ALKALOIDS

Author: JIMÉNEZ JIMÉNEZ JESÚS.
Year: 2003.
University: COMPLUTENSE DE MADRID [www.ucm.es].
Place of defense: FACULTAD DE CIENCIAS BIOLÓGICAS.
Place of preparation: CENTRO DE INVESTIGACIÓN BIOLÓGICAS (CIB-CSIC).

Summary: Proteins desacoplantes (UCPs) are a subfamily of proteins included in mitochondrial inner membrane transporters metabolites. The UCP1, expression exclusively in brown adipose tissue, has as its main function to mediate in the process of termogénesis. Its activity is regulated physiologically by fatty acids and retinoids (activators) and nucleotide (inhibitors). To explain the trigger mechanism, there are two scenarios. One proposes that the substrate fatty acids are transported by UCP1, and the other which is a prosthetic group amending the conductance of the UCP1 to protons. This report demonstrates that in the absence of fatty acids and nucleotides, the UCP1 shows a high conductance of H +, so activation can not be based on a cycle protonofórico involving a translocation of fatty acid mediated by UCP1. Furthermore it is shown that compounds such as retinoic acid, which should not allow the flip-flop are activators of UCP1. The UCP2 and UCP1 share a high homology. However, the UCP2 is not regulated by fatty acids or nucleotides. A slightly alkaline pH the UCP2 it shows regulation by retinoids. To determine the regions of the UCP1 involved in the regulation we used the differences with the UCP2 to create mutant proteins and analyze the effect of its expression in yeast. By mutagenesis, we design mutants of UCP1 incorporating successive mutations in the domain II of UCP1, up into the domain II of UCP2. It was also designed mutants in other domains. The study indicates that these chimeras, for the activation by fatty acids the second domain of the UCP1 is necessary and sufficient. However, the three domains of UCP1 involved in the regulation of transport nucleotide protein.

Author: GARCÍA SÁNCHEZ ALICIA.
Year: 2004.
University: REY JUAN CARLOS [www.urjc.es].
Place of defense: ESCUELA SUPERIOR DE CIENCIAS EXPERIMENTALES Y TECNOLOGÍA.
Place of preparation: ESCUELA SUPERIOR DE CIENCIAS EXPERIMENTALES Y TECNOLOGÍA.

Summary: The isomerization of epoxides is a process widely used in synthesis of organic compounds such as aldehydes, ketones, alcohols or ethers are used as intermediate or final products in fine chemicals processes. This is a catalytic process that can be done using homogeneous catalysis (halides or metallic mineral acids), or conglomerate (oxides and zeolites), and that leads to the formation of different compounds carboníllcos (ketones and aldehydes) and alcaholes alilicos. Despite the large amount of work described in literature on isomerization of epoxides, using both homogeneous and heterogeneous catalysis, the substrates are used primarily epoxides aromatic cicloalcanos or tertiary epoxides and hardly any work with linear epoxides long chain. This is debea that the isomerization of this type of reaction conditions epoxides requires more demanding, such as higher temperatures, reaction times and amounts of catalyst, since they are less reactive substrate. As a result, this work raises the development of a catalytic process that will produce compounds carbonilitos or alcohols industrial interest from epoxides linear. The process relies on the use of heterogeneous catalytic systems that selectively catalyze the isomerization of epoxides terminals to the corresponding linear aldehyde and / or alcohol avoiding the formation of secondary reactions. The program began with the work done synthesis and characterization of catalytic systems with properties suitable for use in isomerization reactions, such as amorphous solids, zeolites and materials mesoestructurados. Completing its characterization addressed the study of the behavior of the same catalytic reaction in the isomerization of 1,2-epoxioctano. Below are conducted various tests that were used in solvents with different properties commonly used in organic synthesis. The next phase of research was to conduct a study of the influence of reaction conditions in the process under study. In a final stage of the investigation also tested epoxides who had very different properties over the 1.2-epoxioctano to include or tertiary carbon cycles in its structure. The main findings in the research are: materials mesoestructurados aluminum in its structure presents a catalytic activity center acid by an order of magnitude higher than values obtained with material zeoliticos. Furthermore, the synthesis method used in obtaining materials a1-mcm-41 significantly influence the properties of the catalysts, catalytic behavior involving different. The nature of the solvent exerts a significant influence on the catalytic activity of the material a1-mcm-41 being solvents that have a low polarity best suited. An increase in temperature reaction favors the isomerization reaction of 1,2-epoxioctano obtaining total conversions to 1800c temperature. The processes of isomerization of epoxides tertiary cyclic aromatic and are fortunate with regard to the difficulties involved in the isomerization of epoxides linear.

Author: CARRANCO MORUNO INÉS.
Year: 2006.
University: BARCELONA [www.ub.es].
Place of defense: FACULTAD DE FARMACIA.
Place of preparation: LABORATORIO QUÍMICA ORGÁNICA, FACULTAD DE FARMACIA, UNIVERSIDAD DE BARCELONA.

Summary: It has developed a study on reducing non biomimética salts piridinio, which generates an intermediate radicalario subsequently was intercepted by alquenos activated to give rise to DHPs substituted in position 4. Furthermore, in a complementary manner, has been described an oxidation not biomimética of dihydropyridines, which develops a methodology for the formation of links type CC on the position 3 of dihydropyridines, by protocol oxidation radicalaria. Given the reaction pathways as alternatives, which circumvents the oxidation biomimética, DHPs offer synthetic very interesting possibilities that would allow access to type compounds piperidina with a high degree of structural complexity and diversity. In this context and taking into account the presence of nuclei piperidina or hetero related drugs and bioactive structures, have addressed the reactivity of these systems in multi reactions (RMCs) to explore its potential application in synthesis of hetero.