Regiochemistry
Mostrando 1-11 de 11 artigos, teses e dissertações.
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1. A regioquímica das reações de Diels-Alder de N-tosil para-benzoquinona iminas / The regiochemistry of the diels-alder reaction of n-tosyl para-benzoquinone imines
Neste trabalho foi realizado um estudo comparativo da reatividade de diferentes dienófilos: para-benzoquinonas, suas mono-oximas, suas mono-oximas tosiladas e as suas N-tosiliminas frente às reações de Diels-Alder com dienos simples. A síntese destes dienófilos foi realizada através de algumas modificações químicas a partir dos fenóis corresponden
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 29/02/2012
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2. SÍNTESE DE HETEROCICLOS VIA REAÇÕES DE CICLOCONDENSAÇÃO DE a-ETILOXALIL E -PIRAZOLIL(ALQUIL) b-DIMETILAMINOENONAS COM 1,2- OU 1,3-DINUCLEÓFILOS / SYNTHESIS OF HETEROCYCLES VIA CYCLOCONDENSATION REACTIONS OF a-ETHYLOXALYL AND -PYRAZOLYL(ALKYL) b-DIMETHYLAMINOENONES WITH 1,2- OR 1,3-DINUCLEOPHILES
Chemoselective synthesis of ethyl 4-pirimidinecarboxylates and/or ethyl 5-pirimidineoxalates via cyclocondensation reaction of b-dimethylaminoenones [R1C(=O)C(=CNMe2)C(=O)CO2Et, where R1 = Ph, 4-MeC6H4, 4-MeOC6H4, 4-BrC6H4, 4-ClC6H4, 4-FC6H4, 4-O2NC6H4, 2-thienyl, benzo[b]furan-2-yl and CF3] with NCN 1,3- dinucleophiles such as benzamidine hydrochloride or 1
Publicado em: 2009
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3. HETEROCICLIZAÇÃO ENTRE 4-ALCÓXI-1,1,1-TRIFLÚOR-3-ALQUEN-2-ONAS E HIDRAZONAS: METODOLOGIAS SELETIVAS PARA A OBTENÇÃO DE HETEROCICLOS TRIFLUORMETILADOS / HETEROCYCLIZATION OF 4-ALKOXY-1,1,1-TRIFLUORO-3-ALKEN-2-ONES WITH HYDRAZONES: SELECTIVE METHODS FOR THE SYNTHESIS OF TRIFLUOROMETHYLATED HETEROCYCLES
Esta tese descreve diversas metodologias para a síntese regiosseletiva de heterociclos trifluormetilados a partir de 4-alcóxi-1,1,1-triflúor-3-alquen-2-onas e hidrazonas. Na primeira parte do trabalho, uma série de (E)-2-[N-benzil(1-feniletil) idenohidrazino]-4-trifluormetilpirimidinas inéditas foi obtida de maneira convergente a partir da ciclocondensa
Publicado em: 2009
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4. REAÇÃO DE β-DIMETILAMINOVINIL CETONAS COM HIDROXILAMINA: REGIOQUÍMICA DE FORMAÇÃO DE 4,5-DIIDROISOXAZÓIS E DE ISOXAZÓIS / REGIOCHEMISTRY STUDY OF THE ISOXAZOLE FORMATION FROM THE REACTION OF β-DIMETHYLAMINOVINYL KETONES AND HYDROXYLAMINE
Este trabalho descreve o estudo da regioquímica de formação de uma série de isoxazóis aril-, heteroaril- e haloalquil substituídos, a partir da reação de β- dimetilaminovinil cetonas e hidroxilamina. O precursor β-dimetilaminovinil cetona foi obtido a partir da reação de condensação de N,N-dimetilformamida dimetil acetal e a cetona subs
Publicado em: 2005
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5. SYNTHESIS, REACTIVITY AND ANTIMICROBIAL ACTIVITY OF α-CHLORO β-ENAMINO ESTERS USING K-10 AND MICROWAVE IRRADIATION / SÍNTESE, REATIVIDADE E ATIVIDADE ANTIMICROBIANA DE β-ENAMINO ÉSTERES α-CLORADOS UTILIZANDO K-10 E IRRADIAÇÃO DE MICROONDAS
Enamino carbonylic compounds are important synthetic intermediates used in the synthesis of heterocycles and natural products. Our group of research has been dedicating much of our efforts to the development and implementation of simple and efficient methodologies to obtain β-enamino carbonylic compounds, mainly due to their functionality and ability to
Publicado em: 2005
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6. Adição de IN3 a derivados de acidos -alquil cinamicos : obtenç2o de 2-alquil-3-fenil-1-azirinas e 3-azido-2-azetidinonas
The present study began with the preparation of 2- phenyl-3-carbomethoxy-1-azirine (16) with the intention of examining the reactivites of the two electrophilic centers of the molecule, that is, the carbon of the imine group and the carbonil of the ester. Reaction of system 16 with hidrazine in benzene produces the 4-aminopyrazol-3-one 26, intercepted in the
Publicado em: 1987
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7. Regiochemistry of Camphor Analog Oxidation by Pseudomonas putida
Pseudomonas putida cooxidized norcamphor and pericyclocamphanone to hydroxylated and lactonized products during growth on camphor. Norcamphor was hydroxylated at the 5 position, similar to the corresponding process in camphor, but pericyclocamphanone was oxidized at the 6 position. We conclude that the regiochemistry of the hydroxylation may be substrate con
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8. (+)-Larreatricin hydroxylase, an enantio-specific polyphenol oxidase from the creosote bush (Larrea tridentata)
An enantio-specific polyphenol oxidase (PPO) was purified ≈1,700-fold to apparent homogeneity from the creosote bush (Larrea tridentata), and its encoding gene was cloned. The posttranslationally processed PPO (≈43 kDa) has a central role in the biosynthesis of the creosote bush 8–8′ linked lignans, whose representatives, such as nordihydroguaiaretic
National Academy of Sciences.
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9. A single amino acid substitution (F363I) converts the regiochemistry of the spearmint (−)-limonene hydroxylase from a C6- to a C3-hydroxylase
The essential oils of peppermint and spearmint are distinguished by the position of oxygenation on the constituent p-menthane monoterpenes. Peppermint produces monoterpenes bearing an oxygen at C3, whereas spearmint produces monoterpenes bearing an oxygen at C6. Branching of the monoterpene biosynthetic pathways in these species is determined by two dis
The National Academy of Sciences.
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10. A single active site residue directs oxygenation stereospecificity in lipoxygenases: Stereocontrol is linked to the position of oxygenation
Lipoxygenases are a class of dioxygenases that form hydroperoxy fatty acids with distinct positional and stereo configurations. Several amino acid residues influencing regiospecificity have been identified, whereas the basis of stereocontrol is not understood. We have now identified a single residue in the lipoxygenase catalytic domain that is important for
National Academy of Sciences.
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11. Regio- and stereospecific oxidation of fluorene, dibenzofuran, and dibenzothiophene by naphthalene dioxygenase from Pseudomonas sp. strain NCIB 9816-4.
The regio- and stereospecific oxidation of fluorene, dibenzofuran, and dibenzothiophene was examined with mutant and recombinant strains expressing naphthalene dioxygenase from Pseudomonas sp. strain NCIB 9816-4. The initial oxidation products were isolated and identified by gas chromatography-mass spectrometry and nuclear magnetic resonance spectrometry. Sa