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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

A concise and straightforward approach to total synthesis of (+)-Strictifolione and formal synthesis of Cryptofolione via a unified strategy

Li, X., Wang, G., Zhang, Z., Wu, Na (Anna), Yang, Q., Huang, S., Wang, X. 26 May 2020 (has links)
Yes / We describe a concise and straightforward approach to the total syntheses of (+)-Strictifolione and Cryptofolione in the longest linear sequences of four steps and six steps from 3-phenyl propanal and trans-cinnamaldehyde, respectively. The route utilized a titanium tetraisopropoxide/(R)-[1,1'-binaphthalene]-2,2'-diol catalyzed Mukaiyama aldol reaction, indium(0)-promoted Barbier reaction, and olefin cross-metathesis as the key reactions. / National Science Foundation of China [21062088, 21562020, and 21462004], the Science and Technology Plan Project of Jiangxi Province [No. 20151BBG70028, 20142BBE50006] and State Key Laboratory for the Chemistry and Molecular Engineering of Medicinal Resources [CMEMR2014-A04] for the funding support.
2

Reação de ciclização de prins na síntetica diastereosseletiva de 31 análogos meso-tetraidropirâneos: determinação de estruturas cristalinas, estudos teóricos e avaliação in vitro da atividade antileucêmica. / Prins cyclization reaction of the diastereoselective synthesis of 31 analogues meso-tetrahydropyran: determination of crystal structures, theoretical studies and evaluation in vitro of antileukemic activity

Silva, Fábio Pedrosa Lins 30 August 2013 (has links)
Made available in DSpace on 2015-05-14T13:21:22Z (GMT). No. of bitstreams: 1 ArquivoTotal.pdf: 18195512 bytes, checksum: 6229ab5e9f367190d5f7b4336c07dfec (MD5) Previous issue date: 2013-08-30 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / This study was designed based on the concept of achiral / meso compound. The importance of preparing achiral compounds is based on their structural simplification, leading to new molecules which require no further investigations pharmacodynamics and pharmacokinetics of the enantiomers. Therefore, it is proposed to the synthesis of analogues tetrahydropyrans achiral/meso using the Prins cyclization reaction. The homoallylic alcohols synthesized in this work were derived from the Barbier reaction obtained in great yields, wherein these products are used as a synthesis intermediate for the preparation of tetrahydropyrans proposed. The Prins cyclization reaction is an efficient method for the preparation of tetrahydropyrans therefore proved to be a powerful tool for synthesis and versatile for the preparation of substituted tetrahydropyrans to give all the compounds synthesized in satisfactory yields. Through spectroscopic and crystallographic studies were possible to determine in detail the relative configuration of the molecules 40a, 41a, 44a, 45a, 46a, 46b and 48b. Furthermore, a theoretical study was developed using the density functional theory to obtain the molecular geometries optimized in the gas phase, making it possible to compare these preferred conformations with geometries defined by crystals. The tetrahydropyrans bioevaluated were synthesized in the leukemic cell line K562 and two types of normal L929 cells and PBMC. The results were very promising in cancer in vitro assays, highlighting the hydrazones 42a-c and the 43a-c aminoguanidines they were the only compounds that were active against resistant cell line K562, highlighting the tetrahydropyran 42c which showed higher activity series counterpart (present value of IC50 7.59 μM) and the tetrahydropyran 42b with an excellent IC50 (8.97 μM) value and a good selectivity index (2.2 in L929 and 1.6 in PBMC). / Este trabalho foi idealizado baseado no conceito de compostos aquirais/meso. A importância da preparação de compostos aquirais está baseada na sua simplificação estrutural, conduzindo a novas moléculas que não necessitam de posteriores investigações farmacodinâmicas e farmacocinéticas dos enantiômeros. Sendo assim, propomos neste trabalho a síntese de análogos tetraidropirânicos aquirais/meso utilizando a reação de ciclização de Prins. Os álcoois homoalílicos sintetizados foram provenientes da reação de Barbier obtidos em ótimos rendimentos, no qual estes produtos foram utilizados como intermediário de síntese para a preparação dos tetraidropiranos propostos. A reação de ciclização de Prins é um método eficiente na preparação dos tetraidropiranos, pois mostrou-se ser uma ferramenta de síntese poderosa e versátil para a preparação dos tetraidropiranos substituídos, obtendo-se todos os compostos sintetizados em rendimentos satisfatórios. Através de estudos espectroscópicos e cristalográficos foi possível determinar detalhadamente a configuração relativa das moléculas 40a, 41a, 44a, 45a, 46a, 46b e 48b. Além disso, foi desenvolvido um estudo teórico utilizando a teoria do funcional densidade para se obter as geometrias moleculares otimizadas em fase gasosa, tornando possível comparar estas conformações preferenciais com as geometrias definidas pelos cristais. Os tetraidropiranos sintetizados foram bioavaliados na linhagem de células leucêmicas K562 e dois tipos de células normais L929 e PBMC. Os resultados em câncer foram bastante promissores nos ensaios in vitro, dando destaque para as hidrazonas 42a-c e as aminoguanidinas 43a-c que foram os únicos compostos que se mostraram ativos contra a linhagem celular resistente K562, destacando-se o tetraidropirano 42c que apresentou maior atividade da série congênere (apresentando valor de CI50 7.59 μM) e o tetraidropirano 42b que apresentou excelente valor de IC50 (8.97 μM) e um bom índice de seletividade (2.2 em L929 e 1.6 em PBMC).
3

Design and synthesis of constrained azacyclic pyrrolidine analogues of FTY720 as anticancer agents & metal coordination-controlled and bifunctional catalysis toward tertiary β-Ketols

Chen, Bin 08 1900 (has links)
Cette thèse se compose en deux parties: Première Partie: La conception et la synthèse d’analogues pyrrolidiniques, utilisés comme agents anticancéreux, dérivés du FTY720. FTY720 est actuellement commercialisé comme médicament (GilenyaTM) pour le traitement de la sclérose en plaques rémittente-récurrente. Il agit comme immunosuppresseur en raison de son effet sur les récepteurs de la sphingosine-1-phosphate. A fortes doses, FTY720 présente un effet antinéoplasique. Cependant, à de telles doses, un des effets secondaires observé est la bradycardie dû à l’activation des récepteurs S1P1 et S1P3. Ceci limite son potentiel d’utilisation lors de chimiothérapie. Nos précédentes études ont montré que des analogues pyrrolidiniques dérivés du FTY720 présentaient une activité anticancéreuse mais aucune sur les récepteurs S1P1 et S1P3. Nous avons soumis l’idée qu’une étude relation structure-activité (SARs) pourrait nous conduire à la découverte de nouveaux agents anti tumoraux. Ainsi, deux séries de composés pyrrolidiniques (O-arylmethyl substitué et C-arylmethyl substitué) ont pu être envisagés et synthétisés (Chapitre 1). Ces analogues ont montré d’excellentes activités cytotoxiques contre diverses cellules cancéreuses humaines (prostate, colon, sein, pancréas et leucémie), plus particulièrement les analogues actifs qui ne peuvent pas être phosphorylés par SphK, présentent un plus grand potentiel pour le traitement du cancer sans effet secondaire comme la bradycardie. Les études mécanistiques suggèrent que ces analogues de déclencheurs de régulation négative sur les transporteurs de nutriments induisent une crise bioénergétique en affamant les cellules cancéreuses. Afin d’approfondir nos connaissances sur les récepteurs cibles, nous avons conçu et synthétisé des sondes diazirine basées sur le marquage d’affinité aux photons (méthode PAL: Photo-Affinity Labeling) (Chapitre 2). En s’appuyant sur la méthode PAL, il est possible de récolter des informations sur les récepteurs cibles à travers l’analyse LC/MS/MS de la protéine. Ces tests sont en cours et les résultats sont prometteurs. Deuxième partie: Coordination métallique et catalyse di fonctionnelle de dérivés β-hydroxy cétones tertiaires. Les réactions de Barbier et de Grignard sont des méthodes classiques pour former des liaisons carbone-carbone, et généralement utilisées pour la préparation d’alcools secondaires et tertiaires. En vue d’améliorer la réaction de Grignard avec le 1-iodobutane dans les conditions « one-pot » de Barbier, nous avons obtenu comme produit majoritaire la β-hydroxy cétone provenant de l’auto aldolisation de la 5-hexen-2-one, plutôt que le produit attendu d’addition de l’alcool (Chapitre 3). La formation inattendue de la β-hydroxy cétone a également été observée en utilisant d’autres dérivés méthyl cétone. Étonnement dans la réaction intramoléculaire d’une tricétone, connue pour former la cétone Hajos-Parrish, le produit majoritaire est rarement la β-hydroxy cétone présentant la fonction alcool en position axiale. Intrigué par ces résultats et après l’étude systématique des conditions de réaction, nous avons développé deux nouvelles méthodes à travers la synthèse sélective et catalytique de β-hydroxy cétones spécifiques par cyclisation intramoléculaire avec des rendements élevés (Chapitre 4). La réaction peut être catalysée soit par une base adaptée et du bromure de lithium comme additif en passant par un état de transition coordonné au lithium, ou bien soit à l’aide d’un catalyseur TBD di fonctionnel, via un état de transition médiée par une coordination bidenté au TBD. Les mécanismes proposés ont été corroborés par calcul DFT. Ces réactions catalytiques ont également été appliquées à d’autres substrats comme les tricétones et les dicétones. Bien que les efforts préliminaires afin d’obtenir une enantioselectivité se sont révélés sans succès, la synthèse et la recherche de nouveaux catalyseurs chiraux sont en cours. / This thesis consists of two parts: Part 1: Design and synthesis of constrained azacyclic pyrrolidine analogues of FTY720 as anticancer agents FTY720 is presently marketed as a drug (GilenyaTM) for the treatment of relapsing-remitting multiple sclerosis. It functions as an immunosuppressant due to its effect on sphingosine-1-phosphate (S1P) receptors. At higher doses, FTY720 also has antineoplastic actions. However, at such doses it induces bradycardia due to the activation of the S1P1 and S1P3 receptors. This limits its potentical to be used as a cancer therapy in humans. Our previous studies have shown that some constrained pyrrolidine analogues of FTY720 have anticancer activity but no activity toward S1P1 and S1P3 receptors. We reasoned that a study of the structure-activity relationships (SARs) could lead to the discovery of new effective antitumor agents. Thus, two series of constrained analogues (O-arylmethyl-substituted pyrrolidines and C-aryl-substituted pyrrolidines) were designed and synthesized (Chapter 1). These analogues showed excellent cytotoxic activity against various human cancer cells (prostate, colon, breast, pancreas and leukemia). Especially, several active analogues, which cannot be phosphorylated by SphK, have the potency to be further studied in the treatment of cancer without inducing bradycardia. Mechanistic studies suggest that these constrained analogues trigger down-regulation of nutrient transporters, which induce a bioenergetic crisis and the cancer cells starve to death. To further investigate their target receptors, we have designed and synthesized diazirine based photo-affinity labeling (PAL) probes (Chapter 2). Aided by the PAL technique, information regarding the target receptor could be obtained through LC/MS/MS protein analysis. These tests are in progress and the preliminary results appear promising. Part 2: Metal coordination-controlled and bifunctional catalysis toward tertiary β-ketols The Barbier and Grignard reactions are classical methods to form carbon-carbon bonds, and generally used to prepare secondary or tertiary alcohols. In an attempt to perform a Grignard reaction with n-butyl iodide under Barbier one-pot conditions, we obtained major product β-hydroxyl ketol from the self-aldol reaction of 5-hexen-2-one, rather than the expected addition alcohol product (Chapter 3). The unusual β-ketol formation was also observed using other methyl ketone substrates. Interestingly, in an intramolecular reaction of a triketone substrate, which is well known to give the Hajos-Parrish ketone, the favored product was a rarely studied β-ketol with the hydroxyl group at axial position. Intrigued by these results, after systematic reaction condition studies, we developed two new methods toward the catalytic synthesis of specific β-ketols by intramolecular cylcization in high yield and selectivity (Chapter 4). The reaction can be catalyzed either by a suitable base and lithium bromide as the additive, through a lithium pre-organized transition state or by a bifunctional catalyst TBD (triazabicyclodecene), through a TBD mediated bidentate transition state. The proposed mechanisms were corroborated by DFT computation. These catalytic reactions were also extended to other triketone and diketone substrates. Although the initial efforts to achieve enantioselectivity were not successful, they merit further study of the synthesis and investigation of new chiral catalysts.

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