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Academic literature on the topic 'Semissíntese'
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Dissertations / Theses on the topic "Semissíntese"
Rodrigues, Ana Clara Beltran. "Betalaínas funcionais: semissíntese, propriedades fotofísicas e interações intermoleculares." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/46/46136/tde-22082017-102205/.
Full textInstituto de Química, Universidade de São Paulo, São Paulo, 2017. Betalains are colorful alkaloids with high antioxidant capacity that are found in plants and fungi. The biosynthesis of these natural products is based on the enzymatic conversion of L-tyrosine into betalamic acid and aldimine condensation thereof with amino acids. The semisynthesis of natural betalains improved the knowledge on this class of pigments and stimulated the development of artificial betalains, including functional derivatives. A coumarinic betalain was created to be used as a fluorescent label for Plasmodium falciparum on red blood cells. This Doctoral Thesis presents the semisynthesis and study of three coumarin betalains (cBeets) and one carbostyril betalain (csBeet). It was sought to establish relationships between the structures of these compounds and their physical-chemical and photophysical properties as a starting point in the development of a new class of functional betalains. Data on lipophilicity, hydrolysis stability, redox potential, one- and two-photon absorption and fluorescence are presented. Intermolecular interactions of these compounds were investigated by fluorescence measurements in binary polar solvent mixtures, bovine serum albumin and AOT reverse micelles in heptane/water.
Cargnin, Simone Tasca. "Triterpenos obtidos de fontes naturais : semissíntese, citotoxicidade e atividade antiprotozoária." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2017. http://hdl.handle.net/10183/166297.
Full textThe protozoans Trichomonas vaginalis, Leishmania amazonensis and Plasmodium falciparum are responsible for a large number of parasitic infections in worldwide, especially malaria, with 438,000 deaths annually. The main problems involved in the combat of these infections involve the treatment, especially by the resistance of parasites to commonly used drugs. Therefore, considering the need for new therapeutic alternatives, this work, through the recovery of waste, the use of natural products as a source of bioactive molecules and the use of semisynthesis tool, aimed to obtain compounds with antiprotozoal activity, particularly antimalarial activity. The ursolic acid (UA) was isolated from apple pomace (Malus domestica) obtained from a local juice manufacture, and betulinic acid (BA) from barks of Platanus acerifolia, and these compounds were modified at C-3 and C-28 positions. Two series of UA and BA derivatives were prepared and identified, totaling 24 compounds, which were tested against the P. falciparum chloroquine resistant strain (W2), T. vaginalis and L. amazonensis. Against all protozoans, compounds only modified at C-3 were the most active. The compound 3β-acetyl betulinic acid (100 μM) reduced the trophozoites viability of T. vaginalis nearly 74% and 3β-isobutyryl ursolic acid (100 μM) inhibited the growth promastigotes of L. amazonensis by 55%. More significantly, the 3β-butyryl betulinic acid showed significant antimalarial activity, IC50 = 3.4 μM. Moreover, the compounds did not shown significant toxicity against mammalian cells (VERO) and human hepatocellular carcinoma (HepG2) cells, demonstrating high selectivity index towards parasites. Nanoemulsions and lipid-core nanocapsules of the compound 3β-butanoyl betulinic were successfully developed by spontaneous nanoemulsification and nanoprecipitation method, respectively, and HPLC-UV method was adequate for the quantification of the triterpene derivative in the nanostructures. In spite of the in vitro antimalarial activity, the compound 3β-butanoyl betulinic acid free and incorporated in the nanoemulsion showed no activity in the in vivo model, not presenting in vitro - in vivo correlation. This was probably due to the low solubility of the compound, which not reached the active site in a concentration satisfactory for its action. Overall, the data obtained in this study contribute to the development of new and low cost therapeutic alternatives, since the utilization of wastes, as well as the use of natural products and semisynthesis process are inexpensive strategies. In addition, it was demonstrated in an unprecedented way the feasibility of the incorporation of triterpenic compounds in biodegradable nanocarrier systems (nanoemulsions and lipid-core nanocapsules) using nanoprecipitation, a simple, effective and reproducible methodology.
Gonçalves, Letícia Christina Pires. "Betalaínas : semissíntese, capacidade antirradicalar e aplicação como sondas em sistemas biológicos." reponame:Repositório Institucional da UFABC, 2012.
Find full textAraújo, Rafael Castro. "Semissíntese de derivados de moléculas biologicamente ativas obtidas de plantas e microrganismos da Amazônia." Universidade Federal do Amazonas, 2016. http://tede.ufam.edu.br/handle/tede/5135.
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CNPq - Conselho Nacional de Desenvolvimento Científico e Tecnológico
The Amazon rainflorest has described by its fauna, flora and microbiota, arousing interest of researchers for this region aggregated knowledge. Such interest is regarding the new findings saying that Amazon has an incredible biodiversity, where new molecules with potential for new drugs are often reported. Among the alternatives to existing drugs in the market is semisynthesis of organic molecules. In this work all semisynthesis were made from secalonic acids, isocoumarin bergenin and triterpene polycarpol. Those bioactive substances where isolated in advance from a microorganism and plants from Amazon. Through simple structural modification reactions, nine compounds were obtained and identified as: dibenzyl secalonic acid, dibenzyl bergenin, 15-O-benzoyl-polycarpol, 24-epoxy-polycarpol, 3-acetyl-policarpol, 15-acetyl-polycarpol, 3,15-diacetyl-polycarpol, 2,6,12,15-tetroxide-polycarpol. Additionally the reaction intermediate O-acyldicicloexylisoureia has been isolated and characterized. This intermediate and polycarpol derivatives are unprecedented in the literature.
A região Amazônica é descrita por sua fauna, flora e microbiota, despertando o interesse de pesquisadores para o conhecimento dessa região. Tal interesse são pelas novas descobertas que afirmam a Amazônia como detentora de uma incrível biodiversidade, onde novas moléculas, com potencial para novos fármacos, são reportadas frequentemente. Entre as alternativas para os fármacos existentes no mercado, estão as semissínteses de moléculas orgânicas. Neste trabalho foram realizadas semissínteses a partir do Ácido Secalônico, da isocumarina Bergenina e do triterpeno Policarpol, substâncias bioativas isoladas, previamente, de um microorganismo e plantas da flora amazônica. Através de reações simples de modificação estrutural foram obtidos nove compostos, sendo identificados como: Ácido dibenzilsecalônico, dibenzilbergenina, 15-O-benzoilPolicarpol, 24-epoxi-Policarpol, 3-acetil- Policarpol, 15-acetil-Policarpol, 3,15-diacetil-Policarpol, 2,6,12,15-tetroxo- Policarpol. Adicionalmente foi isolado e caracterizado o intermediário de reação O-acildicicloexilisoureia. Este intermediário e os derivados do Policarpol são inéditos na literatura.
DIAS, Kris Simone Tranches. "Semissíntese e estudo da relação estrutura-atividade antimicrobiana de novos derivados da Guttiferona-A." Universidade Federal de Alfenas, 2011. https://bdtd.unifal-mg.edu.br:8443/handle/tede/372.
Full textInfections caused by bacteria and fungi are very common and acquired resistance to available antibiotics has become common, showing the need for constant research and investments in new effective antimicrobial drugs. Among the alternatives to the prospection for new drugs, natural products stand out as sources of active ingredients, new molecular models and raw materials with innovative molecular patterns. As part of a project aiming the bioprospection and the design of new bioactive substances, the gender Rheedia was elected as a source of poliprenylated benzophenones to be used as starting materials for new semi-synthetic derivatives with optimized antibacterial profile and structure-activity relationship studies (SAR). The central objective was to synthesize new derivatives of guttiferone-A (LFQM-78), a natural benzophenone, carrying out modifications of their hydro/lipophilic properties by the insertion of substituents on the phenolic hydroxyl groups to optimize the profile of antimicrobial activity of this compound. Semi-synthetic derivatives were evaluated for their effects s against a broad spectrum of Gram-positive and Gram-negative bacteria and fungi. The most sensitive microbial species to the target compounds were Gram-positive (ATCC 6538) and Bacillus cereus (ATCC 11778), and some of the derivatives were more active than chloramphenicol, used as standard. Our results were indicative that a variation in lipophilicity of the molecules was an important requisite for antimicrobial activity modulation, and that the structural modifications made on guttiferone-A led to more potent and selective derivatives, with lower toxicity for different types of pathogens.
GONTIJO, Vanessa Silva. "Planejamento e semissíntese de novos análogos da Fukugetina com potencial atividade antileishmania, antioxidante e antiproteolítica." Universidade Federal de Alfenas, 2011. https://bdtd.unifal-mg.edu.br:8443/handle/tede/373.
Full textThis study aimed to the phytochemical study of ethyl acetate extract epicarp (EAEE) from Garcinia brasiliensis, structural change in the natural biflavonoids fukugetina (LFQM-109) and antioxidant activity assays, and enzymatic leishmanicidal of the natural compound and LFQM-109 its semisynthetic analogues. The species G. brasiliensis belongs to the family Guttifereae and is cultivated throughout the Brazilian territory. It is popularly known as bacuri, bacupari, and Poroca bacuripari species in Brazil and Bolivia as guapomo. It is a native of Brazil, Paraguay and northern Argentina. Fractionation of EAEE led to the isolation of compounds LFQM-105, LFQM-106, LFQM-107, LFQM-108 and Fukugetina (LFQM-109). The compounds were identified by comparison with authentic standards and by spectral and spectroscopic usual. From the natural compound fukugetina, alkylation and acylation reactions were performed in order to obtain more lipophilic semisynthetic derivatives. To evaluate the antioxidant activity (reducing power and DPPH radical scavenger) used concentrations of 400-12.5 μM and standards as ascorbic acid and BHT. For evaluating antiparasitic (promastigote and amastigote form) used concentrations between 100-50 μM as standard and pentamidine. The results showed a reduction in testing the antioxidant potential of semisynthetic derivatives compared with the natural compound LFQM-109, probably because reducing the number of phenolic hydroxyl in the structure with structural changes. In tests of antiparasitic activity (promastigote and amastigote forms) was observed an enhancement of the activity of semisynthetic derivatives, possibly by being more lipophilic than the parent compound LFQM-109. Assays were performed on cysteine and serine proteases, observing a significant inhibitory activity of semisynthetic derivatives compared to the precursor LFQM-109, indicating that the increased lipophilicity enhanced the action on these enzymes. This study has thus contributed to the knowledge of chemistry and the antioxidant, antiparasitic and natural compounds of enzyme obtained from G. brasiliensis and the semisynthetic fukugetin.
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
Ehlert, Everton 1991, Ricardo Andrade 1960 Rebelo, Sandro Lucio 1980 Mireski, and Universidade Regional de Blumenau Programa de Pós-Graduação em Química. "Preparação de derivados do (-)-drimenol como precursores para a semissíntese de quinonas/hidroquinonas sesquiterpênicas marinhas bioativas." reponame:Biblioteca Digital de Teses e Dissertações FURB, 2016. http://www.bc.furb.br/docs/DS/2016/361554_1_1.pdf.
Full textCo-orientador: Sandro Lucio Mireski.
Dissertação (Mestrado em Química) - Programa de Pós-Graduação em Química, Centro de Ciências Exatas e Naturais, Universidade Regional de Blumenau, Blumenau.
Vieira, Patrícia de Brum. "Potencial anti-trichomonas vaginalis de Manilkara rufula análise fitoquímica, semissíntese e mecanismo de morte do parasito." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2015. http://hdl.handle.net/10183/149474.
Full textAlthough it is one of the most endangered areas on Earth, there are few studies on the pharmacological potential of the Caatinga. This is an exclusively Brazilian biome and its plants present unique characteristic that make them an immeasurable source of active compounds. The parasite Trichomonas vaginalis is the etiologic agent of trichomoniasis, the most common non-viral sexually transmitted disease worldwide. The infection has been associated with serious consequences in health and cases of resistance to metronidazole are constantly increasing. Then, the necessity of new alternatives to the treatment of trichomoniasis is evident. The aim of this thesis was to evaluate the anti-T. vaginalis potential of plants from Caatinga. The Manilkara rufula plant showed the most potent activity against the parasite and bioguided fractionation was performed. Pentacyclic triterpenes (α- and β-amyrin caproate and β-amyrin and lupeol acetate) were identified in the nonpolar fractions of M. rufula, however, low antiparasitic activity was observed. Triterpenic semisynthetic derivatives, fractions containing flavonoids, tannins and saponins were also tested. Our results showed that ursolic acid and H100 fraction exhibited potent anti-T. vaginalis activity and both affect growth and viability of trophozoites. In addition, ursolic acid and H100 fraction induced significant alterations in the ultrastructure of the parasite, indicating that the mechanism of death is by membrane damage. The H100 fraction induced complete lysis of erythrocytes and reduced the parasites adhesion to epithelial cells, once again, suggesting that the H100 action was on parasite membrane. The fraction H100 showed no cytotoxicity to epithelial cells. The results demonstrated the potential of the plant M. rufula against T. vaginalis and contributed to the understanding of the pharmacological properties of the Caatinga plants, as well as for the rational development of alternatives for trichomoniasis treatment.
Trassi, Marco Aurélio de Souza. "Hidrólise da betanina na presença de tensoativos e formação de betaxantinas em água." reponame:Repositório Institucional da UFABC, 2012.
Find full textGouveia, Mariana Amaral. "Preparation of new semi-synthetic steroids." Master's thesis, 2018. http://hdl.handle.net/10316/84714.
Full textOs produtos naturais continuam a ser uma fonte inspiradora para a descoberta de medicamentos. No entanto, a modificação estrutural no esqueleto base desses compostos é frequentemente necessária para superar algumas limitações e otimizar o seu perfil farmacológico. Assim, a produção de derivados semissintéticos de produtos naturais tem crescido nas últimas décadas.Vários estudos demonstraram que modificações químicas na estrutura base de esteroides levam à formação de derivados semissintéticos com maior potência e seletividade quando comparados com as moléculas de partida. Estes resultados têm incentivado a realização de estudos adicionais nesta área com vista ao desenvolvimento de novas opções terapêuticas.Dentro dos esteroides, devido à sua versatilidade, preço relativamente baixo e usos medicinais descritos, os ácidos biliares parecem moléculas promissoras para a realização de novas reações semissintéticas.No presente trabalho, foram sintetizados derivados dos ácidos cólico e ursodesoxicólico. Ambos os derivados acetilados destes ácidos biliares foram sintetizados e isolados. O ácido cólico acetilado foi utilizado para preparar derivados de ureia como novos compostos finais, através de intermediários de isocianato. Todos os compostos foram depois analisados através de Ressonância Magnética Nuclear (RMN) para confirmar a sua estrutura e da determinação do ponto de fusão para confirmar a sua pureza.Quanto a perspetivas futuras, é de grande interesse avaliar a atividade biológica destes compostos através ensaios in vitro, bem como preparar reações químicas diferentes em vários ácidos biliares, para diversificação estrutural.
Natural products (NPs) continue to be an inspirational source for drug discovery. Nevertheless, structural modification in the basic skeleton of these compounds is often necessary to overpass some limitations and optimizing their pharmacological profile. Therefore, the production of semisynthetic derivatives of NPs has increased in the last decades.Several studies have shown that chemical modifications in the basic structure of steroids lead to the formation of semisynthetic derivatives with increased potency and selectivity when compared to the initial molecules. These results have been encouraging the realization of additional studies in this field, with new therapeutic options as the final goal.Within the steroids, because of their versatility, relatively low price and described medicinal uses, bile acids (BAs) seem promising molecules to perform new semisynthetic reactions. In the present work, derivatives of cholic and ursodeoxycholic acids were synthesized. Acetylated BAs were both prepared and isolated. The acetylated cholic acid was further used to originate urea derivatives as final new compounds, through isocyanate intermediates. All the compounds were then analysed by Nuclear Magnetic Resonance (NMR) to confirm their structure and by melting point analysis to confirm their purity. As future perspectives, it is of the utmost interest to evaluate the biological activity of these compounds through in vitro assays as well as to conceive different chemical reactions in several BAs, for structural diversification.