Sample records for ethers
from WorldWideScience.org

Sample records 1 - 13 shown.



1

Estudo das condições reacionais da reação de clivagem oxidativa de β-hidróxi éteres bicíclicos promovida por tetróxido de rutênio/ Study of the conditions of the ruthenium tetraoxide-promoted oxidative cleavage reaction of bicyclic β-hydroxy ethers

Ferraz, Helena M. C.; Scalfo, Alexsandra C.; Vilalba, Bruno T.; Longo Jr, Luiz S.
2010-01-01

Resumo em inglês A systematic study of the reaction of β-hydroxy ethers with ruthenium tetraoxide (RuO4), generated in situ from ruthenium trichloride and sodium periodate, is presented, leading to nine-membered ring keto-lactones in moderate yields. Three different solvent systems - AcOEt/MeCN/H2O, MeCN/H2O and DMC/H2O - were studied leading to the desired products in lower yields than those obtained with the classical mixture of CCl4/MeCN/H2O, commonly used in reactions promoted by (mais) this oxidant. However, it is noteworthy that these new solvent systems represent greener alternatives to the chlorinated solvents used in the oxidative cleavage of β-hydroxy ethers by RuO4.

Scientific Electronic Library Online (Portuguese)

2

Determinação das substâncias reativas ao ácido tiobarbitúrico como indicador da peroxidação lipídica em ratos tratados com sevoflurano/ Thiobarbituric acid reactive substances as an index of lipid peroxidation in sevoflurane-treated rats/ Determinación de las substancias reativas al ácido tiobarbitúrico como indicador de la peroxidación lipídica en ratones tratados con sevoflurano

Bezerra, Francisco José Lucena; Rezende, Adriana Augusto; Rodrigues, Sara Jane; Almeida, Maria das Graças
2004-10-01

Resumo em português JUSTIFICATIVA E OBJETIVOS: O sevoflurano é um éter fluorado de baixa solubilidade sangüínea e sua biotransformação ocorre por meio do sistema enzimático hepático oxidativo que envolve o citocromo P450 2E1. A peroxidação lipídica ocorre durante o processo de biotransformação dos éteres sob ação do citocromo P450, um dos possíveis mecanismos de toxicidade hepática e renal promovida por esses compostos. O objetivo deste estudo foi determinar os níveis de s (mais) ubstâncias reativas ao ácido tiobarbitúrico (SRAT), como indicador da peroxidação lipídica, em ratos que receberam sevoflurano, previamente tratados ou não com isoniazida, indutor enzimático do citocromo P450 2E1. MÉTODO: Foram utilizados 42 animais, distribuídos aleatoriamente em 4 grupos que receberam respectivamente: G1 - oxigênio a 100% 1 l.min-1/60 minutos por 5 dias consecutivos; G2 - sevoflurano a 4% em oxigênio a 100%, 1 l.min-1/60 minutos por 5 dias consecutivos; G3 - isoniazida (50 mg.kg-1.dia) por via intraperitoneal durante 4 dias consecutivos, em seguida foi tratado como o G1, no G4 - isoniazida 50 mg.kg-1.dia por via intraperitoneal durante 4 dias consecutivos, sendo tratado, posteriormente, como o G2. Após 12 horas do último tratamento, sacrificaram-se os animais e foi coletado o plasma para a análise das SRAT, sendo removido o lobo esquerdo do fígado e os rins para exame histológico. RESULTADOS: Os resultados mostraram aumento nas taxas de SRAT no G3 e G4, com elevação discreta em G2. O estudo histológico revelou necrose focal no fígado de ratos pré-tratados com isoniazida (G3). CONCLUSÕES: O sevoflurano promoveu peroxidação lipídica apenas quando associado à isoniazida. Resumo em espanhol JUSTIFICATIVA Y OBJETIVOS: El sevoflurano es un éter fluorado de baja solubilidad sanguínea y su biotransformación ocurre por medio del sistema enzimático hepático oxidativo que envuelve el citocromo P450 2E1. La peroxidación lipídica ocurre durante el proceso de biotransformación dos éteres sobre la acción del citocromo P450, uno de los posibles mecanismos de toxicidad hepática y renal promovida por eses compuestos. El objetivo de este estudio fue determinar l (mais) os niveles de substancias reactivas al ácido tiobarbitúrico (SRAT), como indicador de la peroxidación lipídica, en ratones que recibieron sevoflurano, previamente tratados o no con isoniazida, inductora enzimática del citocromo P450 2E1. MÉTODO: Los animales fueron distribuidos aleatoriamente en 4 grupos que recibieron respectivamente: G1 - oxígeno a 100% 1 l.min-1/60 minutos por 5 días consecutivos; G2 - sevoflurano a 4% en oxígeno a 100%, 1 l.min-1/60 minutos por 5 días consecutivos; G3 - isoniazida (50 mg.kg-1.dia) por vía intraperitoneal durante 4 días consecutivos, en seguida fue tratado como el G1, en G4 - isoniazida 50 mg.kg-1.dia por vía intraperitoneal durante 4 días consecutivos, siendo tratado, posteriormente, como el G2. Después de 12 horas del último tratamiento, se sacrificaran los animales y fue colectado el plasma para la análisis de las SRAT, siendo removido el lóbulo izquierdo del hígado y de los riñones para examen histológico. RESULTADOS: Los resultados mostraron aumento en las tasas de SRAT en el G3 y G4, con elevación discreta en G2. El estudio histológico reveló necrosis focal en el hígado de ratones pre-tratados con isoniazida (G3). CONCLUSIONES: El sevoflurano promovió peroxidación lipídica apenas cuando asociado a la isoniazida. Resumo em inglês BACKGROUND AND OBJECTIVES: Sevoflurane is a fluorinated ether with low blood solubility and biotransformed by an oxidative enzymatic liver system involving cytochrome P450 2E1. Lipid peroxidation occurs during ethers biotransformation process under action of cytochrome P450, a possible mechanism for liver and kidney toxicity promoted by such compounds. This study aimed at determining the levels of substances reactive to thiobarbituric acid (TBARS), as an index for lipid p (mais) eroxidation in sevoflurane-treated rats, previously treated or not with isoniazid, enzymatic inducer of cytochrome P450 2E1. METHODS: Forty two male Wistar rats were randomly distributed in 4 groups receiving respectively: G1 - 1 L.min-1/60 minutes of 100% oxygen for 5 consecutive days; G2 - 4% sevoflurane in 1 L.min-1/60 minutes of 100% oxygen for 5 consecutive days; G3 - intraperitoneal isoniazid (50 mg.kg-1/day) for 4 consecutive days and then treated as G1; G4 - intraperitoneal isoniazid (50 mg.kg-1/day) for 4 consecutive days and then treated as G2. Animals were sacrificed 12 hours after the last treatment, plasma was collected for TBARS analysis and the liver left lobe and both kidneys were removed for histological evaluation. RESULTS: Results have shown increased TBARS levels in G3 and G4, with mild increase in G2. Histological evaluation has revealed focal liver necrosis in rats pretreated with isoniazid (G3). CONCLUSION: Sevoflurane has promoted lipid peroxidation only when associated to isoniazid.

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3

Avaliação de parâmetros antioxidantes em ratos tratados com sevoflurano/ Evaluation of antioxidant parameters in eats treated with sevoflurane/ Evaluación de parámetros antioxidantes en ratones tratados con sevoflurano

Bezerra, Francisco J. L; Vale, Nilton Bezerra do; Macedo, Brunno de Oliveira; Rezende, Adriana Augusto; Almeida, Maria das Graças
2010-04-01

Resumo em português JUSTIFICATIVA E OBJETIVOS: O sevoflurano é um éter halogenado com flúor que sofre biotransformação hepática através do citocromo P450 2E1. Éteres halogenados que sofrem biotransformação pelo P450 2E1 podem produzir espécies reativas do oxigênio (ERO) e promover enfraquecimento do sistema de defesa antioxidante. O objetivo deste trabalho foi investigar a relação entre a atividade das enzimas antioxidantes eritrocitárias e o sevoflurano. MÉTODO: Os animais f (mais) oram distribuídos em quatro grupos: Grupo 1 controle: apenas oxigênio a 100% (1 L.min-1 por 60 minutos durante 5 dias consecutivos); Grupo 2 - sevoflurane 4,0% em oxigênio a 100% (1 L.min-1 por 60 minutos durante 5 dias consecutivos); Grupo 3 - isoniazida (i.p.), 50 mg.kg-1 de peso corporal /dia, durante 4 dias e em seguida tratados apenas com oxigênio a 100% (1 L.min-1 por 60 minutos durante 5 dias consecutivos); Grupo 4 - isoniazida por via intraperitoneal na dose de 50 mg.kg-1 de peso corporal, diariamente durante 4 dias, seguido da administração do sevoflurane a 4,0% em oxigênio a 100% (1 L.min-1 por 60 minutos durante 5 dias). Após 12 horas da última exposição ao sevoflurane, os animais foram sacrificados e o sangue foi coletado através da veia porta para análise da atividade das enzimas antioxidantes. RESULTADOS: Aumento da atividade específica da glicose-6-fosfato desidrogenase, diminuição da atividade específica da catalase, principalmente no grupo de animais pré-tratados com isoniazida e, em seguida, tratados com sevoflurano. A glutationa peroxidase não apresentou alteração na sua atividade. CONCLUSÕES: A interação do sevoflurano com indutores enzimáticos do citocromo P450 2E1 pode propiciar a instalação do estresse oxidativo caso a exposição se torne prolongada e repetitiva. Resumo em espanhol JUSTIFICATIVA Y OBJETIVOS: El sevoflurano es un éter halogenado con flúor que sufre una biotransformación hepática a través del citocromo P450 2E1. Los éteres halogenados que sufren biotransformación por el P450 2E1, pueden generar especies reactivas del oxígeno (ERO) y promover el debilitamiento del sistema de defensa antioxidante. El objetivo de este trabajo fue investigar la relación entre la actividad de las enzimas antioxidantes eritrocitarias y el sevoflura (mais) no. MÉTODO: Los animales fueron distribuidos en cuatro grupos: Grupo 1 control: apenas oxígeno a 100% (1 L.min-1 por 60 minutos durante 5 días consecutivos); Grupo 2 - sevoflurano 4,0% en oxígeno a 100% (1 L.min-1 por 60 minutos durante 5 días consecutivos); Grupo 3 - isoniazida (i.p.), 50 mg.kg-1 de peso corporal /día, durante 4 días y enseguida tratados apenas con oxígeno a 100% (1 L.min-1 por 60 minutos durante 5 días consecutivos); Grupo 4 - isoniazido por vía intraperitoneal en dosis de 50 mg.kg-1 de peso corporal, diariamente durante 4 días, seguido de la administración del sevoflurano a 4,0% en oxígeno a 100% (1 L.min-1 por 60 minutos durante 5 días). Después de 12 horas de la última exposición al sevoflurano, los animales se sacrificaron y la sangre se recolectó a través de la vena porta para el análisis de la actividad de las enzimas antioxidantes. RESULTADOS: Aumento de la actividad específica de la glucosa- 6-fosfato deshidrogenasa, reducción de la actividad específica de la catalasis, principalmente en el grupo de animales pretratados con isoniazida y enseguida, tratados con sevoflurano. El glutatión peroxidasa no presentó ninguna alteración en su actividad. CONCLUSIONES: La interacción del sevoflurano con inductores enzimáticos del citocromo P450 2E1 puede propiciar la instalación del estrés oxidativo en el caso que la exposición se prolongue y sea repetitiva. Resumo em inglês BACKGROUND AND OBJECTIVES: Sevoflurane is a halogenated fluorinated ether that undergoes hepatic biotransformation through cytochrome P4502E1. Halogenated ethers undergoing biotransformation by P4502E1 can produce reactive oxygen species (ROS), weakening the antioxidant defense mechanism. The objective of this study was to investigate the relationship between the activity of erythrocyte antioxidant enzymes and sevoflurane. METHODS: Animals were divided in four groups: Gro (mais) up 1 - control: 100% oxygen (1 L.min-1 for 60 min during five consecutive days); Group 2 - 4.0% sevoflurane in 100% oxygen (1 L.min-1 for 60 minutes during five consecutive days); Group 3 - isoniazid (i.p.), 50 mg.kg-1/ day for four consecutive days, followed by 100% oxygen (1 L.min-1 for 60 minutes during four consecutive days); Group 4 - intraperitoneal isoniazid, 50 mg.kg-1 daily for four days, followed by 4.0% sevoflurane in 100% oxygen (1 L.min-1 for 60 minutes during five days). Twelve hours after the last exposure to sevoflurane, animals were sacrificed and their blood was collected through the portal vein for analysis of antioxidant enzymes. RESULTS: An increase in the activity of glucose-6-phosphate dehydrogenase and a decrease in the activity of catalase were observed, especially in the group of animals pre-treated with isoniazid. Changes in the activity of glutathione peroxidase were not observed. CONCLUSIONS: The interaction between sevoflurane and cytochrome P450 2E1 with enzymatic inducers can lead to oxidative stress with prolonged and repetitive exposure.

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4

Fotopolimerização: princípios e métodos/ Photopolymerization: principles and methods

Rodrigues, Máira R.; Neumann, Miguel G.
2003-12-01

Resumo em português O interesse na Fotoquímica de Polímeros tem crescido nas últimas décadas devido não somente ao grande número de novas aplicações como também à repercussão do ponto de vista econômico, técnico e ecológico. A fotopolimerização/fotocura tem recebido a atenção especial devido às incontáveis aplicações e a sua importância na área de Materiais. A cinética destes processos necessita de métodos analíticos precisos e rápidos para ser avaliada. Entre os (mais) métodos analíticos convencionais, os mais usados são a gravimetria e a medida de propriedades macroscópicas, como resistência à tração, à deformação e dureza. Entretanto, para determinações mais analíticas é conveniente usar métodos que permitam estudar a cinética de fotopolimerização em tempo real. Neste sentido têm sido usadas técnicas como dilatometria, espectroscopia Raman, calorimetria, e espectroscopia de infravermelho por transformada de Fourier em tempo real. A atividade no campo da polimerização continua a se expandir em muitas áreas e, recentemente, o interesse nos sistemas do fotoiniciação envolvendo a polimerização via radicais livres, iniciada por luz visível, tem recebido atenção especial. Recentemente, estudos sobre fotopolimerização catiônica induzida pela luz visível começaram a ser pesquisados novamente devido à grande variedade de monômeros que são polimerizáveis por via catiônica mas não por via radicar, como, por exemplo, oxiranas e éteres vinílicos. Resumo em inglês The interest for Polymer Photochemistry has been growing in the last decades as a consequence not only of the great number of new applications as well as due to the repercussion of economical, technical and ecological characters. The photopolymerization - photocuring processes have received special attention due to the countless and important applications in the area of Materials. The kinetics of these processes needs fast and precise analytic methods to be evaluated. Amo (mais) ng the conventional analytic methods, the most used are gravimetry and the determination of macroscopic properties, as resistance to traction, deformation and hardness. However, for a better insight in the reactions it is convenient to use more advanced analytic methods, in order to study the photopolymerization kinetics in real time. Dilatometry, Raman spectroscopy, calorimetry, and real time Fourier transform infrared spectroscopy are some of the techniques that have been used. Activity in the field of photopolymerization continues to expand in many areas and recently, the interest in photoinitiation systems involving the initiation of free-radical polymerization with visible light irradiation has been retaken. Additionally, studies on cationic photopolymerization induced by visible light started again to be studied because of the large variety of monomers that can be photopolymerized by via cation initiation, but not by free radicals, such as oxiranes and vinyl ethers.

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5

Uma estação biológica para o estudo dos mosquitos e dos outros animaes silvestres relacionados com a febre amarela

Aragão, Henrique de Beaurepaire de
1943-01-01

Resumo em inglês The outbreak of the jungle or forest yellow fever, through the adapta¬tion, quite recently of the yellow fever virus o the forest mosquitoes, brou¬ght the necessity of ecological researches on hese mosquitoes, as well as on the wild animals they bite, some of them being susceptible to the desease. This has been done by the special yellow fever Service of the State of Sao Paulo, in a special Biological Station in Perús, São Paulo, which has been built in the midst of t (mais) he jungle. This station was made with plain materials, and covered with straw, but was confortable enough for the technical work, i nthe early months of 1938. During the months in which the investigations were being carried on, the following interesting results were obtained: 1. As we have already pointed out in other places, the forest mosquitoes biting us during daytime, are always new born insects, having not yet sucked blood, as it is the general rule with all mosquitoes, and therefore also, with the anopheles and stegomyia, and this explains why nobody gets malaria or yellow fever, transmitted by anofeles or by aedes aegypti during the day. We think therefore, the jungle yellow fever, got during daytime is not due to the infected jungle or forest mosquito biting, but to infection through the human skin coming into close contact with tre virus, which the forest mosquitoes lay with their dejections, on the leaves of the trees where they remain sitting du¬ring the day. 2. As it is the rule with anopheles, stegomyia and other mosquitoes, the insects once having sucked blood, take nocturnal habits and, therefore, bite us, only during the night, so it happens with the forest mosquito, and insects with developped eggs and blood in stomach have been caught within the sta¬tion house, during the night. During the day, these mosquitoes do not bite, but remain quite still on the leaves of the trees, in the damp parts of the woods. 3. Jungle or forest mosquitoes can easely bite wild animals, some with more avidity then ethers, as it has bee npointed out to the opossum (didei-phis) and other animals. They also bite birds having very thin skin and only exceptionally, cold bloods animals. 5. Is has hot been possible to ascertain how forest mosquitoes are able to live, from onde season to another, through winter, when temperature drops near and even below zero. They have not been found in holes of the terrain, of trees and of animals, as it is the rule in cold countries. During winter, in the forest, it is possible to find larvs in the holes of bambus and trees full of water. As wild animals do not harbour the yellow fever virus for a long time in their body, it is diffcult to explain how the desease lasts from one season to another. Many ecological features on the mosquito, remains yet to be explained and therefore it in necessary to go on with the investigations, in bio¬logical stations, such as that one built up in Perús, São Paulo.

Scientific Electronic Library Online (Portuguese)

6

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.

Scientific Electronic Library Online (Portuguese)

7

Rendimento térmico e emissões de contaminantes atmosféricos de gasolinas formuladas com etanol, MBTE e TAEE/ Thermal yield and emission of atmospheric contaminants from gasolines formulated with ethanol, MTBE and TAEE

Silva, Rosângela da; Menezes, Eliana Weber de; Cataluña, Renato
2008-01-01

Resumo em inglês The specific consumption and carbon monoxide (CO) and nitrogen oxide (NO) emissions from gasolines formulated with ethanol, methyl tert-butyl ether (MTBE) and tert-amyl ethyl ether (TAEE) were evaluated in the rich, stoichiometric and lean-burn regions during the operation of an Otto-cycle engine. The use of ethanol as an additive presented high specific consumption, while gasoline formulated with TAEE showed low specific consumption with the engine operating under lean-b (mais) urn conditions. The ethers evaluated here presented a low percentage of CO in the rich-burn region when compared with ethanol.

Scientific Electronic Library Online (Portuguese)

8

Reações aldólicas assimétricas catalíticas/ Catalytic asymmetric aldol reactions

Corrêa Jr., Ivan R.; Pilli, Ronaldo A.
2003-08-01

Resumo em inglês This review describes the use of catalytic asymmetric aldol reactions of silyl enol ethers and silyl (thio)ketene acetals with aldehydes (the Mukaiyama aldol reaction) in order to illustrate its synthetic utility. A variety of Lewis acid and basic reagents were employed for catalytic aldol reactions with high diastereo- and enantioselectivities. The origins of the selectivity of these reactions are discussed and some representative examples of their application in the syn (mais) thesis of natural products are presented. New developments in chiral heterobimettalic lanthanoid catalysis and enantioselective aldol reactions in aqueous media are also included.

Scientific Electronic Library Online (Portuguese)

9

Gliceroquímica: novos produtos e processos a partir da glicerina de produção de biodiesel/ Glycerochemistry: new products and processes from glycerin of biodiesel production

Mota, Claudio J. A.; Silva, Carolina X. A. da; Gonçalves, Valter L. C.
2009-01-01

Resumo em inglês Glycerol is a byproduct of biodiesel production through transesterification of oils and fat. This article discusses the chemical transformation of glycerol in ethers, acetals and esters of high technological applications, especially in the fuel sector. Glycerol hydrogenolysis, dehydration to acrolein and oxidation are discussed as well, to show the potential use of glycerol for production of plastic monomers. Finally, the article shows other transformations, such as syn gas production, epichloridrin and glycerin carbonate.

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10

Epidemiologia do câncer do pulmão/ Lung cancer epidemiology

ZAMBONI, MAURO
2002-01-01

Resumo em português O câncer do pulmão, de doença rara no início do século XX, tornou-se a neoplasia mais letal em todo o mundo. Essa mudança se iniciou na segunda década do século, quando se observou que o número de casos vinha aumentando em todo o mundo. Somente na década de 1950 os trabalhos da literatura demonstraram, pela primeira vez, que o aparecimento do câncer do pulmão estava relacionado intimamente ao tabagismo. Foram necessários mais 10 anos para que os trabalhos de (mais) Doll e Hill convencessem o público e as autoridades de que o tabagismo era a mais importante causa da doença. O câncer do pulmão é dividido em quatro diferentes tipos: escamoso, adenocarcinoma, carcinoma de pequenas células e carcinoma de grandes células. Atualmente, sabe-se que tanto o carcinoma escamoso quanto o carcinoma indiferenciado de pequenas células e o adenocarcinoma estão relacionados com o tabagismo. A maioria dos carcinógenos ocupacionais dá origem a tumores do pulmão com distribuição histológica semelhante àquela causada pela fumaça do tabaco. Resumo em inglês Once a rare disease, lung cancer has become the most common type of lethal cancer throughout the world. This change has occurred since the 1920s , when it was observed both in Europe and in North America that the number of the cases began to increase. Although mentioned sporadically in the medical literature in the first half of the century, it was in 1950 that several well-performed case-controlled studies first suggested tobacco smoking as the overwhelming cause of lung (mais) cancer. It took even more years before results of large prospective studies, like the pioneering work of Doll and Hill, convinced both the public and the governments that smoking is the most important cause of the disease. Histologically, lung cancer is divided into four major subgroups: squamous-, adeno-, small cell, and large cell carcinomas. In a substantial number of cases, however, accurate histological diagnosis may be difficult, due to both intrinsic tumor heterogeneity and to inter-observer variability. Kreyberg suggested that only squamous and small cell carcinomas were caused by tobacco smoking, but most of the more recent studies indicate that the majority of adenocarcinomas is also caused by tobacco smoking. In all studies the proportion of adenocarcinoma is much higher in females than in males and secular trends during 1980s and 1990s have shown an increase in the occurrence of adenocarcinoma. Most occupational carcinogens, with the exception of chloromethyl ethers and radiation (radon), which have a higher tendency to promote small cell lung cancer, give rise to tumors with a histological distribution that is similar to tumors caused by tobacco smoke.

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11

Constituintes químicos do extrato acetato de etila das partes aéreas de Solanum paludosum Moric

Silva, Tania Maria Sarmento da; Silva, Cleiser de Castro; Braz-Filho, Raimundo; Carvalho, Mario Geraldo de; Silva, Marcelo Sobral da; Agra, Maria de Fátima
2002-01-01

Resumo em inglês Phytochemical investigation of the aerial parts of S. paludosum afforded 3,4,7,8-tetramethyl gossypetinr, 3,7- dimethyl kaempferol, 3-methyl kaempferol, 3-methyl apigenin, and 3-methyl quercetin ethers, besides N-p-transcoumaroyltiramine, and protocatecuid acid. The structures were established from spectral data of the natural substances and the permethyl and acetyl derivatives of tetramethyl gossypetin.

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12

Componentes voláteis do café torrado. Parte II. Compostos alifáticos, alicíclicos e aromáticos/ Volatile components in roasted coffee. Part II. Aliphatic, alicyclic and aromatic compounds

Moreira, Ricardo Felipe Alves; Trugo, Luiz Carlos; De Maria, Carlos Alberto Bastos
2000-04-01

Resumo em inglês This review is about the aliphatic, alicyclic and aromatic compounds (non-heterocyclic compounds) that are present in the volatile fractions of roasted coffees. Herein, the contents, aroma precursors and the sensorial properties of volatile phenols, aldehydes, ketones, alcohols, ethers, hydrocarbons, carboxylic acids, anhydrides, esters, lactones, amines and sulphur compounds are discussed. Special attention is given to the compounds of these groups that are actually important to the final aroma of roasted coffees.

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13

Agentes complexantes: podante, coronante e criptante classificação e nomenclatura/ Complexing agents: podands, coronands and cryptands classification and nomenclature

Whei, Oh Lin; Brito Neto, José Thomé Xavier de
1998-10-01

Resumo em inglês The scientific and practical interest in crown ethers as complexing agents for actions as well as for anions and neutral low molecular species is undeniable. New molecules with crown ether properties are constantly synthesized and new application discovered. This paper presents classification and nomenclature of the classical oligoethers (crown ethers): monocyclic coronands; oligocyclic spherical cryptands; and acyclic podands.

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