Síntese de enaminonas

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 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.

Reparar y sustituir cosas en la compraventa : evolución y últimas tendencias

International texts recognise the buyer's right to the repair or replacement if the goods do not conform with the contract, and at the same time, establish exceptions to their application and certain rules of protection for the seller (Art. 46 CISG, Art. 7.2.3 UNIDROIT Principles of International Commercial Contracts, Art.9:102 PECL and Arts. 4:202 y 4:204 (1) PEL S). This approach is a result of a compromise between civil law systems and the common law and it has been widely extended to the regulation of consumer sales over the last decade (Art. 3.3 of the Directive 1999/44/CE, Art. III.-3:302 DCFR, Art. 26 of the proposal for a Directive on Consumer Rights). These norms regulate the different ways of requiring the fulfilment of a contractual obligation from a new paradigm which has little to do with a need to protect the weak consumer which governed the origins of consumer policy in the European Community. Now the idea of the consumer who shall behave economically efficiently prevails in Art. 3.3 of the Directive 1999/44/CE, a norm which is clearly influenced by the international texts and whose transposing into the national legislation of Member States has created important problems for traditional dogmas. In this sense there are still some unclear issues, such as the possibility of replacing in sales of goods of specific nature or second-hand goods, some aspects on the exercise of repair and replacement, and, even, their use as primary remedies rather than a reduction in price or a rescission of the contract. With regard to this, in England the possibility of offering the consumer free choice between these measures if the goods do not conform with the contract has been raised. This is far from the principle of pacta sunt servanda and is clearly contrary to the economic approach of the proposal for a Directive on Consumer Rights. Up to now Spain has limited itself to implementing Art. 3.3 Directive 1999/44/CE into its legal system in almost literal terms and the case law on the issue has completely turned out to be insufficient. By contrast with Germany, the Spanish legislator has not extended the application of the rules of repair and replacement of Directive 1999/44/CE to nonconsumer sales, even though two draft bill proposals along these lines presented by the General Commission for Codifying (“Comisión General de Codificación”), the last one being in January, 2009

Efeitos de substituintes na ligação de hidrogênio do 3-hidroxipropenal

The effect of substituents on the energies and geometries of 3-hydroxypropenal was studied using the B3LYP/6-311++G(d,p) model. The hydrogen bond energies indicate that the strongest donors and the weakest acceptors present the highest and the weakest hydrogen bonds, respectively, indicating the validity of the Madsen RAHB model. Geometric parameters indicate that the intensity of the hydrogen bond is proportional to the resonance, as suggested by the RHAB model. The effect of substituents diverges from the model proposed by Gilli et al. Sometimes the results indicate that the donor or acceptor effect is more important than the point of substitution.

Síntese e caracterização de perovskitas LaNi(1-x)Co xO3 como precursores de catalisadores para a conversão do metano a gás de síntese pela reforma com CO2

LaNiO3 perovskite was modified by partial substitution of nickel by cobalt in order to increase the stability and resistance to carbon deposition during the methane CO2 reforming. The results showed that a suitable combination of precipitation and calcination steps resulted in oxides with the desired structure and with important properties for application in heterogeneous catalysis. The partial substitution of Ni by Co resulted in lower rates of conversion of both the reactants, but the catalyst stability was highly increased. The LaNi0.3Co0.7O3 catalyst, calcined at 800 ºC, was the most active under the reaction conditions.

Reações de 1,2-dicloro-4,5-dinitrobenzeno com aminas: monossubstituição de nitro e dissubstituição de cloro e nitro

1,2-dichloro-4,5-dinitrobenzene (DCDNB) reacts with primary and secondary amines, in acetonitrile, at room temperature, to give a monosubstituted nitro product with a yield of 85 to 95%. The chloro-nitro-disubstituted product is formed with excess amine under reflux. Piperidine, pyrroline, dimethylamine and methylamine were the most reactive reagents in both mono- and disubstitution.

Effect of reducing and replacing pork fat on the physicochemical, instrumental and sensory characteristics throughout storage time of small caliber non-acid fermented sausages with reduced sodium content

The effect of pork fat reduction (from 44% to 20% final fat content) and its partial substitution by sunflower oil (3% addition) on the physicochemical, instrumental and sensory properties throughout storage time of small caliber non-acid fermented sausages (fuet type) with reduced sodium content (with partial substitution of NaCl by KCl and K-lactate) and without direct addition of nitrate and nitrite (natural nitrate source used instead), was studied. Results showed that sausages with reduced fat (10% initial fat content) and with acceptable sensory characteristics can be obtained by adding to the shoulder lean (8% fat content) during the grinding, either 3.3% backfat (3% fat content) or 3% sunflower oil, both previously finely comminuted with lean. Furthermore, sunflower oil showed to be suitable for partial pork backfat substitution in very lean fermented sausages, conferring desirable sensory properties similar to those of sausages with standard fat content. The sensory quality of the sausages was maintained after three-month cold storage in modified atmosphere.

The determinants of capital intensity in Japan and the U.S

We estimate the determinants of capital intensity in Japan and the US, characterized by striking different paths. We augment an otherwise standard Constant Elasticity of Substitution (CES) model with demand-side considerations, which we find especially relevant in the US. In this augmented setting, the elasticity of substitution between capital and labor is placed around 0.85 in Japan, and 0.30 in the US. We also find evidence of biased technical change, which is capital-saving in Japan but labor-saving in the US. These differences help us explain the diverse experience in the capital deepening process of these economies, and lead us to conclude that demand-side drivers may also be relevant to account for different growth experiences. A close look at the nature of technological change is also needed before designing one-size-fits-all industrial, economic growth, and/or labor market policies.

Biodiesel de soja: reação de transesterificação para aulas práticas de química orgânica

The transesterification procedure of triacylglycerides from soybean oil (in natura and waste oil) to give biodiesel was adapted to semi-micro laboratory scale as an additional experimental technique of nucleophilic acyl substitution for undergraduate courses in Chemistry and related areas.

70º aniversário do biodiesel em 2007: evolução histórica e situação atual no brasil

Periodically, during petroleum shortages, vegetable oils and their derivatives have been proposed as alternatives to petroleum diesel fuel. Different approaches have been proposed, including the use of pure vegetable oils (or blends) or their derivatives. Indeed, the use of fatty-acid methyl or ethyl esters (usually known as "biodiesel") produced by alcoholysis of triacylglycerides or esterification of fatty acids was initially proposed in Belgium 70 years ago, when the first world patent was deposited. Recently, foreign dependence on diesel fuel and the petroleum crisis have increased the discussion in Brazil on starting to use alternatives to diesel fuel, being biodiesel the alternative of choice for a large petroleum diesel substitution program.

Consultoria del procés de logística interna del laboratori d'anàlisis clíniques a l'Hospital General de Vic

Com a resultat de les politiques i estratègies de col·laboració entre la universitat de Vic i de l’hospital i de la voluntat de realitzar activitats formatives conjuntes , s’estableix un línia de treball orientada a l’estudi i anàlisi de la situació logística interna actual del laboratori d’anàlisis clíniques de l’Hospital General de Vic. El treball es centra en el procés intern del laboratori i l’abast de l’estudi es troba limitat a les àrees especifiques d’hematologia i coagulació i bioquí… [+]mica. D’aquestes dues àrees el treball realitza un estudi exhaustiu del seu procés intern, identifica les seves activitats i la seva metodologia de treball amb l’objectiu d’elaborar el Value Stream Map de cadascuna de les àrees. Les àrees de Microbiologia, Banc de Sang i Urgències resten fora d’aquest estudi exhaustiu tot i que són presents en el treball per la inevitable interacció que tenen en la globalitat del procés. El treball es centra bàsicament en els processos automatitzats tot i que els processos que es duen a terme en el laboratori són tant automatitzats com manuals. També es limita al sistema productiu intern del laboratori tot i la interacció que té aquest sistema intern amb altres centres productius del sistema com ara són els centres d’atenció primària, els diversos hospitals i centres d’atenció sociosanitària. El laboratori es troba immers en el moment de l’elaboració d’aquest treball en un situació de canvi i millora del seus processos interns que consisteixen principalment en la substitució de part la maquinària actual que obliguen a la definició d’un nou layout i d’una nova distribució de la producció a cada màquina. A nivell extern també s’estan produint millores en el sistema informàtic de gestió que afecten a part del seu procés. L’objectiu del treball és donar visibilitat total al procés de logística interna actual del laboratori, identificant clarament com són i quina seqüència tenen els processos logístics interns i els mètodes de treball actuals, tant de recursos màquina com recursos persona, per poder identificar sota una perspectiva de generació de valor, aquells punts concrets de la logística interna que poden ser millorats en quant a eficiència i productivitat amb l’objectiu que un cop identificats es puguin emprendre accions i/o projectes de millora. El treball finalitza amb un anàlisis final del procés logística interna des d’una òptica Lean. Per fer-ho, identifica aquelles activitats que no aporten valor al procés o MUDA i les classifica en set categories i es realitzen diverses propostes de millora com són la implantació d’un flux continu , anivellat i basat en un concepte pull , identifica activitats que poden ser estandarditzades i/o simplificades i proposa modificacions en les infraestructures físiques per donar major visibilitat al procés. L’aspecte humà del procés es planteja des d’un punt de vist de metodologia, formació, comunicació i aplicació de les 5S.

Biotransformation and endocrine disruptive effects of contaminants in ringed seals - implications for monitoring and risk assessment

Marine mammals are exposed to persistent organic pollutants (POPs), which may be biotransformed to metabolites some of which are highly toxic. Both POPs and their metabolites may lead to adverse health effects, which have been studied using various biomarkers. Changes in endocrine homeostasis have been suggested to be sensitive biomarkers for contaminant-related effects. The overall objective of this doctoral thesis was to investigate biotransformation capacity of POPs and their potential endocrine disruptive effects in two contrasting ringed seal populations from the low contaminated Svalbard area and from the highly contaminated Baltic Sea. Biotransformation capacity was studied by determining the relationships between congener-specific patterns and concentrations of polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), polybrominated diphenyl ethers (PBDEs) and their hydroxyl (OH)- and/or methylsulfonyl (MeSO₂)-metabolites, and catalytic activities of hepatic xenobiotic-metabolizing phase I and II enzymes. The results suggest that the biotransformation of PCBs, PBDEs and toxaphenes in ringed seals depends on the congener-specific halogen-substitution pattern. Biotransformation products detected in the seals included OH-PCBs, MeSO₂-PCBs and –DDE, pentachlorophenol, 4-OHheptachlorostyrene, and to a minor extent OH-PBDEs. The effects of life history state (moulting and fasting) on contaminant status and potential biomarkers for endocrine disruption, including hormone and vitamin homeostasis, were investigated in the low contaminated ringed seal population from Svalbard. Moulting/fasting status strongly affected thyroid, vitamin A and calcitriol homeostasis, body condition and concentrations of POPs and their OH-metabolites. In contrast, moulting/fasting status was not associated with variations in vitamin E levels. Endocrine disruptive effects on multiple endpoints were investigated in the two contrasting ringed seal populations. The results suggest that thyroid, vitamin A and calcitriol homeostasis may be affected by the exposure of contaminants and/or their metabolites in the Baltic ringed seals. Complex and non-linear relationships were observed between the contaminant levels and the endocrine variables. Positive relationships between circulating free and total thyroid hormone concentration ratios and OH-PCBs suggest that OH-PCBs may mediate the disruption of thyroid hormone transport in plasma. Species differences in thyroid and bone-related effects of contaminants were studied in ringed and grey seals from low contaminated references areas and from the highly contaminated Baltic Sea. The results indicate that these two species living at the same environment approximately at the same trophic level respond in a very different way to contaminant exposure. The results of this thesis suggest that the health status of the Baltic ringed seals has still improved during the last decade. PCB and DDE levels have decreased in these seals and the contaminant-related effects are different today than a decade ago. The health of the Baltic ringed seals is still suggested to be affected by the contaminant exposure. At the present level of the contaminant exposure the Baltic ringed seals seem to be at a zone where their body is able to compensate for the contaminant-mediated endocrine disruption. Based on the results of this thesis, several recommendations that could be applied on monitoring and assessing risk for contaminant effects are provided. Circulating OH-metabolites should be included in monitoring and risk assessment programs due to their high toxic potential. It should be noted that endogenous variables may have complex and highly variable responses to contaminant exposure including non-linear responses. These relationships may be further confounded by life history status. Therefore, it is highly recommended that when using variables related to endocrine homeostasis to investigate/monitor or assess the risk of contaminant effects in seals, the life history status of the animal should be carefully taken into consideration. This applies especially when using thyroid, vitamin A or calcitriolrelated parameters during moulting/fasting period. Extrapolations between species for assessing risk for contaminant effects in phocid seals should be avoided.

Reações de oxidação de derivados de cis-octalinas promovidas por trinitrato de tálio (TTN)

The reaction of ten cis-octalins and cis-octalones with thallium trinitrate (TTN) leads to different products, depending mainly on the substitution pattern of the substrate. Functionalized cis-hydrindanes were obtained from the reaction of 1,2,3,4,4a,5,8,8a-octahydro-4a-methylnaphthalene and of 1,2,3,4,4a,5,8,8a-octahydro-4a,7-dimethylnaphthalene with TTN in acetonitrile, whereas a cyclic ether was formed treating 1,2,3,4,4a,5,8,8a-octahydro-6,8a-dimethylnaphthalen-1-ol with TTN in trimethylorthoformate (TMOF).

Diastereosseletividade na redução de enonas bicíclicas com hidretos volumosos

Reduction of five substituted octalones employing lithium tri-sec-butylborohydride (L-selectride®) in THF and ethyl ether led to allylic alcohols with moderate diastereoselectivity. The stereoselectivity of addition of bulky hydrides showed to be different from most examples in the literature and was strongly influenced by substitution on the octalone ring.

Caracterización de la reactividad intrínseca de los halobencenos en el modelo conceptual de la teoría de funcionales de la densidad (TFD)

The aim of this paper is to study the family of halobenzenes for characterizing their intrinsic reactivity and in this way to establish a rational order of the intrinsic reactivity of this family of molecules in the electrophilic aromatic substitution. This study was carried out in the framework of Density Functional Theory which provides a global and local index that can be used in the characterization of the reactivity. This index is related to some concept derivatives of experimental chemistry, being a good approach to the characterization of halobenzenes.

Progressive Purkinje Cell Degeneration in tambaleante Mutant Mice Is a Consequence of a Missense Mutation in HERC1 E3 Ubiquitin Ligase

The HERC gene family encodes proteins with two characteristic domains: HECT and RCC1-like. Proteins with HECT domain shave been described to function as ubiquitin ligases, and those that contain RCC1-like domains have been reported to function as GTPases regulators. These two activities are essential in a number of important cellular processes such as cell cycle, cell signaling, and membrane trafficking. Mutations affecting these domains have been found associated with retinitis pigmentosa, amyotrophic lateral sclerosis, and cancer. In humans, six HERC genes have been reported which encode two subgroups of HERC proteins: large (HERC1-2) and small (HERC3-6). The giant HERC1 protein was the first to be identified. It has been involved in membrane trafficking and cell proliferation/growth through its interactions with clathrin, M2-pyruvate kinase, and TSC2 proteins. Mutations affecting other members of the HERC family have been found to be associated with sterility and growth retardation. Here, we report the characterization of a recessive mutation named tambaleante, which causes progressive Purkinje cell degeneration leading to severe ataxia with reduced growth and lifespan in homozygous mice aged over two months. We mapped this mutation in mouse chromosome 9 and then performed positional cloning. We found a GuA transition at position 1448, causing a Gly to Glu substitution (Gly483Glu) in the highly conserved N- terminal RCC1-like domain of the HERC1 protein. Successful transgenic rescue, with either a mouse BAC containing the normal copy of Herc1 or with the human HERC1 cDNA, validated our findings. Histological and biochemical studies revealed extensive autophagy associated with an increase of the mutant protein level and a decrease of mTOR activity. Our observations concerning this first mutation in the Herc1 gene contribute to the functional annotation of the encoded E3 ubiquitin ligase and underline the crucial and unexpected role of this protein in Purkinje cell physiology.