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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.
121

Design, Synthesis and Glioblastoma Activity of 1,3-Diazinane Based Aryl Amides and Benzo Fused Heterocycles

Hron, Rebecca 19 May 2017 (has links)
The development of novel targeted therapeutics for the treatment of cancer remains difficult due to the complex nature of the disease itself as well as the challenges associated with the synthesis of these therapeutics. Impediments to the discovery of novel drug candidates include lack of available starting materials and access to well-developed syntheses which are both convenient and economically feasible. Semicarbazides, for instance, are a critical synthon for the manufacture of numerous biologically important molecules. Historically, convenient methods for the synthesis of semicarbazides and their derivatives did not exist. Recently, a facile and efficient method for the preparation of semicarbazides via their corresponding phenyl carbamates was developed. These phenyl carbamate intermediates may also be used to prepare a wide variety of other derivatives such as substituted ureas as well as the aryl carbamoyl derivatives of 1,3-diazinane-5-carboxamide. While exploring the preparation of the aryl carbamoyl derivatives of 1,3-diazinane-5-carboxamide, it was found that these compounds possess anti-cancer activity against the glioblastoma LN-229 cell line. Intrigued by these results, additional analogues were designed, leading to the development of a small library of chromenopyrimidinedione and pyrimidinequinolinedione compounds as potential anti-cancer agents. Indeed, these two classes of compounds, with many of the derivatives novel, produced a selection of interesting molecules with potent anti-cancer activity against the glioblastoma cell line LN-229 at biologically relevant concentrations. Taken together, these results provide a unique approach not only to the design but also towards the synthesis of novel therapeutics intended for use as anti-cancer agents.
122

Conception et synthèse de macrocycles pouvant s'empiler en nanotubes supramoléculaires ou agir comme agonistes opioïde delta

Dao, Thi Thanh Hà January 2017 (has links)
Cet ouvrage porte sur les macrocycles organiques. Une introduction générale sur les propriétés des macrocycles et leurs rôles dans la chimie des matériaux et le développment des médicaments est présentée en premier lieu pour expliquer notre intérêt particulier sur cette classe de molécules. Le premier chapitre parle d’une nouvelle conception des nanotubes supramoléculaires par auto-assemblage des macrocycles de forme persistante. Nous avons exploité la capacité d’auto-assembler des différents types de cyclopeptides de squelette rigidifié en structures nanotubulaires. Cette approche a aussi été bien étudiée par plusieurs groupes de recherche de la littérature. Une caractéristique commune dans toutes ces conceptions est le besoin des fonctions amides qui sont disposées à l’intérieur du macrocycle et responsables des ponts Hydrogènes intermoléculaires pour diriger l’auto-organisation en nanotubes. Cette approche fonctionnait bien mais trouve limitée dans le cas où la structure cyclique manque des motifs (en particulier les amides) responsables de l’auto-assemblage par exemple les structures π-conjuguées. Pour ce genre de molécules, l’incorporation des longues chaînes latérales alkyles en périphérie du cycle représente la méthode habituelle pour obtenir l’empilement efficace entre les molécules. Par contre, le matériau formé présente souvent un désordre moléculaire et une faible cristallinité. Nous proposons une meilleure conception pour stimuler la croissance unidimensionnelle en ajoutant les fonctions amides susceptibles des liaisons Hydrogène intermoléculaire en périphérie du cycle. La tribenzocyclyne (TBC) est choisie comme échafaudage pour examiner cette stratégie qui n’a jamais été appliquée et rapportée sur un système cyclique pour le même objectif. L’intensité et la directionnalité des interactions Hydrogène supporteraient l’auto-organisation efficace de ces dérivés de TBC en nanotubes comme manifestée par quelques calculs semi-empiriques. De différentes générations de TBC portant des amides latéraux ont été conçues, synthétisées et discutées pour améliorer la synthèse et pouvoir obtenir l’arrangement désiré des molécules. Afin de favoriser la compréhension sur les nanotubes supramoléculaires, une introduction sur la chimie supramoléculaire, les interactions non-covalentes et les différentes approches vers les nanotubes supramoléculaires est résumée en détail. Toujours concernant les marcocycles, le deuxième chapitre aborde la conception des nouveaux agonistes cycliques ciblant le récepteur opioïde δ (DOPr). Les résultats préliminaires obtenus par notre groupe ont permi de proposer une conformation de Leu-enképhaline (LENK), le ligand endogène activant le DOPr, qui est très probablement celle trouvée dans le site actif de DOPr. En basant sur ce modèle, nous voulons concevoir des macrocycles dont le squelette est fixé plus ou moins vers cette conformation active hypothétique en incorporant les espaceurs appropriés entre les pharmacophores. Les nouvelles molécules sont considérées comme candidats-agonistes sélectifs δ car la conception fixerait la conformation spécifique pour la liaison avec le DOPr au lieu des autres récepteurs opioïdes surtout le μ (MOPr). L’objectif à long terme de ce projet, qui est en collaboration avec le laboratoire du Professeur Louis Gendron, est d’obtenir les agonistes sélectifs δ puissants pour soulager les douleurs sévères et/ou chroniques avec les effets secondaires réduits ou éliminés. Ces effets indésirables constituent le problème majeur qui limite l’efficacité ou suspend la médication des agonistes opioïdes telles que la morphine dans le traitement de la douleur. Pour comprendre mieux l’arrivée des nouveaux macrocycles synthétisés et discutés dans ce chapitre, une introduction générale sur la douleur et les traitements actuels, les récepteurs opioïdes et leur rôle dans la modulation de la douleur est présentée en premier lieu. Les résultats préliminaires par notre groupe et les collaborations sont aussi résumées. Finalement, une concise annexe sur l’exploration d’une nouvelle conception de nanosphères supramoléculaires est ajoutée en dernier lieu. Ces nanocapsules résulteraient de l’auto-assemblage des dérivés de corannulène portant des amides latéraux, ce qui imitent la structure de la capside sphérique chez plusieurs virus.
123

Komplexy lehkých platinových kovů s ferrocenovým N-fosfinoamidem / Light platinum group metal complexes with a ferrocene N-phosphinoamide

Navrátil, Michal January 2018 (has links)
Title: Light platinum group metal complexes with a ferrocene N-phosphinoamide Author: Bc. Michal Navrátil Department: Department of Inorganic chemistry Supervisor: prof. RNDr. Petr Štěpnička, Ph.D., DSc. Abstract: The aim of this diploma thesis is the preparation of coordination compounds containing ferrocene phosphinoamide FcCONHPPh2 (1, Fc = ferrocenyl), whose preparation was discussed in author's bachelor thesis. Twelve new complexes are described in this thesis, including their characterisation by NMR and infrared spectroscopy, elemental analysis and mass spectrometry. In all cases the crystal structure was determined. Two palladium(II), one rhodium(III) and one ruthenium(II) precursors were used for the preparation of the complexes with each providing three new compounds. A reaction of the precursors with phosphinoamide 1 yielded complexes, in which the phosphinoamide was P-coordinated. This compound was a precursor for the other two complexes. The first one was obtained by a reaction with silver(I) perchlorate producing a cationic P,O-chelate. The other was obtained by a reaction with potassium tert-butoxide resulting in neutral P,O- chelate. All twelve complexes were prepared with optimised yields. Keywords: ferrocene, amides, phosphines, palladium, rhodium, ruthenium, structure elucidation.
124

Síntese de gem-dicloroaziridinas empregando KF/Al2O3 / Synthesis of gem-dichloroaziridine employing KF/Al2O3

Meirelis, Francine Paulina 31 March 2014 (has links)
Nos últimos anos, questões ambientais têm merecido destaque na mídia nacional e internacional. A química tem uma grande participação nos dias atuais com os inúmeros produtos fundamentais à humanidade. A sua presença pode ser destacada desde diversos combustíveis aos mais complexos medicamentos. As reações de síntese orgânica devem ser guiadas por novas práticas mais sustentáveis. Nesse campo, tem-se o conceito da Green Chemistry ou Química Verde, que consiste na estratégia em desenvolver metodologias e processos que usem e gerem a menor quantidade de materiais tóxicos e/ou inflamáveis ou reaproveitáveis. Com o intuito de contribuir com a Química Verde, estudou-se a síntese de iminas que consistiu da primeira etapa do processo de aminação livre de solventes orgânicos e apresentaram rendimentos superiores a 95,0 %; gem-dicloroaziridinas foram preparadas a partir de inserção de diclorocarbeno em iminas em condições mínimas de solvente orgânico, utilizando como catalisador o KF/Al2O3 e com rendimentos superiores a 98,0%. As gem-dicloroaziridinas foram convertidas em amidas por hidrolise, na ausência de solvente e com rendimentos superiores a 98,0%. Dentro do conceito de Química Verde foram preparadas as seis iminas: N-benzilfenilmetanoimina, N-fenil-furilmetanoimina, N-fenilfenilmetanoimina, N-fenil-(4-metoxifenil)-metanoimina, N-benzil-(4-metoxifenil)metanoimina e N-furfurilfurilmetanoimina; duas gem-dicloroaziridinas: 2,2-dicloro-1,3-difenilaziridina e 1-benzil-2,2-dicloro-3-fenilaziridina e duas amidas: cloro-fenilacetanilida e N-benzil-cloro-fenilacetamida. / For the last years Environmental issues have deserved featured in the National and International media. Chemistry has had great participation on currently days with countless products which are fundamental to humanity. Its presence can be detached from various fuels to the most complex drugs.The organic synthesis reactions should be guided by more sustainable new practices. In this field, the Green Chemistry concept or (Química Verde) strategy which aims to develop methodology and and/or processes which use and generate the minimum quality of toxic inflammable material. With the purpose of contribute to green chemistry, we studied the synthesis of imines which consisted of the first stage of the process of amination, free of organic solvents and have yields higher than 95%; gem-dichloroaziridine were prepared from the imines insertion dichlorocarbene in a minimum of organic solvent conditions, using as catalyst KF/Al2O3 and yields higher than 98%. The gem-dichloroaziridines were converted to amides by hydrolysis in absence of solvent and yields higher than 98.0%. Within the concept of Green Chemistry were prepared six imines: N-benzyl- phenylmethanimine, N-phenyl-2- furylmethanimine, N-phenyl- phenylmethanimine, N-phenyl-(4-methoxyphenyl)methanimine, N-benzyl-(4-methoxyphenyl)metha-nimine,N-(2-furylmethyl)-2-furylmethanimine; two gem-dichloroaziridinas: 2,2-dichloro-1,3-diphenyla-ziridine and 1-benzyl-2,2-dichloro-3-phenylaziridine and two amides: chlorophenylacetanilide and N-benzyl-chloro-phenylacetamide.
125

Análise conformacional e aplicações sintéticas de algumas N-metóxi-N-metil-2-feniltiopropanamidas 4\'-substituídas e suas formas mono- e di-oxigenadas / Conformational Analysis and synthetical applications of some N- methoxy- N-methyl-2-[(4\'-substituted)-phenylthio]-propanamides and their mono- e di- oxigenated forms

Domingues, Nelson Luis de Campos 26 June 2007 (has links)
A presente tese relata a síntese e a análise conformacional das: N-metóxi-N-metil- 2-feniltiopropanamidas 4\'-substituídas (I), N-metóxi-N-metil-2- fenilssulfinilpropanamidas 4\'-substituídas (II) e N-metóxi-N-metil-2- fenilssulfonilpropanamidas 4\'-substituídas (III), através da espectroscopia no Infravermelho na região da banda da carbonila (vco), apoiada por cálculos teóricos. A análise conformacional de (I) indicou, através de dados de DFT/cc-pVDZ a existência de um equilíbrio entre duas conformações gauche devido à ocorrência de uma forte interação orbitalar estabilizante π*co/σc-s nas mesmas. A série dos derivados sulfinilados (II) apresentou-se como um par de diastereoisômeros. A análise conformacional para o diast1 (par enantiomérico CRSS/CSSR), através do cálculo HF/6-31G** e IV, indicou a existência de um equilíbrio conformacional entre dois confôrmeros quasi-cis (q-c1 e q-c2) e outro gauche (g), sendo os confôrmeros quasi-cis (q-c1 e q-c2) mais estáveis devido à interação de transferência de carga Oσ-(CO)→Sσ+SO mais intensa do que a interação Oσ-(SO)→Cσ+CO presente no confôrmero gauche (g). A análise para o diast2 utilizando-se o cálculo HF/6-31G** indicou a presença dos confôrmeros quasi-gauche (q-g), e quasi-cis (q-c3) sendo o primeiro mais estável no estado gasoso por apresentar uma interação transferência de carga cruzada Oσ-(CO)→Sσ+SO e Oσ-(SO)→Cσ+CO. Os dados de cálculo HF/6-31G** para os derivados sulfonilados (III) indicaram um equilíbrio conformacional entre duas conformações gauche (g1 e g2) decorrente de uma interação Coulômbica e de transferência de carga cruzada Oδ-(SO2)→Cδ+CO e Oδ-(CO)→Sδ+SO2. A presente Tese também relata a obtenção de compostos ß-lactâmicos acilados no carbono C3 e C4. As N-metóxi-N-metil-2-feniltiopropanamidas-4\'-substituídas (I) agem como acilantes do anel ß-lactâmico (N-fenil-2-azetidinona) para obtenção dos derivados ß-lactâmico C3 acilados. A reação foi realizada com sucesso, contudo, a purificação dos compostos alvo não se mostrou eficaz obtendo-se apenas as 3-[2- (4\'-feniltio)propanoil]-N-fenil- e 3-[2-(4\'- clorofeniltio)propanoil]-N-fenil-2-azetidinonas através de um processo de cristalização. Para a obtenção dos derivados ß-lactâmicos C4 acilados utilizou-se a N-metóxi-N-metil-4-oxo-1-fenilazetidina-2- carboxamida como acilante dos carbânions derivados de 4\'-fenilmetilssulfóxidos [4\'-YPhS(O)CH3 Y= OMe, Me, H]. Esta reação forneceu as 1-fenil- (4-fenilssulfinilacetil- 3 4\'-substituídos)-2-azetidinonas correspondentes com bons rendimentos. A redução destas azetidinonas-sulfóxidos forneceu as azetidinonas-sulfetos correspondentes também com bons rendimentos / This thesis reports the synthesis and the conformational analysis of: N-methoxy-N- methyl-2-[(4\'-substituted)-phenylthio]-propanamides (I), N-methoxy-N-methyl-2-[(4\'- substituted)-phenylsulfinyl]-propanamides (II) and N-methoxy- N-methyl-2-[(4\'- substituted)-phenylsulfonyl]-propanamides (III) by Infrared spectroscopy through the analysis of the carbonyl stretching band supported by theoretical calculations. The conformational analysis of (I) through DFT computations have indicated the equilibrium of two gauche conformations due to a strong stabilizing π*co/σc-s orbital interaction. The group of sulfinyl derivatives (II) exist as a diastereomeric pair. The conformational analysis of diast1 (enantiomeric pair CRSS/CSSR) through IR and HF/6-31G** has shown the existence of an equilibrium between two quasi-cis (q-c1 and q-c2) and one gauche (g) conformers, being the quasi-cis conformers the more stable ones due to the Oσ-(CO)→Sσ+SO charge transfer interaction which in turn is stronger than the Oσ-(SO)→Cσ+CO orbital interaction which takes place in the gauche (g) conformer. As for diast2 the HF/6-31G** computations along IR data has indicated 2 the occurrence of the quasi-gauche (q-g) and quasi-cis (q-c ) conformers, being the former the more stable one in gaseous phase due to the Oσ-(CO)→Sσ+SO e Oσ-(SO)→Sσ+CO crossed charge transfer. The HF/6-31G** and vco data for the sulfonylated derivatives (III) have shown the existence of the equilibrium between two gauche (g1 and g2) conformations which are stabilized through Oδ-(SO2)→Cδ+CO and Oδ-(CO)→Sδ+SO2 electrostatic and charge transfer interactions. This Thesis also deals with the preparation of some C3 and C4 acylated ß-lactamic compounds. The N-methoxy- N-methyl-2-[(4\'-substituted)-phenylthio-propanamides (I) act as acylating agents of the ß-lactamic ring (N-phenyl-2-azetidinone) in order to obtain the C-3 acylated ß-lactamic derivatives. These reactions gave the target products contaminated with starting material in good yields except for the 3-[2- (4\'phenylthio)propanoyl]-N-phenyl- and 3-[2-(4\'-chlorophenylthio)propanoyl]-N- phenyl-2-azetidinones which were obtained in pure form after crystallization. As for the C-3 acylated ß-lactamic derivatives they were obtained from the reaction of N-methoxy-N-methyl-4-oxo-1-phenylazetidine-2-carboxamide and the appropriate carbanions of 4\'-substituted phenylmethylsulfoxides. This reaction gave the corresponding 1-phenyl- (4-substituted-phenylsulfinylacetyl)-2-azetidinones in good yields. The corresponding azetidinone-sulfides were obtained from the reduction of the azetidinone-sulfoxides.
126

Uso da foto- e bio-catálise em condições de fluxo contínuo visando a síntese de novas poliamidas / Use of photo- and bio-catalysis under continuous flow conditions aiming the synthesis of new polyamides

Sanabria, Marialy Nieves 20 October 2017 (has links)
Os polímeros tornaram-se relevantes em nossa vida cotidiana devido à variedade de utilidades que estes possuem. Ao observarmos a nossa volta percebemos que estamos imersos em um mundo cheio de materiais poliméricos. A grande demanda destes materiais exige o incremento da produção global de polímeros. Isto traz consigo um maior consumo de recursos fósseis, acelerando o esgotamento dos mesmos e aumentando a geração e poluentes ambientais. Neste sentido, a polimerização enzimática tem sido considerada uma alternativa importante às técnicas convencionais de polimerização química. Existem descritos na literatura uma variedade de polímeros que foram preparados por polimerização enzimática e em alguns casos usando monômeros de origem biológica comercialmente disponíveis. Na grande maioria dos casos, esses compostos (monômeros) possuem sua reatividade bem estabelecida na literatura. Este projeto teve como motivação o estudo e desenvolvimento de metodologia visando obter novas poliamidas mediante polimerização enzimática em condições de fluxo contínuo, usando monômeros sintetizados a partir da integração de reações fotocatalíticas e reações enzimáticas. Em um primeiro momento, decidiu-se preparar o primeiro intermediário sintético, o 3-carbamoiloctanoato de metila (I), a partir da reação radicalar de amidação do trans-2-octenoato de metila com a formamida. Este composto foi usado como bloco de construção de novos monômeros. O amido-éster I desejado foi obtido a partir de três metodologias: Método fotocatalítico em condições de fluxo contínuo, utilizando como fotoiniciadores acetona e benzofenona; Método fotocatalítico em batelada, usando como fotocatalisador decatungstato de tetrakis(tetrabutilamônio) e método redox catalisado por Fe(II) em presença de ácido viii sulfúrico e peróxido de hidrogênio. A melhor condição reacional avaliada forneceu o composto com 47% de rendimento. Visando obter os monômeros de amida, uma vez obtido o primeiro intermediário de síntese, iniciou-se o estudo da reação de aminólise catalisada enzimaticamente deste substrato com mono e diaminas, em batelada e em fluxo contínuo, para compreensão da reatividade deste tipo de composto. Não foi possível obter o monômero desejado, ao invés disso, foi isolado o produto resultante da reação de aminólise de 1 equivalente do 3-carbamoiloctanoato de metila (I) com a 1,6-hexanodiamina. Este produto foi obtido com 11 % de rendimento. Paralelamente, com o desejo de obter poliamidas a partir de monômeros de base biológica, foi realizado um estudo da reação de aminólise do anidrido itacônico e itaconato de dimetila, com aminas alifáticas catalisada enzimaticamente sob condições de fluxo contínuo. Não foram obtidos os produtos desejados, ao invés disso, foi obtida a lactama correspondente com 70% de rendimento. / Polymers have become relevant in our lives due to their wide variety of applications. As we look around we realize that we are immersed in a world full of polymeric materials. The high demand for these materials requires an increase in the overall production of polymers. As a consequence, a higher consumption of fossil resources and an increasing generation of environmental pollutants would be expected. In this sense, enzymatic polymerization has been considered an important alternative to the conventional chemical polymerization techniques. A wide variety of polymers have been described in the literature, which have been prepared by enzymatic polymerization and in some cases using commercially available monomers from biological sources. In most cases, these compounds (monomers) have their reactivities well established in the literature. This project had as motivation a study and development of methodology to obtain new polyamides by enzymatic polymerization under continuous flow conditions, using monomers synthesized from the integration of photocatalytic reactions and enzymatic reactions. Initially, it was decided to prepare the synthetic intermediate (amide-ester I), from the amidation reaction of methyl trans-2-octenoate with formamide. This compound will be the building block for the new monomers. The desired amide-ester I was obtained from three methodologies: Photocatalytic method under continuous flow conditions, using acetone and benzophenone as photoinitiators; photocatalytic method using tetrabutylammonium decatungstenate photocatalyst and Fe (II) catalyzed redox method in the presence of sulfuric acid and hydrogen peroxide. The best reaction condition provided the compound in 47% yield. x In order to obtain the amide monomers, we began a study to understand the reactivity of this type of compound in aminolysis reaction with mono and diamines catalyzed by lipase, under batch and continuous flow conditions. The desired monomer could not be obtained, instead the product resulting from the aminolysis reaction of 1 equivalent of the methyl 3-carbamoyloctanoate (I) with the 1,6-hexanediamine was isolated. This product was obtained in 11% yield. In parallel, also aiming to obtain polyamides from biologically based monomers, a study of aminolysis reaction of itaconic anhydride and dimethyl itaconate with aliphatic amines catalyzed by lipase was carried out under continuous flow conditions. The desired products were not obtained, instead, the corresponding lactam in 70% yield was obtained.
127

Synthesis and structural characterization of amido- and imido-lanthanide compounds.

January 2000 (has links)
by Chan Hoi Shan. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references (leaves 111-119). / Abstracts in English and Chinese. / Acknowledgement --- p.iii / Abbreviation --- p.iv / List of Compounds --- p.vi / Abstract --- p.vii / Abstract (Chinese) --- p.ix / Chapter Chapter 1. --- Introduction / Chapter 1.1 --- Lanthanide-Amine Compounds --- p.1 / Chapter 1.2 --- Lanthanide-Amide Compounds --- p.3 / Chapter 1.3 --- Lanthanide-Imide Compounds --- p.11 / Chapter 1.4 --- Some Applications of Lanthanide-Amide Compounds in Organic Synthesis --- p.15 / Chapter 1.5 --- Aims --- p.19 / Chapter Chapter 2. --- Synthesis and Structural Characterization of Anionic and Neutral Dichlorolanthanocene Compounds / Chapter 2.1 --- Synthesis --- p.20 / Chapter 2.2 --- Structural Characterization --- p.22 / Chapter 2.3 --- Conclusion --- p.23 / Chapter Chapter 3. --- Synthesis and Structural Characterization of Amido-Lanthanide Compounds / Chapter 3.1 --- Synthesis and Structural Characterization of Yb(NHAr)3(THF)n --- p.26 / Chapter 3.2 --- "Synthesis and Structural Characterization of Yb(NHC6H3iPr2- 2,6)4Na(THF)" --- p.38 / Chapter 3.3 --- "Synthesis and Structural Characterization of Yb(Cp"")(NHAr)2(L)" --- p.45 / Chapter 3.4 --- "Synthesis and Structural Characterization of Yb(Cp"")(NHC6H3iPr2- 2,6)3M(L)" --- p.54 / Chapter 3.5 --- Synthesis and Structural Characterization of Yb(NHAr)3(NH2Ar)(L) --- p.74 / Chapter 3.6 --- Conclusion --- p.76 / Chapter Chapter 4. --- Synthesis and Structural Characterization of Imido-Lanthanide Compounds / Chapter 4.1 --- Synthesis --- p.81 / Chapter 4.2 --- Structural Characterization --- p.82 / Chapter 4.3 --- Conclusion --- p.85 / Chapter Chapter 5. --- Summary and Remarks / Chapter 5.1 --- Summary --- p.96 / Chapter 5.2 --- Remarks --- p.97 / Chapter Chapter 6. --- Experimental Section --- p.98 / References --- p.111 / Appendix --- p.120
128

Uso da foto- e bio-catálise em condições de fluxo contínuo visando a síntese de novas poliamidas / Use of photo- and bio-catalysis under continuous flow conditions aiming the synthesis of new polyamides

Marialy Nieves Sanabria 20 October 2017 (has links)
Os polímeros tornaram-se relevantes em nossa vida cotidiana devido à variedade de utilidades que estes possuem. Ao observarmos a nossa volta percebemos que estamos imersos em um mundo cheio de materiais poliméricos. A grande demanda destes materiais exige o incremento da produção global de polímeros. Isto traz consigo um maior consumo de recursos fósseis, acelerando o esgotamento dos mesmos e aumentando a geração e poluentes ambientais. Neste sentido, a polimerização enzimática tem sido considerada uma alternativa importante às técnicas convencionais de polimerização química. Existem descritos na literatura uma variedade de polímeros que foram preparados por polimerização enzimática e em alguns casos usando monômeros de origem biológica comercialmente disponíveis. Na grande maioria dos casos, esses compostos (monômeros) possuem sua reatividade bem estabelecida na literatura. Este projeto teve como motivação o estudo e desenvolvimento de metodologia visando obter novas poliamidas mediante polimerização enzimática em condições de fluxo contínuo, usando monômeros sintetizados a partir da integração de reações fotocatalíticas e reações enzimáticas. Em um primeiro momento, decidiu-se preparar o primeiro intermediário sintético, o 3-carbamoiloctanoato de metila (I), a partir da reação radicalar de amidação do trans-2-octenoato de metila com a formamida. Este composto foi usado como bloco de construção de novos monômeros. O amido-éster I desejado foi obtido a partir de três metodologias: Método fotocatalítico em condições de fluxo contínuo, utilizando como fotoiniciadores acetona e benzofenona; Método fotocatalítico em batelada, usando como fotocatalisador decatungstato de tetrakis(tetrabutilamônio) e método redox catalisado por Fe(II) em presença de ácido viii sulfúrico e peróxido de hidrogênio. A melhor condição reacional avaliada forneceu o composto com 47% de rendimento. Visando obter os monômeros de amida, uma vez obtido o primeiro intermediário de síntese, iniciou-se o estudo da reação de aminólise catalisada enzimaticamente deste substrato com mono e diaminas, em batelada e em fluxo contínuo, para compreensão da reatividade deste tipo de composto. Não foi possível obter o monômero desejado, ao invés disso, foi isolado o produto resultante da reação de aminólise de 1 equivalente do 3-carbamoiloctanoato de metila (I) com a 1,6-hexanodiamina. Este produto foi obtido com 11 % de rendimento. Paralelamente, com o desejo de obter poliamidas a partir de monômeros de base biológica, foi realizado um estudo da reação de aminólise do anidrido itacônico e itaconato de dimetila, com aminas alifáticas catalisada enzimaticamente sob condições de fluxo contínuo. Não foram obtidos os produtos desejados, ao invés disso, foi obtida a lactama correspondente com 70% de rendimento. / Polymers have become relevant in our lives due to their wide variety of applications. As we look around we realize that we are immersed in a world full of polymeric materials. The high demand for these materials requires an increase in the overall production of polymers. As a consequence, a higher consumption of fossil resources and an increasing generation of environmental pollutants would be expected. In this sense, enzymatic polymerization has been considered an important alternative to the conventional chemical polymerization techniques. A wide variety of polymers have been described in the literature, which have been prepared by enzymatic polymerization and in some cases using commercially available monomers from biological sources. In most cases, these compounds (monomers) have their reactivities well established in the literature. This project had as motivation a study and development of methodology to obtain new polyamides by enzymatic polymerization under continuous flow conditions, using monomers synthesized from the integration of photocatalytic reactions and enzymatic reactions. Initially, it was decided to prepare the synthetic intermediate (amide-ester I), from the amidation reaction of methyl trans-2-octenoate with formamide. This compound will be the building block for the new monomers. The desired amide-ester I was obtained from three methodologies: Photocatalytic method under continuous flow conditions, using acetone and benzophenone as photoinitiators; photocatalytic method using tetrabutylammonium decatungstenate photocatalyst and Fe (II) catalyzed redox method in the presence of sulfuric acid and hydrogen peroxide. The best reaction condition provided the compound in 47% yield. x In order to obtain the amide monomers, we began a study to understand the reactivity of this type of compound in aminolysis reaction with mono and diamines catalyzed by lipase, under batch and continuous flow conditions. The desired monomer could not be obtained, instead the product resulting from the aminolysis reaction of 1 equivalent of the methyl 3-carbamoyloctanoate (I) with the 1,6-hexanediamine was isolated. This product was obtained in 11% yield. In parallel, also aiming to obtain polyamides from biologically based monomers, a study of aminolysis reaction of itaconic anhydride and dimethyl itaconate with aliphatic amines catalyzed by lipase was carried out under continuous flow conditions. The desired products were not obtained, instead, the corresponding lactam in 70% yield was obtained.
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Atom economical and environmentally benign metal catalysed synthesis

Van Der Waals, Dominic January 2014 (has links)
The use of inexpensive metal catalysts for a range of acylation reactions including the activation of anhydrides and the aminolysis of esters. Discussion on the use of a heterogeneous copper catalyst for teh reduction of a range of organic functional groups and its use in amination of nitriles.
130

Designing reagents for the solvent extraction of critical metal resources

Doidge, Euan Douglas January 2018 (has links)
The work in this thesis aims to develop new systems for the more efficient recovery of metals from aqueous solution using solvent extraction. Understanding the underlying coordination chemistry to improve hydrometallurgical methods is crucial in order to meet the demand for critical metals for use in modern technologies, reduce the environment impact of recovery from primary mining deposits, and recycle valuable metals from secondary sources (e.g. mobile phones, WEEE). Chapter 2 examines the use of a simple primary amide that can load gold and other chloridometalates into a toluene phase through an outer-sphere mechanism. The loading of a variety of metals/metalloids from varying [HCl] is reported, highlighting the selectivity for gold over other metalates and chloride due to a combination of speciation of those metals and the relative ease of extraction of lower charged species (the Hofmeister bias). The advantages in loading/stripping, toxicity and mass balances compared to commercial alternatives are also outlined, in particular the efficacy of separating gold from a mixed-metal solution representative of those found in WEEE. The mode of action of the primary amide (and secondary/tertiary analogues) is determined using slope analysis, Karl-Fischer water determinations, NMR and MS measurements, EXAFS and computational models. The extraction occurs by the dynamic assembly of multiple amide ligands and gold metalates to generate supramolecular clusters held together through hydrogen-bonding and electrostatic interactions. The secondary and tertiary amides are found to be able to extract monoanionic metalates in a similar manner as the primary amide, although clustering occurs to a lesser extent. Whilst the secondary and tertiary amides are stronger gold extractants than the primary amide, they are not observed to be as successful when extracting from a mixed-metal solution. Instead, a 3rd phase is seen to form from these amides and some metals at higher metal concentrations, which removes the ligands from solution and prevents successful extraction of gold. Chapter 3 builds on an observation in Chapter 2 that a synergistic combination of a simple primary amide and an amine can extract chloridometalates that are typically difficult to solvent extract, such as iridium(III) and rhodium(III). These metalates, complexes with increased anionic charge and varying speciation in aqueous solution, are typically recovered last in a metal production flowsheet. The combination of a primary amide and primary amine was found to be the most effective at extracting the chloridometalates; the strength and strippability of the system is of particular interest in the context of rhodium(III) recovery as this metal currently is not extracted in commercial circuits. The mode of action of the system is investigated using similar techniques to Chapter 2, and reveals that the amine is the more important component of the synergistic mixture compared to the amide, with an improvement in extraction observed when both components are present. Rh(III) is extracted as a mixture of RhCl6 3– and RhCl5(OH2)2– complexes, dependent on the initial [HCl] concentration and the age of the initial aqueous solution. Chapter 4 investigates the feasibility of the recovery of lanthanides as anionic metalates from chloride-, nitrate- or sulfate-rich feeds. Reagents that have been found to be strong chloridometalate extractants, fragmented versions of these, and ‘classic’ commercial outer-sphere reagents are studied. The variations of ligand, anion type and concentration, proton concentration and solvent for the extraction of lanthanides is investigated. However, despite these permutations, no extraction of lanthanides is observed due to the difficulty in extracting more highly hydrated species and the lack of stability of the metalates in aqueous solution.

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