Aminoalcohols are very important compounds used in various asymmetric transformations as chiral ligands or chiral auxiliaries. In this thesis, four novel heterocyclic amine substituted chiral 1,4-aminoalcohols were synthesized. In the synthetic strategy, amide esters were synthesized from (2S, 3R)-3-methoxycarbonylbicyclo[2.2.1]hept-5-ene-2-carboxylic acid by DCC coupling method. Subsequent reduction of these amide esters lead to target 1,4-aminoalcohols. The activities of these novel chiral 1,4-aminoalcohols were tested in enantioselective diethylzinc addition, Mukaiyama aldol and Diels-Alder reactions. The enantioselectivities were measured by HPLC. All the products were identified by H NMR and C NMR spectroscopy

Amino alcohols are valuable bioactive substances and frequently used as chiral catalyst in various asymmetric transformation reactions. In the synthetic route, the asymmetric synthesis of novel chiral N,N-dialkyl substituted chiral 1,4-amino alcohols are performed starting with meso-anhydride 38. Quinine-mediated desymmetrization of the anhydride with methanol afforded (2S,3R)-cis-monoester 39 with a high enantiomeric excess (up to 98% ee). Chemoselective amidation of hemiester with various N,N-dialkyl substituted amines resulted in amido esters and they were subjected to LAH reduction to afford chiral 1,4-amino alcohol ligands. The activities of the chiral ligands, (2S,3R)-43, (2S,3R)-44, (2S,3R)-45, (2S,3R)-46 were tested in various asymmetric transformation reactions, i.e. asymmetric diethylzinc addition and asymmetric Diels-Alder reactions. Keywords: 1,4-Amino alcohols, chiral ligand, asymmetric diethylzinc addition reaction, Diels-Alder reaction

<p>This thesis describes the use of 2<i>H</i>-azirines, three-membered unsaturatednitrogen-containing heterocycles, as reactive intermediates ina number of Lewis acid promoted alkylations and Diels-Alderreactions providing synthetically useful aziridines.</p><p>In order to carry out this investigation a new generalprocedure for the ring closure of vinyl azides, forming theresultant 3-substituted-2<i>H</i>-azirines, was developed applying low boiling solventsin closed reaction vessels at elevated temperatures.</p><p>The addition of organolithium reagents in the presence ofcommercially available chiral ligands, to the 3-(2-naphthyl)-2<i>H</i>-azirine was studied, which gave the correspondingaziridines.</p><p>Several Lewis acids were shown to catalyze the normalelectron-demand Diels-Alder reaction between 3-alkyl-,3-aromatic-, and 3-ester-substituted 2<i>H</i>-azirines and various dienes. These reactions gave theexpected cycloadducts in moderate yields.</p><p>Using a chiral auxiliary high diastereoselectivity wasobtained in the addition of alkyl radicals to a8-phenylmenthyl-substituted 2<i>H</i>-azirine-3-carboxylate. The alkyl radicals weregenerated from the corresponding trialkyl borane and molecularoxygen. Hydroborations and transmetallations were used toprepare these trialkylboranes. Catalytic amounts of CuClincreased the diastereoselectivity in the radical additionreactions.</p><p>Attempts were made to explain how the coordination of aLewis acid to the azirine nitrogen atom affects thereactivity/stability of the azirine. DFT calculations and NMRexperiments involving Lewis acid-azirine complexes wereperformed.</p><p><b>Keywords:</b>Enantioselective, diastereoselective, vinylazide, 2<i>H</i>-azirines, aziridines, Lewis acid, chiral ligand,chiral auxiliary, organolithiums, Diels-Alder reaction, alkylradicals, triethylborane.</p>

Thèse numérisée par la Division de la gestion de documents et des archives de l'Université de Montréal

O amido termoplástico (TPS) é um material biodegradável, de baixo custo, com grande potencial para aplicação na composição de plásticos biodegradáveis. Muitos estudos têm sido realizados no sentido de melhorar algumas de suas propriedades, principalmente a sua baixa resistência mecânica, elevada hidrofilicidade, e baixa miscibilidade com polímeros comerciais, fatores que dificultam a ampliação da utilização desse material como plástico biodegradável. Uma alternativa para melhorar tais propriedades, é a produção de blendas destes materiais com outros polímeros. Contudo, quando a natureza química dos materiais a serem combinados é muito diversa, faz-se necessário compatibilizar os materiais, em geral obtida pela adição de agentes compatibilizantes ou promovendo reações durante a extrusão, processo denominado compatibilização reativa. No trabalho, diferentes alternativas foram investigadas com o intuito de aumentar o potencial de aplicação do amido, entre elas: o efeito do ácido cítrico na modificação do amido; o uso da ureia para estabilização da massa molar do amido via extrusão reativa permitindo seu reprocessamento; a modificação do amido com ácido cítrico e ou 4,4\'-difenil metano diisocianato e o uso de dois processos de extrusão reativa para produção do amido termoplástico; a produção de blendas de amido com poli(butileno adpato co-tereftalato) e poli(ácido lático); a produção do amido termoplástico com reticulação termorreversível pela incorporação de reações de Diels-Alder. Foram feitas diversas caracterizações entre elas, análise das propriedades térmicas por meio das técnicas de termogravimetria (TGA), calorimetria exploratória diferencial (DSC), análise dinâmicomecânica (DMA) ensaios mecânicos, absorção de umidade, espectroscopia de infravermelho por transformada de Fourier (FTIR), microscopia eletrônica de varredura (MEV), análises reológicas, cromatografia (HPSEC) e viscosimetria. Os resultados das investigações contribuíram para o desenvolvimento de novos polímeros termoplásticos ou termorrígidos a base de amido de milho e esclareceram questões não abordadas na literatura, sobre a modificação do amido via processo de extrusão reativa. / Thermoplastic starch (TPS) is a biodegradable material, inexpensive, with high potential of usage in the biodegradable plastics composition. Many studies have been performed to improve some properties, mainly its low mechanical strength, high hydrophilicity and low miscibility with commercial polymers, factors that hinder the usage expansion such material as plastic. An alternative to improve these properties is the polymer blends of starch production with other polymers. However, when the materials chemical nature is quite variable then is necessary to make the polymers compatible. Usually, the reactive compatibility is obtained by the addition of coupling agents or promoting reactions during extrusion. In the present study, new alternatives were studied in order to increase the starch application potential including: the citric acid effect on starch modification; use of urea to stabilize the starch molecular weight by reactive extrusion allowing its reprocessing; the starch modification with citric acid and 4,4\'-diphenyl methane diisocyanate and the use of two reactive extrusion processes for thermoplastic starch producing; starch blends production with poly (butylene adipate co-terephthalate) and poly (lactic acid); the starch modification by incorporating crosslinking thermoreversible Diels-Alder adduct. Several characterizations were made including thermal analysis by means of thermogravimetry (TGA), differential scanning calorimetry (DSC), dynamical mechanical analysis (DMA) mechanical testing, moisture absorption, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), rheology analysis, chromatography (HPSEC) and viscometry. The research results have contributed to the development of new thermoplastic polymers or thermosetting from corn starch and helped to clarify issues not addressed in the literature about the starch modification by reactive extrusion process.

Furanoeliangolidos são produtos naturais bioativos com peculiar estrutura macrocíclica. A síntese orgânica destes compostos tem despertado grande interesse por parte de vários pesquisadores. Particularmente, há alguns anos, o nosso grupo de pesquisa vem se dedicando, entre outras atividades, ao estudo de métodos sintéticos para a preparação do esqueleto estrutural dos furanoeliangolidos, mais especificamente do goiazensolido. A estrutura simplificada deste produto natural corresponde a um sistema 7-oxabiciclo[6.2.1]undecano. Este produto natural possui as seguintes atividades biológicas: esquistossomicida, citotóxica e antiinflamatória. Nossa metodologia utiliza, como etapa chave, a reação de Diels-Alder. Após a preparação do sistema policíclico, a clivagem da ligação interna dos anéis poderia fornecer o macrociclo desejado. Neste trabalho, foram estudadas três rotas sintéticas para preparação do núcleo básico dos furanoeliangolidos. Na proposta sintética inicial, a reação de Diels-Alder realizada entre o 2-metil-furano e o 3-bromopropiolato de metila, apresentou um aspecto surpreendente, uma alta regiosselevidade. A reação de anelação para formação do sistema policíclico foi investigada com três compostos diferentes. Todavia, nenhuma destas reações forneceu o produto desejado, mas sim resultaram em misturas complexas de produtos. Estes resultados revelaram a dificuldade em se realizar reações de anelação em compostos deste tipo. Outros substratos poderiam ser usados, mas considerando esses resultados insatisfatórios, nós preferimos iniciar o estudo de uma nova rota sintética. Na segunda rota, tentamos introduzir um grupo contendo três carbonos para formar o anel de seis membros, a partir de modificação na parte ?superior? da molécula (éster metílico). O aldeído intermediário pôde ser obtido com bom rendimento, mas o produto resultante da condensação aldólica deste composto com a acetona, é muito instável. A hidrólise de cetais deste tipo, conforme verificamos em experimentos com um cetal mais simples, requer tratamento com ácido forte. O produto obtido da reação aldólica, portanto não poderia resistir a essas condições, então abandonamos a rota. Na terceira rota sintética, a metodologia consistiu na construção do sistema policíclico através de duas reações de Diels-Alder e utilizando uma reação de ozonólise para clivar a dupla ligação central. A estereoquímica do aduto obtido na segunda reação de Diels-Alder foi confirmada por estudos de RMN. A ozonólise deste composto deu origem ao macrociclo desejado, contendo o núcleo estrutural dos furanoeliangolidos. Como o grupo imida presente neste macrociclo é muito resistente à hidrólise e outras reações, nós também desenvolvemos uma modificação que produz um produto mais tratável. O dieno utilizado nesta segunda reação de Diels-Alder não fornece aduto com anidrido maleico, mas ele reage bem com o acetilenodicarboxilato de dimetila dando o aduto correspondente. As duas duplas ligações deste composto são suficientemente diferentes uma da outra para permitir a ozonólise seletiva da dupla ligação central, mais nucleofílica. Nesta última rota sintética, dois macrociclos foram preparados em sete etapas, envolvendo duas reações de Diels-Alder, com rendimento total de 36,3% e 42,1%, respectivamente. / Furanoheliangolides are bioactive natural products containing a peculiar macrocyclic structure. The synthesis of these compounds has been a matter of considerable interest to several researchers. In the last few years, our research group has dedicated some efforts to develop synthetic methods for the preparation of the core structure of the furanoheliangolides, particularly goyazensolide. The core structure of this natural product corresponds to the 7- oxabicyclo[6.2.1]undecane system. This natural product has several biological activities, such as schistosomicidal, cytotoxic and anti-inflammatory. Our methodology uses, as a key step, the Diels-Alder reaction. After the preparation of the polycyclic system, the cleavage of the internal bond of the rings should furnish the desired macrocycle. In this work, three synthetic routes to the preparation of the core structure of the furanoheliangolides were studied. In the first route, the Diels-Alder reaction between 2-methylfuran and methyl 3-bromopropiolate, occurred with unusually high regioselectivity The cyclization reaction for the formation of the polycyclic system was investigated with three different compounds. However, none of these reactions furnished the desired product, but resulted instead in complex mixtures of products. These results showed the difficulty to perform cyclization reactions in compounds of this type. Other substrates could have been used, but considering these discouraging initial results, we preferred to start the studies of a new synthetic route. In the second route we were still attempting to introduce a three-carbon group to form the new six-membered ring; the main modification was that we would now start from the other side of the molecule. The aldehyde could be obtained in good yield, but the aldol reaction product of this aldehyde with the ketone is very unstable. As we have found in experiments with a simple ketal, the hydrolysis of ketals of this type require rather strong acidic treatment. Therefore, the aldol product would not withstand these conditions, so we abandoned these studies. In the third synthetic route, the methodology consisted of building the polycyclic system through two Diels-Alder reactions followed by an ozonolysis reaction to cleave the central double bond. The stereochemistry of the addut obtained in the second Diels-Alder reaction was confirmed by NMR studies. The ozonolysis of this product produced the desired core of the furanoheliangolides. As the imide group of this macrocycle is very resistant to hydrolysis and other reactions, we have also developed a modification that produces a more treatable product. The diene used in this second Diels-Alder reaction does not give Diels-Alder adduct with maleic anhydride, but it reacts well with dimethyl acetylenedicarboxylate to give correspondent addut. The two double bonds of this addut are sufficiently different from each other to permit the selective ozonolysis of the more nucleophilic central bond. In this last synthetic route, two macrocycles were prepared in seven steps, involving two Diels-Alder reactions, with overall yields of 36.3% and 42.1%, respectively.

O interesse acadêmico por tioésteres vem de longa data devido ao papel que desempenham em processos biológicos. A presente dissertação versa sobre as reações de Diels-Alder de tiocinamatos e cinamatos de metila p-substituídos por grupos atraentes e repelentes de elétrons, com ciclopentadieno em diferentes condições reacionais e na presença de diversos ácidos de Lewis. Diversos ácidos de Lewis, tais como Ti(OBu-n)4, ZnCI2, BF3&#183;OEt2, TiCl4, AICl3 brometo de borocatecol e BBr3, que geralmente são utilizados em reações de Diels-Alder, foram testados. Entre esses catalisadores, apenas brometo de borocatecol nos forneceu os adutos esperados, com total estereosseletividade endo na maioria dos casos. O emprego de diferentes meios reacionais, como água e solução etérea 5M de perclorato de lítio em éter também foi avaliado, no entanto não obtivemos resultados positivos. Sugerimos que a forte complexação do oxigênio carbonílico do dienófilo com o átomo de boro do catalisador, suposição esta confirmada com dados de RMN de 1H, e interações secundárias expliquem a eficiência desse catalisador nas reações de Diels-Alder em questão. Um estudo da reatividade dos tiocinamatos acima citados frente à redução catódica também foi apresentado nesta dissertação. Essas eletrólises, foram realizadas a potencial constante em solvente aprótico polar, fornecendo hidrodímeros cíclicos com bons rendimentos e total diastereosseletividade trans-trans. / The aim of this work is to study Diels-Alder reactions of methyl thiocinnamates, substituted at the para position by electron-donating and electron-withdrawing groups, as well as their corresponding ester analogues, towards cyclopentadiene in the presence of Lewis acid catalysts. Several Lewis acids, such as Ti(OBu-n)4, ZnCI2, BF3&#183;OEt2, TiCl4, AICl3 boroncatechol bromide and BBr3, which are usually employed in Diels-Alder reactions, were tested. Only boroncatechol bromide led to the expected adducts with total stereoselectivity in almost all cases. The use of water or a 5 mol&#183;L<SUP-1 ethereal solution of lithium perchlorate did not give good results. We believe the results obtained by the use of boroncatechol bromide are due to the strong complexation of the dienophile carbonyl oxygen with the boron atom, which has been confirmed by 1H NMR, and to secondary interactions. The cathodic reduction of the above thiocinnamates is also presented. The electrolyses, carried out potentiostatically in a polar aprotic solvent, led exclusively to the trans-trans cyclic hydrodimers in good yields.

Orientador: Anita Jocelyne Marsaioli / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Química / Made available in DSpace on 2018-08-23T22:59:17Z (GMT). No. of bitstreams: 1 Rocha_DanieleFernandadeOliveira_D.pdf: 6414836 bytes, checksum: 154b421c3fabef860e5439b2a47d4972 (MD5) Previous issue date: 2013 / Resumo: Opiliões são aracnídeos encontrados em todos os continentes, com mais de 6000 espécies descritas, e secretam uma mistura de compostos voláteis que atuam principalmente como defesa contra predadores naturais. A família Gonyleptidae, pertence à subordem Laniatores, é a mais diversa química e morfologicamente e está presente em todo o território brasileiro. Assim, o estudo da identidade e da origem biossintética dos compostos presentes no exudato de espécimes desta família fornece informações filogenéticas, além de ser uma fonte de novos produtos naturais. Neste trabalho foram caracterizados os exudatos de cinco espécies de opiliões de diferentes subfamílias. As espécies Cobania picea, Roeweria virescens e Serracutisoma proximum secretam uma mistura benzoquinonas. Por outro lado, Iporangaia pustulosa e Neosadocus maximus produzem 1-hepten-3-ona e 1-(6-butil-3,4-diidro-2H-piran-2-il)-pentan-1-ona. Este último foi descrito pela primeira vez na literatura, revelando uma nova classe de compostos com esqueleto piranil em opiliões, originados da reação de hetero-Diels-Alder in vivo de duas moléculas de vinil cetona. Também foi determinada a configuração absoluta da (R)-4-metil-1-hexen-3-ona produzida por Acanthogonyleptes pulcher e Gonyleptes saprophilus. Outras 4-metil-3-cetonas de insetos possuem configuração (S). Adicionalmente foi realizado o primeiro estudo biossintético com opiliões através da incorporação de precursores marcados com C e espectroscopia de RMN de C. Foram estudados I. pustulosa, que produz vinil cetona, e Magnispina neptunus, que produz benzoquinona, revelando que ambas as classes químicas são formadas através de unidades acetato e propionato pela via policetídica / Abstract: Harvestmen are arachnids widespread in all continents, with more than 6,000 described species. They secrete a mixture of volatiles compounds with the main function of defense against natural predators. The family Gonyleptidae belongs to the suborder Laniatores, is the most diverse in chemistry and morphology and is predominant in Brazil. Therefore, studying the identity and biosynthetic origin of this family exudate components gives phylogenetic information and is a source of new natural products. In this work five species exudate from different subfamilies were characterized. The species Cobania picea, Roeweria virescens and Serracutisoma proximum secrete a mixture of benzoquinones, while Iporangaia pustulosa and Neosadocus maximus produce 1-hepten-3-one and 1-(6-butil-3,4-dihydro-2H-piran-2-yl)-pentan-1-one. The latter was described for the first time, and belongs to a new class of harvestman metabolites with piranyl moiety in harvestmen, which were rationalized as the hetero-Diels-Alder adduct of two vinyl ketone molecules. Additionally the absolute configuration of (R)-4-methyl-1-hexen-3-one from Acanthogonyleptes pulcher and Gonyleptes saprophilus was determined. Analogous 4-methyl-3-cetones from insects have S configuration. It was also performed the first biosynthetic investigation with harvestmen by C labeled precursors incorporation and C NMR. The studied species were /.pustulosa and Magnispina neptunus, which produce vinyl ketones and benzoquinones, respectively. The results revealed that these chemical classes are biosynthesized with acetate and propionate units via polyketide pathway / Doutorado / Quimica Organica / Doutora em Ciências

Depuis la découverte des propriétés physiques et électroniques du graphène, un très grand nombre de méthodes visant à produire et modifier chimiquement le graphène ont été développées afin d'étendre et améliorer ses capacités en vue de futures applications. Les travaux réalisés au cours de cette thèse ont portés sur une méthode exfoliation du graphite en phase liquide assistée d'une réaction de cycloaddition réversible. Cette approche repose sur la réaction de Diels-Alder entre le graphite et un diène masqué très réactif, et se révèle être très efficace dans des solvants organiques volatils qui ne permettent pas l'exfoliation directe du graphite. L'introduction de groupements fonctionnels sur le diène a permis de moduler les propriétés de surface de films de graphène, ainsi que de post-fonctionnaliser les feuillets de graphène afin d'apporter une plus-value au matériau. / Since the discovery of the exciting properties of graphene, many techniques to produce and chemically modify graphene have been developed in order to expand and improve its properties in view of future applications. The study presented in this thesis focus on a process for the chemically-assisted exfoliation of graphite based on a reversible cycloaddition reaction. It relies on the Diels-Alder reaction between graphite and highly reactive masked diene, and it is effective even in solvents that are otherwise ineffective for exfoliation of graphite. Furthermore, it is possible to introduce functional groups on the diene, thereby enabling the tuning of the surface properties of graphene, as well as the post-functionalization of graphene sheets.

Cette thèse porte sur la conception, la synthèse et la caractérisation de nouveaux dérivés accepteurs d'électrons. Elle se concentre sur l’étude des dérivés de la 1,2,4,5-tétrazine, mais contient également l’étude de dérivés du benzonitrile, précurseurs typiques de la préparation des 1,2,4,5-tétrazines et de dérivés de la pyridazine, les produits dérivés de la réaction de Diels – Alder à Demande Inverse (IEDDA) des dérivés de la tétrazine. De plus, les dérivés de 1,2,3,4-thiatriazole, en tant que produits imprévus de la synthèse de Pinner modifiée, sont également étudiés de manière approfondie. En raison des états de transfert de charge (CT) introduits dans le système donneur-accepteur, les dérivés préparés accepteur d'électrons présentent en général des propriétés photophysiques et électrochimiques intéressantes, et ont donc un intérêt particulier pour l'électronique organique.Le point culminant de cette thèse est le développement de méthodologies synthétiques dans chaque chapitre. En résumé, le chapitre 2 met en évidence une nouvelle approche synthétique sans métal pour les 1,2,4,5-tétrazines 3-monosubstituées, qui sont très utiles pour la chimie du click bioorthogonal. Le chapitre 3 décrit une stratégie de synthèse élaborée pour de nouveaux dérivés de benzonitrile donneur-accepteur qui présentent de la TADF, de l’ AIE et du mécanochromisme. Le chapitre 4 présente une étude détaillée de la réaction de couplage croisé Buchwald – Hartwig en tant que méthodologie de synthèse importante dans la synthèse de molécules de tétrazine. Le chapitre 5 décrit l'étude de la réaction à l'IEDDA comme un outil synthétique utile pour préparer des dérivés de pyridazine. Le chapitre 6 présente une nouvelle synthèse pratique de 1,2,3,4-thiatriazoles à partir de composés nitriles. / This PhD thesis deals with the design, synthesis and characterization of novel electron-acceptor derivatives. It is focused on the study of 1,2,4,5-tetrazine derivatives, but also involves the study of benzonitrile derivatives which are the typical precursors for the preparation of 1,2,4,5-tetrazines, and pyridazine derivatives which are the products derived from Inverse Electron Demand Diels–Alder (IEDDA) reaction of tetrazine derivatives. Moreover, 1,2,3,4-thiatriazole derivatives, as unpredicted products from modified Pinner synthesis, are also elaborately investigated. Due to the charge-transfer (CT) states introduced in the donor-acceptor system, the prepared electron-acceptor derivatives exhibit interesting photophysical and electrochemical properties, and therefore are of particular interest in organic electronics.The highlight of this thesis is the development of synthetic methodologies in each chapter. To sum up, Chapter 2 demonstrates a novel metal-free synthetic approach to 3-monosubstituted 1,2,4,5-tetrazines, which are highly useful for bioorthogonal click chemistry. Chapter 3 describes an elaborative synthetic strategy for novel donor-acceptor benzonitrile derivatives which exhibit TADF, AIE and mechanochromism. Chapter 4 presents a detailed study of Buchwald–Hartwig cross-coupling reaction as an important synthetic methodology in the synthesis of tetrazine molecules. Chapter 5 described the study of IEDDA reaction as a useful synthetic tool to prepare pyridazine derivatves. Chapter 6 presented a novel convenient one-pot synthesis of 1,2,3,4-thiatriazoles directly from nitrile compounds.