Sample records for synthesis
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1

Síntese de enaminonas/ Synthesis of enaminones

Ferraz, Helena M. C; Pereira, Fernando L. C.
2004-02-01

Resumo em inglês The general term "enaminone" is applied to any compound bearing the conjugated system N-C=C-C=O. Enaminones are typical capto-dative ethylenes, showing particular properties due to pi-electron delocalization. Their reactivity can be predicted by structural patterns of substitution, conformation and configuration, making them versatile synthetic building blocks. In this review, a variety of methods for the synthesis of enaminones is described. The methods were divided into (mais) condensation of amines to beta-dicarbonyl compounds, addition of amines to a,b-unsaturated carbonyl compounds, condensation between carbonyl compounds and N-unsaturated functions and other methods, covering the period from 1993 to 2001.

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2

Síntese orgânica limpa/ Clean organic synthesis

Sanseverino, Antonio Manzolillo
2000-02-01

Resumo em inglês An introduction to the fundamental concepts and main aspects of organic clean synthesis is given, and relevant industrial examples which have implemented the philosophy of cleaner synthesis are also presented. Recent trends in organic synthesis which are environmentally friendly are also discussed.

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3

Síntese do anti-helmíntico praziquantel,a partir da glicina/ Praziquantel synthesis

Novaes, Maria Rita Carvalho Garbi; Souza, João Pedro de; Araújo, Hugo Clemente de
1999-02-01

Resumo em inglês This paper deals mainly with the synthesis of praziquantel, a powerful anti-helminthic used against schistosomiasis, an endemic disease which infest millions of people around the world.

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4

Síntese de aminoálcoois derivados do D-manitol/ Synthesis of aminoalcohols from D-mannitol

Oliveira, Pedro S. M. de; Ferreira, Vitor F.; Souza, Marcus Vinicius N. de; Carvalho, Erika Martins de
2008-01-01

Resumo em inglês Aminoalcohols have found important applications in synthetic and medicinal chemistry, being used as chiral building blocks for the synthesis of many biologically active compounds. This class of compounds has been also used as chiral auxiliaries and ligands in asymmetric synthesis. Due to the importance of aminoalcohols in the treatment of several diseases, such as tuberculosis, the aim of this article is the synthesis and preliminary evaluation against tuberculosis of six (mais) aminoalcohols in 5 or 6 steps using D-mannitol as starting material, which is a useful carbohydrate employed in many syntheses.

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5

Síntese de glicoaminoácidos de interesse biológico/ Synthesis of glycosyl-amino acids of biological interest

Campo, Vanessa Leiria; Carvalho, Ivone
2008-01-01

Resumo em inglês This work describes the synthesis of the glycosylated amino acids αGlcNAc-Thr, βGlcNAc-Thr and αLacNAc-Thr by the glycosylation reaction of the amino acid threonine with the corresponding glycosyl donors αGlcNAcCl and αLacN3Cl. The glycosylated amino acids containing the sugar units α-D-GlcNAc and α-D-LacNAc O-linked to threonine amino acids are related to O-glycans found in mucins of the parasite Trypanosoma cruzi, while the corresponding β-D-GlcNAc isomer is involved in cellular signaling events.

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6

Síntese de sulfadiazina e sulfadiazina de prata em escala semi-micro: prática experimental em síntese de fármacos/ Synthesis of sulfadiazine and silver sulfadiazine in semi-micro scale, as an experimental practice in drug synthesis

Borges, Áurea Donizete Lanchote; Ponte, Gino Del; Federman Neto, Alberto; Carvalho, Ivone
2005-08-01

Resumo em inglês The total synthesis of sulfadiazine and silver sulfadiazine from readily available starting materials was adapted to semi-micro laboratory scale and is proposed as an experiment in drug synthesis for undergraduate courses.

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7

Síntese de copolímeros em bloco com propriedades líquido cristalinas/ Synthesis of liquid crystalline block copolymers

Coelho, Maria Rita Guinancio; Gomes, Ailton de Souza
2007-06-01

Resumo em inglês The principal techniques for the synthesis of liquid crystalline block copolymers are reviewed. The syntheses are done by living/controlled free radical chain polymerization. The copolymers display an amorphous continuous phase and a discontinuous liquid crystalline phase (LC). The presence of oxypropylenic segments disturbs the range of mesophase transitions at lower temperatures. This behavior is not observed when styrenic segments are employed and suggests that the liq (mais) uid crystalline behavior can be modified in block copolymers to show mesophases at higher and lower temperatures according to the flexibility of the chain segment that is present.

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8

A síntese da amônia: alguns aspectos históricos/ The ammonia synthesis: some historical aspects

Chagas, Aécio Pereira
2007-02-01

Resumo em inglês The ammonia synthesis from its elements plays an important role in the survival of humankind. A short historical development of discoveries of the nitrogen cycle, the nitrogen sources for agriculture and the ammonia synthesis (in laboratory and industry) are presented. Some brief aspects of nitrogen chemistry are described. Short biographies of Fritz Haber and Carl Bosch, the main persons in this epopee, are also presented.

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9

A síntese dos sesquiterpenos baquenolidas/ The synthesis of the bakkenolide sesquiterpenes

Brocksom, Timothy John; Brocksom, Ursula; Constantino, Maurício G.
2008-01-01

Resumo em inglês The bakkenolide group of sesquiterpenes has been a focal point of synthetic efforts amongst several research laboratories all linked to our common origins at the Chemistry Institute at the State University in São Paulo. In this review we would like to present a historical perspective of this research, with unpublished background information, and a definitive retrosynthetic analysis of these molecules. This chemistry spans the time period from 1972 to 2006, and traces the initial steps with Prof. Dr. Helena Ferraz to the present day.

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10

Síntese de indanos: uma seleção de métodos gerais e eficientes/ Synthesis of indans: a selection of general and efficient methods

Ferraz, Helena M. C.; Aguilar, Andrea M.; Silva Jr., Luiz F.; Craveiro, Marcus V.
2005-08-01

Resumo em inglês The indan ring system is present in several compounds with important pharmacological properties. In this account recent examples of selected methods (Friedel-Crafts acylation, cycloaddition reactions, ring contraction, cyclization and resolution) for the synthesis of indans are discussed.

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11

Síntese de novas amidas graxas a partir da aminólise de ésteres metílicos/ Synthesis of new fatty acids amides from aminolysis of fames

Lopes, Carolina R.; D'Oca, Caroline Da Ros Montes; Duarte, Rodrigo da C.; Kurz, Márcia H. S.; Primel, Ednei G.; Clementin, Rosilene M.; Villarreyes, Joaquín Ariel M.; D'Oca, Marcelo G. Montes
2010-01-01

Resumo em inglês Recent biochemical and pharmacological studies have led to the characterization of different fatty acid amides as a new family of biologically active lipids. Here, we describe the synthesis of new amides from C16:0, 18:0, 18:1 and 18:1, OH fatty acids (FFA) families with cyclic and acyclic amines and demonstrate for the first time that these compounds produce citotoxic effects. Application of this method to the synthesis of fatty acid amides was performed using the esters (mais) aminolysis as a key step and various carboxylic amides were prepared in good yield from fatty acid methyl esters (FAMEs).

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12

Síntese de catalisadores Ziegler-Natta: algumas rotas e suas dificuldades/ Synthesis of Ziegler-Natta catalysts: some routes and their difficulties

Costa, Thaís H. S.; Costa, Marcos A. S.; Santa Maria, Luiz Claudio de; Coutinho, Fernanda M. B.; Pires, Neusa M. T.
1997-02-01

Resumo em inglês The Ziegler-Natta catalyst and the polymerization thereof are systems which require careful handling and special treatment of chemicals. In spite of the use of inert atmosphere and dry chemicals, some Ziegler-Natta systems may present low activities or even may deactivate because of unsuitable handling. Some features of the TiCl3 synthesis and its characterization when related to the presence of impurities are described. Evidences of poor handling of chemicals and/or labo (mais) ratory devices while in synthesis of the catalyst are emphasized. The problems arising from butadiene polymerization and some relevant details in propylene polymerization are also presented with teaching objectives.

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13

Síntese e estudo de ortossilicatos de zinco luminescentes com aplicação da técnica sol-gel/ Synthesis and study of zinc orthosilicates luminophores by the sol-gel technique

Oliveira, Heitor Fernando Nunes de; Trinca, Rafael Bergamo; Gushikem, Yoshitaka
2009-01-01

Resumo em inglês Usually, the concepts of the Sol-Gel technique are not applied in experimental chemistry courses. This work presents a feasible experiment for chemistry instruction, which involves the synthesis of luminescent materials - Zn2SiO4, with and without Mn2+ as a dopant - by the Sol-Gel technique. The obtained materials were analyzed by scanning electron microscopy, X-Ray diffraction, IR spectroscopy and luminescence measures by UV-vis spectroscopy. The results allow the studen (mais) ts to confirm the luminescent properties of the zinc orthosilicate luminophores as well as the structural features expected from literature data.

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14

Síntese e emprego do ciclometalado [Pd(dmba)(N3)(PPh3)] em processos catalíticos envolvendo a n-carbonilação redutiva de nitroarenos a carbamatos e na síntese de derivados da uréia/ Synthesis of [Pd(dmba)(N3)(PPh3)] and its use in catalytic processes involving the reductive n-carbonylation of nitroarenes to carbamates and in the synthesis of urea derivatives

Caires, Antonio Carlos Fávero; Mauro, Antonio Eduardo; Moro, Antonio Carlos; Legendre, Alexandre de Oliveira; Ananias, Sandra Regina
2006-07-01

Resumo em inglês This work deals with the use of the cyclometallated compound [Pd(dmba)(N3)(PPh3)] in homogeneous catalytic processes comprising the reductive N-carbonylation of nitrobenzene and p-nitrotoluene to ethyl-phenylcarbamate and ethyl-4-methylphenylcarbamate, respectively. The cyclopalladated compound was also employed in the synthesis of urea derivatives by reacting p-nitrotoluene and m-nitrotoluene, respectively, with p-toluidine and and m-chloroaniline.

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15

Síntese do pigmento cerâmico verde vitória (Ca3Cr2Si3O12) a partir de CaCO3, Cr2O3 e SiO2/ Synthesis of the Ceramic Pigment Victoria Green (Ca3Cr2Si3O12) from CaCO3, Cr2O3 and SiO2

Della, Viviana Possamai; Junkes, Janaina Accordi; Rambo, Carlos Renato; Hotza, Dachamir
2008-01-01

Resumo em inglês The synthesis of the ceramic pigment Victoria Green (Ca3Cr2Si3O12 ) is described. As raw materials CaCO3, Cr2O3, and SiO2 obtained from rice husk were used. Borax was used as mineralizer. Raw materials were formulated stoichiometrically and calcined from 1000 to 1200 ºC for 180 min. The main phase detected was uvarovite with particle size below 45 mm. The pigments were applied on ceramic tiles and sintered at 1150 ºC for 40 min. The synthesis process showed to be adequate to produce the green pigment, whose characteristics resemble those of a commercial pigment.

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16

Síntese e reatividade de complexos platina-trifenilestibina: uma revisão bibliográfica/ Synthesis and reactivity of triphenylstibine-platinum complexes: a bibliographic revision

Barbiéri, Roberto Santos; Bellato, Carlos Roberto; Massabni, Antonio Carlos
2006-07-01

Resumo em inglês This article deals with synthesis and reactivity of complexes with triphenylstibine (SbPh3) as the ligand. A comparative study of analogous complexes of triphenylphosphine (PPh3) and triphenylarsine (AsPh3) with platinum in the oxidation states zero, two and four is included. The bibliographic revision includes publications since 1936, when the first Pt(II) complex with triphenylstibine was described.

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17

Síntese de 1,3,5-triazinas substituídas e avaliação da toxicidade frente a Artemia Salina leach/ Synthesis of substituted 1,3,5-triazines and toxicity evaluation against Artemia Salina leach

Cavalcante, Márcia Ferreira; Oliveira, Márcia Cristina Campos de; Velandia, Javier Rincón; Echevarria, Aurea
2000-02-01

Resumo em inglês The synthesis of ten symmetrically and unsymmetrically substituted 1,3,5-triazines by Phase Transfer Catalysis (PTC) method is described. Their toxicities were determined against Artemia salina Leach. The LD50 values have also been obtained for these compounds.

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18

A síntese orgânica em fase sólida e seus suportes poliméricos mais empregados/ The solid phase organic synthesis and its most used polymeric suports

Marquardt, Marcos; Eifler-Lima, Vera Lucia
2001-12-01

Resumo em inglês In the last decade we have seen improved a powerfull tool to medicinal chemistry: the Solid Phase Organic Synthesis (SPOS). This metodology can be used to synthesize a large library of compounds in a short time by combinatorial chemistry, where simple chemical substances can be combinated one to each other building a library of complex compounds. In this work we present the solid phase organic synthesis and their advantage upon the tradicional organic synthesis methodology, as well as the main polimers used in the SPOS technique.

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19

Síntese e reatividade de azaindóis: aplicações na preparação de moléculas de interesse biológico/ Synthesis and reactivity of azaindoles: applications in the preparation of bioactive molecules

Le Hyaric, Mireille; Almeida, Mauro Vieira de; Souza, Marcus Vinicius Nora de
2002-12-01

Resumo em inglês Synthetic methods used for the preparation of azaindoles are described in this article. Applications in the preparation of bioactive molecules are given: synthesis of substituted 6-azaindoles as benzodiazepines receptor ligands, substituted 7-azaindoles as dopamine D4 ligands and preparation of an olivacine analogue.

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20

Síntese e caracterização de complexos de platina(IV) com derivados N-benzilados da 1,3-propanodiamina/ Synthesis and characterization of platinum(IV) complexes derived from N-benzyl-propanediamine

Fontes, Ana Paula Soares; Almeida, Mauro Vieira de; Faria, Bruno de Araújo; César, Eloi Teixeira
2010-01-01

Resumo em inglês The present work describes the synthesis of a series of platinum(IV) complexes with N-benzyl 1,3-propanediamine derivatives. Since substitution of the axial ligands in the platinum(IV) complexes may alter their pharmacological properties, we have prepared complexes with different groups, such as hydroxide, chloride and acetate using a sequence of substitution reactions. The resulting complexes were fully characterized by IR, ¹H, 13C and 195Pt NMR spectroscopies, and elemental analysis.

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21

Síntese de regioisômeros quirais a partir de D-manitol: obtenção de uma mistura de álcoois acetilênicos/ Synthesis of chirals regioisomers from D-mannitol: obtainment of a acetylenic alcohols mixture

Citó, Antônia Maria das Graças Lopes; Araújo, Bruno Quirino; Lopes, José Arimatéia Dantas; Magalhães, Aderbal Farias; Magalhães, Eva Gonçalves
2009-01-01

Resumo em inglês The synthesis of chiral acetylenic regioisomers was described by using an appropriate intermediate such as isopropylidene glycerol, a synthon widely used in the enantioselective syntheses. This intermediate was prepared from D-mannitol. The nine obtained compounds have been characterized by their respective spectral data. The mixture of chiral acetylenic alcohols showed activity against Escherichia coli when tested through the monitoring of CO2 released during microbial respiration by using a conductimetric system.

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22

Síntese e avaliação preliminar da atividade antinociceptiva de novas isoxazolil-aril-hidrazonas/ Synthesis and preliminary evaluation of antinociceptive activity of novel isoxazolyl-aryl-hydrazones

Reis, Sílvio Leandro Gonçalves Bomfim; Almeida, Valderes Moraes de; Almeida, Gleybson Correia de; Boaviagem, Karinna Moura; Mendes, Charles Christophe Du Barriere; Faria, Antônio Rodolfo de; Góes, Alexandre José da Silva; Magalhães, Laudelina Rodrigues; Silva, Teresinha Gonçalves da
2011-01-01

Resumo em inglês New 2-isoxazoline aldehydes were synthesized, in good yields, from cycloadduct of the 1,3-dipolar cycloaddition reaction between endocyclic enecarbamate and carboethoxyformonitrile oxide (CEFNO). Condensation of these 2-isoxazoline aldehydes with several phenyl-hydrazines produced new isoxazolyl-aryl-hydrazones, which showed low toxicity and excellent antinociceptive activity, when compared to dipyrone. The antinociceptive activity of isoxazolyl-aryl-hydrazones was performed using the acetic acid-induced mice abdominal constrictions test.

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23

Síntese de beta-N-acetilglicosaminídeos de arila modificados em C-6 como potenciais agentes antimicrobianos/ Synthesis of aryl beta-N-acetylglucosaminedes modified at C-6 as potential antimicrovial agents

Manfrini, Rozângela Magalhães; Souza Filho, José Dias de; Figueiredo, Rute Cunha; D'Angelis, Allison Fabiano; Prado, Maria Auxiliadora Fontes; Nunan, Elzíria de Aguiar; Martins, Gabriela Aires; Alves, Ricardo José
2008-01-01

Resumo em inglês We report herein the synthesis of aryl beta-N-acetylglucosaminides containing azido, amino and acetamido groups at C-6 as potential antimicrobial agents. It was expected that these compounds could interfere with the biosynthesis and/or biotransformation of N-acetylglucosamine in fungi and bacteria. None of the compounds showed antimicrobial activity against bacteria (Bacillus subtilis, Micrococcus luteus, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa) (mais) , filamentous fungus (Aspergillus niger) and yeasts (Saccharomyces cerevisae, Candida albicans and Candida tropicallis), at the concentration of 1 mg/mL in agar diffusion assay.

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24

Síntese e caracterização de novos complexos de platina (II) com ligantes derivados do furano e nitrofurano/ Synthesis and characterization of new platinum (II) complexes containing furan and nitrofuran derived ligands

Guerra, Wendell; Fontes, Ana Paula Soares; Almeida, Mauro Vieira de; Silva, Heveline
2005-10-01

Resumo em inglês Platinum (II) complexes, for example, cisplatin and carboplatin, have been used as chemotherapeutic agents for the treatment of various types of cancer. Several other complexes of this metallic ion are also under clinical evaluation. This work describes the synthesis of five new platinum (II) complexes having furan and 5-nitrofuran derivatives and chloride as ligands. The compounds were characterized by NMR, IR and elemental analysis.

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25

Síntese e avaliação da propriedade reguladora de crescimento vegetal de compostos indólicos derivados do safrol/ Synthesis and evaluation of the plant growth regulator property of indolic compounds derived from safrole

Marchi, Irineu; Rebelo, Ricardo Andrade; Rosa, Flávia A. Fernandes da; Maiochi, Riceli A.
2007-08-01

Resumo em inglês The present work describes the use of piperonal, a derivative of the secondary metabolite safrole, for the synthesis of new 5,6-methylenedioxysubstituted indole carboxylic acids structurally related to the indol-3-yl-acetic acid (AIA, I). The route comprises six steps beginning with piperonal with an overall yield of 19%. Compound IX was tested towards its plant growth regulator properties in bioassays specific for auxine activity. The in vitro assays were performed in a (mais) germination chamber and were of two types: root growth in germinated seeds of Lactuca sativa, Cucumbis sativus and Raphanus sativus and peciole biotest using Phaseolus vulgaris.

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26

Síntese do isobutileno e seu emprego em reações de esterificação: propostas de aulas práticas de química orgânica para a graduação/ Synthesis and esterification reactions of isobutylene: an undergratuate organic chemistry experiment

Cunha, Silvio; Lião, Luciano M.; Bonfim, Ricardo R.; Bastos, Rodrigo M.; Monteiro, Ana Paula M.; Alencar, Kelly S.
2003-05-01

Resumo em inglês An experiment for the synthesis of isobutylene from tert-butanol dehydratation using oxalic acid as catalyst, followed by preparations of tert-butyl benzoate and tert-butyl cinnamate is described. The synthesis are simple, requiring two periods of 4 hours and are suitable for undergraduate organic chemistry experimental courses.

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27

Síntese e avaliação da atividade antimicrobiana de furanonas halogenadas e de compostos análogos aos nostoclídeos/ Synthesis and evaluation of antimicrobial activity of halogenated furanones and compounds analogues to nostoclides

Barbosa, Luiz C. A.; Maltha, Célia R. A.; Demuner, Antônio J.; Pinheiro, Patrícia F.; Varejão, Jodieh O. S.; Montanari, Ricardo M.; Andrade, Nélio J.
2010-01-01

Resumo em inglês Considering the broad spectrum of biological activity of gamma-butyrolactone derivatives, we presented the synthesis of 3,4-dihalo-5-arylidenefuran-2(5H)-ones (17-21) and analogues (24-28) of the natural product nostoclide (7,8). Furanones 17-21 were synthesized from the condensation of aromatic aldehydes with lactones 14 and 15, that were obtained from mucobromic and mucochloric acids. Lactone 15 was converted into the intermediate 23 in 36% overall yield. Compound 23 wa (mais) s then transformed into the nostoclide analogues 24-28. Some of the compounds prepared showed antimicrobial activities against Escherichia coli, Staphylococcus aureus and Bacillus cereus comparable to commercial antibiotics.

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28

Síntese de 1-indanonas através da reação de acilação de Friedel-Crafts intramolecular utilizando NbCl5 como ácido de Lewis/ Synthesis of 1-indanones through the intramolecular Friedel-Crafts acylation reaction using NbCl5 as Lewis acid

Polo, Ellen Christine; Silva-Filho, Luiz Carlos da; Silva, Gil Valdo José da; Constantino, Mauricio Gomes
2008-01-01

Resumo em inglês The intramolecular Friedel-Crafts acylation reaction of 3-arylpropanoic acids to give 1-indanones can be effected in good yields under mild conditions (room temperature) by using niobium pentachloride. Our results indicate that NbCl5 acts both as reagent (to transform carboxylic acids into acyl chlorides) and as catalyst in the Friedel-Crafts cyclization.

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30

Síntese, caracterização e análise térmica dos sais de lítio, sódio e potássio do ácido palmítico e do seu éster etílico/ Synthesis, characterization and thermal analysis of lithium, sodium and potassium salts of the palmitic acid and its ethyl ester

Sales, André Luis Castro de; Ramos, Luiz Antônio; Nunes, Ronaldo Spezia; Claro Neto, Salvador; Cavalheiro, Éder Tadeu Gomes
2008-01-01

Resumo em inglês Alkaline salts of the palmitic acid were synthesized and characterized from aqueous and ethanolic medium. The salts were characterized by elemental analysis (EA) and infrared spectroscopy (IR). EA and IR, being its synthesis comproved, also characterized the ethyl palmitate. All the salts and the ester were submitted to thermal analysis using thermogravimetry (TG), and differential thermal analysis (DTA) in the temperature ranging from room to 700 ºC under air dynamic at (mais) mosphere. Differential scanning calorimetry (DSC) measurements were taken from -90 ºC up to temperatures close to the starting of the decomposition temperature, determined by thermogravimetry, using heating and cooling cycles.

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31

Síntese de complexo ferro(II)-nitrogênio: abordagem dos conceitos de reatividade e retro-doação para alunos de graduação em química/ Synthesis of the iron(II)-nitrogen complex: concepts of reactivity and back-bonding for undergraduate chemistry students

Pissetti, Fábio L.; Nonô, Rogério S.; Gushikem, Yoshitaka; Dias, Gilson H. M.
2007-06-01

Resumo em inglês There has been a considerable interest in coordination complexes of molecular nitrogen (N2), partly due to a possible relationship between such complexes and the nitrogen activation process in nature. The present paper describes the synthesis and infrared spectroscopic characterization of an iron-nitrogen derivative with ethylenediamine-N,N,N',N'-tetraacetate (edta) as an experiment for an undergraduate course. The topics covered here include synthesis, reactivity and spectroscopy.

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32

Síntese de β-D-galactopiranosídeos de arila diméricos para avaliação de sua interação com a lectina de Erythrina cristagalli/ Synthesis of dimeric aryl β-D-galactopyranosides for the evaluation of their interaction with the Erythrina cristagalli lectin

Figueiredo, Rute Cunha; Meyer, Nádia Burkowski; Prado, Maria Auxiliadôra Fontes; Alves, Ricardo José; Rojo, Javier
2009-01-01

Resumo em inglês The synthesis of two new D-galactose-based dimers having a 1,4-butanediamine spacer is reported aiming at the evaluation of their interaction with the Erythrina cristagalli lectin. The title compounds were prepared in four and five steps from 2,3,4,6-tetra-O-acetyl-β-D-galactopyranoside bromide, in 20 % and 15 % overall yield, respectively, using the Doebner modification of the Koenavenagel reaction as the key sep. The lectin-carbohydrate interaction could be evaluat (mais) ed for only one dimer, due to solubility problems. A twofold enhancement of affinity was observed, compared to the corresponding monovalent ligand.

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33

Síntese dos analgésicos paracetamol e fenacetina e do adoçante dulcina: um projeto para química orgânica experimental/ Synthesis of analgesics paracetamol and phenacetin and the sweetener dulcin: a project for undergraduate organic chemistry laboratory

Baptistella, Lúcia H. B.; Giacomini, Rosana A.; Imamura, Paulo M.
2003-03-01

Resumo em inglês A synthesis of artificial sweetener dulcin starting from nitrobenzene was elaborated for undergraduate organic laboratory course. Paracetamol and phenacetin, both physiologically active analgesic compounds, were also prepared as intermediates. Besides a large scope of discussion subjects related with organic synthesis, interesting lectures about analgesics and sweeteners may also be performed in this project. The advantage of this project is the adaptability according to the conditions offered by the course, i.e., convenience and/or availability of time and reagents.

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34

Síntese e modificações de derivados heterocíclicos de D-arabinose: potenciais inibidores de glicose-6-fosfato isomerase e de glicosamina-6-fosfato sintase/ Synthesis and modifications of heterocyclic derivatives of D-arabinose: potential inhibitors of glucose-6-phosphate isomerase and glucosamine-6-phosphate synthase

Viana, Renato Márcio Ribeiro; Prado, Maria Auxiliadora Fontes; Alves, Ricardo José
2008-01-01

Resumo em inglês The synthesis of -5-(D-arabino-1,2,3,4-tetrahydroxybutyl)tetrazole and -2-(D-arabino-1,2,3,4-tetra-acetoxybutyl)-5-methyl-1,3,4-oxadiazole from D-arabinose is described. Attempts at removing the protecting groups of the oxadiazole derivative were unsuccessful, leading to products resulting from the opening of the oxadiazole ring. The unprotected tetrazole derivative was selectively phosphorylated at the primary hydroxyl group with diethylphosphoryl chloride. The resulting (mais) 5-[D-arabino-4-(diethylphosphoryloxy)-1,2,3-trihydroxybutyl]tetrazole is a protected form of a potential inhibitor of the enzymes glucose-6-phosphate isomerase and glucosamine synthase.

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35

Síntese de padrões cromatográficos e estabelecimento de método para dosagem da composição de ésteres de ácidos graxos presentes no biodiesel a partir do óleo de babaçu/ Synthesis of chromatographic standards and establishment of a method for the quantification of the fatty ester composition of biodiesel from babassu oil

Urioste, Daniele; Castro, Matheus B. A.; Biaggio, Francisco C.; Castro, Heizir F. de
2008-01-01

Resumo em inglês Several alkyl esters were synthesized, purified, characterized by ¹H NMR and employed as standards for establishing chromatographic methods to monitor their formation in the synthesis of biodiesel. The efficiency of the chromatographic methods was confirmed with the products of enzymatic transesterification of babassu oil with different alcohols (C2 to C4), using Lipozyme as catalyst.

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36

Uma nova síntese de alfa-bromo-acetofenonas e sua aplicação na obtenção de 2-benzoil-benzofuranas/ A novel synthesis of alpha-bromoacetophenones and its application in obtaining 2-benzoylbenzofuranes

Azevedo, Mariangela S.; Alves, Ana Paula L.; Alves, Glaucia B. C.; Cardoso, Jari N.; Lopes, Rosângela S. C.; Lopes, Cláudio C.
2006-12-01

Resumo em inglês alpha-Bromoacetophenones are important in organic synthesis. They have been widely used as precursors of several natural products. Several methods of bromination aiming at their synthesis have been described, however they furnish a mixture of starting material 10, mono 8 and dibromide 11 products. We developed a novel, simple and efficient synthesis of these compounds with applications in the synthesis of benzoylbenzofurans 9, compounds with important pharmacological prop (mais) erties, such as the ability of dilating the coronary artery and analgesic action. Such compounds have also been used as key intermediates to obtain quinone systems.

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37

Estudo da síntese da zeólita ZSM-5 a partir de argilas naturais/ Study of ZSM-5 zeolite synthesis from natural clays

Mignoni, Marcelo L.; Detoni, Chaline; Pergher, Sibele B. C.
2007-02-01

Resumo em inglês The synthesis of ZSM-5 zeolite was studied by three synthesis methods: standard synthesis, three day synthesis and synthesis employing clays (kaolin and montmorillonite). The raw materials and prepared materials were characterized by Chemical Analysis by X-Ray Fluorescence (XRF) and X-Ray Diffraction (XRD). The results show that it is possible to synthesized ZSM-5 zeolite using clays as raw materials. Kaolin gives phases of higher crystalinity than montmorillonite.

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Estudo da síntese da zeólita MCM-71/ Study of MCM-71 zeolite synthesis

Luvison, Caroline; Mignoni, Marcelo L.; Pergher, Sibele B. C.
2009-01-01

Resumo em inglês A new kind of material, denominated MCM-71, was synthesized and characterized by several complementary techniques: X Ray Diffractometry, textural analysis by nitrogen adsorption, Scanning electronic microscopy and infrared spectroscopy. MCM-71 zeolite was successfully synthesized by hydrothermal synthesis in the presence of triethanolamine. Mordenite phase as impurity was not detected, otherwise quartz was observed. The MCM-71 sample obtained presented a BET surface area (mais) of 20 m²/g in the as synthesized form and of 85 m²/g in protonic form. By SEM was observed crystals with rectangular shape with average size of 2 x 0,2 x 0,05 µm and this crystals were agglomerated in spherical particles with average diameter between 14 and 24 µm.

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Uma proposta de síntese para o ensino integrado das disciplinas experimentais de química orgânica e inorgânica nos cursos de graduação/ A proposal of synthesis for the integrated teaching of organic and inorganic experimental chemistry in the undergraduate courses

Farias, Robson Fernandes de
2003-01-01

Resumo em inglês The synthesis of the layered compound VO(PO4)(H2O)2 and its use to oxidize 2-butanol to the ketone 2-butanone, is proposed as an experiment to integrate the organic and inorganic experimental undergraduate chemistry courses, in an atempt to overcome the observed disrupture between organic and inorganic chemistry.

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Sucroquímica: síntese e potencialidades de aplicações de alguns derivados químicos de sacarose/ Sucrochemistry: synthesis and potentialities for applications of some sucrose chemical derivates

Boscolo, Maurício
2003-12-01

Resumo em inglês The interest on the use of sucrose as raw material increased in the last years. In this work, the synthesis and applications of sucrose derivatives as esters, ethers, and other products are discussed in a concise manner aiming to presenting the sucrochemistry as a promising field in organic chemistry from a rather accessible, low-priced, ecological, and renewable source.

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42

Bisfosfonatos: síntese, análises químicas e aplicações farmacológicas/ Bisphosphonates: synthesis, chemical analysis and pharmacological applications

Fernandes, Christian; Leite, Rodrigo Souza; Lanças, Fernando Mauro
2005-03-01

Resumo em inglês Bisphosphonates are drugs that have been widely used in different bone diseases, and have recently been used successfully against many parasites. Various synthetic routes to prepare different types of bisphosphonates have been described, with distinct potency and pharmacological activity. A number of analytical techniques are currently being used to analyze these drugs; among these, the high performance liquid chromatography (HPLC), with different systems of detection, is (mais) worth highlighting. However, the development of more sensitive methods is still necessary, once they are essential for bioavailability and bioequivalence studies. This paper reports the major synthesis routes, chemical analysis methodologies and pharmacological applications of bisphosphonates.

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43

Macrolactamas bioativas e síntese de macrociclos por reação de carbociclização radicalar mediada por hidreto de tri-n-butilestanho/ Bioactive macrolactams and synthesis of macrocycles by tri-n-butyltin hydride-mediated radical carbocyclization reaction

Faraco, Renata Fontes Prado; Pires, Magno Carvalho; Rocha, Ana Paula Campos; Prado, Maria Auxiliadôra Fontes
2008-01-01

Resumo em inglês This review presents natural, semi-synthetic and synthetic bioactive macrolactams and their structure-activity relationships when available. For macrolactams in clinical use the advantages and disadvantages in relation to other drugs are presented, and for synthetic macrolactams the method used in the cyclization is showed. Regarding macrocyclic synthesis by the tri-n-butyltin hydride-mediated radicalar carbocyclization reaction the precursor, the reaction conditions, products and yields, mechanism and cyclization mode are discussed.

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Do isolamento à síntese da convolutamidina A/ From the isolation to the synthesis of convolutamydine A

Silva, Rosângela B.; Torres, José C.; Garden, Simon J.; Violante, Flavio de Almeida; Rezende, Michelle J. C.; Silva, Bárbara V. da; Pinto, Angelo C.
2008-01-01

Resumo em inglês Convolutamydine A is a member of a family of oxindole alkaloids isolated from the Floridian marine bryozan Amathia convoluta in 8.6x10-6 % yield. This compound is interesting as it has been described in the literature to have significant pharmacological activity. When bioactive substances are isolated in low yields, such as in the case of convolutamydine A, the use of synthetic organic chemistry to prepare larger quantities of these substances is necessary. This paper des (mais) cribes the isolation, structural characterization and synthesis of convolutamydine A, using readily available reagents and reaction conditions that may be applied in any organic chemistry undergraduate laboratory course.

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Metodologias de síntese de 2-arilcicloexanonas/ Methodologies of synthesis of 2-arylcyclohexanones

Santos, Roberto P.; Amorim, Mauro B. de; Lopes, Rosangela S. C.; Lopes, Claudio C.
2003-03-01

Resumo em inglês Several methodologies concerning the preparation of 2-aryl and 2-heteroarylcyclohexanones are presented. The use of these intermediates in the synthesis of chemically and biologically interesting organic compounds is also discussed.

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Abordagens em síntese assimétrica/ Approaches in asymmetric synthesis

Pinheiro, Sergio; Ferreira, Vítor F.
1998-06-01

Resumo em inglês The approaches in asymmetric synthesis as the chiron approach, chiral auxiliaries, chiral reagents and asymmetric catalysis are described in a simplified way.

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Microondas em síntese orgânica/ Microwaves in organic synthesis

Sanseverino, Antonio Manzolillo
2002-07-01

Resumo em inglês The application of microwave heating to organic synthesis is presented in a concise manner. Issues such as the history of the microwave oven, dielectric heating, reactions techniques (dry reactions, MORE chemistry), domestic ovens, microwave reactors, microwave effect and control of selectivities are discussed. Selected examples from the literature showed faster reactions, improved yields, less thermal degradations and cleaner reactions.

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Um novo procedimento de síntese da zeólita A empregando argilas naturais/ A new procedure for a zeolite synthesis from natural clays

Rigo, Reus T.; Pergher, Sibele B. C.; Petkowicz, Diego I.; Santos, João H. Z. dos
2009-01-01

Resumo em inglês This work proposes the synthesis of zeolite A by IZA standard proceedures starting from a natural clay. The clay was used in its natural form and after calcination at 900ºC. The resulting materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and porosity analysis by nitrogen adsorption. Results showed low surface area for Na-A zeolite in sodium form, but a higher one in CaA based on the nitrogen accessibility. The presence of cubic c (mais) rystals for the A phase was observed in the SEM micrographies. The new procedure starting from natural clay favors the formation of sodalite while that using the calcinated clay gives A.

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Alcóxidos como precursores na síntese de novos materiais através do processo sol-gel/ Alkoxide as precursors in the synthesis of new materials through the sol-gel process

Airoldi, Claudio; Farias, Robson Fernandes de
2004-02-01

Resumo em inglês An overview about the role of alkoxides in the most recent uses of the sol-gel process in the synthesis of new materials is presented. Special attention is focused on the uses of silicon, aluminum, zirconium and titanium alkoxides. This review shows that the alkoxides enable the synthesis of new matrices with controlled surface area, acidity and porosity, as well as some unusual properties. The property associated with the solubility of metal alkoxides opens enormous possibilities of combining them for the synthesis films of powders with a very large range of metal compositions.

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Influência da quantidade de amônio na síntese de nanopartículas de óxido de ferro por microemulsão/ The influence of ammonium quantity on the synthesis of iron oxide nanoparticles in microemulsion

Fernandes, Maria Tereza Cortez; Kawachi, Elizabete Yoshie
2010-01-01

Resumo em inglês Iron oxide nanoparticles were synthesized in microemulsion systems composed by Triton X-100/hexyl alcohol/cyclohexane/aqueous solution. The nanoparticles were synthesized in microemulsions containing different amounts of ammonium, in order to evaluate the influence of this parameter on the size of the nanoparticles and on the phase transformation after heat treatment. Powder materials were obtained after centrifugation, washing and drying, and they were analyzed as synthe (mais) sized and after heating at 350, 500 and 1000 °C. It was observed that the higher amount of ammonium induced smaller particles and minor phase transformation, possibly due to a preferential nucleation process.

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Dióxido de estanho nanoestruturado: síntese e crescimento de nanocristais e nanofitas/ Nanostructured tin dioxide: synthesis and growth of nanocrystals and nanoribbons

Maciel, Adeilton P.; Longo, Elson; Leite, Edson R.
2003-12-01

Resumo em inglês The objectives of this work are to supply a basic background on nanostructured materials and also to report about the obtaining of nanoparticles, mainly, tin dioxide nanocrystalline particles (obtained by using the polymeric precursor method) presenting a high stability against particle growth due to the usage of a metastable solid solution. The synthesis and growth of SnO2 nanoribbons by a carbothermal reduction process are also discussed.

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53

Influência da acidez do meio sobre a síntese e o comportamento redox do polipirrol/ Influence of the medium acidity on the synthesis and redox behavior of polypyrrole

Giacomini, Márcia T.; Ticianelli, Edson A.
1999-09-01

Resumo em inglês The influence of acidity on the synthesis and redox behavior of polypyrrole films was studied using galvanostatic and potentiodynamic techniques employing aqueous solutions formed by H2SO4/Na2SO4 , HCl/NaCl and HCl/CsCl. The chemical structure of the films were investigated using the FTIR technique. The polymer behavior as a function of the pH used in the cyclic voltammetric measurements is explained in terms of the mechanism responsible for the charge compensation formed (mais) during the polymer chain oxidation. From the FTIR measurements, it is seen that the water nucleophilic attack during the synthesis, does not occur under the experimental conditions employed in this work.

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Safrol e eugenol: estudo da reatividade química e uso em síntese de produtos naturais biologicamente ativos e seus derivados/ Safrole and eugenol: study of the chemical reactivity and use in the synthesis of biologically active natural products and its derivatives

Costa, Paulo R. R.
2000-06-01

Resumo em inglês The chemical reactivity of safrole, eugenol, piperonal, vanillin and derivates toward ozone, aluminium chloride, brominating agents and butyl lithium was investigated. The synthesis of naturally occuring anthraquinones, furonaphthoquinones, naphthoquinones, lignans and pterocarpans from these easily available staring materials is also discussed.

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Principais métodos de síntese de amidinas/ Synthetic approaches to amidines

Santos, Maurício Silva dos; Bernardino, Alice Maria Rolim; Souza, Marcos Costa de
2006-12-01

Resumo em inglês The amidine functional group is found in a wide range of natural products and is biologically active against several pathogens. In addition, amidines have long been regarded as useful intermediates in the synthesis of heterocyclic compounds. Consequently, a great number of methods have been developed for the preparation of amidines. Pinner's method is the most commonly used. Conventional methods include: - the addition of metal amides or amines to nitriles, the addition o (mais) f amines to imido esters and the condensation of amides with amines in the presence of halogenating reagents. In this report, the main methods for synthesis of amidines will be described.

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O uso do forno de microondas na síntese orgânica em fase sólida/ The use of microwave ovens in solid-phase organic synthesis

Graebin, Cedric Stephan; Eifler-Lima, Vera Lucia
2005-02-01

Resumo em inglês Solid-phase organic synthesis (SPOS) has been considered the main strategy for the construction of combinatorial libraries, because its simplicity leads to faster synthetic procedures. In addition to that, a series of reports in the specialized literature show great advantages in the use of microwave activation, when compared to classical heating, for instance: shorter reaction times, in some cases from several hours to a few minutes, increase of selectivity and product y (mais) ields, energy economy and reduction and/or elimination of solvent. This review describes the use of microwave ovens/reactors in solid phase organic synthesis, describing the advantages, equipment and reactions using both techniques.

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57

Ambergris: perfume e síntese/ Ambergris: perfume and synthesis

Tenius, Beatriz Soares Machado; Schroeder, Evelyn Koeche; Schenato, Rossana Angélica
2000-04-01

Resumo em inglês Rules for the occurence of the ambergris odor is presented and discussed in terms of the relationship between chemical structure and odor. A general overview of the major approaches in the synthesis of Ambrox® , the key ambergris-type compound, is also presented.

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Desenvolvimento de abordagem objetivando a síntese da 3-desidroxi-4-metoxi-tubastrina/ Development of an approach for the synthesis of 3-dehydroxy-4methoxy tubastrine

Santos, Kelly de Oliveira; Craveiro, Marcus Vinícius; Berlinck, Roberto G. S.
2007-01-01

Resumo em inglês We report the synthesis of amino(2-hydroxy-2-(4-methoxyphenyl)ethylamino)methaniminium (14) as a direct precursor of a tubastrine derivative (3-dehydroxy-4-methoxytubastrine). The synthetic steps involved functional group interconversions starting from 1-(4-methoxyphenyl)ethanone to obtain the guanidine-protected derivative 13. Tentative dehydration of 13 with SiOH-adsorbed CuSO4 resulted in guanidine deprotection only. This was an unexpected result, since there are no re (mais) ports of CuSO4.SiOH as Boc-deprotecting of guanidines. The product 14 was obtained in five steps and 5.4 % overall yield, and constitutes a direct precursor of 3-dehydroxy-4-methoxytubastrine.

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A reação de ciclização de prins: uma estratégia eficiente para síntese estereosseletiva de anéis tetraidropirânicos substituídos/ The prins cyclization reaction: an efficient stractegy for the stereoselective synthesis of substituted tetrahydropyran rings

Vasconcellos, Mário Luiz A. A.; Miranda, Leandro S. M.
2006-07-01

Resumo em inglês The Prins cyclization reaction has significantly advanced in the last years as demonstrated by a number of applications described in the literature. The objective of this report is to introduce this powerful synthetic methodology to the undergraduate and graduated student, since it is rarely presented in an organic synthesis formal course. This reaction is, in some cases, the methodology of choice for the preparation of natural products or drugs that present the tetrahydr (mais) opyrane moiety in their structures. In this report we show some aspects of this reaction, including mechanism, scope and limitations.

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Os polimorfos de carbonato de cálcio: uma síntese fácil de aragonita/ The polymorphs of calcium carbonate: an easy synthesis of aragonite

Bessler, Karl E.; Rodrigues, Laécio C.
2008-01-01

Resumo em inglês Aragonite is a metastable polymorph of calcium carbonate. The calcareous exoskeletons of some organisms like corals or molluscs consist essentially of aragonite. The questions of how, and why these organisms prefer the thermodynamically unstable aragonite for the construction of their hard shells are discussed. The importance of the biomineralization process for the development of new materials is outlined. In the experimental part, a very simple synthesis of polycrystall (mais) ine aragonite is performed, using carbonated mineral water available at the market. The synthesized aragonite is easily identified by its infrared spectrum.

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Utilização do D-manitol em síntese orgânica/ D-Mannitol in Organic Synthesis

Oliveira, Pedro S. M. de; Ferreira, Vitor F.; Souza, Marcus Vinicius N. de
2009-01-01

Resumo em inglês D-mannitol is used in several fields including food, pharmaceuticals, cosmetics and textiles being an important carbohydrate found widespread in nature. Due to its chirality, it is largely used in organic synthesis with several applications, such as ligands, polymers, chiral pool, for preparation of small chiral building blocks, key intermediates in total synthesis. In this context, the aim of this review is to highlights recent applications of D-mannitol, especially in total synthesis.

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Estudo da influência do solvente, carboidrato e ácido graxo na síntese enzimática de ésteres de açúcares/ Study of the influence of solvent, carbohydrate and fatty acid in the enzymatic synthesis of sugar esters by lipases

Paula, Ariela V. de; Barboza, Jayne C. de Souza; Castro, Heizir F. de
2005-10-01

Resumo em inglês The aim of this work was to gain knowledge of enzymatic processes for the synthesis fatty acid esters of sugar, with the objective to develop an enzymatic process for the preparation of non-toxic biodegradable surface-active agents derived entirely from renewable resources. A wide range of data were collected for reaction conditions involving different sugars (glucose, fructose and sucrose), fatty acids (oleic, palmitic, lauric), solvents (hexane, heptane and t-butanol) a (mais) nd different sources of lipases in both free and immobilized forms. As a solvent t-butanol provided the best conditions to create a catalytic liquid phase in which the reaction occurs. Sugars were preferentially esterified in the following order: fructose > glucose > sucrose, depending on the enzyme preparation. For fructose no influence was found concerning de acyl donor and similar rates were achieved for all tested fatty acids. Ester synthesis was maximized for substrates containing fructose, lauric or oleic acids, t-butanol and lipase from porcine pancreas immobilized on polysiloxane-polyvinyl alcohol particles. Under such conditions molar conversions were higher than 50%.

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63

Adesivos à base de cianoacrilato para síntese de tecido mole/ Cyanoacrylate adhesives for the synthesis of soft tissue

Saska, Sybele; Gaspar, Ana Maria Minarelli; Hochuli-Vieira, Eduardo
2009-12-01

Resumo em português FUNDAMENTOS - Adesivos teciduais têm sido muito usados para síntese de ferida, em função de ser um método indolor, rápido e de fácil execução. OBJETIVOS -Analisar e comparar compatibilidade dos adesivos, etil- cianoacrilato (Super Bonder) e butilcianoacrilato (Histoacryl), e a reparação de incisões em dorso de ratos entre o fio de sutura e os respectivos adesivos. MÉTODOS - Foram usados 15 ratos. Realizaram-se duas lojas cirúrgicas no dorso. Em cada uma, foi (mais) implantado um tubo de polietileno (10mm x 1mm), os quais foram preenchidos com os adesivos Super Bonder (lado direito) e Histoacryl (lado esquerdo). As incisões, do lado esquerdo, foram coaptadas com Super Bonder, e as do lado direito, com Histoacryl. Uma incisão mediana, entre as duas incisões,foi realizada e suturada com fio de seda. Os animais foram mortos, depois de 7(sete), 35(trinta) e 120 (cento e vinte dia) dias. RESULTADOS: Os adesivos usados, no presente estudo, não promoveram reação inflamatória, quando usados para síntese das incisões. Porém, estes adesivos, quando implantados no subcutâneo, promoveram reação inflamatória até 120 (cento e vinte dia) dias, no entanto, a reação é mais intensa com Histoacryl. CONCLUSÕES: Super Bonder e Histoacryl permitem o processo cicatricial dos tecidos incisados; facilitam a sutura das incisões. Desta forma, estes podem ser utilizados para sínteses de feridas, lacerações ou incisões cutâneas. Resumo em inglês BACKGROUND: Tissue adhesives have been used for the synthesis of wound due to their painless application and quick and easy handling. OBJECTIVES: The purpose of this study was to analyze and compare the compatibility of the adhesives ethylcyanoacrylate (Super Bonder) and butyl-cyanoacrylate (Histoacryl), and to compare the reparation of incisions in the dorsum of rats with suture and the respective adhesives. METHODS: Fifteen rats were used. Two surgical pockets were crea (mais) ted in their dorsum. A polyethylene tube (10mm x 1mm) was implanted in each one. Each tube was filled with the adhesives Super Bonder(left side) and Histoacryl (right side). The incisions on the left side were closed with Super Bonder, and the incisions on the right side, with Histoacryl. A median incision between the two other incisions was made and closed with braided silk suture. The animals were killed after, 7, 35 and 120 days. RESULTS: The adhesives used in the present study did not promote inflammatory reaction when used for the synthesis of incisions. However, when implanted subcutaneously, they caused an inflammatory reaction within 120 days. Reaction is more severe with Histoacryl. CONCLUSIONS: Super Bonder and Histoacryl can be used effectively in the healing of incised tissues; they aid in the suture of incisions. However, these adhesives can be used for the synthesis of wounds, lacerations or cutaneous incisions.

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Nanoestruturas em fotocatálise: uma revisão sobre estratégias de síntese de fotocatalisadores em escala nanométrica/ Nanostructures in photocatalysis: a review about synthesis strategies of photocatalysts in nanometric size

Mourão, Henrique A. J. L.; Mendonça, Vagner R. de; Malagutti, Andréa R.; Ribeiro, Caue
2009-01-01

Resumo em inglês Advanced oxidative processes (AOPs) are based on chemical processes that can generate free radicals, such as hydroxyl radicals (.OH) which are strong, non-selective oxidant species that react with the vast majority of organic compounds. Nanostructured semiconductors, especially titanium dioxide (TiO2) in the anatase phase, are well-established photocatalysts for this process, which have proved to be useful in the degradation of dyes, pesticides and other contaminants. Res (mais) earch in different strategies for the synthesis of nanostructured semiconductors, with particular characteristic is currently a topic of interest in many studies. Thus, this paper presents a review about various synthesis strategies of nanostructured photocatalysts.

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Curiosidades sobre a reação aldólica utilizada como etapa chave na síntese Brasileira dos ácidos pterídicos A e B/ Curiosities about the aldol reaction employed as a key step in the synthesis of pteridic acids A and B

Dias, Luiz C.; Salles Jr., Airton G.
2010-01-01

Resumo em inglês 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 aldehyde has driven us to a series of experiments showing the remarkable relation between enolization selectivity and reaction conditions.

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Aplicação de α-oxoceteno ditiocetais em síntese orgânica/ Reactivity of α-oxoketene dithiocetals in organic synthesis

Siqueira, Geonir M.; Neuenfeldt, Patrícia D.; Duarte, Anaí; Bretanha, Lizandra C.; Freitag, Rogério A.; Cunico, Wilson
2010-01-01

Resumo em inglês The synthesis and reactivity of α-oxoketenes dithioacetals (S,S-acetals), general structure [(R¹C=OC(R²)=C(SR³)(SR4)], are reported. We also showed the application of S,S acetals as synthons for efficient synthesis of isoxazoles, pyrazoles, indazoles, thiophenes, dithiol thiones, pyridines, pyrimidines and other heterocycles. This work aims to review the importance of α-oxoketenes dithioacetals in organic chemistry during the past few years.

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Oligômeros e polímeros derivados do tiofeno: síntese e aplicações/ Thiophene-based oligomers and polymers: syntheses and applications

Alves, Marcos Roberto de Abreu; Calado, Hállen Daniel Rezende; Matencio, Tulio; Donnici, Claudio Luis
2010-01-01

Resumo em inglês In this review we summarize recent synthetic investigations about the preparation of oligothiophenes and polythiophenes, the most important π-conjugated organic materials for applications in electrochromic and electroluminescent devices. It is showed that many interesting and novel functionalized oligothiophenes have been synthesized by convenient coupling strategies (Heck, Kumada, Negishi, Suzuki, Stille and Ullmann) and oxidative coupling methods. Synthesis of poly (mais) thiophenes are also presented and described according to chemical and electrochemical polymerization methodologies. The description of these noteworthy synthetic methods illustrates how important and promising are the interdisciplinary approaches in the obtaining of oligothiophenes and polythiophenes.

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O emprego de fermento de pão, Saccharomyces cerevisiae, na síntese de feromônios/ Baker's yeast, Saccharomyces cerevisiae, as a tool for the synthesis of pheromones

Baraldi, Patrícia T.; Corrêa, Arlene G.
2004-06-01

Resumo em inglês The use of pheromones in integrated pest management has been increasing in the last years due to environmental concern. This development is accompanied by the search for simple, efficient and less aggressive synthetic methodologies for the preparation of pheromones. One of these methodologies includes microbiological reactions, more specifically biocatalytic reduction of carbonyl compounds using baker's yeast (Saccharomyces cerevisiae). This review presents the use of bak (mais) er's yeast as an easy and cheap alternative to obtain enantiomerically enriched compounds employed in the synthesis of pheromones.

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Farelo da vagem de algaroba em dietas para cabras lactantes: parâmetros ruminais e síntese de proteína microbiana/ Mesquite pod meal in diets of lactating goats: ruminal parameters and microbial efficiency synthesis

Argôlo, Lizziane da Silva; Pereira, Mara Lúcia Albuquerque; Dias, João Carlos Teixeira; Cruz, Jurandir Ferreira da; Del Rei, Antonio Jorge; Oliveira, Carlos Alberto Santana de
2010-03-01

Resumo em português Objetivou-se avaliar os efeitos da adição de farelo da vagem de algaroba (0; 33,3; 66,7 e 100%) em substituição ao fubá de milho sobre a excreção de derivados de purina, estimada com coleta total de urina, e sobre os parâmetros ruminais (pH, amônia e ácidos graxos voláteis) de cabras em lactação. Utilizaram-se oito cabras adultas lactantes distribuídas em dois quadrados latinos 4 × 4 e alimentadas com dietas isoproteicas, compostas de 40% de silagem de capi (mais) m-elefante e 60% de concentrado. Não houve efeito significativo da adição de farelo da vagem de algaroba sobre os parâmetros ruminais. O pH manteve-se em faixa adequada, entre 6,85 e 7,03, e a concentração média de nitrogênio amoniacal ruminal foi de 6,97 mg de N/100 mL de fluido ruminal. As concentrações de acetato e propionato variaram de 9,47 a 10,54 e de 4,79 a 6,58 mM, respectivamente. As excreções (mmol/dia) de alantoína, ácido úrico, xantinahipoxantina, a quantidade (mmol/dia) de purinas absorvidas, o fluxo intestinal (g/dia) de nitrogênio microbiano e a eficiência de síntese microbiana (PM/kg NDT) apresentaram resposta linear negativa à substituição do fubá de milho pelo farelo da vagem de algaroba. A estimativa da síntese de proteína microbiana em cabras deve ser calculada pela excreção de derivados de purinas a partir de equações obtidas com caprinos. Resumo em inglês The objective of this study was to evaluate the effect of adding mesquite pod meal (0, 33.3, 66.7 and 100%) to substitute corn meal on purin derivative the excretion, estimated by total urine collection, and on the ruminal parameters (pH, ammonia and volatile fatty acids). Eight lactating goats were used and distributed in a 4 × 4 Latin square and fed iso-protein diets consisting of 40% elephant grass silage and 60% concentrate. There was no significant effect from addin (mais) g mesquite pod meal on the ruminal parameters. The pH ranged from 6.85 to 7.03 and the ruminal ammonia concentration averaged 6.97 mg/100 mL. The acetate and propionate concentrations ranged from 9.47 to 10.54 and 4.79 to 6.58 mM, respectively. The excretion (mmol/day) of allantoin, uric acid and xanthine-hypoxanthine, the quantity of absorbed purines, the nitrogen microbial intestinal flow (g/day), microbial nitrogen synthesis (g/day) and efficiency of microbial protein synthesis efficiency, expressed in g of microbial crude protein/kg of the total digestible nutrients, presented linear negative response to corn replacement with mesquite pod meal. Microbial synthesis in goats must be estimated by the purine derivatives excretion using equations obtained from goats.

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Influência do nitrogênio degradável no rúmen sobre a degradabilidade in situ, os parâmetros ruminais e a eficiência de síntese microbiana em novilhos alimentados com cana-de-açúcar/ Ruminal degradable nitrogen for steers fed sugar cane: in situ degradability, ruminal parameters and microbial synthesis efficiency

Silveira, Roselene Nunes da; Berchielli, Telma Teresinha; Canesin, Roberta Carrilho; Messana, Juliana Duarte; Fernandes, Juliano José de Resende; Pires, Alexandre Vaz
2009-03-01

Resumo em português Objetivou-se avaliar o efeito da deficiência de nitrogênio degradável no rúmen (NDR), utilizando como volumoso cana-de-açúcar suplementada com uréia, farelo de soja ou farelo de glúten de milho - 60, sobre a eficiência de síntese microbiana e a degradabilidade in situ da matéria seca (MS) e da fibra em detergente neutro (FDN) em novilhos mestiços. Utilizaram-se oito novilhos canulados no rúmen e duodeno, distribuídos em dois quadrados latinos 4 × 4 e al (mais) imentados com cana-de-açúcar e cana-de-açúcar suplementada com uréia, farelo de soja ou farelo de glúten de milho-60. O pH e a concentração de N-NH3 foram mensurados no fluido ruminal antes e 2, 4, 6 e 8 horas após o fornecimento da ração. Utilizou-se a fibra em detergente ácido indigestível como indicador de fluxo duodenal. A eficiência microbiana foi determinada pelas bases purinas.As fontes de proteína degradável no rúmen não influenciaram a degradabilidade da matéria seca, entretanto, o maior valor de degradabilidade efetiva da FDN foi obtido com a cana-de-açúcar com farelo de soja. O pH e a concentração de N-NH3 observados com todas as dietas foram adequados para o crescimento dos microrganismos ruminais. A deficiência de nitrogênio degradável no rúmen não influencia a síntese de proteína microbiana e a dinâmica de fase líquida. Resumo em inglês The objective of this work was to evaluate the ruminal degradable nitrogen (RDN) deficit using as roughage sugar cane supplemented with urea, soybean meal, or corn gluten meal 60 on the microbial synthesis efficiency, in situ dry matter (DM) and neutral detergent fiber (NDF) degradability. The treatments were: sugar cane, sugar cane with urea, soybean meal or corn gluten meal 60. Eight rumen and duodenum cannulated steers were used and arranged according to two 4 × 4 (mais) Latin Squares. The pH and N-NH3 were determined in the ruminal fluid before and 2, 4, 6 and 8 hours after feeding. The duodenal flow was estimated by indigestible acid detergent fiber. The microbial efficiency was determined by purine. RDN did not affect the DM and the highest effective degradability was observed in sugar cane supplemented with soybean meal in the NDF degradability. The pH, N-NH3 values were appropriate to the microbial synthesis in all the evaluated diets. The RDN deficiency did not affect the microbial protein synthesis and the dynamics of the liquid phase.

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71

Compostos alfa-diazo carbonílicos: uma estratégia atraente para a síntese orgânica/ alpha-diazo carbonyl compounds: an atractive estrategy in organic synthesis

Ferreira, Vítor F.; Pereira, Letícia O. R.; Souza, Maria Cecília B. V. de; Cunha, Anna C.
2001-08-01

Resumo em inglês Diazocarbonyl compounds are a very important class of organic substances which have a long history of useful aplications in organic chemistry. The focus of this report deals with the use of diazocarbonyl compounds in a ariety of important reactions and their application in organic synthesis. These reactions are briefly summarized showing their broad scope.

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72

Metátese de olefinas aplicada ao fechamento de anéis: uma ferramenta poderosa para a síntese de macrociclos naturais/ Ring-closing olefin metathesis: a powerful tool for the synthesis of natural macrocycles

Santos, Anderson Rouge dos; Kaiser, Carlos Roland; Férézou, Jean-Pierre
2008-01-01

Resumo em inglês For a quarter of a century, metathesis has become indispensable for the synthesis of natural and non-natural products, particularly of biologically active compounds. This review illustrates through a maximum of appropriate examples the power and the versatility of the metathesis ring-closure (RCM) reaction as a key ring-closure methodology for the synthesis of natural macrocycles. Its high functional group compatibility as well as the possibility of further transformation (mais) s makes this reaction a powerful tool in the cases where the structural framework and function requirements are difficult to meet.

Scientific Electronic Library Online (Portuguese)

73

Reações de organocatálise com aminas quirais: aspectos mecanísticos e aplicações em síntese orgânica/ Organocatalysis reactions with chiral amines: mechanistic aspects and use on organic synthesis

Amarante, Giovanni W.; Coelho, Fernando
2009-01-01

Resumo em inglês The philosophy of organocatalysis is based on the utilization of organic compounds to catalyze organic transformations without the intervention of metals. This area has attracted much attention of the synthetic chemistry community on the last years, which can be confirmed by the explosion of published papers dealing with this subject. Phosphorus compounds, urea and thiourea derivatives, alkaloids, guanidine derivatives, for example, have already been used as organocatalys (mais) ts. In this review we have focused on the use of chiral amines as organocatalyst. We have also chosen some outstanding examples to demonstrate the potentiality of this strategy in the synthesis of natural products and biologically active compounds.

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74

Polímeros com capacidade de reconhecimento molecular no controlo da libertação de fármacos. Parte 1: síntese e caracterização/ Molecularly imprinted polymers for controlling drug release. Part 1: synthesis and characterization

Sousa, Margarita Domingues; Barbosa, Carlos Maurício
2009-01-01

Resumo em inglês Molecularly imprinted polymers (MIPs) consist of synthetic macromolecular matrix, obtained through molecular imprinting-based methods that show ability to selectively recognize important biological molecules and its application in the drug delivery field is under development. In the present review the main aspects related to the synthesis and characterization of MIPs are studied. The fundamental variables participating in the synthesis process, such as template molecule, (mais) functional monomers, cross-linking agents, solvents and imprinting approaches are discussed. Moreover, the main available methods for MIPs chemical and morphological characterization are presented and the importance of the obtained information is discussed.

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75

Sínteses totais das crocacinas A, C e D: novos antibióticos isolados de Chondromyces crocatus e Chondromyces pediculatus/ Total synthesis of crocacins A, C and D: new antibiotics isolated from Chondromyces crocatus and Chondromyces pediculatus

Oliveira, Luciana G. de; Dias, Luiz C.; Rosso, Giovanni B.
2008-01-01

Resumo em inglês This review describes the endeavors that led to the total synthesis of a novel class of antibiotic compounds: the crocacins A-D. Other aspects such as isolation, structural elucidation as well as the biological activities are also presented.

Scientific Electronic Library Online (Portuguese)

76

Glicerol: um breve histórico e aplicação em sínteses estereosseletivas/ Glycerol: a brief history and their application in stereoselective syntheses

Beatriz, Adilson; Araújo, Yara J. K.; Lima, Dênis Pires de
2011-01-01

Resumo em inglês Presently glycerol is considered a co-product of biodiesel industry. As the biodiesel production is exponentially increasing, glycerol generated from the transesterification of vegetable oils and fats is also being produced on a large scale, and turned out to be essential seeking for novel alternatives to the consumption of the extra volume, in crude and/or as derivatives high added value. This review mainly deals with chemical and enzymatic transformations of glycerol to obtain chiral building blocks for synthesis of pharmaceuticals and natural products.

Scientific Electronic Library Online (Portuguese)

77

Catalisadores contendo carbenos n-heterocíclicos como ligantes: propriedades, sínteses, aplicações e comparação com outros ligantes/ Catalysts containing n-heterocyclic carbenes as ligands: properties, syntheses, applications and comparison with other catalysts

Pastre, Julio Cezar; Correia, Carlos Roque Duarte
2008-01-01

Resumo em inglês N-heterocyclic carbenes (NHCs) have become of considerable importance in modern organometallic chemistry and homogeneous catalysis. There are several advantages in the use NHCs over their phosphorus analogues, which explains the enormous development of NHC ligands in the field of organometallic catalysis in the past few years. In this article, we present an overview of the importance of the catalysts containing NHC ligands, their synthesis, some pertinent synthetic applications, and a brief comparison with other catalysts.

Scientific Electronic Library Online (Portuguese)

78

Da Índia a Portugal - trajectórias sociais e estratégias colectivas dos comerciantes indianos

Ávila, Patrícia; Alves, Mariana

O presente artigo constitui uma síntese de resultados de uma pesquisa desenvolvida no ano lectivo de 1991/92 no âmbito do Seminário de Sociologia Urbana do lSCTE. Essa investigação incidiu sobre uma categoria social presente há menos de 20 anos na sociedade portuguesa, que evidencia a diversos nívei...

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79

Medicinas Alternativas e Complementares: uma metassíntese/ Complementary and Alternative Medicines: a meta-synthesis

Spadacio, Cristiane; Castellanos, Marcelo Eduardo Pfeiffer; Barros, Nelson Filice de; Alegre, Sarah Monte; Tovey, Philip; Broom, Alex
2010-01-01

Resumo em português O aumento do uso de Medicinas Alternativas e Complementares (MAC) motivou o crescimento do número de estudos qualitativos sobre o tema, justificando a realização de sínteses sobre esse material. Este artigo apresenta uma revisão sistemática de pesquisas qualitativas sobre MAC publicadas em periódicos internacionais. Esta revisão se orientou pela metodologia dos metaestudos. Foi realizada busca em revistas do Portal Periódicos da Coordenação de Aperfeiçoamento (mais) de Pessoal de Nível Superior e foram selecionados 32 artigos para análise. Os estudos revisados apresentam questões que têm como foco: o paciente, suas experiências terapêuticas e seus contextos sociais e culturais; o profissional, as relações profissionais e o processo de profissionalização das MAC; a MAC e sua relação com a biomedicina. Conclui-se que as pesquisas qualitativas sobre as MAC ensejam um olhar exploratório sobre o tema, procurando identificar as experiências de pacientes e profissionais com essas terapêuticas, assim como buscam discutir as conseqüências desse uso para a Medicina Convencional ou biomedicina. Resumo em inglês The growing use of Complementary and Alternative Medicines (CAM) has led to an increase in the number of qualitative studies on the subject, thus justifying a meta-synthesis of the resulting material. The current article presents a systematic review of qualitative studies on CAM published in international journals. The review was conducted according to the meta-synthesis methodology. A search was performed in journals through the Periodicals Periodical of CAPES, the Natio (mais) nal Agency for the Evaluation of Graduate Studies, and 32 articles were selected for analysis. The reviewed studies raise questions focusing on: patients, their therapeutic experiences, and their social and cultural contexts; professionals, professional relations, and the process of professionalization of CAM; and CAM and their relationship to biomedicine. The article concludes that qualitative studies on CAM call for an exploratory view of the theme, seeking to identify the experiences of patients and professionals with these therapies and discussing the impact of their use on conventional medicine or biomedicine.

Scientific Electronic Library Online (Portuguese)

80

Medicinas Alternativas e Complementares: uma metassíntese/ Complementary and Alternative Medicines: a meta-synthesis

Spadacio, Cristiane; Castellanos, Marcelo Eduardo Pfeiffer; Barros, Nelson Filice de; Alegre, Sarah Monte; Tovey, Philip; Broom, Alex
2010-01-01

Resumo em português O aumento do uso de Medicinas Alternativas e Complementares (MAC) motivou o crescimento do número de estudos qualitativos sobre o tema, justificando a realização de sínteses sobre esse material. Este artigo apresenta uma revisão sistemática de pesquisas qualitativas sobre MAC publicadas em periódicos internacionais. Esta revisão se orientou pela metodologia dos metaestudos. Foi realizada busca em revistas do Portal Periódicos da Coordenação de Aperfeiçoamento (mais) de Pessoal de Nível Superior e foram selecionados 32 artigos para análise. Os estudos revisados apresentam questões que têm como foco: o paciente, suas experiências terapêuticas e seus contextos sociais e culturais; o profissional, as relações profissionais e o processo de profissionalização das MAC; a MAC e sua relação com a biomedicina. Conclui-se que as pesquisas qualitativas sobre as MAC ensejam um olhar exploratório sobre o tema, procurando identificar as experiências de pacientes e profissionais com essas terapêuticas, assim como buscam discutir as conseqüências desse uso para a Medicina Convencional ou biomedicina. Resumo em inglês The growing use of Complementary and Alternative Medicines (CAM) has led to an increase in the number of qualitative studies on the subject, thus justifying a meta-synthesis of the resulting material. The current article presents a systematic review of qualitative studies on CAM published in international journals. The review was conducted according to the meta-synthesis methodology. A search was performed in journals through the Periodicals Periodical of CAPES, the Natio (mais) nal Agency for the Evaluation of Graduate Studies, and 32 articles were selected for analysis. The reviewed studies raise questions focusing on: patients, their therapeutic experiences, and their social and cultural contexts; professionals, professional relations, and the process of professionalization of CAM; and CAM and their relationship to biomedicine. The article concludes that qualitative studies on CAM call for an exploratory view of the theme, seeking to identify the experiences of patients and professionals with these therapies and discussing the impact of their use on conventional medicine or biomedicine.

Scientific Electronic Library Online (Portuguese)

81

Um método simples para preparação de metalocenos sensíveis ao ar/ A simple laboratory technique for the synthesis of air sensitive metallocenes

Federman Neto, Alberto; Lanchote, Áurea Donizete
1998-04-01

Resumo em inglês A simple laboratory technique is described for the synthesis of cyclopentadienylthallium and methylcyclopentadienylthallium and their use in the preparation of air sensitive metallocenes in solution. It does not use manifold, drybox or any other special glassware and was applied to the synthesis of cobaltocene, nickelocene and their methyl substituted analogs.

Scientific Electronic Library Online (Portuguese)

82

Tiossemicarbazonas: métodos de obtenção, aplicações sintéticas e importância biológica/ Thiosemicarbazones: preparation methods, synthetic applications and biological importance

Tenório, Rômulo P.; Góes, Alexandre J. S.; Lima, José G. de; Faria, Antônio R. de; Alves, Antônio J.; Aquino, Thiago M. de
2005-12-01

Resumo em inglês Thiosemicarbazones are a class of compounds known by their chemical and biological properties, such as antitumor, antibacterial, antiviral and antiprotozoal activity. Their ability to form chelates with metals has great importance in their biological activities. Their synthesis is very simple, versatile and clean, usually giving high yields. They are largely employed as intermediates, in the synthesis of others compounds. This article is a survey of some of these characteristics showing their great importance to organic and medicinal chemistry.

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87

Synthesis about a collaborative project on “Technology Assessment of Autonomous Systems”

Moniz, António

The project started in 2009 with the support of DAAD in Germany and CRUP in Portugal under the “Collaborative German-Portuguese University Actions” programme. One central goal is the further development of a theory of technology assessment applied to robotics and autonomous systems in general that r...

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89

Sensores ópticos com detecção no infravermelho próximo e médio/ Near and mid infrared optical sensors

Lima, Kássio M. G.; Raimundo Jr., Ivo M.; Silva, Andréa Monteiro S.; Pimentel, Maria Fernanda
2009-01-01

Resumo em inglês Optical chemical sensors with detection in the near and mid infrared region are reviewed. Fundamental concepts of infrared spectroscopy and optical chemical sensors are briefly described, before presenting some aspects on optical chemical sensors, such as synthesis of NIR and IR reagents, preparation of new materials as well as application in determinations of species of biological, industrial and environmental importance.

Scientific Electronic Library Online (Portuguese)

90

Resposta antioxidante, formação de fitoquelatinas e composição de pigmentos fotoprotetores em Brachiaria decumbens Stapf submetida à contaminação com Cd e Zn/ Antioxidative response, phytochelatin production and photoprotective pigments composition of Brachiaria decumbens Stapf plants exposed to Cd and Zn

Santos, Fabiana Soares dos; Amaral Sobrinho, Nelson Moura Brasil do; Mazur, Nelson; Garbisu, Carlos; Barrutia, Oihana; Becerril, José Maria
2011-01-01

Resumo em inglês In order to evaluate the response of Brachiaria decumbens Stapf to Cd and Zn, plants were hydroponically exposed to 50 and 100 mmol L-1 of Cd and 500 and 2000 mmol L-1 of Zn. Metal content of shoots and roots was determined, as well as alterations in photosynthetic and photoprotective pigments, antioxidant metabolites and phytochelatin synthesis. Plants concentrated elevated levels of Cd and Zn, especially in roots. Zinc exposure negatively affected chlorophyll and β (mais) -carotene content, whereas the highest dose of Cd reduced VAZ cycle pigments and tocopherol levels in plant shoots. Cadmium was the maximum inducer of the phytochelatin synthesis pathway.

Scientific Electronic Library Online (Portuguese)

91

Recentes avanços na preparação de aziridinas. Aplicações sintéticas e implicações mecanísticas/ Recent advances in the preparation of aziridines and their application in organic synthesis

Bisol, Tula Beck; Sá, Marcus Mandolesi
2007-02-01

Resumo em inglês This article surveys a selection of the most recent advances in aziridine synthesis. Novel synthetic methods and new insights into existing methodologies for the selective construction of the title compounds reported in the past decade are discussed in terms of synthetic applicability and environmentally benign conditions. Mechanisms involving stereoselective preparation of structurally diverse aziridines are also presented in order to highlight the most important issues associated with the synthesis of these versatile building blocks.

Scientific Electronic Library Online (Portuguese)

92

Preparações e aplicações sintéticas recentes de enaminonas/ Recent preparations and synthetic applications of enaminones

Ferraz, Helena M. C.; Gonçalo, Erika R. S.
2007-08-01

Resumo em inglês Enaminones are beta-enamino carbonylic compounds bearing the conjugated system N-C=C-C=O, which makes them versatile ambident synthetic building blocks, particularly in synthesis of heterocycles. This review covers the last three years of the literature concerning the preparation and synthetic applications of enaminones.

Scientific Electronic Library Online (Portuguese)

93

Preparação e caracterização de pós cerâmicos de aluminatos de lítio/ Preparation and characterization of lithium aluminates ceramic powders

Ribeiro, Roberto Ananias; Mohallem, Nelcy Della Santina
2001-12-01

Resumo em inglês The preparation of gamma-LiAlO2 by coprecipitation and sol-gel synthesis was investigated. Ceramic powders obtained by coprecipitation synthesis were prepared from aqueous solutions of aluminum and lithium nitrates using sodium hydroxide as precipitant agent. By sol-gel synthesis, the ceramic powders were prepared from hydrolysis of aluminum isopropoxide. The materials obtained by two routes of synthesis were dried at 80ºC and calcined at 550, 750, 950 and 1150ºC. The c (mais) haracterization was done by X-ray diffraction, infrared spectroscopy, emission and absorption atomic spectrometry, helium picnometry, specific surface area (BET method) and scanning electronic microscopy. Mixtures of crystalline phases were obtained by coprecipitation synthesis: 80ºC- LiAl2(OH)7.2H2O + Al(OH)3; 550 and 750ºC- alpha-LiAlO2 + eta-Al2O3; 950 and 1150ºC- gamma-LiAlO2 + LiAl5O8. Chemical analysis showed molar ration Al/Li @ 3. Crystalline single-phases were obtained by sol-gel synthesis above 550ºC: 550ºC-alpha-LiAlO2; 750, 950 and 1150ºC-gamma-LiAlO2. These powders presented molar ration Al/Li @ 1. Thus, gamma-LiAlO2 crystalline phase was obtained at 750ºC by sol-gel synthesis while by coprecipitation synthesis, a mixture of crystalline phases was obtained. These results showed the superiority of the sol-gel synthesis for the preparation of pure gamma-LiAlO2.

Scientific Electronic Library Online (Portuguese)

94

Preparação do (+)-±-terpineol a partir do (+)-limoneno: monoterpenos de odor agradável em um projeto para química orgânica experimental/ Preparation of (+)-±-Terpineol from (+)-limonene: monoterpenes with pleasant odor in a project for undergraduate organic chemistry laboratory

Baptistella, Lúcia Helena Brito; Imamura, Paulo Mitsuo; Melo, Leandro Vilela de; Castello, Cláudio
2009-01-01

Resumo em inglês A synthesis of (+)-±-terpineol from (+)-limonene was proposed as a project for undergraduate organic laboratory course. Terpineol is a useful flavor and fragrance compound, and several aspects of this preparation are suited for experimental organic classes, including basic techniques for extraction and analyses of essential oils, different reaction types and the possibility of a high degree of student interest.

Scientific Electronic Library Online (Portuguese)

95

Polyurethanes as a viable route to valorise lignin

Cateto, C.A.; Barreiro, M.F.; Rodrigues, A.E.; Belgacem, M.N.

This work presents a study concerning the use of lignin as a macromonomer in polyurethane (PU) synthesis based on four lignin samples (Sarkanda (Granit SA), Indulin AT (MeadWestvaco), Curan 27-11P (BorregaardLigno Tech) and Alcell (Repap Enterprises)). The work started with lignin characterization, ...

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96

Métodos de preparação de lactonas de anel médio/ Methods for the preparation of medium ring lactones

Longo Junior, Luiz S.; Bombonato, Fernanda I.; Ferraz, Helena M. C.
2007-04-01

Resumo em inglês There are several natural products bearing medium ring lactone moieties, which are those containing a ring size in the range of 8 to 11 members. This review intends to cover the last 10 years (1996-2005) of the literature concerning the synthesis of medium ring lactones.

Scientific Electronic Library Online (Portuguese)

97

Monoglicerídeos: produção por via enzimática e algumas aplicações/ Monoglycerides: production by enzymatic route and applications

Freitas, Larissa; Bueno, Tânia; Perez, Victor Haber; Castro, Heizir F. de
2008-01-01

Resumo em inglês Monoglycerides (MAG) are non-ionic surfactants, widely used in the pharmaceutical, food and cosmetic industries. Although MAGs are manufactured on an industrial scale by chemical glycerolysis of oils and fats, new developments in lipase catalyzed synthesis have been studied as an alternative to the classical method seeking to use clean technology and green chemistry. In this work, different methods such as glycerolysis, selective hydrolysis of fats and oils, and esterific (mais) ation of fatty acids or transesterification of esters with glycerol are presented. The properties and applications of the monoglycerides are also included in this review.

Scientific Electronic Library Online (Portuguese)

98

Materiais híbridos à base de sílica obtidos pelo método sol-gel/ Silica based hybrid materials obtained by the sol-gel method

Benvenutti, Edilson V.; Moro, Celso C.; Costa, Tania M. H.; Gallas, Marcia R.
2009-01-01

Resumo em inglês This review deals with silica based hybrid materials obtained by the sol-gel method. It involves concepts, classifications and important definitions regarding the sol-gel method that allows obtaining materials with organic and inorganic components dispersed in a molecular or nanometric level. We discuss the properties and characteristics of hybrid materials related to experimental synthesis conditions. We devote a special attention to the nanostructured materials, where t (mais) he self-organization is imposed by the organic component. Finally, we present some important applications of these materials based on their specific properties.

Scientific Electronic Library Online (Portuguese)

99

Lignin-based polyurethane materials

Cateto, C.A.; Barreiro, M.F.; Rodrigues, A.E.; Belgacem, M.N.

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100

Jovens, espaços, trajectórias e delinquências

Carvalho, Maria João Leote de

Tendo como pano de fundo a reforma do sistema de justiça tutelar de menores em Portugal, este artigo sintetiza as principais conclusões de um estudo que teve por principal objectivo traçar um retrato sociográfico sobre o universo de jovens aí internados no final do ano de 2000, antes da entrada em v...

DRIVER (Portuguese)

101

Inserção C-H de carbenóides de ródio em água e reutilização do catalisador/ Rhodium (II) carbene C-H insertion in water and catalyst reuse

Candeias, Nuno R.; Gois, Pedro M. P.; Afonso, Carlos A. M.
2007-01-01

Resumo em inglês A five-session laboratory experiment is described for the synthesis of a beta-lactam via Rh(II) catalysed intramolecular C-H insertion of a alpha-diazo-alpha-ethoxycarbonylacetamide. The metallo-carbene, responsible for the C-H bond activation, was generated from the diazo substrate and the catalyst Rh2(OAc)4. The high stability and solubility of the catalyst and the exclusive C-H insertion of the Rh-carbene allows the synthesis of this important heterocycle in water and the catalyst reutilization.

Scientific Electronic Library Online (Portuguese)

104

Estudo e caracterização da zeólita OFF Tipo T empregando diferentes fontes de silício/ Study and characterization of zeolite Offretite Type T employing differents silicon sources

Caovilla, Alessandra; Rigo, Reus T.; Penha, Fábio G.; Pergher, Sibele B. C.
2009-01-01

Resumo em inglês Offretite T zeolite was synthesized using different source of Si (Ludox AS-30, Ludox LS-30 and Aerosil 200 Degussa). The obtained materials were characterized by different complementary techniques: XRD, textural analysis by N2 adsorption, IV, SEM and chemistry analysis. This zeolite has an intermediary structure between offretite and erionite zeolites. In all experiments offretite T phase was obtained. Offretite phase presenting better crystalility are obtained in synthes (mais) is with stirring and employing aerosil as silicon source. This zeolite presents a potencial application as catalyst for hydroisodewaxing process.

Scientific Electronic Library Online (Portuguese)

105

Estudo do comportamento eletroquímico de substâncias complexantes utilizando eletrodo de cobre/ Study of electrochemical behavior of complexing compounds using copper electrode

Coutinho, Cláudia F. B.; Coutinho, Lincoln F. M.; Mazo, Luiz H.
2009-01-01

Resumo em inglês Copper electrode can be used for determination of complexing compounds through complexation reactions between Cu(II) and the analites. In this work some studies with three compounds were performed: glycine (precursor of glyphosate synthesis), herbicide glyphosate and aminomethylphosphonic acid (main metabolite of glyphosate). These compounds are complexing agents for Cu electrodes. Through simple experiments (cyclic voltammetry and corrosion studies) the applicability of (mais) the copper electrode as electrochemical sensor for complexing compounds in flow systems was presented.

Scientific Electronic Library Online (Portuguese)

106

Cristais Líquidos Ferroelétricos - CLF. Uma abordagem sintética/ Ferroelectric Liquid Crystals - FLCs. A synthetic approach

Merlo, Aloir A.; Gallardo, Hugo; Taylor, Ted R.
2001-06-01

Resumo em inglês Synthetic methods used for the synthesis of the Ferroelectric Liquid Crystals (FLCs) will be considered with emphasis on the chiral synthesis methodologies and mesomorphic electrooptical properties.

Scientific Electronic Library Online (Portuguese)

107

Crescimento de cristais de rubi e safira pelo método do fluxo/ Growth of ruby and sapphire crystals by the flux method

Ribeiro, Gislene da Silva; Prado, Rogério Junqueira
2010-01-01

Resumo em inglês This work reports the growth of corundum crystals by the flux method. The main objective was the evaluation of versatility, effectiveness and real possibilities of the flux method to the synthesis and doping of monocrystals with impurities of particular interest. In this work the chosen impurities were i) Cr and ii) Fe and Ti, aiming the synthesis of rubies and sapphires, respectively. The crystals were grown by heating a mixture of Al2O3:Cr or Al2O3:Fe:Ti and flux (MoO3) (mais) . The maximum crystal size obtained was 1.0 mm, all transparent, presenting well developed faces, bipiramidal hexagonal shape, and showing a typical red (ruby) and/or light blue (sapphire) color. EDX and XPD experiments were performed in order to characterize some of the synthesized crystals. All crystallized specimens presented the α-alumina atomic structure.

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109

Alilação e crotilação catalítica e enantiosseletiva de aldeídos/ Enantioselective catalytic allylation and crotylation of aldehydes

Fátima, Ângelo de; Robello, Luís Gustavo; Pilli, Ronaldo Aloise
2006-10-01

Resumo em inglês The field of chiral catalysis has experienced explosive growth over the last two decades. By now, many of the classical reactions in organic synthesis can be carried out efficiently in asymmetric manner. As one of the fundamental and powerful C-C bond-forming reactions, enantioselective catalytic allylation (ECA) and crotylation (ECC) of aldehydes has attracted considerable attention. In this article, we present an overview about the importance of chiral Lewis acids and b (mais) ases in catalytic enantioselective addition of allyl- and crotyl metals to aldehydes and the application of this methodology in the total synthesis of natural and non-natural products.

Scientific Electronic Library Online (Portuguese)

110

A reação de Diels-Alder no início do século vinte um/ The Diels-Alder reaction at the beginning of the twenty-first century

Brocksom, Timothy John; Donatoni, Maria Carolina; Uliana, Marciana Pierina; Vieira, Ygor William
2010-01-01

Resumo em inglês The Diels-Alder reaction continues to be the premier method for the construction of complex organic molecules. In the last 10 years many developments have been introduced, and have led to increased utility of this reaction. In this review we present some of these novelties, which are of fundamental importance in organic synthesis.

Scientific Electronic Library Online (Portuguese)

111

A prosody model to TTS systems

Teixeira, João Paulo

This PhD thesis presents the development of a prosody system for European Portuguese (EP) for text-to-speech (TTS) applications. Basically, TTS systems carry out the automatic utterance of a text and consist in a sequence of several modules. Those modules implement the pre-processing of the text inp...

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A project of speech input and output in an e-commerce application

Freitas, D.; Moura, António; Braga, Daniela; Ferreira, Helder; Teixeira, João Paulo; Barros, Maria João; Gouveia, Paulo D.F.

The present paper describes the work done during the last year in the development of European Portuguese (EP) speech recognition and synthesis channels for an Internet e-commerce application. The objective of this work was to develop the appropriate speech input and output, to enable the user to mor...

DRIVER (Portuguese)