Teses / dissertações sobre o tema "Amides"

The intercalation of primary, secondary, tertiary, and aromatic amines into layered TiOCl have been investigated by a variety of methods. The intercalation reaction does not appear to be a redox process. A key step for intercalation of amines into host TiOCl is proposed to be a coordination via nitrogen lone electron pair to Ti$\sp{3+}$ metal centres. Subsequent substitution of the interlayer chloride ions of TiOCl by the amine molecules is strongly dependent on the properties of the organic compounds and their ability to form ammonium salts. Based on X-ray diffraction, fluorescence, elemental analysis and thermal analysis, a model for the interaction of amines with TiOCl is proposed. The intercalation of primary, secondary, and tertiary amides into TiOCl and VOCl have been studied. A redox intercalation process is ruled out by using variety of amides with a range of redox potentials. The proposed interaction of intercalated amides with the host is different from that of amines and may dominated by formation of hydrogen bonds between the amides protons and Cl ions of the host.

Described in this thesis is work based on silica and palladium catalysis which focusses on the formation of amide-containing compounds. Efforts were made towards expanding the substrate scope of direct amide bond formation reactions catalysed by an activated K60 silica catalyst. Two of the resulting amides were then investigated as substrates in single and oxidative C–H functionalisation reactions to form phenanthridin-6(5H)-ones.

Primary fatty acid amides (PFAMs) and N-acylglycines (NAGs) are important signaling molecules in the mammalian nervous system, binding to many drug receptors and demonstrating control over sleep, locomotor activity, angiogenesis, vasodilatation, gap junction communication, and many other processes. Oleamide is the best-studied of the PFAMs, while the in vivo activity of the others is largely unstudied. Even less is known about the NAGs, as their discovery as novel compounds is much more recent due to low endogenous levels. Herein is described extraction and quantification techniques for PFAMs and NAGs in cultured cells and media using solvent extraction combined with solid phase extraction (PFAM) or thin layer chromatography (NAG), followed by gas chromatography-mass spectroscopy to isolate and quantify these lipid metabolites. The assays were used to examine the endogenous amounts of a panel of PFAMs as well as the conversion of corresponding free fatty acids (FFAs) to PFAMs over time in several cell lines. The cell lines demonstrated the ability to convert all FFAs, including a non-natural FFA, and an ethanolamine to the corresponding PFAM. Different patterns of relative amounts of endogenous and FFA-derived PFAMs were observed in the cell lines tested. Essential to identifying therapeutic targets for the many disorders associated with PFAM signaling is understanding the mechanism(s) of PFAM and NAG biosynthesis. Enzyme expression studies were conducted to determine potential metabolic enzymes in the model cell lines in an attempt to understand the mechanism(s) of PFAM biosynthesis. It was found that two of the cell lines which show distinct metabolisms of PFAMs also demonstrate unique enzyme expression patterns, and candidate enzymes proposed to perform PFAM and NAG metabolism are described. RNAi knockdown studies revealed further information about the metabolism of PFAMs and calls into question the recently proposed involvement of cytochrome c. Isotopic labeling studies showed there are two pathways for PFAM formation. A novel enzyme is likely to be involved in formation of NAGs from acyl-CoA intermediates.

The synthesis of 7-N-acetyldemethyllavendamycin butyl amide (47), 7-Nacetyldemethyllavendamycin isopropyl amide (48), 7-N-acetyldemethyllavendamycin amide of piperidine (49), 7-N-acetyldemethyllavendamycin amide of pyrrolidine (50), 7N-acetyldemethyllavendamycin amide of morpholine (51), demethyllavendamycin butyl amide (52), demethyllavendamycin amide of pyrrolidine (53), and demethyllavendamycin amide of morpholine (54) are described. Pictet Spengler condesation of 7-acetamido-2formylquinoline-5,8-dione (28) with tryptophan butyl amide (66), tryptophan isopropyl amide (67), tryptophan amide of piperidine (68), tryptophan amide of pyrrolidine (69), and tryptophan amide of morpholine (70) in an anisole - pyridine solution directly afforded the five lavendamycin amides 47-51. Compounds 52, 53, and 54 were obtained by hydrolysis of 47, 50, and 51 with 70% H2SO4-H20 solution.Aldehyde 28 was prepared according to the following general procedure.Nitration of 8-hydroxy-2-methylquinoline (30) yielded 8-hydroxy-2-methyl-5,7 dinitroquinoline (31). Compound 31 was then hydrogenated and acylated with acetic anhydride to yield 5,7-diacetamido-2-methyl-8-acetoxyquinoline (33). Compound 33 was oxidized by potassium dichromate to give 7-acetamido-2-methylquinoline-5,8-dione (27). Treatment of 27 with selenium dioxide in refluxing 1,4-dioxane afforded compound 28.Compounds 66, 67, 68, 69, and 70 were synthesized from compounds 61,62, 63, 64, and 65. These compounds were deprotected with ammonium formate in the presence of 10% Palladium on charcoal in methanol under an argon balloon at atmospheric pressure.Compounds 61, 62, 63, 64, and 65 were obtained from 58 with butylamine, isopropylamine, piperidine, pyrrolidine, and morpholine respectively in the presence of triethylamine under an argon balloon at atmospheric pressure.Compound 58 was synthesized by the reaction of N-carbobenzyloxytryptophan, with N-hydroxy succinimide, in the presence of N-dicyclohexylcarbodimide in dried and distilled dioxane under an argon balloon at atmospheric pressure.The structures of the novel compounds 58, 47, 48, 49, 50, 51, 52, 53, and 54 were confirmed by 1H NMR, IR, EIMS, and HRMS.The structures of protected and deprotected amides 61, 62, 63, 64, 65, 66, 67, 68, 69, and 70 were also confirmed by 1 H NMR and IR spectroscopy.
Department of Chemistry

Le dioxyde de manganese depose sur silice permet d'hydrater avec une bonne selectivite les nitriles hydroxyles en position beta. On a pu ainsi realiser la conversion tres efficace, inedite, de l'hydroxyglutaronitrile en monoamide correspondant. De bons arguments en faveur de la formation, lors de ces transformations de nitriles en amides, d'esters manganiques sont presentes. La preparation de ces derives sous forme optiquement active a ete reussie simplement en traitant une solution aqueuse du dinitrile par un aminoacide naturel tres accessible, la cysteine. Bien que la reaction de condensation de ce nitrile avec l'aminoacide ne soit pas stereoselective, la protection sous forme d'ether ou d'ester des fonctions hydroxylees dans les monopeptides formes, suivie d'une separation des deux composes diastereomeres et de leur conversion en ester du mononitrile glutarique fournit deux synthons optiquement purs, utiles pour la synthese de composes aussi importants que le gabob ou la carnithine. Ils peuvent egalement etre utilises pour preparer des composes anti-cholesterol

The reactivity of a new class of hindered amides has been investigated. These amides have been found to undergo facile nucleophilic substitution reactions with a range of nucleophiles. The enhanced reactivity of these compounds, described as "rotamides", is attributed to an exceptionally low barrier to C-N bond rotation, as a result of their sterically hindered structures. This thesis describes the studies undeliaken to elucidate the reaction mechanism. The case for the previously proposed proton switchlketene mechanism has been strengthened by a kinetics study into the nucleophilic substitution reaction of a highly reactive rotamide with butanol. Ketene trapping experiments have also provided strong evidence to support the existence of the ketene intermediate suggested by the proposed proton switch/ketene mechanism.

Diaqua Cu(II) complexes are effective catalysts in promoting the hydrolysis of activated and unactivated amides.
The complex (Cu(2,2$ sp prime$-dipyridylamine)(OH$ sb2$)$ sb2$) $ sp{+2}$ efficiently catalyzes the hydrolysis of the acyl-activated amides trifluoro-N-methyl-p-nitroacetanilide (MNTA), p-nitrotrifluoroacetanilide (NTA), and p-methoxytrifluoroacetanilide (MTA).
A cooperative effect between N-methylmorpholine buffer and (Cu(2,2$ sp prime$-dipyridylamine)(OH$ sb2$)$ sb2$) $ sp{+2}$ is observed in the hydrolysis of p-methoxytrifluoroacetanilide.
(Cu(2,2$ sp prime$-dipyridylamine)(OH$ sb2$)$ sb2$) $ sp{+2}$ hydrolyzes the unactivated amides with poor leaving groups formamide (FA) and N-methylformamide (MFA). In contrast, the monoaqua complex (Cu(2,2$ sp prime$:6$ sp prime$,2$ sp{ prime prime}$-terpyridine)(OH$ sb2$)) $ sp{+2}$ is not active. A detailed mechanism of the copper complex catalyzed hydrolysis reactions is proposed to explain the structural requirements of an amide-cleaving catalyst.
A copper complex is shown to be an effective metalloprotein model. A potential hapten capable of generating catalytic metalloantibodies with peptidase activity has been proposed. The role of the metal ion in carboxypeptidase A is compared to that of the metal ion in (Cu(2,2$ sp prime$-dipyridylamine)(OH$ sb2$)$ sb2$) $ sp{+2}$.

The thesis describes the research conducted towards the development of more sustainable methods for amide bond formation. The first chapter describes the importance of amide bond formation and the methods currently used for this type of transformation. Crucially, current methodologies defy in many aspects the 12 principles of green chemistry and are thus not sustainable. The subsequent chapters describe the work conducted directed at addressing problems with the current state of the art of amide bond formation. The development of a novel catalytic method for direct amidation of carboxylic acids with amines using borate esters is described. The applicability of this method for the synthesis a wide selection of amides and pharmaceutically relevant compounds is discussed and the extension of this methodology with unprotected amino demonstrated. Studies were also conducted towards understanding the mechanism of boron catalysed systems for amidation. A mechanistic hypothesis for borate systems based on kinetic studies, NMR studies and isolated reaction intermediates was elaborated. Conclusions and future outlooks based on these findings are presented.

Metal hydride materials have attracted much interest for their potential use as hydrogen storage materials. Complex hydrides are amongst the most promising due to their high gravimetric storage capacities and favourable de/rehydrogenation conditions. Here, mixed anion complex hydrides are investigated both through halide doping of LiNH\(_2\) and Li\(_2\)NH, and though a mixed LiNH\(_2\)-LiBH\(_4\) system. The reaction of LiNH\(_2\) and Li\(_2\)NH with lithium or magnesium chloride, bromide and iodide has been shown to form a series of amide- and imide-halide phases. The structures of these phases were investigated through powder diffraction methods as well as Raman spectroscopy. The hydrogen releasing properties of these materials were investigated through reaction with LiH and MgH\(_2\); while the equivalent hydrogenation reactions were also tested. In both cases these materials performed more favourably than the pure LiNH\(_2\)-LiH system. The lithium ion conductivity of these materials was also investigated; it was shown that the most conducting materials were also the quickest to release and uptake hydrogen. The LiNH\(_2\)-LiBH\(_4\) system was studied, with particular focus on the decomposition product, Li\(_3\)BN\(_2\). All three known polymorphs of this compound were shown to be able to form by the reaction of \(_2\)LiNH\(_2\) + LiBH\(_4\) by carefully changing the reaction conditions. Further stages of this system were investigated through reaction of Li\(_2\)NH and Li\(_3\)N with LiBH\(_4\). Here the products from these reactions were studied along with the thermal desorption properties of the systems.

Ce manuscrit traite du développement d’une nouvelle méthodologie de synthèse peptidique inversée. En premier lieu, une procédure simple et dans des conditions douces de formation de liaison peptidique est abordée. Contrairement à la stratégie classique où un acide carboxylique est activé, la réaction à lieu en présence d’amines activées. La stratégie a été appliquée à la synthèse de dipeptides et s’est révélée particulièrement efficace dans le cas très sensible de la cystéine où aucune trace d’épimérisation a été détectée. Cette stratégie a également prouvé son efficacité dans les cas du test d’Anderson. La synthèse d’un tétrapeptide modèle dans la direction naturelle (N->C) a permis d’illustrer le champ d’application de la méthodologie. Parallèlement à ce travail, le développement de nouveaux groupements protecteurs silylés de la fonction acide carboxylique est abordé, potentiellement applicables dans le cadre d’une synthèse peptidique dans le sens naturel (N->C)
This manuscript deals with the development of a new inverse peptide synthesis. First, a mild, practical, and simple procedure for peptide-bond formation is reported. Instead of activation of the carboxylic acid functionality, the reaction involves an unprecedented use of activated α-aminoesters. The method provides a straightforward entry to dipeptides and was effective when a sensitive cysteine residue was used, as no epimerization was detected in this case. In a same time, the methodology has proved his efficiency concerning the Anderson’s test. The applicability of this method to iterative peptide synthesis was illustrated by the synthesis of a model tetrapeptide in the challenging reverse NC direction. Finally, the development of a new strategy of protection of carboxylic acid function into silyl esters was described en route to an application in reverse NC direction

The metabolites of the basic tertiary arylaliphatic amine N,N,α-trimethyl-7-phenylbenzenepropanamine (RecipavrinR) from male Wistar rats were characterized by gas chromatography-mass spectrometry (GCMS). The work was undertaken in an attempt to determine the source of a novel metabolite, N-(1-methyl-3,3-diphenylpropyl) formamide. The formamide metabolite was isolated from the bile of recipavrin dosed rats only after hydrolysis with the enzyme β-glucuronidase, suggesting that it arose from a glucuronide conjugated precursor. Recipavrin was chosen for the study based on structural similarity to the narcotic analgesic methadone which was shown to give rise to a similar metabolite, 6-formamido-4,4-diphenyl-3-heptanone. The secondary formamide was not a plausible candidate for a β-glucuronidase liberated metabolite of recipavrin, suggesting that a labile aglycone was responsible for the GCMS observation of the formamide metabolite. Labile isomeric compounds, α-methyl-(N-methylene)-7-phenylbenzenepropanamine N-oxide, N-(α-methyl-7-phenylbenzenpropylidene) methylamine N-oxide, and 2-(4',4'-diphenyl-but-2'-yl) oxaziridine were synthesized as possible precursors of the formamide. N-hydroxy-a-methyl-7-phenylbenzenepropanamine, and N-hydroxy-N,α-dimethyl-7-phenylbenzenepropanamine were synthesized as candidates for labile β-glucuronidase liberated aglycone precursors of the nitrones. The biliary nonconjugated and conjugated metabolites of recipavrin were characterized in detail. In addition to the formamide, 15 different metabolites representing the N- dealkylation, oxidative deamination, N-oxidation and phenyl ring oxidation pathways were identified by GCMS. To determine if thermal decomposition of the methylene nitrone in the GC inlet was responsible for the GCMS observation of the formamide metabolite, liquid chromatography-mass spectrometry (LCMS) was used to show that the formamide and not the isomeric methylene nitrone was present in bile prior to GCMS analysis. Although the synthetic methylene nitrone was shown to degrade in the GC inlet to the formamide, the LCMS experiment ruled out the thermal generation of the biliary formamide from a nitrone precursor. The nonconjugated and conjugated metabolites of the recipavrin metabolite, norrecipavrin were characterized in detail by GCMS. Since the secondary formamide metabolite was observed in the β-glucuronidase hydrolyzed bile extract, norrecipavrin was implicated as an intermediate in the biotransformation of recipavrin to the formamide. The possibility of solvent mediated formylation or free radical oxidation of desalkyl metabolites to afford the formamides was ruled out. The methylene nitrone was shown to afford the formamide metabolite under simulated workup conditions. An alkali catalyzed Beckmann rearrangement of nitrone to amide was used to account for this transformation. The secondary hydroxylamine was shown to give rise to the methylene nitrone under simulated workup conditions. It was concluded that the oxidation of a β-glucuronidase liberated secondary hydroxylamine metabolite to the methylene nitrone followed by Beckmann rearrangement of the nitrone to the formamide was the probable source of the formamide observed by GCMS in extracts of bile from recipavrin dosed rats. The metabolism of N-methyl-N-(1-methyl-3,3- diphenylpropyl) formamide was investigated in detail to determine whether the carbinolamide, N-hydroxymethyl-N-(1-methyl-3,3-diphenylpropyl) formamide was involved in the genesis of the formamide metabolite of recipavrin. The above carbinolamide and N-(1-hydroxy-1-methyl-3,3-diphenylpropyl) formamide were identified by GCMS along with 16 other metabolites representing the metabolic pathways N-deformylation, N-dealkylation, N-oxidation and phenyl ring oxidation. The carbinolamides were not found in bile from recipavrin dosed rats, ruling out the possibility of a carbinolamide glucuronide precursor of the recipavrin formamide metabolite. This was the first report of the isolation of stable dealkylation intermediates of a high molecular weight formamide. The hepatotoxicity of the anticancer agent N-methyl formamide and the solvent dimethylformamide, suggests that the recipavrin formamides could also be metabolized to toxic carbinolamide or glutathione related metabolites.
Pharmaceutical Sciences, Faculty of
Graduate

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As matrizes hidrofílicas destacam-se como sistemas sólidos para a liberação controlada de fármacos destinados à via oral de administração de medicamentos, devido à relativa facilidade de processamento, possibilidade de incorporação de elevadas doses de fármaco e obtenção de perfis de liberação reprodutíveis. O amido resistente tipo 3 (AR3) e a pectina (P) são polímeros resistentes à ação das enzimas digestivas, sendo seletivamente degradados pela microbiota colônica, o que os tornam potenciais candidatos para a obtenção de sistemas de liberação controlada de fármacos. Nesse trabalho, o AR3 foi obtido através da retrogradação do amido por dois métodos diferentes: Método 1 (M1) – armazenamento sob resfriamento, por 8 dias (4°C) e Método 2 (M2) – armazenamento por 16 dias em ciclos alternados de temperatura (4°C e 30°C, 2 dias em cada temperatura). As propriedades físico-químicas dos materiais retrogradados (cristalinidade, comportamento térmico, intumescimento e porosidade) foram avaliadas e o conjunto de resultados evidenciou modificações estruturais promovidas pelo processo de retrogradação. As propriedades micromeríticas desses materiais (distribuição de tamanho, forma, densidade e fluxo) foram também avaliadas e mostraram-se favoráveis ao processo de compressão. O desempenho dos materiais como excipiente de comprimidos destinados à liberação controlada de fármacos foi avaliado através do ensaio de liberação in vitro do diclofenaco de sódio, em meios com diferentes valores de pH (1,2 e 7,4). A influência da incorporação da pectina aos sistemas no controle das taxas de liberação do fármaco foi avaliada. Os perfis de liberação obtidos demonstraram um efetivo controle das taxas de liberação do fármaco em meio ácido, visto que, em 120 min, os comprimidos obtidos por M1 ou M2 (20 e 40%) liberaram de 42% a 49,49% do fármaco, enquanto os comprimidos obtidos com APR e APM liberaram..
Hydrophilic matrices represent important solid systems for controlled drug delivery intended to oral administration of drugs, because of the relative ease of processing, possibility of incorporating large amounts of drug, and obtaining reproducible release profiles. Resistant starch type 3 (AR3) and pectin (P) are polymers resistant to the action of digestive enzymes and are selectively degraded by colonic microbiota, making them potential candidates for drug delivery systems. In this work, retrograded starch (AR3) was prepared by starch retrogradation by two different methods: Method 1 (M1) - cooling for 8 days at 4° C and Method 2 (M2) - storage for 16 days in alternating temperature cycles (4° C and 30° C, 2 days at each temperature). The physico-chemical properties of the retrograded materials (crystallinity, thermal behavior, swelling and porosity) were evaluated and the results showed structural changes caused by the retrogradation process. Micromeritic properties of these materials (size distribution, shape, density and flow) were also evaluated and showed to be suitable to the compression process. The performance of the materials as tablet excipient intended for controlled drug release was evaluated through the in vitro release of sodium diclofenac in media with different pH values (1.2 and 7.4). The influence of the incorporation of pectin to the systems in controlling the drug release rates was evaluated. The release profiles of all obtained tablets demonstrated effective control of drug release in acid media since tablets prepared with M1 or M2 released from 42 to 49% of drug. Tablets prepared with APR and APM released about 34.5% and 22.8%, respectively. In enteric media, the tablets obtained by M1 or M2 (20 and 40%) showed an increased rate of drug release, so that the t80% occurred at approximately 60 min, while for the tablets obtained with AA this time was of approximately 120 min. The tablets obtained with APR and APM ...

Dissertação composta por 02 artigos.
CNPq; Capes
O leite é uma das principais fontes de nutrientes da dieta humana e é um alimento que acompanha o ser humano durante toda a vida, tanto como leite de consumo como através de seus derivados. Entretanto, são inúmeras as formas e os tipos de contaminação que acometem o leite, destacando-se, dentre os contaminantes de ordem química, as aflatoxinas. Dentre os métodos de análise de aflatoxinas em leite e derivados, destaca-se a Cromatografia Líquida de Alta Eficiência (CLAE), principalmente devido a sua versatilidade, rapidez e acuracidade das medidas quantitativas. Entretanto, trata-se de um sistema complexo em que as propriedades dos constituintes da fase móvel são afetadas por mudanças nas condições de processo nas quais são realizados os experimentos. Normalmente as condições de análise por CLAE são determinadas empiricamente, pelo método “tentativa e erro” em que inúmeras tentativas são realizadas sem um estudo mais detalhado do sistema. Diante disso, a primeira etapa deste estudo objetivou a otimização de multirrespostas em CLAE, por meio da seleção das condições ótimas como a composição da fase móvel, sua vazão no sistema cromatográfico e a temperatura da coluna, a fim de identificar, separar e quantificar simultaneamente a aflatoxina M1 (AFM1) e a aflatoxina B1 (AFB1). Para tanto, realizou-se planejamento experimental de misturas para três componentes com restrições combinado com um planejamento fatorial 22 para as variáveis de processo (temperatura da coluna e vazão). Após a definição dos modelos para as variáveis dependentes, foi realizada busca das condições ótimas usando o método simplex sequencial e as funções de desejabilidade de Derringer e Suich. As variáveis avaliadas foram: composição da fase móvel (acetonitrila, metanol e solução aquosa de ácido acético 1%), vazão da fase móvel e temperatura da coluna. Os parâmetros cromatográficos obtidos como respostas foram: tempo e fator de retenção para ambas as aflatoxinas, fator de separação, resolução da coluna e altura dos picos. Após a validação do planejamento, foi realizada a validação analítica do método otimizado através das figuras analíticas de mérito: linearidade, precisão, exatidão e limites de detecção e quantificação. O planejamento realizado foi capaz de produzir modelos confiáveis que possibilitaram a estimativa das melhores condições atendendo aos múltiplos objetivos. Na validação analítica do método cromatográfico, os parâmetros analíticos avaliados ficaram dentro dos intervalos de confiança, podendo o método ser considerado exato e preciso, apresentando limites de quantificação de 0,3 e 0,5 μg L-1 para AFM1 e AFB1, respectivamente e linearidade com R2 > 0,99 para ambas as aflatoxinas. A segunda etapa do estudo objetivou a avaliação da interação entre as AFM1 e AFB1 com proteínas lácteas, tendo em vista que estudos demonstram que aquelas, especialmente a AFM1, localizam-se predominantemente nas frações proteicas. Entretanto, esses estudos não avaliaram a interação entre aflatoxinas e as proteínas do leite, mas apenas baseiam-se na sua quantificação nas frações proteicas do leite. Portanto, buscou-se por meio deste estudo avaliar a possível interação entre as AFM1 e AFB1 com as frações proteicas do leite. Análises por Espectroscopia na região de infravermelho com transformada de Fourier (FTIR) foram realizadas para avaliação de possíveis modificações na estrutura secundária das proteínas lácteas quando fortificadas com as aflatoxinas e Calorimetria Exploratória Diferencial (DSC). Para tanto, preliminarmente foram avaliados os espectros obtidos com padrões de caseína e β-lactoglobulina em solução tampão fosfato-salino (PBS) e em solução modelo, assim como no leite propriamente dito, integral e desnatado. Na segunda etapa, regiões espectrais específicas foram avaliadas por meio de técnicas de deconvolução e curve-fitting. Os resultados indicam que a solução PBS foi mais adequada para o estudo da interação entre as AFB1 e AFM1 e proteínas lácteas avaliadas, β-lactoglobulina e caseína. Foram observadas alterações nas estruturas secundárias e essas sugerem que, embora possivelmente ocorram interações de caráter hidrofílico entre β-lactoglobulina e as aflatoxinas (especialmente com AFM1), ocorram também interações de caráter hidrofóbico (especialmente de AFB1) com os pacotes hidrofóbicos da β-lactoglobulina. Já com a caseína, as alterações promovidas nas estruturas secundárias proteicas foram mais discretas, porém deslocamentos de picos foram observados indicando alterações estruturais da proteína, especialmente na presença de AFB1, o que sugere que ocorram interações químicas entre os componentes avaliados. As alterações espectrais, mais evidentes com a fração β-lactoglobulina, do que com a fração caseína sugerem que, embora a quantificação de aflatoxinas seja comumente superior na fração caseína, não se pode afirmar que por esse motivo ocorram interações mais tangíveis entre aflatoxinas e caseína do que entre aflatoxinas e β-lactoglobulina. Possivelmente a quantificação em maior percentual de aflatoxinas na fração caseína é atribuída ao fato dessa proteína encontrar-se, no leite, em percentual superior às proteínas do soro. Outra hipótese levantada pelo estudo é a possibilidade das aflatoxinas avaliadas encontrarem-se “mascaradas” por estarem conjugadas com a β-lactoglobulina e não sendo, portanto, detectadas pelos métodos analíticos convencionais ocasionando sua subestimação nessa fração.
Milk is one of the main sources of nutrients in the human diet and is a food that accompanies the human being throughout life, both as drinking milk as through its derivatives. However, there are countless forms and types of contamination that affect milk, especially among the contaminants of chemical order, aflatoxins. Among the methods of analysis of aflatoxins in milk and dairy products, the High Performance Liquid Chromatography (HPLC) stands out mainly due to its versatility, speed and accuracy of quantitative measurements. However, it is a complex system in which the properties of the constituents of the mobile phase are affected by changes in process conditions under which the experiments are performed. Typically the HPLC analysis conditions are determined empirically, using the "trial and error" in which numerous attempts are made without a more detailed study of the system. Therefore, the first step of this aimed to optimize multiresponses in HPLC, by selecting the optimal conditions as the mobile phase composition, its flow into the chromatographic system and the column temperature in order to identify, separate and quantify aflatoxin M1 (AFM1) and aflatoxin B1 (AFB1) simultaneously. Therefore, it was carried out experimental a mixture design for three components with restrictions combined with a 22 factorial design to the process variables (flow and column temperature). After defining the models for the dependent variables, a search of the optimum conditions was made using the sequential simplex method and the Derringer and Suich desirability functions. The variables evaluated were: mobile phase composition (acetonitrile, methanol and aqueous solution of acetic acid 1%), the mobile phase flow rate and column temperature. The chromatographic parameters obtained as responses were time and factor of retention for both aflatoxins, separation factor, column resolution and height of the peaks. After the design validation, analytical validation was performed through the analytical figures of merit: linearity, precision, accuracy and limits of detection and quantification. The experimental design carried out was able to produce reliable models that allowed better conditions estimation regarding multiple objectives. In the analytical validation of the chromatographic method, the analytical parameters evaluated were within the confidence interval, the method can be considered accurate and precise showing quantitation limits of 0.3 and 0.5 μg L-1 for AFB1 and AFM1, respectively, and linearity with R2> 0.99 for both aflatoxins. The second stage of the study aimed to evaluate the interaction between the AFB1 and AFM1 with dairy proteins, considering that studies show that those, especially AFM1, are located predominantly in the protein fractions. However, these studies did not evaluate the possibility of interaction between aflatoxins and dairy proteins, but only based on its quantification in the dairy protein fractions. Therefore, we sought through this study to evaluate a possible interaction between AFM1 and AFB1 with dairy protein fractions. Analyzes were performed by Fourier transformation infrared spectroscopy (FTIR) to assess possible changes in the secondary structure of dairy proteins when spiked with aflatoxins and Differential Scanning Calorimetry (DSC). For this purpose, preliminarily the spectra obtained were evaluated with standard casein and β-lactoglobulin in phosphate buffer saline solution (PBS) and a bovine milk model solution as well as in actual milk, whole and skim. In the second step, specific spectra bands were assessed through deconvolution and curve-fitting techniques. The results show that PBS was more suitable for the interaction study between aflatoxins B1 and M1 and the dairy proteins evaluated, β-lactoglobulin and casein. Changes in secondary structures suggest that although possibly occurring interactions with hydrophilic characters between β-lactoglobulin and aflatoxins were observed (especially with AFM1) also occur interactions with hydrophobic character (especially AFB1) with the hydrophobic β-lactoglobulin packages. Already with the casein, the changes introduced in protein secondary structure were more discreet but peak shifts were observed indicating structural changes of the protein, especially in the presence of AFB1, which suggests that chemical interactions occur between the components evaluated. The spectral changes, more evident with the β-lactoglobulin fraction than the casein fraction, suggests that although the quantification of aflatoxins is commonly higher in the casein fraction, it’s not possible to ensure that for this reason occur more tangible interactions between aflatoxins and casein than between aflatoxins and whey proteins (β-lactoglobulin). The greater quantify percentage of aflatoxins in the casein fraction, apparently, is attributed to the fact that this protein is found, in milk, in superior percentage to the whey proteins. Another hypothesis is the possibility of the aflatoxins evaluated are "masked" by being combined with β-lactoglobulin and not, therefore, being detected by conventional analytical methods leading to their underestimation in this fraction.
5000

Orientador: Raul Cesar Evangelista
Coorientador: Beatriz Stringhetti Ferreira Cury
Banca: Marco Vinícius Chaud
Banca: Ana Dóris de Castro
Resumo: As matrizes hidrofílicas destacam-se como sistemas sólidos para a liberação controlada de fármacos destinados à via oral de administração de medicamentos, devido à relativa facilidade de processamento, possibilidade de incorporação de elevadas doses de fármaco e obtenção de perfis de liberação reprodutíveis. O amido resistente tipo 3 (AR3) e a pectina (P) são polímeros resistentes à ação das enzimas digestivas, sendo seletivamente degradados pela microbiota colônica, o que os tornam potenciais candidatos para a obtenção de sistemas de liberação controlada de fármacos. Nesse trabalho, o AR3 foi obtido através da retrogradação do amido por dois métodos diferentes: Método 1 (M1) - armazenamento sob resfriamento, por 8 dias (4°C) e Método 2 (M2) - armazenamento por 16 dias em ciclos alternados de temperatura (4°C e 30°C, 2 dias em cada temperatura). As propriedades físico-químicas dos materiais retrogradados (cristalinidade, comportamento térmico, intumescimento e porosidade) foram avaliadas e o conjunto de resultados evidenciou modificações estruturais promovidas pelo processo de retrogradação. As propriedades micromeríticas desses materiais (distribuição de tamanho, forma, densidade e fluxo) foram também avaliadas e mostraram-se favoráveis ao processo de compressão. O desempenho dos materiais como excipiente de comprimidos destinados à liberação controlada de fármacos foi avaliado através do ensaio de liberação in vitro do diclofenaco de sódio, em meios com diferentes valores de pH (1,2 e 7,4). A influência da incorporação da pectina aos sistemas no controle das taxas de liberação do fármaco foi avaliada. Os perfis de liberação obtidos demonstraram um efetivo controle das taxas de liberação do fármaco em meio ácido, visto que, em 120 min, os comprimidos obtidos por M1 ou M2 (20 e 40%) liberaram de 42% a 49,49% do fármaco, enquanto os comprimidos obtidos com APR e APM liberaram..
Abstract: Hydrophilic matrices represent important solid systems for controlled drug delivery intended to oral administration of drugs, because of the relative ease of processing, possibility of incorporating large amounts of drug, and obtaining reproducible release profiles. Resistant starch type 3 (AR3) and pectin (P) are polymers resistant to the action of digestive enzymes and are selectively degraded by colonic microbiota, making them potential candidates for drug delivery systems. In this work, retrograded starch (AR3) was prepared by starch retrogradation by two different methods: Method 1 (M1) - cooling for 8 days at 4° C and Method 2 (M2) - storage for 16 days in alternating temperature cycles (4° C and 30° C, 2 days at each temperature). The physico-chemical properties of the retrograded materials (crystallinity, thermal behavior, swelling and porosity) were evaluated and the results showed structural changes caused by the retrogradation process. Micromeritic properties of these materials (size distribution, shape, density and flow) were also evaluated and showed to be suitable to the compression process. The performance of the materials as tablet excipient intended for controlled drug release was evaluated through the in vitro release of sodium diclofenac in media with different pH values (1.2 and 7.4). The influence of the incorporation of pectin to the systems in controlling the drug release rates was evaluated. The release profiles of all obtained tablets demonstrated effective control of drug release in acid media since tablets prepared with M1 or M2 released from 42 to 49% of drug. Tablets prepared with APR and APM released about 34.5% and 22.8%, respectively. In enteric media, the tablets obtained by M1 or M2 (20 and 40%) showed an increased rate of drug release, so that the t80% occurred at approximately 60 min, while for the tablets obtained with AA this time was of approximately 120 min. The tablets obtained with APR and APM ...
Mestre

Le travail présenté dans cette thèse est dédié à la création de modèles du site actif des enzymes hydrogénases. Cette problèmatique est soumise à trois approches différentes. La première stratégie utilisée est de type bioorganométallique. Un grand nombre de dérivés ferrocenoyl-peptide contenant des résidus soufrés (cystéine, méthionine) ont été synthétisés et caractérisés. Lors de la deuxième approche, concernant le domaine de la chimie organique, des hélices supramoléculaires à base d'oligoamides aromatiques ont été créées et isolées. Ces deux différents types de structures seront utilisés comme échelle moléculaire pour la création de modèle synthétique des enzymes hydrogénases. La troisième approche consiste en l'étude théorique des composés ferrocenoyl-peptides, en utilisant la dynamique moléculaire. Un champ de force a été implémenté dans CHARMM concernant ces composés et validé avec succès. Les calculs de mécanique moléculaire sont utilisés pour étudier les différentes structures pouvant servir d'échelle moléculaire. Après déprotection des groupements thiols sur les dérivés obtenus lors de l'approche bioorganométallique, les groupements SH sont coordonnés à un centre ferrocarbonylé, reproduisant le site actif de l'enzyme "Fe-only hydrogenase". Les complexes ainsi obtenus ont été caractérisés et leur propriétés électroniques et électrochimiques largement étudiées.

Described in this thesis is the isolation of two microorganisms containing a nitrile hydratase and amidase to effect the enantioselective hydrolysis of a-substituted nitriles to their corresponding amides and acids. Isolate NP3854 was identified as an atypical Rhodococcus sp. The nitrile hydratase proved to be non-selective for all the substrates tested. However, carboxylic acids with excellent enantiomeric excess were obtained from a large number of amides. X R~CN H nitr-il-e--h-y-d-r.a~tase ~X amidas.e RH CONH2 X R~"""CO H H 2 Optically active acids with an enantiomeric excess of, generally, >98 %, were obtained when X = NH2, Me and Cl, but proved to be racemic for OH and Br. R could be a variety of aromatic, cyclic and acyclic alkyl residues without adversely affecting the enantioselectivity. The pH-activity profile was determined for the amidase of NP3854 using propionamide as the substrate. From this data, coupled with inhibition studies, it may ,.tentatively be suggested that the amidase has a histidine residue in the active site, which may act as a general base for a serine amino acid. The pH-activity profile was determined for 2-amino-2-phenylacetamide 2b, and this suggested that the unprotonated form of the amine acted as the substrate. Within a pH range of 3 - 9 the enantiomeric excess remains high (>98 %) and experimentally invariant. The amidase was found to have a temperature optimum of 60°C and could tolerate 20 % THF with a loss of only 15 % activity. Attempts made to hydrolyse 4,5,6-amino nitriles and amides to the corresponding amino acids and isolate any reaction intermediates failed. This was presumed to be due to the large fraction of the unprotonated amine due to the higher pKa (- 9 - 10).

The synthesis of 7-N-acetyl-3'-demethyllavendamycin propyl ester (61 ), 7-N-butr-3'-demethyllavendamycin amide of N,N-dimethylethylenediamine (62), 7-N-acetyllavendamycin butyl amide (64), 7-N- acetyllavendamycin amide of ethanolamine (63) are described. Incorporation of the Pictet-Spengler condensation of 7acetamido-2-formylquinoline-5, 8-dione (32) or 7-butyramido-2-formylquinoline-5, 8dione (7) with tryptophan propyl ester (65), L-tryptophan amide of N, N dimethylethylenediamine (66), f3-methyltryptophan butyl amide (68), or methyltryptophan amide of ethanolamine (67) in xylene afforded four lavendamycin analogs.Aldehydes 32, 74 and 86 were prepared according to the following general procedure. Nitration of 8-hydroxy-2-methylquinoline (69) yielded 8-hydroxy-2-methyl - 5,7-dinitroquinoline (29). Compound 29 was then hydrogenated and acylated with acetic anhydride or butyric anhydride or 2-furoyl chloride followed by hydrolysis to yield 5,7diacetamido-8-hydroxy-2-methylquinoline (75) or 5,7- dibutyramido-8- hydroxy-2methylquinoline (73) or 5,7-difuroylamino-8-hydroxy-2- methylquinoline (84). Compounds 75 and 73 and 84 were oxidized by potassium dichromate to give the corresponding 5,8-diones 31 or 72 or 85. Treatment of 31 or 72 or 85 with selenium dioxide in refluxing 1,4-dioxane afforded compounds 32 and 74 and 86, respectively.Tryptophan propyl ester (65) was synthesized via a Fischer esterification of Ltryptophan with propyl alcohol saturated with hydrogen chloride. Compounds 66, 67, 68, 76, 77, 78, 79, and 80 were synthesized via the conversion of esters to amides with dimethylaluminum amides. Tryptophan methyl ester (23) and (3-methyltryptophan methylester (11) were treated with premixed trimethylaluminum and primary amines and refluxed to afford the desired tryptophan and (3-methyltryptophan amides.The structures of the novel compounds 61, 62, 63, 64, 66, 67, 68, 76, 77, 78, 79, 80, were confirmed through 1H NMR, IR, EIMS, and HRMS. Elemental analyses of Compounds 66, 68, 76, 77, 78 and 80 were also included. 1H NMR and IR for known compounds 29, 30, 31, 32, 71, 73, 74, 75, 84, 85, 86 were provided also.
Department of Chemistry

Chapter One presents an overview of olefin polymerisation, which provides the context for the majority of the work described in later chapters. Both Ziegler-Natta and late transition metal systems are described. Chapter Two describes the synthesis and reactivity of trisamido titanium complexes with the diarylamido fragments derived from diphenylamine and di-p-tolylamine. These complexes have been thoroughly studied using NMR spectroscopy. This chapter also presents the syntheses of two rare examples of trisamido methyl complexes. In addition, an improved synthetic route to the cocatalyst, KB(C6F5)4 and the structures of [B(C6F5)3·C4H8O] and [Mg(C6F5)2(Et2O)(dioxane)] are described. Chapter Three describes the polymerisation activity of the catalysts derived from (R2N)3TiCl, (R2N)3TiMe, and [(R2N)3Ti]+ with the cocatalysts MAO, B(C6F5)3, and KB(C6F5)4. Data was recorded for each of the catalysts, and the consumption of propene over time was plotted. Rate constants were found for each of the polymerisation reactions. The mechanism for the polymerisation of each of these was also examined. Chapter Four presents the synthesis and reactivities of new trisamido complexes using 10,11-dihydro-dibenz(b,f )azepinyl, hereafter abbrievated as dda, as the amide fragment. Specifically, syntheses of (dda)3TiCl, (dda)3TiMe and (dda)3TiBH4 are described and their characterisation by NMR spectroscopy and X-ray crystallography is presented. The use of these complexes in synthetic approaches to (dda)3TiH are described. Initial steps in the characterisation of hydride transfer to CO2 from (dda)3TiH are also presented. Chapter Five presents details for the experimental work and Appendices are included, containing selected experimental data.

The following thesis outlines work carried out during the last three years for the development and investigation of methodologies using amides as N- and O- acylating agents. Chapter 1 highlights the range of methodologies and protocols reported in the literature that use amides as precursors for the synthesis of both functionalised amides and esters. The introduction will highlight the range of catalysts and promoters used as well as the scope of the current methodologies. As well as this it will highlight the limitations of the methodologies so emphasising where the following research fits into these areas. Chapter 2 presents the development of a transamidation methodology using zirconocene dichloride as a catalyst. The scope with respect to functional group tolerance is presented as well as the investigations into the mechanism of the reaction. Chapter 3 builds on the research presented in Chapter 2 and details the development of a more catalytically active zirconocene transamidation methodology. By the addition of a catalytic additive the temperature or time required for the reaction to be carried out could be lowered. Investigations into the mechanism were also carried out highlighting the in situ formation of an active catalytic species. Chapter 4 details the development of an operationally simple methodology for the O-acylation of alcohols using amides. Using a catalytic amount scandium triflate the substrate scope of the reaction was explored with a proposed mechanism presented based on activation of the amide.

In the past, aminocyclohexanol rings have been successfully utilized as pH-triggered molecular switches in various trans-2-aminocyclohexanol derivatives. By changing the groups on the amine nitrogen, these models provided a wide pH range in which a switch can occur. The pH-induced switch of conformation was monitored by 1H-NMR spectroscopy. The models were also incorporated into the bilayer membrane of liposome structures and tested for their ability to disrupt their membrane upon their conformational flip induced by a decrease in pH. In this work, the amide bond has been studied as a molecular switch and various amide derivatives have been tested for their potential as lipid-like compounds that also exhibit a pH-sensitive conformational flip. The conformational analysis of these compounds was achieved by various NMR techniques and NMR acid-base titration studies were utilized to estimate the pKa of a number of the compounds described.

The vast variety of long-chain fatty acid amides identified in biological systems is intriguing. The general structure of a fatty acid amide is R-CO-NH-X, where R is an alkyl group and X is derived from an immense variety of biogenic amines. Although structurally simple, the bioactivities of these molecules as signaling lipids are very diverse and have just recently begun to emerge in the literature. Interest in the long-chain fatty acid amides dramatically increased following the identification and characterization of one specific N-acylethanolamine, N-arachidonoylethanolamine (anandamide), as the endogenous ligand for the cannabinoid receptors in the mammalian brain. Since this discovery, the details of N-acylethanolamine metabolism have been elucidated. However, a lesser extent of progress has been made in the last twenty years to identify and study the non-N-acylethanolamine long-chain fatty acid amides. The focus of this dissertation is the elucidation of the biosynthetic pathways for long-chain fatty acid amides, including N-acylglycines, primary fatty acid amides, N-acylarylalkylamides, and N-acylethanolamines. The details of long-chain fatty acid amide metabolism will lead to the determination of possible therapeutic targets. We identified mammalian glycine N-acyltransferase like 3 as the enzyme that catalyzes the formation of long-chain N-acylglycines in mouse N18TG2 neuoblastoma cells, identified and quantified a panel of long-chain fatty acid amides in Drosophila melanogaster extracts by LC/QTOF-MS, established Drosophila melanogaster as a model system to study long-chain fatty acid amide metabolism, and identified arylalkylamine N-acyltransferase like 2 as the enzyme that catalyzes the formation of long-chain N-acylserotonins and N-acyldopamines in Drosophila melanogaster.

In this project the use of amides as precursors for imidoyl radicals in heterocyclic chemistry has been developed. Amides were converted to thioamides, which function as precursors for imidoyl radical equivalents. Also, a novel protocol for the synthesis of imidoyl selanides was developed for the purpose of using these as imidoyl radical precursors. The precursors were used in a study of intramolecular oxidative cyclisation of imidoyl radicals onto electron deficient pyrroles and indoles. The imidoyl radical equivalents derived from thioamides did not cyclise onto heteroarene double bonds. In contrast, imidoyl radicals derived from imidoyl selanides did cyclise 6-exo onto activated heteroarenes, but yields were generally low due mainly to competing reduction of the imidoyl radical, but also due to adduct formation with isobutyronitrile radicals originating from the initiator.

A química de carboidratos têm sido um importante link entre a síntese orgânica, a biologia e a química medicinal devido ao papel fundamental que açúcares apresentam na glicobiologia. Neste contexto, a ligação amida glicosídica é uma importante conexão encontrada na natureza, sendo uma das formas de ligar um núcleo de carboidrato a outras biomoléculas e produtos naturais, como glicopeptídeos e N-glicosil amidas. Dessa forma, o desenvolvimento de métodos sintéticos para a introdução de núcleos de carboidratos em diferentes estruturas é fundamental. Tendo em vista o interesse do nosso grupo de pesquisa em desenvolver novas estratégias utilizando a química de selênio na funcionalização de derivados de carboidratos, o presente projeto descreve uma metodologia de síntese de N-glicosil amidas e de glicoconjugação via formação de ligação amida, envolvendo a reação entre selenocarboxilatos, gerados in situ, com azidas glicosídicas. Foi possível sintetizar com sucesso uma série de derivados de carboidratos, para uma variedade de substratos que incluíram: N-glicosil amidas furanosídicas (20 exemplos), piranosídicas (13 exemplos) e também N-glicoconjugados graxos (10 exemplos). A metodologia foi baseada na geração in situ de selenocarboxilatos de lítio, a partir de Se0/ LiEt3BH e derivados de ácidos carboxílicos, e suas reações com azidas derivadas de açúcares. Um aspecto importante deste protocolo é que a reação se inicia com selênio elementar e apresenta como subprodutos N2 e Se0. O isolamento e manipulação de espécies intermediárias reativas de selênio são evitadas durante o curso reacional, conferindo ao selenocarboxilato o status de reagente traceless.
Carbohydrate chemistry has been an important link between organic synthesis, biology and medicinal chemistry due to the fundamental roles that sugars play in glycobiology. In this context, the glycosyl amide linkage is an important connection found in nature, since it is one of the ways in which a sugar unit can be found attached to other biomolecules and natural products, such as N-glycosyl amides and glycopeptides that are known for possessing a wide range of bioactivities. Therefore, the development of synthetic methods for the introduction of sugar moieties into various different scaffolds is of paramount importance. In connection with our interest on the development of new strategies using selenium chemistry for the functionalization of carbohydrate derivatives, we describe herein an efficient synthesis of glycosyl amides and glycoconjugation methodology via amide bond-formation, enabled by the reaction of in situ generated selenocarboxylates with glycosyl azides. Carbohydrate-derived amides were successfully prepared in good yields for a broad range of substrates, including: furanosyl (20 examples), pyranosyl (13 examples) N-glycosil amides derivatives and also fatty acids glycoconjugates (10 examples). The methodology relied in the in situ generation of lithium selenocarboxylates, from Se/LiEt3BH and acyl chlorides or carboxylic acids and their reaction with sugar azides. A key aspect of the present protocol is that we start from elemental selenium and as by-products we have harmless gaseous nitrogen and elemental selenium. Isolation and handling of all reactive and sensitive seleniumcontaining intermediates is avoided, therefore assigning to the selenocarboxylate the status of a traceless reagent.

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Universidade Estadual Paulista (UNESP)
O etanol no Brasil representa uma fonte alternativa de energia fortemente empregada como bicombustível, em mistura à gasolina como etanol anidro ou diretamente como álcool carburante hidratado. Há diversas matérias primas capazes de fornecer carboidratos para ser convertidas em etanol por processo fermentativo, sendo a cana-de-açúcar a mais utilizada em escala industrial. Existem outras fontes que podem ser empregadas de forma alternativa, considerando fatores como produtividade, condições edafoclimáticas e aspectos sócio-econômicos. Desta maneira, a mandioca está entre várias matérias primas existente para ser utilizada. O objetivo deste trabalho foi avaliar a produção de etanol a partir de substratos de mandioca com diferentes concentrações de carboidratos assimiláveis. O experimento foi conduzido em um delineamento fatorial com quatro fatores: tempo de fermentação (0, 1, 2, 4, 6, 8 e 10 horas) x leveduras de Saccharomyces cerevisae (Y670 e Y904) x micro-aeração (com e sem) x concentração de sólidos solúveis (180, 220 e 260 g L-1). Na produção do hidrolisado de mandioca através de processo enzimático, foi utilizado um reator de aço inox com agitação e controle de temperatura e capacidade de 18 litros. Uma suspensão de fécula de mandioca e água a 30% de matéria seca foi preparada e utilizou-se as enzimas Liquozyme 300L KNU/g (0,5kg t-1 amido, 90-95ºC, pH 6,0, 1 hora com agitação constante) e Saczyme 750L AGU/g (1kg t-1 amido, 60-65ºC, pH 4,0, 24 h com agitação constante). O hidrolisado obtido foi caracterizado quanto ao perfil e concentração de açúcares e, posteriormente, foi diluído para as concentrações nos ensaios. Os hidrolisados nas diferentes concentrações de sólidos solúveis foram acondicionados em erlenmeyers de 500 mL e procedeu-se a inoculação...
Ethanol in Brazil represents an alternative source of energy heavily used as biofuel in the blend anhydrous ethanol or gasoline as directly as fuel alcohol hydrated. There are various raw materials capable of supplying carbohydrates to be converted into ethanol by fermentation process, and the cane sugar most used at industrial scale. There are other sources that can be used alternatively, considering factors such as productivity, environmental conditions and socio-economic aspects. Thus, cassava is among several existing raw materials to be used. The aim of this study was to evaluate the production of ethanol from cassava substrates with different concentrations of digestible carbohydrates. The experiment was conducted in a factorial design with four factors: fermentation time (0, 1, 2, 4, 6, 8 and 10 hours) x yeast Saccharomyces cerevisiae (Y670 and Y904) x micro-aeration (with and without) x soluble solids concentration (180, 220 and 260 g L-1). In the hydrolyzate of cassava production by enzymatic process, we used a stainless steel reactor with stirring and temperature control and capacity of 18 liters. A suspension of tapioca starch and water to 30% dry matter was prepared and used... (Complete abstract click electronic access below)

Orientador: Cláudio Cabello
Banca: Waldemar Gastoni Venturini Filho
Banca: Manoel Lima Menezes
Resumo: O etanol no Brasil representa uma fonte alternativa de energia fortemente empregada como bicombustível, em mistura à gasolina como etanol anidro ou diretamente como álcool carburante hidratado. Há diversas matérias primas capazes de fornecer carboidratos para ser convertidas em etanol por processo fermentativo, sendo a cana-de-açúcar a mais utilizada em escala industrial. Existem outras fontes que podem ser empregadas de forma alternativa, considerando fatores como produtividade, condições edafoclimáticas e aspectos sócio-econômicos. Desta maneira, a mandioca está entre várias matérias primas existente para ser utilizada. O objetivo deste trabalho foi avaliar a produção de etanol a partir de substratos de mandioca com diferentes concentrações de carboidratos assimiláveis. O experimento foi conduzido em um delineamento fatorial com quatro fatores: tempo de fermentação (0, 1, 2, 4, 6, 8 e 10 horas) x leveduras de Saccharomyces cerevisae (Y670 e Y904) x micro-aeração (com e sem) x concentração de sólidos solúveis (180, 220 e 260 g L-1). Na produção do hidrolisado de mandioca através de processo enzimático, foi utilizado um reator de aço inox com agitação e controle de temperatura e capacidade de 18 litros. Uma suspensão de fécula de mandioca e água a 30% de matéria seca foi preparada e utilizou-se as enzimas Liquozyme 300L KNU/g (0,5kg t-1 amido, 90-95ºC, pH 6,0, 1 hora com agitação constante) e Saczyme 750L AGU/g (1kg t-1 amido, 60-65ºC, pH 4,0, 24 h com agitação constante). O hidrolisado obtido foi caracterizado quanto ao perfil e concentração de açúcares e, posteriormente, foi diluído para as concentrações nos ensaios. Os hidrolisados nas diferentes concentrações de sólidos solúveis foram acondicionados em erlenmeyers de 500 mL e procedeu-se a inoculação... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Ethanol in Brazil represents an alternative source of energy heavily used as biofuel in the blend anhydrous ethanol or gasoline as directly as fuel alcohol hydrated. There are various raw materials capable of supplying carbohydrates to be converted into ethanol by fermentation process, and the cane sugar most used at industrial scale. There are other sources that can be used alternatively, considering factors such as productivity, environmental conditions and socio-economic aspects. Thus, cassava is among several existing raw materials to be used. The aim of this study was to evaluate the production of ethanol from cassava substrates with different concentrations of digestible carbohydrates. The experiment was conducted in a factorial design with four factors: fermentation time (0, 1, 2, 4, 6, 8 and 10 hours) x yeast Saccharomyces cerevisiae (Y670 and Y904) x micro-aeration (with and without) x soluble solids concentration (180, 220 and 260 g L-1). In the hydrolyzate of cassava production by enzymatic process, we used a stainless steel reactor with stirring and temperature control and capacity of 18 liters. A suspension of tapioca starch and water to 30% dry matter was prepared and used... (Complete abstract click electronic access below)
Mestre

Ces dernières années, les recherches industrielles et académiques ont connu des bouleversements sans précédents liés à la notion de Développement Durable. Les exigences en matière de santé et d’environnement ont poussé les chimistes à concevoir des produits et procédés chimiques qui permettent de réduire ou d’éliminer les substances dangereuses. Les travaux de recherche décrits dans cette thèse s’inscrivent dans ce contexte et concernent la mise au point de nouveaux systèmes réducteurs utilisant des hydrosiloxanes comme substituts des hydrures d’aluminium et de bore. Dans cet objectif, des systèmes associant le 1,1,3,3-tétraméthyldisiloxane (TMDS) ou le polyméthylhydrosiloxane (PMHS) avec des complexes de titane ou de vanadium ont été développés pour la réduction des fonctions amides et nitriles. La nature de l’association hydrosiloxane – métal et du substrat étudié a joué un rôle important sur la performance et la sélectivité des réactions misent en oeuvre. D’une part, les réductions sélectives d’amides (tertiaires et secondaires) et de nitriles en aldéhydes ont été réalisées respectivement en présence du tétraisopropylate de titane(IV) et du triisopropylate d’oxyde de vanadium(V). D’autre part, les réductions d’amides primaires et de nitriles ont conduit aux amines primaires en présence de tétraisopropylate de titane(IV). Enfin, ces systèmes réducteurs ont été utilisés pour la synthèse d’hétérocycles azotés saturés. La réduction de composés dinitriles donne lieu à une réaction d’alkylation réductrice intramoléculaire qui conduit à la formation de dérivés de la pipéridine, de la pyrrolidine et de l’azétidine en une étape
In recent years, industrial and academic researches have experienced unprecedented changes related to the concept of sustainable development. Health and environment new requirements have prompted chemists to develop chemical products and processes that reduce or eliminate hazardous substances. The research work described in this thesis is focused on the development of new reducing systems using hydrosiloxanes as substitutes for aluminum and boron hydrides. In order to achieve this goal, reducing systems combining 1,1,3,3-tetramethyldisiloxane (TMDS) or polymethylhydrosiloxane (PMHS) with titanium or vanadium complexes have been developed for the reduction of amides and nitriles. The nature of both the association “hydrosiloxane – metal” as well as the studied substrate played an important role on the performance and the selectivity of the reaction. On the one hand, selective reductions of amides (tertiary and secondary) and nitriles to aldehydes were carried out respectively in the presence of titanium(IV) tetraisopropoxide and vanadium(V) triisopropoxide oxide. On the other hand, reductions of amides (primary) and nitriles afforded the corresponding primary amines in the presence of titanium(IV) tetraisopropoxide. Finally, these systems have been applied for the synthesis of saturated N-heterocycles. Reduction of dinitrile compounds led, in one step, to piperidine, pyrrolidine and azetidine derivatives through an intramolecular reductive alkylation reaction

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico
CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior
Piplartine and piperine are alkaloids/amides isolated from Piper species. The activity of these compounds was initially evaluated on the brine shrimp lethality assay, sea urchin development, MTT assay using tumor cell lines, and hemolytic assay. Piperine showed a higher toxicity in brine shrimp than piplartine. Both piplartine and piperine inhibited the sea urchin development, but in this assay piplartine was more potent than piperine. In MTT assay, piplartine was also the most active with IC50 values ranging from 0.7 to 1.7 Âg/mL. None of the tested substances induced hemolysis. Since the piplartine showed the best results, its mode of action was studied. Viability of HL-60, K562, JUKART, and MOLT-4 cell lines were affected by piplartine only after an exposure time of 24h, as analyzed by the Trypan blue exclusion. Piplatine reduced the number of viable cells associated with an increasing of the number of non-viable cells, which corroborate data from morphologic analysis. The cytotoxic activity of piplartine was related to the inhibition of DNA synthesis, as revealed by the reduction of BrdU incorporation. Administration of piplartine or piperine (50 or 100 mg/kg/day) inhibited the solid tumor development in mice transplanted with Sarcoma 180. The inhibition rates were of 28.7 and 52.3% for piplartine and 55.1 and 56.8% for piperine at lowest and highest dose, respectively. Piplartine-antitumor activity was related to the tumor proliferation rate inhibition, as observed by reduction of Ki67 staining in tumor of the treated-animals. The histopathological analysis of liver and kidney showed that both organs were reversible affected by piplartine and piperine treatment, but in a different way. Piperine was more toxic to the liver while piplartine affected more the kidney. Thus, both amides may act as antitumor agents, although, they seem to act through different pathways. Piplartine activity seems to be related to direct cytotoxicity on tumor cells, while piperine presented a host mediated activity
Piplartina e piperina sÃo alcalÃides/amidas presentes em plantas do gÃnero Piper. A atividade desses compostos foi inicialmente avaliada atravÃs do ensaio de toxicidade aguda em Artemia sp., desenvolvimento de ovos de ouriÃo do mar, ensaio do MTT usando cÃlulas tumorais e ensaio hemolÃtico. A piperina apresentou toxicidade maior em Artemia sp. que a piplartina. Ambas inibiram o desenvolvimento de ouriÃo do mar, mas neste ensaio a piplartina foi mais potente que a piperina. No ensaio do MTT, a piplartina tambÃm foi a mais ativa com valores de CI50 variando de 0,7 a 1,7 Âg/mL. Nenhuma das substÃncias testadas induziu hemÃlise. O mecanismo de aÃÃo da piplartina foi, entÃo, estudado. A viabilidade de cÃlulas HL-60, K562, JUKART e MOLT-4 foi afetada por piplartina apenas apÃs de um perÃodo de exposiÃÃo de 24h, quando analisada por exclusÃo por azul de tripan. A piplatina reduziu o nÃmero de cÃlulas viÃveis associado com um aumento no nÃmero de cÃlulas nÃo-viÃveis, o que colabora com os achados da analise morfolÃgica, onde observou-se um aumento do nÃmero de cÃlulas mortas. A atividade citotÃxica da piplartina està relacionada com a inibiÃÃo da sÃntese de DNA, como revelado pela incorporaÃÃo do BrdU. A administraÃÃo de piplartina ou piperina (50 ou 100 mg/kg/dia) inibe o desenvolvimento de tumor sÃlido em camundongos transplantados com Sarcoma 180. A inibiÃÃo foi de 28,7 e 52,3% para piplartina e 55,1 e 56,8% para piperina na menor e maior dose, respectivamente. A atividade antitumoral da piplartina, mas nÃo da piperina, està relacionada com a inibiÃÃo da proliferaÃÃo do tumor, como observada pela reduÃÃo da marcaÃÃo com Ki67 em tumores de animais tratados. A analise histopatolÃgica do fÃgado e rins demostrou que ambos os ÃrgÃos foram reversivelmente afetados pelo tratamento com piplartina e piperina, mas de maneira diferente. A piperina foi mais tÃxica para o fÃgado, enquanto que a piplartina afetou mais os rins. Assim, ambas as amidas podem atuar como agentes antitumorais, embora, elas pareÃam atuar por vias diferentes. Sendo que a atividade da piplartina parece estar relacionada diretamente a sua aÃÃo citotÃxica, enquanto que a atividade da piperina sÃria mediada pelo hospedeiro.

Based on new methodology for nitration of pyridine and pyridine derivatives developed at our department by Professor Jan Bakke and coworkers at NTNU, a whole range of substituted nitropyridines are now readily available. The method provides new possibilities in heterocyclic chemistry for the preparation of new materials. Due to the importance and useful properties of many pyridine-based compounds, the chemistry of nitropyridine derivatives is being investigated by our group at NTNU and results for nitropyridine carbamates, amides and carboxylates are presented in this thesis. These nitropyridine derivatives have been used as substrates for the formation of new bisheterocyclic compounds and pyridine derivatives. New synthetic routes to fused heterocycles have been developed.

Chapter 2 and Paper I presents the preparation, stability and reactivity of nitropyridine isocyanates (13, 23), a new class of compounds in organic chemistry. The introduction of an electronegative substituent represented by the nitro group was expected to reduce the basisity of the pyridine nitrogen, hence decrease the rate of dimerisation and increase the reactivity of the isocyanate carbon towards a nucleophile. The preparation of nitropyridine isocyanates (13, 23) are reported.

Isocyanates constitute an important class of compounds in organic chemistry and undergo a series of reactions to yield a variety of interesting products includingheterocyclic derivatives. Heterocyclic isocyanates, however, have not received the same attention as the respective aromatic compounds in synthesis and reactivity studies because of their instability and high reactivity. 2-Pyridine isocyanate dimerises while the 4-isomer trimerises to form the trimer.

Chapter 3 and Paper I presents the preparation, stability and reactivity of the isocyanate dimer and trimer. The isocyanate dimer (28) was formed in high yield from the reactive 5-nitro-2-pyridine isocyanate (23) by a [2+4]-cycloaddition reaction. Another byproduct in the preparation of the isocyanate using oxalyl chloride was the tetrone (26).

The isocyanate trimer was formed from the unstable 4-pyridine isocyanate for reference purposes. The trimer proved to be less stable than previously reported and afforded 4-aminopyridine and methyl 4-pyridine carbamate as decomposition products in the presence of moisture and alcohols, respectively. This demonstrates that the reactive trimer can be used as a protected version of the isocyanate for synthetic purposes.

Chapter 4 and Paper II presents studies of the nitropyridine isocyanates in cycloaddition reactions. The reactivity of the nitropyridine isocyanates in 1,3-dipolar cycloaddition reactions with trimethylsilylazide and 3,5-dimethylpyridine N-oxide to afford tetrazolinones (41, 43) and substituted amines (52, 55) was investigated. A [2+4]-cycloaddition reaction of nitropyridine isocyanate with diphenylketene was also studied. The cycloadduct (59) was formed. These results demonstrate the potential of the nitropyridine isocyanates to undergo cycloaddition reactions.

Application of nitropyridine carbamates, amides and carboxylates in the formation of new heterocyclic compounds have been investigated and discussed in Chapter 5-7.

Chapter 5 and Paper III presents the aromatic nucleophilic substitution reaction of the nitro group of methyl 3-nitro-4-pyridine carboxylate. The nitro group was successfully replaced by nitrogen, oxygen and sulfur nucleophiles to afford the substitution products (16a-d) in moderate yields.

Chapter 6 and Paper IV presents the cyclization reaction of nitropyridine carbamates for the formation of 1,3-dihydro-2H-imidazo[4,5-c]pyridin-2-one (79a-b), a biologically active compound. A facile acid-catalysed cyclization method for the preparation of the cyclic urea by traditional heating and the corresponding microwave-promoted reaction were developed. Both methods afforded the cyclic urea in high yield and represent a “green method” for the preparation of this compound.

Chapter 7 and Paper V presents the preparation of 1H-1,2,3-triazol [4,5-c]pyridine (86) and N-acyl and N-alkoxycarbonyl triazolo[4,5-c]pyridine derivatives (96a-e, 98a-e). The triazolopyridine derivatives were readily formed by diazotization and cyclization of the respective nitropyridine carbamates and amides in high yields. The application of triazolo[4,5-c]pyridine derivatives (98a-e) in the acylation of amines and amino acids was investigated. They proved to be more effective than the commercially available benzotriazole and afforded the protected amines in high yields under mild conditions.

Reduction of amides to amines is an important transformation in organic synthesis, which has been identified as among the 'top ten most important reactions' by a consortium of pharmaceutical companies. Presently achieved by hydride or borane reagents, it is both hazardous and generates excessive volumes of effluent and waste. Similarly, chemoselective reduction of C=C bonds, particularly conjugated double bonds, also presents a significant challenge in organic synthesis. Electrochemical synthesis using a flow reactor offers an environmentally benign and energy efficient technology for producing key intermediates in the synthesis of candidate drug molecules; its benefits include: improved control of reaction parameters, reproducibility and scalability. The first part of the thesis describes a study on the kinetics of the selective electrochemical reduction of C=C maleimide derivatives using a rotating disc electrode system. The resulting data was used to define the reactor's operating conditions. Subsequently, the chemoselective and stereoselective reduction of maleimide derivatives were carried out in the electrochemical flow reactor with a graphite felt cathode and the rate of reactant depletion, monitored by UV-visible spectroscopy. In the second part, amide reduction was studied in an electrochemical flow reactor using vitreous carbon and boron-doped diamond cathodes. The reduction of N,N- dimethylbenzamide produced the corresponding amine, benzaldehyde and benzyl alcohol. The selectivity of the reaction was investigated as a function of reaction conditions, and a mechanism for the reduction was proposed. Subsequently, a range of functionalised amides were subjected to electrochemical reduction under optimised conditions, to further assess the scope of the methodology as a tool for organic synthesis. The influence of electron donating and withdrawing groups incorporated in to N-benzoylpyrrolidine derivatives were investigated, as well as the pattern of substitution on the amides. The result revealed observable trends in the product distribution between the corresponding amine, benzaldehyde and benzyl alcohol compounds.

This project was concerned with extending the scope of the non-classical Wittig reaction of alkylidenephosphoranes on Weinreb amides discovered previously in Prof. John A. Murphy's group by Aurelien G. J. Commeureuc during his study towards the total synthesis of Muscothiazoles A and B.