Enone
Mostrando 1-11 de 11 artigos, teses e dissertações.
-
1. Síntese de 3-haloacetil-4-metilquinolinas utilizando líquido iônico sob irradiação de micro-ondas / Microwave-assisted synthesis of 3-haloacetyl-4- methylquinolines in ionic liquid
Neste trabalho é descrita a síntese de uma série de 3-haloacetil-4-metilquinolinas a partir da reação de ciclocondensação de 4-alcoxivinil cetonas [R1C(O)CH=C(R2)(OCH3), onde R1 = CF3, CCl3, CHCl2, CF2Cl, CF2CF3 e R2 = Me, Et, Pr, Bu, i-Bu, i-Pent] com 2-aminoacetofenona. As condições reacionais utilizadas para a obtenção dos compostos heterocícl
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 27/07/2011
-
2. Enantioselective synthesis of (R)-isocarvone from (S)-perillaldehyde
Este trabalho descreve a preparação enantiosseletiva da (R)-(+)-isocarvona, (S)-(-)-5-isopropenilcicloex-2-enona e (S)-(-)-3-isopropenilcicloexanona, a partir do (S)-(-)-perilaldeído. Estes compostos podem ser usados como blocos de construção importantes para a síntese orgânica.
Publicado em: 2010
-
3. Curiosidades sobre a reação aldólica utilizada como etapa chave na síntese Brasileira dos ácidos pterídicos A e B
This work describes an overview of our synthesis of pteridic acids A and B and discloses some interesting results related to the lithium enolate-mediated aldol reaction used as key step to set up the C5-C15 fragment of these natural products. This first example, as far we know, of an aldol reaction between a chiral enolate of a (Z) enone and a chiral aldehyd
Química Nova. Publicado em: 2010
-
4. Síntese total dos ácidos pterídicos A e B / Total synthesis of pteridic acids A and B
This work describes the convergent stereoselective synthesis of pteridic acids A and B. Our strategy involved a lithium enolate-mediated aldol reaction between ethyl ketone 5 and aldehyde 4 as the key step to set up C5-C15 fragment favoring 1,2-syn anti-Felkin adduct. As far we know, this is the first example of an aldol reaction between a chiral enolate of
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 04/12/2009
-
5. Estudo etnofarmacológico e fitoquímico das espécies medicinais Cleome spinosa Jacq, Pavonia varians Moric e Croton cajucara Benth
In this present work an ethnographic research was performed with 84 native medicinal specimens from the Litoral Norte Riograndense, from which two plants Cleome spinosa Jacq e Pavonia varians Moric were submitted to ethnobotanic, phytochemistry and pharmacologic investigations. Additionally, a phytopharmacological research of the medicinal specimen Croton ca
Publicado em: 2009
-
6. Niobium Pentachloride as Lewis acid in [2 + 2] and [4 + 2] cycloadditions reactions / Pentacloreto de nióbio como ácido de Lewis em reações de cicloadição [2+2] e [4+2]
The aim of this work was to investigate the use of NbCl5 as Lewis acid in cycloadittion reactions. We have studied [2 + 2] cycloaddition reactions, Diels-Alder reactions between enonas and cyclopentadiene and aza-Diels-Alder reactions with Schiff bases. The effects of the temperature and of the molar concentration of NbCl5 were also evaluated. Comparasion of
Publicado em: 2006
-
7. Transformação de carbociclo em carboidrato : rotas sinteticas para analogos de açucares superiores
In this work are described methodologies for a synthetic pathway that aim the transformation of a carbocycle in a high carbohydrate (more than 6 atoms of C in its chain). The carbohydrate in study is interesting for the preparation of sialic acid analogous (carbohydrates with 9C), being the N-acetilneuraminic acid the most known among them. The purpose of th
Publicado em: 2001
-
8. Desymmetrization of enone-diones via rhodium-catalyzed diastereo- and enantioselective tandem conjugate addition-aldol cyclization
Catalytic tandem conjugate addition-enolate trapping represents an effective strategy for the design of catalytic transformations that enable formation of multiple C—C bonds. Recently, using enantioselective rhodium-catalyzed conjugate addition methodology, we developed a catalytic tandem conjugate addition-aldol cyclization of keto-enones. Here, we report
National Academy of Sciences.
-
9. Mechanistic studies on the catalytic cycle of rhodium-catalyzed asymmetric 1,4-addition of aryltitanate reagents to α,β-unsaturated ketones
Addition of lithium aryl(tetraisopropoxy)titanates [ArTi(OPr-i)4–Li+] to α,β-unsaturated ketones proceeded with high enantioselectivity (up to 99% ee) in the presence of an excess amount of chlorotrimethylsilane and a rhodium catalyst (3 mol % Rh), generated from [RhCl(C2H4)2]2 and (S)-binap, in tetrahydrofuran at 20°C to give high yields of the corresp
National Academy of Sciences.
-
10. A total synthesis of estrone based on a novel cascade of radical cyclizations
Two conceptually different and novel radical-mediated cascade reactions leading to a total synthesis of the steroid (±)-estrone 1 and to a synthesis of 14-epiestrone 40 are described. Treatment of the iododienynone 23 with Bu3SnH/2,2′-azobis(isobutyronitrile) (AIBN) triggers a 13-endo-dig radical macrocyclization followed by two sequential radical transan
National Academy of Sciences.
-
11. Extremely potent triterpenoid inducers of the phase 2 response: Correlations of protection against oxidant and inflammatory stress
A series of synthetic triterpenoid (TP) analogues of oleanolic acid are powerful inhibitors of cellular inflammatory processes such as the induction by IFN-γ of inducible nitric oxide synthase (iNOS) and of cyclooxygenase 2 in mouse macrophages. Here, we show that these analogues are also extremely potent inducers of the phase 2 response [e.g., elevation of
National Academy of Sciences.