Enantioselectivity
Mostrando 1-12 de 60 artigos, teses e dissertações.
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1. New Strategies in Enantioselective Hydrogenation on Supported Transition Metal Catalyst: Effects of Metal Sintering and Support Swelling
The effect of noble metal catalysts supported on an ionic exchange resin for the enantioselective hydrogenation of ethyl pyruvate to ethyl lactate was studied. High activity and moderate enantioselectivity levels were obtained. Pt was the best enantioselective metallic phase, followed by Pd and Au; Rh was the less enantioselective metallic phase. The effect
J. Braz. Chem. Soc.. Publicado em: 12/08/2019
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2. Synthesis of the C(7)-C(20) Fragment of Spirotoamides A, B and C
This work describes the preparation of the C(7)-C(20) fragment of spirotoamides A to C in a very elegant fashion, achievement very high levels of stereocontrol. The synthesis has been accomplished by a sequence involving 14 steps (0.36% overall yield, average of 81% for each step) in high diastereo and enantioselectivity, employing, as determining steps, asy
J. Braz. Chem. Soc.. Publicado em: 12/08/2019
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3. The Role of L-Proline and Co-Catalysts in the Enantioselectivity of OXA-Michael-Henry Reactions
The use of L-proline derivatives employed in OXA-Michael-Henry tandem reactions has been an efficient method to produce enantiomerically enriched compounds. In this work it was carried out a study of the OXA-Michael-Henry reactions between salicylaldehyde and β-nitrostyrenes, catalyzed by L-proline and its derivatives. The corresponding (R)-3-nitro-2-phenyl
J. Braz. Chem. Soc.. Publicado em: 08/04/2019
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4. Easy and Simple SiO2 Immobilization of Lipozyme CaLB-L: Its Use as a Catalyst in Acylation Reactions and Comparison with Other Lipases
In this study, lipase from Candida antarctica B (Lipozyme CaLB-L) was successfully immobilized on SiO2 through adsorption and used to obtain (R)-(+)-esters derived from (R,S)-1-phenylethanol. The new immobilized enzyme was compared with commercially immobilized lipases (Novozyme 435, Lipozyme 435 and Pseudomonas cepacia (PSC-II and PSD-I)). Lipozyme CaLB-L a
J. Braz. Chem. Soc.. Publicado em: 2017-07
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5. ASYMMETRIC SULFOXIDATION OF ALBENDAZOLE TO RICOBENDAZOLE BY FUNGI: EFFECT OF pH
Albendazole (ABZ) is an anthelmintic drug used for the treatment of infectious diseases in veterinary and human medicine. This drug is a prochiral drug that after administration, is rapidly oxidized in the pharmacologically active sulfoxide metabolite, which is also known as ricobendazole (ABZSOX). ABZSOX has a stereogenic center and possibly two enantiomers
Quím. Nova. Publicado em: 2015-08
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6. Zingiber officinale (GENGIBRE) COMO FONTE ENZIMÁTICA NA REDUÇÃO DE COMPOSTOS CARBONÍLICOS
Various vegetables as biological catalysts were evaluated in enantioselective reduction of carbonyl compounds. The stereoselectivity of the process was in agreement with Prelog's rule for twelve of the vegetables, whereas okra and green peppers formed anti-Prelog products. Zingiber officinale exhibited the best results with 30% conversion and 89% ee. The par
Quím. Nova. Publicado em: 2015-05
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7. ENZYMATIC RESOLUTION OF ANTIDEPRESSANT DRUG PRECURSORS IN AN UNDERGRADUATE LABORATORY
The use of biocatalysts in synthetic chemistry is a conventional methodology for preparing enantiomerically enriched compounds. Despite this fact, the number of experiments in chemical teaching laboratories that demonstrate the potential of enzymes in synthetic organic chemistry is limited. We describe a laboratory experiment in which students synthesized a
Quím. Nova. Publicado em: 2015-02
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8. Investigação da seletividade de mono-oxigenases frente a substratos orgânicos de boro ou de selênio / Investigation on selectivity of mono-oxigenases in the presence of boron-containing or seleniun-containing organic compounds
Neste trabalho foi avaliada a seletividade (quimio ou enantiosseletividade) de quatro enzimas Baeyer-Villiger mono-oxigenases (BVMOs: PAMO, PAMO M446G, HAPMO e CHMO) frente a substratos contendo boro ou selênio. Inicialmente uma série de boro-acetofenonas foram submetidas à bio-oxidação catalisada por estas BVMOs. A enzima CHMO mostrou quimiosseletivida
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 25/05/2012
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9. Estudos visando a síntese do alcaloide indolizidínico (+)-ipalbidina / Studies toward the synthesis of the indolizidine alkaloid (+)-ipalbidine
A ipalbidina é um alcaloide indolizidínico com propriedades analgésica e antirradicais livres. Este alcaloide possui como fonte natural a Ipomoea alba L., uma espécie de dama-da-noite, sendo isolado das suas sementes na forma de aglicona da ipalbina (ligada à D-glicose). A ipalbidina possui estrutura química relativamente simples, porém sua síntese n
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 02/02/2012
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10. Investigação in vitro do efeito da restrição proteica no metabolismo do albendazol em ratos e estudos de inibição do crescimento de células tumorais humanas pelos enantiômeros do albendazol sulfóxido / Investigation in vitro of effect of protein restrict in the metabolism of albendazole in rats and growth inhibition studies in human tumor cells by enantiomers of albendazole sulphoxide
This work presents an in vitro investigation of protein restriction in the metabolism of albendazole (ABZ). The study was conducted with microsomal fractions obtained from Wistar rats using a High Performance Multidimensional Liquid Chromatography method which was developed and fully validated for the determination of the ABZ metabolites albendazole sulphoxi
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 02/12/2011
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11. Triagem, aplicação e engenharia de biocatalisadores para transformações enantio e regiosseletivas / Screening, applying and engineering biocatalysts for enantio and regioselective transformations
Biocatalysts have been widely applied in recent decades for industrial processes yielding high value products under environmentally friendly reaction conditions. The development of biocatalysts often begins with screening to identify enzymes with suitable activities followed by characterization of the enzymes chemo-, regio- and stereoselectivity or stability
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 03/06/2011
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12. Potencial biotecnológico de fungos isolados do molusco Pugilina morio / Biotechnological potential of fungi isolated from shellfish Pugilina morio
This study aimed to investigate the biotechnological potential of fungi isolated from mollusk Pugilina morio. The development work began with the collection of mollusk P. morio in Barra do Ceará, a beach situated in Fortaleza-CE. Of the specimens collected were isolated three filamentous fungi, known as PM3, PM6 and PM9. The isolates were identified by mole
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 24/02/2011