énantiopure par réduction stéréocontrôlée d’un β-énaminoester oxazolidinique obtenu par condensation du (S)-phénylglycinol sur un ω-oxo-β-cétoester correctement fonctionnalisé. Ceci nous a permis de réaliser une synthèse formelle efficace de la (+) géphyroxine, alcaloïde tricyclique extrait de la peau d’une grenouille colombienne. Nous avons ensuite mis en place des stratégies générales de synthèse de structures indolizidinique et pyrrolizinique fonctionnalisées. À partir de la même pyrrolidine énantiopure cis 2,5-disubstituée, nous avons ainsi pu accéder diastéréosélectivement à un composé tricyclique, intermédiaire clé dans la synthèse totale des myrmicarines (-)-217, (+)215A et (-)-215B, alcaloïdes extraits du venin de fourmis africaines
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Tumidajski, Stephanie. "[4 + 2] cycloadditions of iminoacetonitriles : synthesis of highly substituted tetrahydropyridines and indolizidine alkaloids." Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/84378.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 2013.Cataloged from PDF version of thesis.
Includes bibliographical references.
Iminoacetonitriles participate as activated imino dienophiles in intermolecular and intramolecular aza Diels-Alder reactions affording tetrahydropyridines and indolizidines. The [alpha]-amino nitrile cycloadducts are versatile synthetic intermediates that participate in a variety of stereoselective transformations to further elaborate the six-membered ring. This thesis describes the scope of the intermolecular [4 + 2] cycloaddition of N-benzyliminoacetonitrile with unactivated and activated dienes, as well as, the synthetic elaboration of the cycloadducts. This thesis also describes the worked performed to complete the total syntheses of indolizidines (-)- 235B', (-)-235B", and (+)-235B" using the aza Diels-Alder reaction of an iminoacetonitrile as the key step.
by Stephanie Tumidajski.
Ph.D.
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Lu, Yuanyuan. "Indolizidine and quinolizidine motifs for the synthesis of conformationally constrained smac mimetics and chloroquine conjugates." Doctoral thesis, Universitat Autònoma de Barcelona, 2014. http://hdl.handle.net/10803/283725.
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L’esquelet d’indolizidina o quinolizidina és present a molts productes naturals i sintètics, alguns del quals presenten activitats biològiques diverses. Aquesta tesi es centra en la preparació estereoselectiva de derivats quirals d’indolizidina i quinolizidina amb un doble propòsit: i) com a precursors de peptidomimètics d’Smac conformacionalment limitats i ii) per formar conjugats amb residus de cloroquina a la recerca de nous fàrmacs antimalàrics contra soques resistents.
Pel primer propòsit, s’ha aplicat una aproximació prèviament desenvolupada en el nostre grup per a la síntesi estèreo-controlada d’indolizidines i quinolizidines N-substituïdes. La primera etapa clau de la seqüència és l’al·lilació enantioselectiva de succinimida i glutarimida amb monòxid de butadiè racèmic catalitzada per pal·ladi, on la configuració absoluta del producte al·lilat ve marcada pel sentit de quiralitat del lligand del pal·ladi. Les etapes restants fins als azabicicles fusionats inclogueren la reducció regioselectiva de la imida, una al·lilació nucleòfila i una metàtesi de tancament d’anell (RCM). Eventualment, les configuracions dels intermedis i productes es varen establir mitjançant anàlisi per difracció de raigs X.
Posteriorment, aquesta estratègia es va estendre a substrats del tipus α-amino succinimida i glutarimida. Per a derivats d’indolizidina, la nova seqüència va partir de l’àcid L-aspàrtic, que es convertí en pocs passos en (3S)-3-amino-2,5-pirrolidinodiona. L’al·lilació asimètrica sobre aquest substrat va resultar satisfactòria, conduint a un únic estereoisòmer. S’aconseguí la reducció regioselectiva clau utilitzant DIBAL-H i l’al·lilació nucleòfila i RCM consecutives van portar a l’α-aminoindolizidina esperada, com a una barreja equilibrada de dos epímers, la configuració relativa dels quals es va establir mitjançant experiments de RMN, incloent espectres COSY i NOSY. Els estudis per a obtenir els peptidomimètics d’indolizidina s’estan desenvolupant actualment. Pels anàlegs de tipus α-aminoquinolizidina, es va explorar una seqüència paral·lela a partir de l’àcid L-glutàmic. Malauradament, l’al·lilació asimètrica no va portar al producte esperat i la substitució del lligand del pal·ladi per PPh3 no va resultar prou resolutiva. Els resultats d’alguns intents realitzats amb diferents grups protectors de l’àtom de nitrogen també van ser negatius i s’examinaran més detalladament en un futur.
Pel segon propòsit, es varen considerar dues aproximacions alternatives depenent del caràcter nucleòfil o electròfil de cada reactiu. A tal fi, es van preparar varis azabicicles i derivats de cloroquina nucleòfils i electròfils. Lamentablement, en les reaccions explorades fins ara, els conjugats esperats no van ser mai detectats.The indolizidine and quinolizidine framework is present in many natural and synthetic compounds, some of which display diverse bioactivities. This thesis focuses on the stereoselective preparation of chiral indolizidine and quinolizidine derivatives with a double purpose: i) as precursors of conformationally constrained Smac peptidomimetics and ii) to form conjugates with chloroquine residues, in the search for new antimalarial drugs against resistant strains. For the first purpose, it has been applied an approach previously developed in our group for the stereocontrolled synthesis of N-substituted indolizidines and quinolizidines. The first key step of the sequence is the palladium-catalyzed enantioselective allylation of succinimide and glutarimide with racemic butadiene monoxide, wherein the absolute configuration of the allylated products is controlled by the sense of chirality of the palladium ligand. The next steps to the fused azabicyclic compounds included regioselective reduction of the imide, followed by nucleophilic allylation and then ring closing metathesis (RCM). In the event, the configurations of the intermediates and products were established by X-ray diffraction analysis. This strategy was later on extended to α-amino succinimide and glutarimide substrates. The new sequence for the indolizidine derivatives started from L-aspartic acid, which was converted into a protected (3S)-3-amino-2,5-pyrrolidinedione in a few steps. The asymmetric allylation worked well on this substrate, providing a unique stereoisomer. The key regioselective reduction was achieved by using DIBAL-H, and the subsequent nucleophilic allylation and RCM furnished the expected α-aminoindolizidine as a balanced mixture of two epimers. Their relative and absolute configuration was inferred from NMR experiments, including COSY and NOESY spectra. The conversion of these intermediates into the targeted indolizidine peptidomimetics is currently in progress. For the α-aminoquinolizidine analogs, a parallel sequence starting from L-glutamic acid was explored. Unfortunately, in this case the asymmetric allylation did not furnish the expected product and the replacement of the palladium ligand by PPh3 showed limited assistance. Several attempts with a different nitrogen protection were also negative and will be re-examined in the future. For the second purpose, two alternative approaches were considered depending of the nucleophilic or electrophilic character of each reaction partner. With this aim, several nucleophilic and electrophilic azabicycles and chloroquine derivatives were prepared. Unluckily, in the different reactions explored up to now, the expected conjugate was never detected.
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Katavic, Peter L., and n/a. "Chemical Investigations of the Alkaloids from the Plants of the Family Elaeocarpaceae." Griffith University. School of Science, 2006. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20070710.160928.
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A phytochemical survey to detect alkaloids was performed on extracts of 339 discrete plants parts from a total of 77 species from five genera of Elaeocarpaceae, including 30 species from Queensland, 38 from PNG, and nine from China. An alkaloid detecting reagent, bismuth (III) tetraiodide (Dragendorff's reagent) was used in a preliminary test for alkaloids, with positive ESIMS used to confirm the presence of alkaloids. A total of 35 extracts of various plant parts produced positive results with Dragendorff's reagent. Positive ESIMS detected alkaloids in only 13 of these extracts. Bismuth (III) tetraiodide was demonstrated to produce false positive results with the new non-alkaloidal poly-oxygenated compounds 112 and 113, which were purified from the extract of Sloanea tieghemii. Two new alkaloid producing species, Elaeocarpus habbeniensis, and E. fuscoides were detected from the survey. These species were chemically investigated for the first time. Two other previously investigated species, E. grandis and Peripentadenia mearsii, were also studied. A total of 16 alkaloids, 11 of which are new, were purified from the extracts of these four species. The novel pyrrolidine alkaloids habbenine (114) and peripentonine (123), were isolated from the leaves of E. habbeniensis and Peripentadenia mearsii, respectively. Both of these compounds were purified as inseparable mixtures of diastereomers. The new pyrrolidine alkaloid mearsamine 1 (124), and the novel amino alkaloid mearsamine 2 (125), were also purified from the leaves of P. mearsii. The known pyrrolidine alkaloid peripentadenine (81), was purified from the bark of P. mearsii. Peripentonine (123) was reduced to peripentadenine (81) upon reaction with Pd/C. Four aromatic indolizidine alkaloids were isolated from the extract of the leaves of E. fuscoides. One new compound, elaeocarpenine (122), was isolated from this New Guinean plant. Three known Elaeocarpus alkaloids, isoelaeocarpicine (62), elaeocarpine (60) and isoelaeocarpine (61) were also purified from E. fuscoides. Elaeocarpenine (122) was demonstrated to produce the epimeric compounds elaeocarpine and isoelaeocarpine via reaction with ammonia. The chemical investigation of the Queensland plant E. grandis by two separate purification procedures was performed. An SCX/C18 isolation protocol was used to purify the new indolizidine alkaloids grandisine C (127), D (126), and E (128), in conjunction with the known tetracyclic indolizidine isoelaeocarpiline (63). The second purification of E. grandis was achieved with the use of ammonia in an acid/base partitioning protocol. Grandisine F (129) and G (130), and compounds 131a and b were purified by this procedure, as were 63, 126 and 127. Grandisine F and G were proposed to be ammonia adducts of grandisine D (126). Compound 131a and b were isolated as a mixture of diastereomers. The reduction of grandisine D (126) with Pd/C yielded a mixture of isoelaeocarpine (61) and elaeocarpine (60), whereas the reduction of isoelaeocarpiline (63) produced isoelaeocarpine (61). All of the alkaloids isolated from the Elaeocarpaceae, except grandisine E (128) and 131a and b, were evaluated for binding affinity against the human ? opioid receptor. Every compound except mearsamine 2 (125) possessed a binding affinity of less than 100 ?M. The most active compounds were grandisine F (129), D (126), C (127), elaeocarpenine (122), isoelaeocarpine (61), isoelaeocarpiline (63) and peripentadenine (81). The IC50 values for these compounds were 1.55, 1.65, 14.6, 2.74, 13.6, 9.86 and 11.4 ?M, respectively. The SAR of the active compounds was compared. These observations indicated that the indolizidine alkaloids were more active than the pyrrolidine alkaloids, and a phenol or ketone at position C-12 of the indolizidine alkaloids produced better binding affinity. All of these alkaloids, except 129, were proposed to interact with two of the three binding domains of the ? opioid receptor. Grandisine F (129) was proposed to have a different mode of action than the other alkaloids in the series. Synthetic modifications to isoelaeocarpine (61) and peripentadenine (81) were investigated in an attempt to incorporate an extra aromatic group into these molecules. An extra aromatic group was proposed to provide increased binding affinity to the ? opioid receptor by interaction with the third binding domain of the receptor. Two different aromatic amines were successfully attached to peripentadenine (81) by a reductive amination reaction using NaBH(OAc)3 and a titanium catalyst. The reductive amination of the ketone in isoelaecarpine (61) with various amines and NaBH(OAc)3 or NaBH4 proved unsuccessful.
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Fellah, Mouloud. "Synthèses diastéréosélectives de l’indolizidine (+)-223A, de la (-)-lasubine II et de la quinolizidine (-)-217A." Paris 6, 2009. http://www.theses.fr/2010PA066034.
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Les cycles indolizidiniques et quinolizidiniques sont présents dans de nombreux alcaloïdes ainsi que dans des molécules possédant des activités biologiques intéressantes. La recherche de nouvelles voies d’accès à ce type de composés est donc un enjeu important, le travail effectué au cours de cette thèse s’inscrit dans cette thématique. Notre stratégie de synthèse repose sur les intermédiaires clefs β-énaminoesters pyrrolidiniques et pipéridiniques chiraux dont les réductions diastéréosélectives conduisent respectivement à des pyrrolidines et à des pipéridines fonctionnalisées énantiopures comprenant les premiers centres stéréogènes des alcaloïdes cibles. Les derniers centres asymétriques sont, quant à eux, obtenus par hydrogénation diastéréosélective après aménagement fonctionnel. Cette méthodologie a été adaptée en fonction des alcaloïdes cibles et a ainsi permis de préparer avec de bons rendements et de façon énantiopure trois alcaloïdes : l’indolizidine (+)-223A, (-)-lasubine II et la quinolizidine ( ) 217A
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Katavic, Peter L. "Chemical Investigations of the Alkaloids from the Plants of the Family Elaeocarpaceae." Thesis, Griffith University, 2006. http://hdl.handle.net/10072/367380.
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A phytochemical survey to detect alkaloids was performed on extracts of 339 discrete plants parts from a total of 77 species from five genera of Elaeocarpaceae, including 30 species from Queensland, 38 from PNG, and nine from China. An alkaloid detecting reagent, bismuth (III) tetraiodide (Dragendorff's reagent) was used in a preliminary test for alkaloids, with positive ESIMS used to confirm the presence of alkaloids. A total of 35 extracts of various plant parts produced positive results with Dragendorff's reagent. Positive ESIMS detected alkaloids in only 13 of these extracts. Bismuth (III) tetraiodide was demonstrated to produce false positive results with the new non-alkaloidal poly-oxygenated compounds 112 and 113, which were purified from the extract of Sloanea tieghemii. Two new alkaloid producing species, Elaeocarpus habbeniensis, and E. fuscoides were detected from the survey. These species were chemically investigated for the first time. Two other previously investigated species, E. grandis and Peripentadenia mearsii, were also studied. A total of 16 alkaloids, 11 of which are new, were purified from the extracts of these four species. The novel pyrrolidine alkaloids habbenine (114) and peripentonine (123), were isolated from the leaves of E. habbeniensis and Peripentadenia mearsii, respectively. Both of these compounds were purified as inseparable mixtures of diastereomers. The new pyrrolidine alkaloid mearsamine 1 (124), and the novel amino alkaloid mearsamine 2 (125), were also purified from the leaves of P. mearsii. The known pyrrolidine alkaloid peripentadenine (81), was purified from the bark of P. mearsii. Peripentonine (123) was reduced to peripentadenine (81) upon reaction with Pd/C. Four aromatic indolizidine alkaloids were isolated from the extract of the leaves of E. fuscoides. One new compound, elaeocarpenine (122), was isolated from this New Guinean plant. Three known Elaeocarpus alkaloids, isoelaeocarpicine (62), elaeocarpine (60) and isoelaeocarpine (61) were also purified from E. fuscoides. Elaeocarpenine (122) was demonstrated to produce the epimeric compounds elaeocarpine and isoelaeocarpine via reaction with ammonia. The chemical investigation of the Queensland plant E. grandis by two separate purification procedures was performed. An SCX/C18 isolation protocol was used to purify the new indolizidine alkaloids grandisine C (127), D (126), and E (128), in conjunction with the known tetracyclic indolizidine isoelaeocarpiline (63). The second purification of E. grandis was achieved with the use of ammonia in an acid/base partitioning protocol. Grandisine F (129) and G (130), and compounds 131a and b were purified by this procedure, as were 63, 126 and 127. Grandisine F and G were proposed to be ammonia adducts of grandisine D (126). Compound 131a and b were isolated as a mixture of diastereomers. The reduction of grandisine D (126) with Pd/C yielded a mixture of isoelaeocarpine (61) and elaeocarpine (60), whereas the reduction of isoelaeocarpiline (63) produced isoelaeocarpine (61). All of the alkaloids isolated from the Elaeocarpaceae, except grandisine E (128) and 131a and b, were evaluated for binding affinity against the human ? opioid receptor. Every compound except mearsamine 2 (125) possessed a binding affinity of less than 100 ?M. The most active compounds were grandisine F (129), D (126), C (127), elaeocarpenine (122), isoelaeocarpine (61), isoelaeocarpiline (63) and peripentadenine (81). The IC50 values for these compounds were 1.55, 1.65, 14.6, 2.74, 13.6, 9.86 and 11.4 ?M, respectively. The SAR of the active compounds was compared. These observations indicated that the indolizidine alkaloids were more active than the pyrrolidine alkaloids, and a phenol or ketone at position C-12 of the indolizidine alkaloids produced better binding affinity. All of these alkaloids, except 129, were proposed to interact with two of the three binding domains of the ? opioid receptor. Grandisine F (129) was proposed to have a different mode of action than the other alkaloids in the series. Synthetic modifications to isoelaeocarpine (61) and peripentadenine (81) were investigated in an attempt to incorporate an extra aromatic group into these molecules. An extra aromatic group was proposed to provide increased binding affinity to the ? opioid receptor by interaction with the third binding domain of the receptor. Two different aromatic amines were successfully attached to peripentadenine (81) by a reductive amination reaction using NaBH(OAc)3 and a titanium catalyst. The reductive amination of the ketone in isoelaecarpine (61) with various amines and NaBH(OAc)3 or NaBH4 proved unsuccessful.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Science
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Bur, Scott Kenneth. "Studies on the vinylogous Mannich reaction and its application to the synthesis of indolizidine natural products /." Digital version:, 2000. http://wwwlib.umi.com/cr/utexas/fullcit?p9992758.
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Kawamura, Meire Yasuko. "Emprego de diazocetonas α,β-insaturadas com geometria Z na direta construção de esqueletos indolizidínicos e piperidínicos funcionalizados." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/75/75133/tde-26082016-104019/.
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Pumiliotoxinas e seus congêneres são compostos isolados da pele de algumas espécies de sapos das famílias Dendrobatidae, Mantellidae, Bufonidae, e Myobatrachidae, apresentando interessantes propriedades farmacológicas. As pumiliotoxinas, embora tóxicas, apresentam consideráveis atividades cardiotônicas, assim, acredita-se que as homopumiliotoxinas, as desmetilpumiliotoxinas e as desidrodesmetilpumiliotoxinas também devam apresentar. Nesse sentido, a síntese destes compostos é de extrema valia para a comunidade científica. As diazocetonas α,β-insaturadas são intermediários promissores para a síntese rápida e eficiente de diversos tipos de esqueletos químicos, entre eles, a construção do esqueleto indolizidínico presentes nas pumiliotoxinas. Cabe ressaltar que para as diazocetonas α,β-insaturadas com geometria Z provenientes de amino aldeídos, elas já apresentam a estereoquímica correta para uma direta ciclização para a construção de esqueletos indolizidínicos. Dessa forma, as etapas chaves do trabalho consistiram na preparação de amino aldeídos N-protegidos, na avaliação da reação de Horner-Wadsworth-Emmons para fornecer as diazocetonas α,β-insaturadas com geometria Z, e na reação de inserção N-H intramolecular para a obtenção do ciclo indolizidínico. Outra parte do trabalho consistiu na síntese de imino açúcares de esqueleto piperidínico com cadeias laterais alifáticas (aplicação na química medicinal) e da (-)-1deoxi-altronojirimicina, utilizando-se a mesma metodologia (uso de diazocetonas α,β-insaturadas com geometria Z).Pumiliotoxins and their congeners are a class of compounds isolated from the skin of some frogs from the Dendrobatidae, Mantellidae, Bufonidae, e Myobatrachidae families, possessing interesting pharmacological activities (cardiotonic activity in low concentrations). Because of the big number of compounds among these toxins (about 100), synthetic methodologies that provide the preparation of these compounds (as well as analogues) in great amounts and in a fast and efficient way using common intermediates, are very important for application in chemical-biology. The α,β-unsaturated diazoketones are promising intermediates for the rapid and efficient synthesis of a range of chemical skeletons, among them, the construction of indolizidine skeleton that pumiliotoxins present. It is important to note that α,β-unsaturated diazoketones with Z geometry (prepared from amino aldehydes) have already the correct stereochemistry for a direct cyclization to construct indolizidine skeletons. The key steps of the work consisted in the preparation of N-protected amino aldehydes, evaluation of Horner-Wadsworth-Emmons reaction in order to obtain α,β-unsaturated diazoketones with Z geometry, and the intramolecular N-H insertion reaction to provide the indolizidine cycle. Another part of the work consisted in the synthesis of iminosugars with piperidine core and aliphatic side chains (application in medicinal chemistry) and in the synthesis of (-)-1-deoxy-altronojirimycin, applying the same methodology (use of α,β-unsaturated diazoketones with Z geometry).
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Bertonha, Ariane Fernandes. "Construção do esqueleto 6-aril indolizidínico a partir de α-clorocetonas derivadas da (S)-prolina: síntese da (S)-desoxiipalbidina." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/75/75133/tde-03072014-144521/.
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A estrutura básica dos alcaloides indolizidínicos é formada por anéis bicíclicos de cinco e seis membros contendo um átomo de nitrogênio compartilhado na posição 4. Esse sistema de anéis possui grande destaque dentre os alcaloides, pois está presente em um grande número de compostos e apresenta um interessante perfil biológico. A ipalbidina, por exemplo, é um alcaloide indolizidínico com propriedades analgésicas e antioxidantes. Este composto possui estrutura química relativamente simples, entretanto, poucas são as rotas que apresentam sínteses curtas e divergentes, sendo apenas quatro delas enantiosseletivas. Assim, este trabalho de dissertação visa o estudo de uma nova estratégia sintética que permite a preparação da (+)-ipalbidina, bem como de outros alcaloides que possuem o sistema 4-azabiciclo[4.3.0]-non-3-eno com um substituinte fenólico na posição 3. Uma rota promitente para a síntese desses alcaloides (objetivo deste trabalho) é a obtenção do esqueleto indolizidínico a partir da reação de ciclização de uma α-clorocetona funcionalizada derivada do (S)-prolinal protegido (Boc e Cbz). As etapas chaves dessa estratégia são: uma reação de olefinação (Wittig), a preparação de α-clorocetonas, adição do grupo aril a α-clorocetona e a conversão destas no esqueleto indolizidínico por uma reação de ciclização. A α-clorocetona pode ser preparada com rendimentos globais de 56% (Cbz) e 81% (Boc) a partir do (S)-prolinal protegido em apenas 3 etapas: reação de olefinação, seguida de uma reação de redução da olefina obtida e a preparação da α-cloroacetona a partir do éster. A adição do grupo aril a α-clorocetona foi obtida tanto para o grupo Boc (40%) quanto para o grupo Cbz (42%). O α-cloroálcool protegido com Boc foi convertido no esqueleto indolizidínico por meio de uma reação \"one-pot\" de desproteção seguida de ciclização (80%). O produto de ciclização, por sua vez, foi convertido ao análogo inédito da (+)-ipalbidina, a (S)-desoxiipalbidina (30%). Essa estratégia levou a síntese da (S)-desoxiipalbidina em 6 etapas e com rendimento global de 8%. Cabe ressaltar que este tipo de abordagem utilizando α-clorocetonas nunca foi empregado na síntese de alcaloides indolizidínicos, sendo que esta estratégia também poderá ser aplicada a síntese total da (+)-ipalbidina e de outros alcaloides indolizidínicos tais como as fenantroindolizidinas.The basic structure of indolizidine alkaloids is formed by a five and sixmembered bicyclic ring containing one nitrogen atom shared at the 4 position. This ring system has great prominence among the alkaloids, it is present in a large number of compounds and possess interesting biological profiles. Ipalbidine, for example, is an indolizidine alkaloid with analgesic and anti-oxidant properties. Although this compound has a relatively simple chemical structure, only four enantioselective synthesis are described for this compound. Thus, this dissertation aims to study a new synthetic strategy that allows the preparation of (+)-ipalbidine, as well as other alkaloids having the system 4- azabicyclo[4.3.0]non-3-ene with a phenolic substituent in position 3. A possible interesting route for the synthesis of these alkaloids is to obtain the indolizidine skeleton from a cyclization reaction using a functionalized α-chloroketone (derivative of protected (S)-prolinal (Boc and Cbz)). The key steps of this strategy are: an olefination reaction (Wittig), the preparation of α-chloroketones, addition of aryl group to the α-chloroketones and converting them into the indolizidine skeleton by a cyclization reaction. The α-chloroketones were prepared with overall yields varying from 56 % (Cbz) to 81% (Boc) starting from protected (S)-prolinal in just three steps: olefination reaction , followed by a reduction reaction of the obtained olefin and preparation of the α-chloroketone from an ester . The addition step of the aryl group to α-chloroketone was obtained for both Boc (40%) and Cbz (42%) groups. The Boc-protected α-chloroalcohol was converted to indolizidine skeleton through an \"one-pot\" deprotection reaction, followed by a cyclization reaction (80 %). The cyclization product, in turn, was converted to the novel (+)-ipalbidine analog, (S)-desoxyipalbidine (30 %). This strategy led to the synthesis of (S)-desoxyipalbidine in 6 steps and overall yield of 8 %. It is noteworthy that this type of approach using α-chloroketones was never employed in the synthesis of indolizidine alkaloids, and that strategy can be applied also to the total synthesis of (+)-ipalbidine and other indolizidine alkaloids such as phenanthroindolizidine.
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Davis, Jonathan C. "Section one : photochemical methodologies towards the pyrrolizidine and indolizidine alkaloid skeleta; section two; synthesis of novel leukotriene photoaffinity labels." Thesis, University of Reading, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.360717.
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Outin, Johanne. "Synthèse de composés polycycliques azotés par cyclisation de Vilsmeier-Haack et cyclisation de Mannich organocatalysée en séquence." Thèse, Université de Sherbrooke, 2017. http://hdl.handle.net/11143/10979.
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Les recherches présentées dans cette thèse découlent de problématiques rencontrées lors de précédents travaux effectués dans notre groupe au sujet de cyclisations séquentielles de Vilsmeier-Haack et de Mannich par une activation chimiosélective d’amides. Deux limitations avaient été soulevées : une faible réactivité lors de la seconde cyclisation de Mannich et aucune possibilité d’obtention de produit de double cyclisation de façon énantiosélective.
Au chapitre un, une étude de double cyclisation de Vilsmeier-Haack et de Mannich est présentée, tout d’abord sur des substrats allylsilane-aldéhyde puis vératrol-aldéhyde. Une étude mécanistique est détaillée dans le but d’améliorer le rendement de la réaction. Les bases de notre méthodologie avec l’aldéhyde sont établies dans ce premier chapitre.
Au chapitre deux, une étude de double cyclisation de Vilsmeier-Haack et de Mannich en présence d’une cétone est exposée. Les conditions de première cyclisation sont rapidement déterminées tandis que pour la seconde étape, les divers paramètres pouvant influencer la réaction sont examinés. Aussi, une tentative de formation de centres quaternaires produisant des squelettes carbonés de type quinolizidine et spirocyclique est présentée, ainsi qu’une variation de tailles de cycles formés.
Au chapitre trois, l’étendue de notre méthodologie est étudiée et celle-ci est appliquée sur divers substrats. Les nucléophiles de type indole, pyrrole, éther d’énol et allylsilane sont couverts et la variation de taille de cycle est également testée.
Au chapitre quatre, une étude sur le développement catalytique et un effort vers une version non racémique de notre méthodologie sera présentée. Diverses amines secondaires chirales sont investiguées et les excès énantiomériques mesurés.
Le chapitre cinq propose des suites au projet de thèse, incluant des pistes au sujet de l’induction asymétrique en s’appuyant sur des exemples concrets de la littérature.
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CHALARD, PIERRE. "Cyclisation d'allylsilanes chiraux sur des ions n-acyliminium. Syntheses totales enantioselectives des ()-lasubines i et ii, (+)-subcosine ii et ()-indolizidine 167b." Clermont-Ferrand 2, 1999. http://www.theses.fr/1999CLF22093.
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Les alcaloides bicycliques a squelettes quinolizidine et indolizidine constituent une classe de composes tres importante, qui presentent pour la plupart de nombreuses activites biologiques. Nous avons developpe une nouvelle methode de synthese asymetrique de ces alcaloides basee sur la cyclisation intramoleculaire d'un allylsilane sur un ion n-acyliminium chiral. Les synthons de depart sont des -aminoesters chiraux obtenus par une reaction de michael enantioselective du lithien de l'-methylbenzylbenzylamine sur un ester ,-ethylenique. Ces synthons sont condenses sur l'anhydride glutarique ou succinique qui servent a edifier le premier cycle du squelette. L'allylsilane est prepare in situ a partir de la fonction ester. Sa cyclisation sur l'ion n-acyliminium conduit aux squelettes quinolizidine et indolizidine avec une bonne diastereoselectivite. Les amenagements fonctionnels ulterieurs permettent la synthese des quinolizidines et indolizidines naturelles. Cette methode a ete appliquee a la synthese de trois alcaloides a squelette quinolizidine : les ()-lasubines i et ii, obtenues en 6 etapes avec des rendements respectifs de 7% et 14%, et la (+)-subcosine ii, obtenue en 7 etapes avec un rendement global de 9%. Ce sont les premieres syntheses asymetriques de la ()-lasubine ii et de la (+)-subcosine ii decrites a ce jour. Nous avons egalement prepare un alcaloide a squelette indolizidine, la ()-indolizidine 167b, en 7 etapes avec un rendement global de 17%. Les alcaloides sont obtenus avec des exces enantiomeriques superieurs a 90%. Cette methode est suffisamment generale pour etre appliquee a la synthese d'une grande variete d'alcaloides bicycliques.
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Teodoro, Bruno Vinicius Motta 1985. "Síntese de núcleos indolizidínicos a partir de adutos de Morita-Baylis-Hillman. Avaliação de uma metodologia para a dessimetrização de adutos de Morita-Baylis-Hillman." [s.n.], 2014. http://repositorio.unicamp.br/jspui/handle/REPOSIP/250238.
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Orientador: Fernando Antonio Santos CoelhoDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Química
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Resumo: Esta dissertação de mestrado está dividida em duas partes. Na primeira parte descrevemos os resultados obtidos na síntese de núcleos indolizidínicos, a partir de adutos de Morita-Baylis-Hillman (MBH). Na segunda parte, descrevemos os resultados obtidos na avaliação de uma reação de dessimetrização de adutos de MBH. Os núcleos indolizidínicos representam um padrão estrutural de grande interesse sintético, pois existem inúmeros alcaloides, com atividade biológica pronunciada, que contêm este núcleo. A metodologia desenvolvida nesse trabalho permite a preparação de núcleos indolizidínicos, a partir de adutos de MBH, em duas etapas. Assim, uma reação de ciclização intramolecular de um aduto, gera indolizinas que, após uma reação de hidrogenação total, conduz as indolizidinas. A rota desenvolvida é rápida, simples, eficiente e estereosseletiva. Os rendimentos globais variaram de 43 a 55%. Os excessos diastereoisoméricos obtidos variaram entre 68 e 86%, em favor do isômero cis. Nesta parte do trabalho avaliamos também um procedimento para preparar tetraidroindolizinas, a partir da hidrogenação parcial das indolizinas. Usando a mesma estratégia, descrevemos a preparação de tetraidroindolizinas com rendimentos que variaram entre 40-93%. Na segunda parte desse trabalho avaliamos uma alternativa de dessimetrização de adutos de MBH. A redução de ?-ceto-?-metileno-ésteres, obtidos a partir de uma reação de oxidação de adutos de MBH racêmicos, nos permite acessar a esses adutos em suas formas enantiomericamente puras. Após realizar uma triagem de catalisadores de redução assimétrica, a melhor condição encontrada nos forneceu o aduto de MBH enantioenrriquecidos, com um rendimento de 25% e um excesso enantiomérico de 68%, utilizando o catalisador CBS. A partir deste dado, outros estudos poderão ser realizados visando verificar a generalidade do método desenvolvido
Abstract: This work is divided in two parts. In the first part, we described the development of a strategy for preparing indolizidine skeletons starting from Morita-Baylis-Hillman (MBH) adducts. In the second part, the preliminary results of study for the desymmetrization of MBH adducts is reported. The indolizidine core is a structural pattern of great synthetic interest since it's present in the structure of several alkaloids with remarkable biological activity. The two-step methodology developed in this work allowed the efficient preparation of indolizidine nucleus from MBH adducts. Thus, an intramolecular cyclization reaction of MBH adducts derived from 2-pyridine-carboxaldehyde followed by platinum mediated hydrogenation affords the indolizidines in good overall yield. The developed methodology is simple, fast and stereoselective. The overall yields ranged from 43 and 55% and the diastereoisomeric excesses obtained ranged from 68 to 86%, in favor of the cis isomer. The partial hydrogenation of the indolizines allowed the preparation of tetrahydroindolizines. Thus, using the same strategy, we also described the preparation of tetrahydroindolizines with yields ranging from 40-93 %. In the second part of this work we described the preliminary results of an evaluation of an alternative desymmetrization strategy of MBH adducts. The reduction of ?-keto-?-methylene esters obtained from an oxidation of racemic MBH adducts could allow us to access these adducts in their enantiomerically pure forms. A screening of asymmetric reduction catalysts showed us that the CBS catalyst provided the best condition. An enantioenriched MBH adduct was obtained in 25% yield and 68% enantiomeric excess. This result will stimulate new studies in order to check the scope of this method
Mestrado
Quimica Organica
Mestre em Química
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Pinho, Vagner Dantas. "Abordagens divergentes na preparação de alcaloides indolizidínicos." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/75/75133/tde-30072013-093827/.
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O presente trabalho descreve 3 abordagens divergentes para obtenção do esqueleto bicíclico presente nos alcaloides indolizidínicos. A primeira abordagem consiste no desenvolvimento de um novo método de preparação de diazocetonas α,β-insaturadas a partir da reação de Horner-Wadsworth-Emmons (HWE) entre diazofosfonato e aldeídos. As dizocetonas α,β-insaturadas obtidas foram utilizadas como bloco de construção do esqueleto cabocíclico indolizidínico, onde o intermediário chave foi obtido através do rearranjo de Wolff. A segunda estratégia consiste no desenvolvimento do acoplamento redutivo entre derivados α-aminocarbonílicos e acrilato de metila mediado por SmI2, onde em apenas duas etapas foram obtidos os intermediários avançados da síntese da (-)-pumiliotoxina 251D e da (+/-)-epiquinamida. A terceira estratégia utiliza como etapa chave a reação de Wittig/HWE intramolecular para preparação do intermediário bicíclico contendo o sistema α,β-insaturado que pode ser utilizado na síntese divergente dessas substâncias.Herein were described three diverted oriented approaches for the construction of the bicyclic scaffold of indolizidines alkaloids, that figures between one of the most important classes of natural products. In the first approach, a new method to prepare α,β - unsaturated diazoketones was described using the Horner-Wadsworth-Emmons (HWE) reaction between diazophosphonate and aldehydes. The unsaturated diazoketones were used as powerful plataforms to construct the indolizidine carbocyclic scaffold, enploying the Wolff rearrangement as the key step. The second approach was the development of a reductive coupling between α-aminocarbonyl derivatives and methyl acrylate, mediate by SmI2, from this approach, the well-known advanced intermediate for the synthesis of (-)-pumiliotoxin 251D e of the (+/-)-epiquinamide was obtained in only two steps. The third approach uses the intermolecular Wittig/HWE reaction as the key step in the construction of a bicyclic intermediate containing an α,β -unsaturated moiety that could be used for a diverted oriented approach in the indolizidine alkaloids synthesis.
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Conegero, Leila de Souza. "Estudos visando a sintese de alcaloides pirrolizidinicos e indolizidinicos : aproveitamento da (+)-retronecina e do acido D-isoascorbico." [s.n.], 2006. http://repositorio.unicamp.br/jspui/handle/REPOSIP/249280.
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Orientador: Ronaldo Aloise PilliTese (doutorado) - Universidade Estadual de Campinas, Instituto de Quimica
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Resumo: O trabalho desenvolvido visou a obtenção de alcalóides pirrolizidínicos e indolizidínicos utilizando a (+)-retronecina (1) e o ácido D-isoascórbico (35D) como matérias primas, respectivamente. A retronecina (1) foi isolada da espécie vegetal Senecio brasiliensis. Para a preparação da base necínica (1R,6S,7S,8R)-7- (hidroximetil)-hexaidro-1H-pirrolizina-1,6-diol (37), a retronecina (1) foi submetida à reação de epoxidação com ácido meta-cloroperbenzóico. A a-epóxi-retronecina (44), após proteção das hidroxilas com cloreto de tercbutildimetilsilila, foi submetida à abertura com níquel de Raney, e a posterior desproteção forneceu o triol 37, que foi obtido em 5 etapas e 15 % de rendimento. Os compostos (1R,2R,7R,8S)-1-(hidroximetil)-hexaidro-1H-pirrolizina-1,2,7-triol (39) e a platinecina (72) foram preparados a partir de reações de diidroxilação e hidrogenação estereosseletiva da retronecina (1) em 70 e 86 % de rendimento, respectivamente. A abordagem síntética inicial para obtenção de alcalóides indolizidínicos foi baseada na adição do 2-terc-butildimetilsililoxifurano (94) ao íon N-acilimínio derivado da lactama 90. Em função do moderado rendimento e da modesta diastereosseletividade obtida foi proposta uma segunda abordagem sintética para obtenção de indolizidinas. Os alcalóides indolizidínicos, (1R,2S,8aR)- octaidroindolizina-1,2-diol (100) (ent-epi-lentiginosina) e (1R,2S,6R,7S,8aR)- octaidroindolizina-1,2,6,7-tetrol (101) foram preparados a partir da lactona 77. Os compostos 100 e 101 foram obtidos do intermediário-chave 82, que foi preparado a partir da adição de alilamina à lactona 77, derivada do ácido isoascórbico. Em seguida a hidroxiamida 82 foi oxidada à hidroxilactama correspondente, que foi submetida à reação de acetilação fornecendo o composto 91. Reação de alilação de 91, seguido de metátese de olefinas forneceu a indolizidinona 99. Reação de hidrogenação/hidroxilação de 99, redução da lactama e desproteção do acetal levou ao diol 100 e ao tetrol 101 em rendimentos de 27 e 31 %, respectivamente, a partir da lactona 77
Abstract: The aim of the present work was the synthesis of pyrrolizidine and indolizidine alkaloids using (+)-retronecine (1) and D-isoascorbic acid (35D) as starting materials, respectively. Retronecine (1) was isolated from the vegetal species Senecio brasiliensis. The synthesis of the necine base (1R,6S,7S,7aR)-7-(hydroxymethyl)-hexahydro-1H-pirrolizine-1,6-diol (37) was accomplished by the m-chloroperbenzoic acid epoxidation of retronecine (1). After hydroxyl protection with tert-butyldimethylsilyl chloride, epoxide 44 was subjected to ring opening with nickel Raney and deprotection to yield triol 37, in 5 steps and 15 % yield. Compounds (1R,7S,8R)-7-(hydroxymethyl)-hexahydro-1H-pirrolizin-1-ol (39) and platynecine (72) were prepared after stereoselective dihydroxylation and hydrogenation reactions of retronecine (1) in 70 and 86 % yield, respectively. The first approach to the synthesis of indolizidine alkaloids was based on the 2-tert-butyldimethylsilyloxyfuran addition to lactam 90-derived N-acyliminium ion. Due to moderate yield and diastereoselectivity obtained, a second synthetic approach to the synthesis of indolizidines was suggested. Indolizidine alkaloids 100 and 101 were prepared from lactone 77. Compounds 100 and 101 were obtained from key intermediate 82, which was prepared from allylamine addition to isoascorbic acid-derived lactone 77. Following that, hydroxyamide 82 was oxidized to the corresponding hydroxylactam which was subjected to acetylation, yielding compound 91. Allylation of 91 and subsequent ring closing olefin metathesisyielded indolizidinone 99. Hydrogenation/hydroxylation reaction of 99 followed by lactam reduction and deprotection of acetonide provided diol 100 and tetrol 101, in 27 and 31 % yield, respectively, from lactone 77
Doutorado
Quimica Organica
Doutor em Ciências
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Dener, Jeffrey Mark. "Part I, the enantioselective synthesis of pyrrolizidine alkaloids using alpha-acylamino radical cyclizations ; Part II, the enantioselective synthesis of the indolizidine alkaloid (-)-swainsonine using an alpha-acylamino radical cyclization /." The Ohio State University, 1988. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487591658176567.
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Pereira, Elaine. "Adição de enolatos de titanio derivados de N-acil-(4S)-4-isopropil-1,3-tiazolidin-2-tiona a ions N-aciliminios ciclicos : sintese assimetrica dos alcaloides (+)-isoretronecanol e (+)-5-epi-tashiromina." [s.n.], 2005. http://repositorio.unicamp.br/jspui/handle/REPOSIP/249250.
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Orientador: Ronaldo Aloise PilliDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Quimica
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Mestrado
Quimica Organica
Mestre em Química
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Buckley, L. "Transition Metal Approaches to Indolizidines." Thesis, Queen's University Belfast, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.527666.
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Thompson, Stephen Harold James. "Synthetic approaches towards polyhydroxylated indolizidines." Thesis, University of Bristol, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.260223.
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Howard, Steven. "The synthesis of polyhydroxy indolizidines." Thesis, University of Cambridge, 1994. https://www.repository.cam.ac.uk/handle/1810/272794.
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Giles, Melvyn Edward. "Novel synthetic approaches to polyhydroxylated indolizidines." Thesis, University of Bath, 1991. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.760620.
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Beck, Daniel Antony Speedie, and beckautomatic@gmail com. "Stereoselective intramolecular Michael addition reactions of pyrrole and their application to natural product syntheses." The Australian National University. Research School of Chemistry, 2006. http://thesis.anu.edu.au./public/adt-ANU20070130.130009.
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Chapter one; (-)-Rhazinilam and (-)-Rhazinal: Alkaloids with Anti-mitotic Properties Derived from Kopsia teoi, provides the background information behind the motives that initiated this research project. The plant alkaloid (-)-rhazinilam [(-)-1] and its naturally-occurring derivative (-)-rhazinal [(-)-13] both exhibit potent anti-mitotic activities and, as such, are interesting targets for total synthesis. Chapter one is a review of the literature regarding these two compounds and discusses the occurrence, proposed biosynthetic origins, structural elucidation and biological activites of compound (-)-1 and that of its analogues including alkaloid (-)-13. Previous total syntheses of these two compounds are then examined, concluding with the only reported total synthesis of compound (-)-13. Developed within the Banwell research group, this total synthesis produced the racemic modification of alkaloid (-)-13 due to a lack of any stereocontrol in the key intramolecular Michael addition step. This unprecedented key step, involving cyclisation of the C2 of pyrrole onto an N-tethered and ?,?-disubstituted acrylate to produce a quaternary-carbon stereogenic centre, would be of greatly enhanced utility if it could be achieved in a catalytic-enantioselective fashion. The realisation of this goal is the central aim of the research conducted within this thesis.
¶
Chapter two; Investigating Asymmetric Induction in the Intramolecular Michael Addition of pyrrole to N-Tethered Acrylates and Related Species, introduces the model study used to direct research towards achieving the goal of asymmetric induction in the title process. The model is a somewhat simplified version of the original process used in the total synthesis of compound (-)-13 involving cyclisation of the C2 of pyrrole onto an N-tethered and ?-monosubstituted Michael acceptor, to produce a tertiary-carbon stereogenic centre. This simplification allows the rapid synthesis of a broad range of potential substrates for use in the title process, thus enabling the investigation of various different approaches to inducing asymmetry therein. High levels of asymmetric induction are observed with the use of chiral substrates or catalysts, facilitating the synthesis of both 6- and 7-membered rings annulated to pyrrole with construction of the relevant tertiary-carbon stereogenic centre in enantio-enriched form. For the reactions producing a 6-membered ring annulated to pyrrole, unambiguous proof of the absolute sense of asymmetric induction observed in the intramolecular Michael addition event is established using a chemical correlation study involving elaboration of a key indolizine-type cyclisation product, to the plant alkaloid of known absolute stereochemistry, (-)-tashiromine [(-)-75]. For the reaction producing a 7-membered ring annulated to pyrrole, the same information is obtained via X-ray crystallographic analyses of a dibrominated derivative of a key pyrroloazepine-type cyclisation product.
¶
Chapter three An Enantioselective Total Synthesis of the Alkaloid (-)-Rhazinal: An Anti-mitotic Agent Isolated from Kopsia teoi., focuses on the application of methodology developed in the previous chapter, to the original goal of inducing asymmetry in the intramolecular Michael addition reaction, involving cyclisation of the C2 of pyrrole onto an N-tethered and ?,?-disubstituted acrylate to produce a quaternary-carbon stereogenic centre. This is ultimately achieved in a catalytic-enantioselective fashion, resulting in the first such total synthesis of the anti-mitotic alkaloid (-)-rhazinal [(-)-13].
¶
Chapter four Extending the Reaction Manifold to the Syntheses of Related Natural Products: A Formal Total Synthesis of (+)-Aspidospermidine and Syntheses of (-)-Rhazinilam and (-)-Leuconolam from (-)-Rhazinal, describes three extensions to the reaction manifold used in the enantioselective total synthesis of alkaloid (-)-13:
The acquisition in an enantioselective manner, of an intermediate previously obtained in racemic form, en route to the racemic modification of the natural product (±)-aspidospermidine [(±)-134], constitutes a formal and enantioselective total synthesis of (+)-aspidospermidine
[(+)-134].
The direct deformylation of (-)-rhazinal [(-)-13], is carried out, to produce the parent alkaloid
(-)-rhazinilam [(-)-1].
The pyrrole ring present in (-)-rhazinilam [(-)-1] is oxidised, to produce the related natural product (-)-Leuconolam [(-)-12] which has not, hitherto, been prepared by total synthesis.
¶Chapter five contains the experimental procedures and characterisation data associated with compounds described in chapters two to four.
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Collins, Ian James. "Studies towards the synthesis of polyhydroxylated indolizidines." Thesis, University of Cambridge, 1991. https://www.repository.cam.ac.uk/handle/1810/272578.
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Célimène, Catherine. "Voie d'acces generale aux indolizidines 3,5-disubstituees via des acyliminiums derives de la l-proline : syntheses generales des indolizidines (-) 195b, (-) 223ab et (-) 239ab." Paris 6, 1995. http://www.theses.fr/1995PA066556.
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Les alcaloides extraits des secretions cutanees des grenouilles d'amerique centrale sont reputes pour leur variete et leur toxicite. Nous nous interessons a la sous-classe d'indolizidines disubstituees en position 3 et 5. Nous avons cherche a mettre au point une synthese enantioselective des trois molecules ayant une chaine n-butyle en position 3 et un radical different en 5 a partir de la l-proline portant le futur centre c-3 de ces composes. L'addition du penten-1-ylcuivreux sur l'acyliminium derive de ce precurseur conduit a la pyrrolidine trans disubstituee en position 2 et 5 avec une selectivite de 92%. Cette alcoylation permet d'introduire le centre c-8a des molecules recherchees. A partir de cet intermediaire pivot, deux strategies sont envisageables pour former le squelette indolizidinique et controler le troisieme centre asymetrique c-5 des composes attendus. La premiere voie consiste a transformer la double liaison terminale de la pyrrolidine clef en groupe carbonyle portant le radical specifique a chaque molecule en position 5. Une amination reductrice cree le squelette indolizidinique et le centre c-5. La derniere etape est l'amenagement de la fonction ester en position 2 de la pyrrolidine trans en chaine n-butyle. Dans la seconde stategie, la chaine n-butyle est elaboree au niveau de la pyrrolidine intermediaire. La double liaison terminale est transformee en carbonyle portant le radical adequat. L'amination reductrice conduit au bicycle indolizidinique et favorise le controle du dernier centre asymetrique. De cette etude, nous deduisons que la diastereoselectivite de l'amination reductrice dependait de la nature du substituant en position 2 de la pyrrolidine pivot. Il est donc indispensable de realiser l'amination reductrice sur une dialkylpyrrolidine trans pour avoir une geometrie cis sur le cycle piperidinique. La seconde voie nous a permis de preparer ces trois indolizidines avec des resultats satisfaisants
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Sibley, A. William. "Slaframine, australines and castanospermines." Thesis, University of Nottingham, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.363593.
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Meldrum, Kevin Patrick. "Functionalized cyclic nitrones in the synthesis of polyhydroxylated pyrrolizidines and indolizidines." Thesis, Heriot-Watt University, 1997. http://hdl.handle.net/10399/660.
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Fletcher, Rodney Justin. "Radical cyclisation in routes to cis-fused heterocycles." Thesis, University of Nottingham, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.283701.
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Lombart, Henry-Georges. "Développement d'un nouvel aminé indolizidinone et applications en mimétique peptidique." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/NQ33047.pdf.
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Ikhiri, Halid. "Alcaloïdes pyrrolizidiniques de Hugonia oreogena et H. Penicillanthemum (Linacées) : détermination structurale et synthèse : étude ethnobotanique des plantes de la pharmacopée traditionnelle au Niger et détermination structurale de constituants de l'une d'elles, Ipomoea muricata (Convolvulacées)." Paris 11, 1987. http://www.theses.fr/1987PA112172.
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Quatre alcaloïdes pyrrolizidiniques nouveaux ont été isolés de deux plantes de Nouvelle Calédonie: Hugonia oreogena et H. PenicilZanthemum (Linacées). Le composé majoritaire (appelé absouline) est la p-méthoxy-transcinnamido-1 pyrrolizidine: sa synthèse a été réalisée en six étapes à partir de la ()1-proline. Une étude ethnobotanique des plantes médicinales du Niger a été entreprise : une partie des résultats est exposée. Parmi les plantes répertoriées, l'une d'elles, Ipomoea muricata (Convolvulacées) réputée antivenimeuse et antispasmodique, a fait l'objet d'une étude chimique et d'un début d'essais biologiques. A côté de la columbine, diterpène connu dans d'autres familles végétales, sept alcaloïdes ont été extraits: ils sont tous de type indolizidinique; quatre sont décrits ici pour la première fois: isoipornine, méthoxy-ipomine, diméthoxy-ipomine et ipalbidinium.
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Rasmussen, Martin Ohsten. "Nouvelle approche asymetrique des indolizidines polyhydroxylees : synthese de la (+)-lentiginosine et de la (-)-2-epilentiginosine." Université Joseph Fourier (Grenoble), 2001. http://www.theses.fr/2001GRE10059.
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Les syntheses asymetriques de deux indolizidines dihydroxylees, la (+)-lentiginosine et la ()-2-epilentiginosine, ainsi que celles de deux indolizidines monohydroxylees, la (1r,8as)-1-hydroxyindolizine et la (1s,8as)-1-hydroxyindolizidine ont ete realisees. La strategie de synthese de ces quatre produits naturels est basee sur une cycloaddition de type 2+2 hautement diastereoselective (d. R. =95 : 5) entre le dichlorocetene et un ether d'enol portant un inducteur chiral. Un rearrangement de beckmann des oximes derivant des cyclobutanones ainsi obtenues permet d'introduire la fonction azotee. Ce rearrangement totalement regioselectif a permis d'acceder a des -lactames hautement fonctionnalises avec une tres grande purete stereochimique. L'acces aux deux diastereomeres dihydroxyles cibles a ete effectue par osmylation du lactame insature. La ()-2-epilentiginosine a ete obtenue par reduction du lactame cis dihydroxyle protege, tandis que la (+)-lentiginosine a ete preparee grace a une procedure d'inversion hautement regioselective de ce lactame.
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Razavi, Hossein. "Amino acid Schiff base methodology for the synthesis of glycosidase inhibitors: Polyhydroxylated pyrrolidines and indolizidines." Diss., The University of Arizona, 1999. http://hdl.handle.net/10150/284049.
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The concise enantioselective syntheses of iminolyxitol and iminoribitol glycosidase inhibitors starting from benzophenone imines, of D-serine and L-alanine esters are presented. The reductive alkenylation of the Schiff bases followed by substrate-directed dihydroxylation and cyclization under various amino dehydration conditions (Ph₃P, CCl₄, or TEMPO oxidation/NaCNBH₃ reduction) gave the polyhydroxylated pyrrolidines in excellent overall yields (23% for 1 → 8a, 12% for 1 → 8b, 13% for 11 → 18a). In addition, synthesis of indolizidine glycosidase inhibitor 8- epi-swainsonine has been achieved. This approach featured trihydroxylated pyrrolidine 8a as an advanced intermediate in the synthesis of polyhydroxylated indolizidine alkaloid 25a, and highlighted efficiency in protecting group manipulation and stereocontrol in allylation with various allyltin reagents. In particular, a tandem protection-deprotection method converted pyrrolidine 8a to its corresponding partially protected analog which upon Swern oxidation and highly diastereoselective allylation afforded the required 3-carbon homologue. Subsequent hydroboration and cyclization furnished the polyhydroxylated indolizidine alkaloid in a limited number of steps and a good overall yield (29% for 8a → 25a). In a parallel sequence of reactions, pyrrolidine 8b was converted to 1,2-di-epi-swainsonine triacetate 25b in 32% overall yield.
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Bohland, Frank [Verfasser]. "Stereoselektive Synthese von polyhydroxylierten Indolizidinderivaten – Aufbau optisch aktiver Indolizidinon-carbamide / Frank Bohland." Mainz : Universitätsbibliothek Mainz, 2017. http://d-nb.info/1133223214/34.
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Maloney, Kevin M. (Kevin Matthew). "[4+2] cycloadditions of iminoacetonitriles : a general strategy for the synthesis of quinolizidines, indolizidines, and piperidines." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/39739.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 2007.Vita.
Includes bibliographical references.
Iminoacetonitriles participate as reactive dienophiles in intermolecular and intramolecular Diels-Alder cycloadditions leading to quinolizidines, indolizidines, and piperidines. The resultant a-amino nitrile cycloadducts are versatile synthetic intermediates which can be further elaborated by stereoselective alkylation, reduction, reductive cyclization, and Bruylants reactions. The first part of this thesis describes the full details of our studies on the synthesis of iminoacetonitriles, the scope of their Diels-Alder reactions, and the synthetic elaboration of the a-amino nitrile cycloadducts to provide access to a variety of substituted quinolizidine and indolizidine derivatives. The second part of this thesis reports on the total synthesis of quinolizidine (-)-217A and our efforts directed toward the total synthesis of indolizidine (-)-235B'.
by Kevin M. Maloney.
Ph.D.
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Souza, Barbara Bernardim de. "Síntese de indolizidinas e quinolizidinas diidroxiladas a partir de diazocetonas α,β-insaturadas." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/75/75133/tde-23042013-112347/.
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Alcaloides indolizidínicos, quinolizidínicos e piperidínicos poliidroxilados representam classes de compostos amplamente investigados atualmente. Este fato se deve às pronunciadas atividades biológicas como inibidores de glicosidases expressadas por estes heterociclos, o que significa um grande atrativo para que muitos grupos de pesquisas desenvolvam metodologias sintéticas para a sua obtenção de forma efetiva e em poucas etapas. Neste trabalho de dissertação é apresentada uma rota sintética para a preparação de alcaloides indolizidínicos e quinolizidínicos diidroxilados a partir de diazocetonas α,β-insaturadas. A estratégia para a síntese destes alcaloides baseia-se na mesma metodologia, tendo como etapas chaves: uma reação de olefinação de Horner-Wadsworth-Emmons (HWE) a partir de aminoaldeídos, seguida de um Rearranjo de Wolff. Como material de partida para o esqueleto indolizidínico foi empregado o Cbz-S-prolinal. Este aminoaldeído foi empregado como fonte do centro estereogênico e de um dos anéis presentes na estrutura final. O acoplamento (reação de HWE) entre o Cbz-S-prolinal e um diazofosfonato recentemente descrito por nosso grupo de pesquisa forneceu um composto diazocarbonílico α,β-insaturado (67%), que em seguida, foi submetido a um rearranjo de Wolff fornecendo um éster β,γ-insaturado (96%). Este intermediário avançado foi funcionalizado através de uma reação de diidroxilação, a qual forneceu uma lactona (66%). A síntese foi completada através de uma reação de ciclização intramolecular (94%) seguida de uma reação de redução para fornecer a indolizidina diidroxilada em 71% de rendimento. Para o esqueleto quinolizidínico, foi empregado o aminoaldeído racêmico Cbz-(±)-pipecolinal como material de partida. A partir da reação de olefinação, foi obtida uma diazocetona α,β-insaturada (91%), que após Rearranjo de Wolff (95%), diidroxilação (75%), ciclização (54-74%) e reação de redução (87-90%), forneceu duas novas quinolizidinas diidroxiladas. Estes alcaloides indolizidínicos e quinolizidínicos poderão ser avaliados como inibidores de glicosidases.Polyhydroxylated Indolizidine, quinolizidine and piperidine alkaloids represent classes of compounds widely investigated in the chemical community. This fact is due to their pronounced biological activities as glycosidase inhibitors. Considering that, many research groups have been developing new synthetic methodologies to obtain these alkaloids and analogs effectively and in few steps. This work presents a synthetic route for the preparation of dihydroxylated indolizidine and quinolizidine alkaloids from α,β-unsaturated diazoketones. The strategy for the synthesis of these compounds is based on the same methodology to construct the indolizidine and quinolizidine skeleton. The key steps involve a Horner-Wadsworth-Emmons (HWE) olefination reaction from aminoaldehydes, followed by a Wolff Rearrangement. As the starting material to construct the indolizidine skeleton, Cbz-S-prolinal was employed. This aminoaldehyde is also the source of the stereogenic center and one of the rings present in the final structure. The coupling reaction (HWE reaction) between Cbz-S-prolinal and a diazophosphonate (methodology recently described by our research group) has provided an α,β-unsaturated diazoketone in 67% yield. This compound was then subjected to a Wolff Rearrangement, providing a β,γ-unsaturated ester in 96% yield. This advanced intermediate was functionalized through a high selective dihydroxylation reaction, furnishing a hydroxylated lactone in 66% yield. The synthesis was then completed employing an intramolecular cyclization reaction (94% yield), followed by lactam reduction to provide the dihydroxylated indolizidine (1,6-dideoxyepicastanospermine) in 71% yield. For the construction of the quinolizidine skeleton, was employed racemic Cbz-pipecolinal as the starting material. From the olefination reaction, the corresponding α,β-unsaturated diazoketone was obtained in 91% yield. After a Wolff Rearrangement (95%), dihydroxylation reaction (75%), cyclization (54-74%) and lactam reduction (87-90%), two novel dihydroxylated quinolizidines could be synthesized. These indolizidine and quinolizidine alkaloids may be evaluated as new inhibitors of glycosidases.
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Vidal, Virginie. "Synthèse asymétrique d'analogues d'alcaloïdes pipéridiniques et indolizidiniques à l'aide d'un synthon chiral dérivé d'amino-acide." Paris 11, 1988. http://www.theses.fr/1988PA112316.
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La cyano 2S phényloxazolo 6S pipéridinel (synthon) obtenue en une étape à partir du R(-)phénylglycinol, du glutaraldéhyde et du cyanure de potassium permet des alcoylations régio et stéréosélectives en position C-2 du cycle pipéridinique. Cette thèse décrit l'utilisation de ce composé pour la synthèse asymétrique plusieurs produits en série pipéridinique et indolizidinique. L'alcoylation du synthon l par le dibromopropane a permis d'obtenir après cyclisation de l'azote de la pipéridine sur le brome et élimination de la partie auxiliaire chirale, la première synthèse asymétrique de la (-)-delta-conicéine en trois étapes. L'alcoylation du synthon l par le chloroformiate d'éthyle suivie d'une réduction par !e borohydrure de sodium et hydrogénolyse conduit auR(-)pipécolinol. La réaction de l'anion du synthon sur des aldéhydes a été particulièrement étudiée, elle conduit de manière hautement stéréosélective à des béta aminoalcools. La préparation de la (+)-béta-conhydrine a ainsi été effectuée par alcoylation de. L avec le propionaldéhyde et a ainsi permis de déterminer la configuration absolue de ce produit. En utilisant la même stratégie, une synthèse asymétrique d'une dihydroxyindoliziàine, analogue d'un produit naturel (swainsonine), inhibiteur d'alpha mannosidase a pu être réalisée. Ainsi, l'alcoylation du synthonl par le crotonaldéhyde suivie d'une décyanation par le borohydrure de sodium et époxydarion permet d'obtenir, après cyclisation de l'azote, sur l'époxyde un analogue de la swainsonineThe 2S cyano 6S oxazolo piperidine (synthon) which is obtained in one step starting from R(-) phenylglycinol, glutaraldehyde and potassium cyanide allows regio and stereoselective alkylations at the C-2 position of the piperidine ring. This thesis describes the usage of this compound in the asymmetric synthesis of severa] products from the piperidinic and indolizidini c series. Alkylation of the synthon I with dibromopropane permitted to obtain, after cyclisation of nitrogen on brome and elimination of the auxiliar chiral chain the first asymmetric synthesis of (-)-delta coniceine in three steps. Reaction of synthon 1 with ethyl chloroformate followed by a reduction with sodium borohydride and hydrogenolysis leads to R(-) pipecolinol. The reaction of the anion of the synthon on aldehydes was studied, in particular, it leads with a high stereoselectivity to beta amino alcohols. The preparation of (+)-beta -conhydrine was thus carried out by alkylation of 1 with propionaldehyde and permitted in this way the determination of the absolute configuration of this product. Following this strategy, an asymmetric synthesis of an indolizidine diol, a natural product analog (swainsonine), inhibitor of alpha mannosidase , was achieved. Alkylation of synthon 1 with crotonaldehyde followed by decyanation with sodium borohydride and epoxydation supplies after cyclisation of the nitrogen atom on the epoxide a swainsonine analog
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González, Soria María José. "Selective synthesis and reactivity of indolizines." Doctoral thesis, Universidad de Alicante, 2018. http://hdl.handle.net/10045/98672.
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Se ha llevado a cabo la síntesis multicomponente de una serie de 1-aminoindolizinas y pirrolo[1,2-a]quinolonas de manera efectiva a partir de derivados de 2-piridincarbaldehído, aminas secundarias y alquinos terminales utilizando CuNPs/C como catalizador en diclorometano a 70 ºC. La metodología se ha aplicado a una variedad de aminas y alquinos, los últimos incluyendo arilacetilenos así como alquilacetilenos, con rendimientos de moderados a altos. Dicho catalizador ha demostrado ser superior a una serie de catalizadores de cobre comerciales. Finalmente, se ha propuesto un mecanismo de reacción basado en la probada participación de aminas propargílicas como intermedios de reacción. Se han sintetizado indolizidinas a través de la hidrogenación catalítica heterogénea de indolizinas usando PtO2 como catalizador en ácido acético como disolvente y a una presión de 3,7 atm. Las indolizidinas se han obtenido con una elevada diastereoselectividad, incluso en el caso de poseer cuatro estereocentros. Se ha demostrado experimentalmente que la hidrogenación de la indolizina se produce a través del intermedio pirrólico 5,6,7,8-tetrahidroindolizina. Además, estas indolizidinas se han podido mono- o di-desbencilar usando un catalizador diferente. Se ha sintetizado una nueva familia de compuestos orgánicos por reacción de las indolizinas en medio ácido. Estos productos son tintes de indolizina de color violeta-rojizos que tienen una estructura D-A-π-A bien definida. La estructura de los tintes de indolizina se ha establecido mediante análisis de rayos X en estado sólido, pero se pueden distinguir dos rotámeros en disolución. Se ha propuesto un mecanismo de reacción en el que la propia indolizina actúa como nucleófilo y electrófilo; en éste, una molécula sufre hidrólisis en medio ácido y la adición Michael de la segunda molécula de indolizina. Un estudio de las características ópticas de estos tintes ha revelado un cambio de color dependiente del tamaño de partícula, un alto poder de coloración y un carácter solvatocrómico (es decir, que el color de la disolución del compuesto depende de la polaridad del disolvente usado), también en materiales plásticos. Finalmente, se ha estudiado la reactividad de las indolizinas con nitrosocompuestos, obteniendo dos productos diferentes según el sustituyente en la posición tres de éstas. En el caso de poseer un sustituyente aromático se obtienen β-enaminonas. Se ha realizado un estudio del alcance de esta metodología cambiando los sustituyentes 1, 3 y 6 de las indolizinas y usando compuestos nitrosoaromáticos con distintos sustituyentes en orto y para, obteniendo las correspondientes β-enaminonas con rendimientos aislados de moderados a buenos. El uso de esta metodología ha demostrado ser el más apropiado para obtener ese tipo de regioisómero, comparado con las metodologías clásicas de condensación de compuestos 1,3-dicarbonilos con aminas que dan el regioisómero opuesto. Para sustituyentes alifáticos, se han obtenido pirroles tetrasustituidos con rendimientos de moderados a buenos, variando los cuatro sustituyentes en la estructura de pirrol. Se han llevado a cabo varios experimentos para elucidar el mecanismo de reacción. Se ha demostrado que proceden vía iónica, no radicalaria. La presencia de agua es beneficiosa para la obtención de β-enaminonas, en cambio, una atmósfera de oxígeno o de argón no lo son. Con todo ello, se ha propuesto un mecanismo para la obtención de éstas en el que participa una estructura de isooxazol como intermedio. En el caso de los pirroles, se ha demostrado que hay una migración de la dibencilamina en la estructura. Tras varios experimentos, enfocados en la obtención de un posible intermedio de reacción, se ha propuesto la secuencia del mecanismo para la obtención de pirroles. En primer lugar, se ha propuesto el ataque nucleófilo al nitrosocompuesto, abriendo la estructura y perdiendo dibencilamina, formando así una cetona α,β-insaturada, seguido del ataque de la dibencialamina y posterior ciclación para la obtención del pirrol.
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Miaskiewicz, Solène. "Or et azacycles : vers la synthèse totale de molécules naturelles." Thesis, Strasbourg, 2017. http://www.theses.fr/2017STRAF006/document.
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La Nature est une source quasi inépuisable de molécules possédant des propriétés biologiques souvent remarquables. Ainsi, les plantes fournissent chaque jour de nouvelles structures dont les chimistes s’inspirent afin de créer de façon synthétique des molécules similaires ou dérivées pouvant avoir de potentielles applications en tant qu’agents thérapeutiques par exemple.L’émergence de la catalyse organométallique a permis d’améliorer considérablement les méthodes de synthèse de molécules complexes. La catalyse homogène à l’or, dont le potentiel n’a été exploité qu’à partir des années 2000, a prouvé son efficacité pour effectuer de nombreuses réactions permettant de créer plusieurs liaisons carbone-carbone ou carbone-hétéroatome en une étape. Les conditions douces et la grande tolérance des catalyseurs d’or vis-à-vis de groupements fonctionnels divers ont naturellement mené à l’application de la catalyse à l’or à la synthèse de produits naturels. Ces études s’inscrivent dans cette dynamique et exploitent la réactivité d’azacycles contraints et d’alcynes en présence d’or(I) pour former des squelettes hétérocycliques couramment rencontrés au sein de produits naturels. La réactivité particulière des groupements sulfonyles protecteurs de l’azote a également été étudiée pour synthétiser différentes molécules azabicycliques. Les méthodes de synthèse mises au point ont finalement été appliquées à la synthèse de molécules ciblesNature is a nearly endless source of molecules, often possessing remarkable biological properties. Thus, plants provide new structures every day, inspiring chemists to synthetically create similar molecules or analogs, which are potential therapeutic agents for example. The emergence of organometallic chemistry allowed for considerable improvement of synthetic methods to make complex molecular scaffolds. Homogeneous gold catalysis, whose potential has only been explored starting from 2000, proved its efficiency to make numerous reactions. Most of them can generate several carbon-carbon or carbon-heteroatom bonds in one step. Soft conditions as well as good tolerance of gold catalysts toward multiple functional groups naturally led to the application of gold-catalyzed steps in various total syntheses of natural products.The present study evolves in this context and explores the reactivity of strained azacycles and alkynes in the presence of gold(I) to form heterocyclic skeletons that are commonly found in natural products. The specific reactivity of sulfonyl nitrogen-protecting groups has also been studied to synthesize azabicyclic compounds. The application of those various new methodologies to the synthesis of target molecules has finally been studied
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Faria, Antonio Rodolfo de. "Sintese de indolizidinas e pirrolizidinas via reação de cicloadição [2+2] de enecarbonatos endociclicos com alquilcetenos e halo-alquilcetenos." [s.n.], 1996. http://repositorio.unicamp.br/jspui/handle/REPOSIP/249870.
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Orientador: Carlos Roque Duarte CorreiaTese (doutorado) - Universidade Estadual de Campinas, Instituto de Quimica
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