The construction of tertiary alkylamines is a synthetic challenge exacerbated by the poor electrophilicity of imines. Due to the presence of this kind of building block in a large number of bioactive molecules, the development of new strategies to synthesise the quaternary carbon centre is essential. This thesis describes the work carried out on the rearrangement of lithiated vinyl ureas in order to form α-tertiary amines. The first part presents how vinyl ureas were synthesised, using the reaction between an imine and an aryl isocyanate. The development of one-pot process allows the synthesis of a range of ureas in large scale. These vinyl ureas present unusual reactivity: the electron-rich double bond can undergo syn umpolung carbolithiation followed by retentive aryl migration in order to generate highly substituted amines after cleavage of the urea. The complete mechanism is investigated to understand fully the diastereoselective pathway of the reaction. In the next part, the rearrangement of lithiated ureas is extended to the N to C vinyl transfer. Different vinyl migrating group are investigated and α-tertiary amines have been synthesised in high yields and enantiomerically pure form using this new rearrangement. The mechanistic insights of the reaction are also studied and a retentive mechanism will be identified. Finally, N to C vinyl transfer is applied toward the synthesis of Erythrina alkaloids.

<p>Organic nitrogen compounds are important in environmental systems because they are prevalent in natural waters but are also components of polymers within membrane filters that are used for water treatment. In both of these cases, these compounds can be exposed to free chlorine during disinfection, which can trigger a set of reactions that can form a host of different halogenated by-products. When such by-products form during water treatment disinfection, these by-products, known as nitrogen-based disinfection by-products (N-DBPs), can be highly toxic and affect human and ecosystem health. Alternatively, when such reactions occur during membrane filtration, the organic nitrogen compounds, which are embedded within the upper layer polymer structure of the membrane filter, can degrade when free chlorine is applied. Therefore, this research was aimed at exploring the chemistry behind how specific types of organic nitrogen compounds which are found in these applications, such as tertiary amines and amides, react with free chlorine. It particularly focused on assessing the kinetics and by-product formation of these reactions under variable water quality conditions (e.g., pH, halide concentrations, and precursor doses).</p> <p> </p> <p>More specifically, in the first phase of this work, the roles of tertiary amines in enhancing disinfection by-product (DBP) formation, such as trihalomethanes (THMs) and haloacetic acids (HAAs), during chlorination of aromatic compounds were studied. The results indicated that in synthetic solutions, chloroform (CHCl₃) and trichloroacetic acid (TCAA) were enhanced by up to 20× with tertiary amines at low dose ([tertiary amine]₀ = 0.5×[aromatic compound]₀). The enhancement effect was also dependent on the aromatic compound type, tertiary amine type and dose, and water conditions such as pH and bromide concentrations. Thus, THMs and HAAs were predicted to be enhanced when the aromatic compound reacted with R₃N-X⁺ (X=Br or Cl) and was not outcompeted by aromatic compound or tertiary amine reaction with free chlorine or bromine alone. In the second phase of this work, the reaction kinetics, by-product formation, and overall mechanisms of a polyamide-based monomer with chlorine were evaluated under varying water conditions. The current known mechanism, Orton Rearrangement, was reevaluated, and new mechanisms were proposed, where it was found that N-halogenation and ring halogenation were two independent pathways. The ability to choose either pathway was highly dependent on the water quality condition of the aqueous solution. The roles of different chlorinating/brominating agents were also investigated where certain species-specific rate constants were obtained. For the N-halogenation pathway, only chlorination and no bromination occurred in which the reactivity of the chlorinating agents likely decreased such that ClO^->HOCl. However, for the ring halogenation pathway, both chlorination and bromination occurred in which the reactivity of the chlorinating and brominating agents decreased such that Cl₂ >HOCl, and BrCl > BrOCl > Br₂ > Br₂O > HOBr, respectively. Overall, this study suggests that a number of unique reactions can occur for various types of organic nitrogen compounds which: (i) allow them to affect water quality by enhancing DBP formation, (ii) but, when integrated into a polymer matrix used for water treatment, can induce reactions that lead to permanent structural damage of the polymer. In all cases, the extent of these reactions is strongly governed by the surrounding water matrix.</p>

Quaternary centres bearing a nitrogen atom are found in natural products and therapeutic agents but they represent a remarkably challenging synthetic motif to access when stereochemical control is required. This thesis details investigations into the development of an innovative approach that - by combining biocatalysis with organolithium chemistry - allows the synthesis of enantioenriched α-tertiary amines. The strategy relies on the initial enzymatic asymmetric synthesis of amines. Two complementary pathways were identified: deracemisation with amine oxidases or enantioselective reduction with imine reductases. The enantioenriched amines were converted to the corresponding N-benzyl-N'-aryl ureas and subsequent organolithium-mediated stereospecific aryl migration developed in the Clayden group were carried out to obtain α-tertiary amines. Various scaffold were investigated: 1,1-disubstituted 1,2,3,4-tetrahydroisoquinoline, 2,2-disubstituted azepane and 1,1-disubstituted 2,3,4,5-tetrahydro-1H-benzo[c]azepine derivatives were successfully synthesised. The methodology was extended to acyclic systems, giving 3-pyridyl-derived α-tertiary amines.

Nitrosamines have garnered increasing attention from researchers and policy makers in recent years due to potential human health implications associated with their unintentional formation in water and wastewater treatment facilities. This work addresses a crucial nitrosamine formation pathway concerning the catalysis of amine nitrosation by activated carbon materials whose use is widespread in municipal and industrial systems. Experimental results show that this catalysis is highly pH dependent, with maximum formation achieved near the pKa value for each of the secondary amines tested. This result suggests that the overall formation potential is governed by individual amine properties and their interactions with carbon surfaces, rather than solely nitrite speciation as previously reported. Formation of the most commonly studied nitrosamine, N-nitrosodimethylamine, was shown to be highly dependent on initial dimethylamine (DMA) solution concentration, with yields of approximately 0.11% of the spiked secondary amine at pH 7.5. Morpholine and dibutylamine, larger and bulkier secondary amines, formed their corresponding nitrosamines at higher yields than DMA (0.21% and 1.69%, respectively). Additionally, select tertiary amines were shown to be capable of undergoing nitrosation on the same order of magnitude as the secondary amines under neutral conditions in the presence of activated carbons. The magnitude of these results indicates that greater attention should be paid to this previously overlooked mechanism for nitrosamine formation.

No description available.

No description available.

Submitted by Geandra Rodrigues (geandrar@gmail.com) on 2018-10-11T13:35:50Z No. of bitstreams: 1 amandacatharinodemello.pdf: 10070208 bytes, checksum: b00c39e2e5a28a1be7b81ed6260d151b (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2018-10-16T13:59:05Z (GMT) No. of bitstreams: 1 amandacatharinodemello.pdf: 10070208 bytes, checksum: b00c39e2e5a28a1be7b81ed6260d151b (MD5) / Made available in DSpace on 2018-10-16T13:59:06Z (GMT). No. of bitstreams: 1 amandacatharinodemello.pdf: 10070208 bytes, checksum: b00c39e2e5a28a1be7b81ed6260d151b (MD5) Previous issue date: 2018-07-26 / Desde a síntese do primeiro diazocomposto por Theodor Curtius em 1883, a química envolvendo compostos contendo o grupo diazo tem sido amplamente explorada. Essa é uma importante classe de composto, visto o grande número de transformações químicas as quais estão associados. Dentre elas, pode-se destacar reações de ciclopropanação, rearranjo de Wolff, cicloadição, inserção em ligação C-H e X-H. No presente trabalho é apresentada uma nova metodologia para reações de inserção entre compostos diazocarbonílicos e azalactonas, na presença de uma amina terciária. Após a otimização da reação, o método desenvolvido pôde ser aplicado a diferentes azalactonas e diazocompostos, levando a um extenso escopo, com rendimentos variando de 74 a 98%. Substratos com substituintes aromáticos, alifáticos e insaturados puderam ser explorados e efeitos doadores e retiradores de elétrons foram avaliados. E, ainda, diazocompostos contendo centros estereogênicos também foram aplicados e a análise por CLAE com coluna quiral mostrou que não houve processo de racemização. Parte dos compostos foram submetidos a uma avaliação de atividade biológica, onde os mesmos demonstraram citotoxicidade frente a duas linhagens tumorais, sendo compostos promissores para futuros ensaios biológicos. / Since the synthesis of the first diazo compound by Theodor Curtius in 1883, the chemistry involving substances containing a diazo group has been extensively investigated. They are a remarkable class of compounds due to the range of different transformations they can perform. Cyclopropanations, Wolff rearrangement, cycloadditions, insertion to C-H and X-H bonds are some of the reactions that diazocarbonyl compounds can have. In the present study, a new methodology which consists in tertiary base-promoted insertion reactions of diazo carbonyls to azlactones is described. Under the optimized reaction conditions, the developed method allows the preparation of a wide range substrate scope concerning both diazocarbonyl substrates and azlactones, in yields ranging from 74 to 98%. Aromatic, aliphatic and unsaturated substituents were well tolerated and electronic effects were evaluated. Moreover, diazo bearing stereogenic centers were successfully adopted and chiral HPLC analyses revealed no racemization process. Some of the compounds were submitted to biological evaluation and showed cytotoxic activity against two cancer cell lines, appearing as promising compounds for further biological activities.

O objetivo deste trabalho foi avaliar os efeitos do biorregulador MBTA [cloridrato de N,N-dietil-2-(4-metilbenziloxi) etilamina] aplicado em diferentes épocas e concentrações sobre a produtividade e qualidade dos frutos das laranjeiras &#39;Hamlin&#39;, &#39;Valência&#39; e &#39;Pêra&#39; e em características fisiológicas da laranjeira &#39;Hamlin&#39;. Em duas safras consecutivas, o MBTA foi aplicado em três diferentes concentrações (8; 16 e 32 mg L-1) e em duas diferentes fases fenológicas (25% e 100% de flores abertas) em árvores cítricas adultas, utilizando um volume de 7 litros de solução por planta acompanhada do adjuvante Silwett L-77 0,05%. Foram amostrados 20 frutos por planta em quatro diferentes épocas para cada cultivar estudado para determinar o teor de sólidos solúveis totais; acidez; quantidade de sólidos solúveis totais em caixa industrial de 40,8 kg; pH; rendimento de suco; cor do suco, massa média e diâmetro médio dos frutos. Os efeitos do MBTA variaram de acordo com o cultivar, concentração aplicada e com a fase fenológica de aplicação. Na laranjeira &#39;Hamlin&#39;, o MBTA na concentração de 16 mg L-1 aplicado com 25% de flores abertas incrementou o teor de sólidos solúveis totais, o rendimento de suco e a quantidade de sólidos solúveis totais por caixa de 40,8 kg. Este mesmo tratamento também reduziu a massa média dos frutos e não alterou a acidez, o &#34;ratio&#34;, a cor do suco, o diâmetro médio dos frutos e a produtividade final da laranjeira &#39;Hamlin&#39;. O incremento médio foi de 0,45 a 0,56% na concentração de sólidos solúveis totais e de 0,16 a 0,18 kg na quantidade de sólidos solúveis por caixa padrão de 40,8 kg. Na laranjeira &#39;Pêra&#39;, o MBTA na concentração de 8 mg L-1 aplicado com 25% de flores abertas incrementou o teor de sólidos solúveis totais, a acidez, a quantidade de sólidos solúveis totais por caixa de 40,8 kg e a produtividade. Este mesmo tratamento também reduziu a massa média dos frutos e não alterou o rendimento de suco, o ratio, a cor do suco e o diâmetro médio dos frutos. O incremento médio foi de 0,49 a 0,65% na concentração de sólidos solúveis totais, de 0,11 a 0,13 kg na quantidade de sólidos solúveis totais por caixa padrão de 40,8 kg e de 20,4 kg/planta na produtividade. Na laranjeira &#39;Valência&#39;, o MBTA na concentração de 16 mg L-1 aplicado com 25% ou 100% de flores abertas incrementou a quantidade de sólidos solúveis totais por caixa de 40,8 kg. Estes tratamentos não promoveram alterações consistentes sobre o teor de sólidos solúveis totais, o rendimento de suco, a acidez, o ratio, a massa média dos frutos, o diâmetro médio dos frutos, a cor dos frutos e a produtividade. O incremento médio foi de 0,11 a 0,14 kg na quantidade de sólidos solúveis totais por caixa industrial padrão de 40,8 kg. Aumentos na assimilação de CO2 e uma diminuição no conteúdo foliar de carboidratos foram observados nas folhas tratadas com MBTA na concentração de 16 mg L-1. Os efeitos do MBTA sobre a produtividade e a qualidade dos frutos estão possivelmente relacionados com a fotossíntese a com relações fonte-dreno. / The purpose of this research was to evaluate effects of MBTA [N,N-diethyl-2-(4- metylbenzyloxy) ethylamine hydrochloride] bioregulator applied on different times and concentrations on the yield and fruit quality of &#39;Hamlin&#39;, &#39;Pera&#39; and &#39;Valencia&#39; sweet orange and on physiological characteristics of &#39;Hamlin&#39; sweet orange. In two consecutive harvest seasons, the MBTA was sprayed in three different concentrations (8; 16 and 32 mg L-1) and in two different phenological phases (25% and 100% open flowers) in citrus mature trees, using 7 L of spray per tree added with Silwett L-77 adjuvant at 0.05%. For each cultivar, twenty fruits per tree were sampled in four different times to determine the total soluble solids concentration, acidity, quantity of total soluble solids in 40.8 kg box, pH, juice concentration, juice color, fruit weight and diameter. The effects of MBTA varied according to the cultivar, concentration and phenological phase of application. In &#39;Hamlin&#39; sweet orange, the MBTA at 16 mg L-1 concentration sprayed with 25% open flowers increased the total soluble solids concentration, juice concentration and the quantity of total soluble solids per 40,8 kg box. This same treatment decreased the fruit weight and didn´t affect the acidity, ratio, juice color, fruit diameter and yield. The average increase was from 0.45 to 0.56% on total soluble solids concentration and from 0.16 to 0.18 kg on the quantity of total soluble solids per 40.8 kg box. In &#39;Pera&#39; sweet orange, the MBTA at 8 mg L-1 concentration sprayed with 25% open flowers increased the total soluble solids concentration, acidity, the quantity of total soluble solids per 40.8 kg box and the yield. This same treatment decreased the fruit weight and didn´t affect the juice concentration, ratio, juice color and fruit diameter. The average increase was from 0.49 to 0.65% on total soluble solids concentration, from 0.11 to 0.13 kg on the quantity of total soluble solids per 40.8 kg box and 20.4 kg/tree on yield. In &#39;Valencia&#39; sweet orange, the MBTA at 16 mg L-1 concentration sprayed with 25% or 100% open flowers increased the quantity of total soluble solids per 40.8 kg box. These treatments didn&#39;t cause consistent changes in the total soluble solids concentration, acidity, fruit diameter, fruit weight, juice concentration, ratio, juice color and the yield. The average increase was from 0.11 to 0.14 kg on the quantity of total soluble solids per 40.8 kg box. An increase on the CO2 assimilation and a decrease on foliar carbohydrate content were observed in the leaves sprayed with MBTA at 16 mg L-1 concentration. The MBTA effects on the yield and fruit quality are possibly related to the photosynthesis and source-sink relations.

O objetivo deste trabalho foi avaliar os efeitos do biorregulador MBTA [cloridrato de N,N-dietil-2-(4-metilbenziloxi) etilamina] aplicado em diferentes épocas e concentrações sobre a produtividade e qualidade dos frutos das laranjeiras &#39;Hamlin&#39;, &#39;Valência&#39; e &#39;Pêra&#39; e em características fisiológicas da laranjeira &#39;Hamlin&#39;. Em duas safras consecutivas, o MBTA foi aplicado em três diferentes concentrações (8; 16 e 32 mg L-1) e em duas diferentes fases fenológicas (25% e 100% de flores abertas) em árvores cítricas adultas, utilizando um volume de 7 litros de solução por planta acompanhada do adjuvante Silwett L-77 0,05%. Foram amostrados 20 frutos por planta em quatro diferentes épocas para cada cultivar estudado para determinar o teor de sólidos solúveis totais; acidez; quantidade de sólidos solúveis totais em caixa industrial de 40,8 kg; pH; rendimento de suco; cor do suco, massa média e diâmetro médio dos frutos. Os efeitos do MBTA variaram de acordo com o cultivar, concentração aplicada e com a fase fenológica de aplicação. Na laranjeira &#39;Hamlin&#39;, o MBTA na concentração de 16 mg L-1 aplicado com 25% de flores abertas incrementou o teor de sólidos solúveis totais, o rendimento de suco e a quantidade de sólidos solúveis totais por caixa de 40,8 kg. Este mesmo tratamento também reduziu a massa média dos frutos e não alterou a acidez, o &#34;ratio&#34;, a cor do suco, o diâmetro médio dos frutos e a produtividade final da laranjeira &#39;Hamlin&#39;. O incremento médio foi de 0,45 a 0,56% na concentração de sólidos solúveis totais e de 0,16 a 0,18 kg na quantidade de sólidos solúveis por caixa padrão de 40,8 kg. Na laranjeira &#39;Pêra&#39;, o MBTA na concentração de 8 mg L-1 aplicado com 25% de flores abertas incrementou o teor de sólidos solúveis totais, a acidez, a quantidade de sólidos solúveis totais por caixa de 40,8 kg e a produtividade. Este mesmo tratamento também reduziu a massa média dos frutos e não alterou o rendimento de suco, o ratio, a cor do suco e o diâmetro médio dos frutos. O incremento médio foi de 0,49 a 0,65% na concentração de sólidos solúveis totais, de 0,11 a 0,13 kg na quantidade de sólidos solúveis totais por caixa padrão de 40,8 kg e de 20,4 kg/planta na produtividade. Na laranjeira &#39;Valência&#39;, o MBTA na concentração de 16 mg L-1 aplicado com 25% ou 100% de flores abertas incrementou a quantidade de sólidos solúveis totais por caixa de 40,8 kg. Estes tratamentos não promoveram alterações consistentes sobre o teor de sólidos solúveis totais, o rendimento de suco, a acidez, o ratio, a massa média dos frutos, o diâmetro médio dos frutos, a cor dos frutos e a produtividade. O incremento médio foi de 0,11 a 0,14 kg na quantidade de sólidos solúveis totais por caixa industrial padrão de 40,8 kg. Aumentos na assimilação de CO2 e uma diminuição no conteúdo foliar de carboidratos foram observados nas folhas tratadas com MBTA na concentração de 16 mg L-1. Os efeitos do MBTA sobre a produtividade e a qualidade dos frutos estão possivelmente relacionados com a fotossíntese a com relações fonte-dreno. / The purpose of this research was to evaluate effects of MBTA [N,N-diethyl-2-(4- metylbenzyloxy) ethylamine hydrochloride] bioregulator applied on different times and concentrations on the yield and fruit quality of &#39;Hamlin&#39;, &#39;Pera&#39; and &#39;Valencia&#39; sweet orange and on physiological characteristics of &#39;Hamlin&#39; sweet orange. In two consecutive harvest seasons, the MBTA was sprayed in three different concentrations (8; 16 and 32 mg L-1) and in two different phenological phases (25% and 100% open flowers) in citrus mature trees, using 7 L of spray per tree added with Silwett L-77 adjuvant at 0.05%. For each cultivar, twenty fruits per tree were sampled in four different times to determine the total soluble solids concentration, acidity, quantity of total soluble solids in 40.8 kg box, pH, juice concentration, juice color, fruit weight and diameter. The effects of MBTA varied according to the cultivar, concentration and phenological phase of application. In &#39;Hamlin&#39; sweet orange, the MBTA at 16 mg L-1 concentration sprayed with 25% open flowers increased the total soluble solids concentration, juice concentration and the quantity of total soluble solids per 40,8 kg box. This same treatment decreased the fruit weight and didn´t affect the acidity, ratio, juice color, fruit diameter and yield. The average increase was from 0.45 to 0.56% on total soluble solids concentration and from 0.16 to 0.18 kg on the quantity of total soluble solids per 40.8 kg box. In &#39;Pera&#39; sweet orange, the MBTA at 8 mg L-1 concentration sprayed with 25% open flowers increased the total soluble solids concentration, acidity, the quantity of total soluble solids per 40.8 kg box and the yield. This same treatment decreased the fruit weight and didn´t affect the juice concentration, ratio, juice color and fruit diameter. The average increase was from 0.49 to 0.65% on total soluble solids concentration, from 0.11 to 0.13 kg on the quantity of total soluble solids per 40.8 kg box and 20.4 kg/tree on yield. In &#39;Valencia&#39; sweet orange, the MBTA at 16 mg L-1 concentration sprayed with 25% or 100% open flowers increased the quantity of total soluble solids per 40.8 kg box. These treatments didn&#39;t cause consistent changes in the total soluble solids concentration, acidity, fruit diameter, fruit weight, juice concentration, ratio, juice color and the yield. The average increase was from 0.11 to 0.14 kg on the quantity of total soluble solids per 40.8 kg box. An increase on the CO2 assimilation and a decrease on foliar carbohydrate content were observed in the leaves sprayed with MBTA at 16 mg L-1 concentration. The MBTA effects on the yield and fruit quality are possibly related to the photosynthesis and source-sink relations.

Este trabajo tiene como objetivo el desarrollo de la metodología de diseño óptimo de procesos de separación con membranas líquidas selectivas en su aplicación a la separación de mezclas multicomponentes con recuperación selectiva del componente de interés. Para ello se ha investigado la separación selectiva y concentración de cromo(VI) presente inicialmente en un acuífero subterráneo contaminado por acción de la actividad industrial desarrollada a nivel superficial y donde a su vez, coexisten otras especies aniónicas competitivas (sulfato y cloruro mayoritariamente) presentes por las propias características del acuífero y por su localización en una zona litoral. Tras la selección de Alamine 336 (amina terciaria) y NaOH como agentes de extracción y reextracción respectivamente, se caracterizaron experimentalmente las reacciones químicas responsables de la etapa de extracción, así como la cinética del proceso de separación-concentración cuando se emplea la tecnología de pertracción en emulsión (EPT) en contactores de fibra hueca. Finalmente, se desarrolló un modelo matemático multicomponente y se determinaron los parámetros característicos del mismo con el fin de llevar a cabo el diseño óptimo del proceso mediante técnicas de optimización matemática. / This work aims at the development of the methodology for the optimal design of selective liquid membrane processes as efficient alternatives for the separation and selective recovery of raw materials and valuable compounds from multicomponent systems. For this purpose, the proposed methodology has been applied to the remediation of polluted groundwater containing hexavalent chromium as a consequence of effluent leaking from surface deposition of industrial wastes. Furthermore, other competitive anionic species (mainly sulphate and chloride anions) were also present in the groundwaters due to the specific location being close to the shore.After selecting Alamine 336 (tertiary amine) and NaOH as the best extraction and back-extraction agents respectively, a careful experimental design was performed in order to analyse the chemical equilibria involved in the extraction step. Once the emulsion pertraction technology (EPT) was selected as the most suitable separation-concentration process configuration, the experimental kinetic analysis and mathematical modeling of EPT were carried calculating the values of the design parameters. Finally, the proposed multicomponent model was employed to carry out the optimal process design by means of mathematical optimization techniques.