Aldol
Mostrando 1-12 de 80 artigos, teses e dissertações.
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1. 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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2. A Facile Synthesis of Novel Isatinspirooxazine Derivatives and Potential in vitro Anti-Proliferative Activity
Novel isatinspirooxazine derivatives were designed and synthesized as potential anti-proliferative agents. The new compounds were obtained from aldol condensation reactions between isatin and 3-(hydroxyimino)butan-2-one in the presence of an organic base in order to generate an aldol adduct, followed by cyclization in trifluoroacetic acid, providing the desi
J. Braz. Chem. Soc.. Publicado em: 2019-01
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3. Synthesis, Photophysical and Electrochemical Properties of Novel D-π-D and D-π-A Triphenylamino-Chalcones and β-Arylchalcones
A series of triphenylamino (TPA)-chalcones and triphenylamino-β-arylchalcones, displaying either D-π-D or D-π-A architecture, were synthesized through aldol condensations and Heck reactions. The chalcone derivatives display intense absorption bands ranging from 389 to 432 nm and molar extinction coefficients of ca. 105 L mol-1 cm-1 corresponding to π-π*
J. Braz. Chem. Soc.. Publicado em: 2019-01
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4. Ketalization of Ketones to 1,3-Dioxolanes and Concurring Self-Aldolization Catalyzed by an Amorphous, Hydrophilic SiO2-SO3H Catalyst under Microwave Irradiation
The amorphous, mesoporous SiO2-SO3H catalyst with a surface area of 115 m2 g-1 and 1.32 mmol H+ per g was very efficient for the protonation of ketones on a 10% (m/m) basis, and the catalyst-bound intermediates can be trapped by polyalcohols to produce ketals in high yields or suffer aldol condensations within minutes under low-power microwave irradiation. T
J. Braz. Chem. Soc.. Publicado em: 2018-08
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5. CONDENSAÇÃO ALDÓLICA DE FURFURAL E ACETONA CATALISADA POR BASES ORGÂNICAS NITROGENADAS: UM ESTUDO PRELIMINAR DE DESEMPENHO CATALÍTICO VISANDO A PRODUÇÃO DE BIOQUEROSENE DE AVIAÇÃO
The aldol condensation between furfural and acetone was studied in the presence of organic bases, such as Piperazine (PIP), 3-Aminopropyltriethoxysilane (APTES) and 1,5,7-Triazabicyclo [4.4.0] dec-5-ene (TBD), as basic catalysts. The latter base showed the highest conversion rates of furfural and high selectivity to the single-condensation product 4-(2-Furyl
Quím. Nova. Publicado em: 2018-06
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6. Molecular And 3D-Structural Characterization Of Fructose-1,6-Bisphosphate Aldolase Derived From Metroxylon Sagu
ABSTRACT Fructose-1,6-bisphosphate aldolase (FBAld) is an enzyme that catalyzes the cleavage of D-fructose-1,6-phosphate (FBP) to D-glyceraldehyde-3-phosphate (G3P) and dihydroxyacetone phosphate (DHAP), and plays vital role in glycolysis and gluconeogenesis. However, molecular characterization and functional roles of FBAld remain unknown in sago palm. Here
Braz. arch. biol. technol.. Publicado em: 22/06/2017
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7. Multiple Monohydroxylation Products from rac-Camphor by Marine Fungus Botryosphaeria sp. Isolated from Marine Alga Bostrychia radicans
This manuscript describes the biooxidation of rac-camphor using whole cells of marine-derived fungus Botryosphaeria sp. CBMAI 1197. The main biotransformation products of this monoterpene were achieved via a hydroxylation reaction and occurred with 5 days of rac-camphor incubation. Products were identified by means of gas chromatography mass spectrometry (GC
J. Braz. Chem. Soc.. Publicado em: 2017-03
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8. Formal synthesis of the biciclic polyketides saliniketals A and B / Síntese formal dos policetídeos bicíclicos salinecetais A e B
Os salinecetais A e B foram isolados em 2007 por Fenical e colaboradores a partir da actinobactéria marinha Salinispora arenicola, e mostraram ser importantes alvos na quimioprevenção do câncer como inibidores da ornitina descarboxilase. Concluímos a síntese do fragmento avançado C-4/C-17 (19) envolvendo 19 etapas em 5,5% de rendimento global a partir
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 29/06/2012
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9. Metal-catalyzed asymmetric aldol reactions
A reação aldólica é uma das ferramentas mais poderosas e versáteis para a construção de ligações C-C. Tradicionalmente, esta reação foi desenvolvida em sua versão estequiométrica, no entanto, grandes esforços no desenvolvimento de catalisadores quirais para reações aldólicas foram realizados nos últimos anos. Desta forma, neste artigo de re
J. Braz. Chem. Soc.. Publicado em: 2012-12
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10. Síntese e avaliação biológica de derivados de goniotalamina / Synthesis and biological evaluation of derivatives goniotalamina
A goniotalamina (9), produto natural isolado de diversas plantas do gênero Goniothalamus, vem se destacando por sua potência em teste de triagem in vitro contra linhagens de células tumorais, bem como pelos resultados positivos em modelos tumorais in vivo. Isso faz com que a goniotalamina sirva como modelo para a síntese e avaliação de novos compostos.
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 12/08/2011
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11. Estudo da Aplicação de Brometo de Índio(I) em Reações para Formação de Ligações Carbono-Carbono / Studies on the Application of Indium(I) Bromide in Carbon-Carbon
This PhD thesis describes our results on the application of indium(I) bromide in carbon-carbon bond forming reactions. Indium enolates, generated in situ from the reaction between indium(I) bromide and α,α-dichloroketones, react with carbonyl compounds and electron-deficient alkenes. Reactions of indium enolate with α,α-dichloroketones, i
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 01/03/2011
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12. Estudo do efeito do substituinte em ß nas reações aldólicas envolvendo enolatos de boro de metilcetonas / Investigation of the influence of ß substituent in aldol reactions involving boron enolates of methylketones
As reações aldólicas envolvendo os enolatos de boro 71 (P = TBS, R = t-Bu), 72 (P = PMB, R = t-Bu) e 96 (P = TPS, R = t-Bu) levaram à formação de adutos de aldol com seletividades de moderadas a boas em favor do isômero 1,5-syn. As reações aldólicas envolvendo os enolatos de boro 90 (P = Tr, R = t-Bu), 91 (P = Tr, R = Me) e 97 (P = TPS, R = Me) lev
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 21/02/2011