THE MECHANISMS OF ORGANIC REACTIONS

Author: CABELLO SÁNCHEZ ESTER NOEMÍ.
Year: 2001.
University: EXTREMADURA.
Place of defense: FACULTAD.
Place of preparation: FACULTAD DE CIENCIAS.

Summary: This tesi doctoral focuses on the study of the reactivity of 6.6 dimetoxiciclomexadienonas with vinyl compounds furanicos and these changes have been studied in classic conditions and low ultrasonidos.Se has determined the course regioquímico and estereoquímico through X-ray diffraction in the majority of the cases. The study includes ultrasound optimization of various parameters (temperature, power, viscosity, pularidad), which has led wing proposition of a reaction mechanism different from that commonly accepted. The effect sonoquímico noticed is justified by the effects of mechanical cavitation.

Author: GARCÍA VÁZQUEZ BÁRBARA.
Year: 2003.
University: LA RIOJA.
Place of defense: ENSEÑANZAS CIENTIFICAS Y TECNICAS.
Place of preparation: CENTRO CIENTÍFICO . TECNOLÓGICO.

Summary: The main theme of this Doctoral Thesis is studying the funcionalización compounds insarurados with the system formed by molecular iodine and salts of copper (II) in the presence of nucleotide hydrogenated and nitrogen. Throughout this Doctoral Thesis has developed a method of hidroyodación systems in unsaturated conditions anhidras by adding regioselectiva of iodide higrógeno generated in situ from molecular iodine and trietilsilano in the presence of salts of copper (II). Has been described dimerizadción ionic of a-metilestireno catalysed by iodide higrógeno generated in situ from molecular iodine and trietilsilano in presincia salts combre (II) in aqueous conditions, leading to the formation of various structures dímeras depending on the solvent used, because in acetonitrile leads to the formation of dimers of a blended linear insarurados, but only gets a dichloromethane dímero cyclic structure. The dimerización ionic of p-metil and p-metoxiestireno is carried out using equivalent amounts of iodide hydrogen generated in situ conditions using aqueous acetonitrile as desolvente. The reaction leads to fomación derivative dímero linear insarurado for not being detected the formation of cyclic dímero in dichloromethane. It has developed a method of synthesizing B-nitroestirenos funcionalizados from the corresponding derivatives of styrene through the addition radicalaria the kind NO2I generated in the middle of racción from nitrico and molecular iodine in the presence of sodium salts copper (II), giving preferentially stereoisomers configuration E. Within the study photochemical of drivados of oximes has described the formation of a system policíclico nitrogenous, fenantridina from acetate oxime of 2-fenilbenzaldehído through the processes ciclación intramolecular of nitrogen radicals generated in photochemical breakdown of the link of NO the oxime. This result has helped launch a new line of research within which are being carried out studies on the reaction mechanism and to expand the number of compounds to study.

Author: PAZO LLORENTE ROMÁN.
Year: 2003.
University: VIGO.
Place of defense: FACULTAD DE QUÍMICA.
Place of preparation: FACULTAD DE CIENCIAS.

Summary: This Doctoral thesis focuses on the study of the mechanisms of degradation of various ions arendiazonio.Se has studied how they affect their reactivity to certain factors, including the solvent used, the presence of certain electrolytes, temperature, the presence of different substituents or the position in which they find these substituents. He also has addressed the study of the influence of the presence of aggregates micerales of dodecil sodium sulfate, SDS, both in the reaction of desdiazonización as in the relacción of copulation of ions arendiazonio with different actors copulantes.La reaction as a method of copulation stop desdiazonización at the time desired by consumption of fast ion arendizonio, which allows siguimiento kinetic of the formation of different products reacción.Por therefore, the need to use this tool, reactions copulation, in any studies reactivity ion arendiazonio in the presence of aggregates micelares ago essential conducting a study on the reactions of copulation media micerales. Finally, it includes a study on the influence of short-chain alcohols, methanol and ethanol, breaking micelar aggregates formed by the monomers bromide hexadeciltrimetilamonio, CTAB.Este study has been conducted using, as a probe chemistry, ions arendiazonio, in practice and represents an example of the potential applications and utilities that you can give ions arendiazonio.

Author: SERRANO NAVARRO PEDRO.
Year: 2004.
University: BARCELONA.
Place of defense: FACULTAD DE QUÍMICA.
Place of preparation: FACULTAD DE QUÍMICA (UB).

Summary: The number of patients with diseases associated with fungus has grown alarmente in recent years. This paper pays particular attention to the preparation of molecules that can cope with the systemic fungal infections because they cause a high degree of mortality and the incidence has been increasing in a meaningful way. Based on the limited effectiveness of the drugs available at present this work deals with the synthesis of potential antifungal agents based on the inhibition of metabolism esfingolípidos in fungi, in particular enzyme inositol fosfoceramida synthase. To this end, they have prepared as seeded, inositol analogues for further derivatization through combinatorial techniques in solution. An alternative approach has led us to the synthesis of analogues Kafrefungina, one of the few known inhibitors has compared this enzyme. In addition, there have been mechanistic studies of the opening of epoxides in the presence of LiClO4 and Yb (OTf) 3 through NMR techniques and ab initio calculations. Finally, the preliminary assessment of the antifungal activity of the compounds synthesized has allowed information about its applicability in this area.

Author: LUQUE ALVAREZ DE SOTOMAYOR RAFAEL.
Year: 2004.
University: CÓRDOBA.
Place of defense: FACULTAD DE CIENCIAS.
Place of preparation: FACULTAD DE CIENCIAS.

Summary: We have synthesized aluminolicatos mesoporosos type MCM-41 and MCM-48 and galosilicatos type MCM-41 as well as materials Pt supported Pt/Al-MCM-41 and Pt/Al-MCM-48 and complex Pd and Ni supported on materials orgánicos-inorgánicos, with the influence of aluminum content of the influence the content of aluminum and / or gallium on the structure mesoporosa of alumnosilicatos, and the influence of precursors and the materials used in support of Pt, Pd and Ni. The materials Al-MCM-41 and Al-MCM-48 subjected to the post with NH4F present some textural properties and / or structural improved in relation to materials obtained by the use of synthesis directa.La Spectrometry MAS NMR of 27Al has allowed know coordination, tetrahedral (materials obtained by direct synthesis) or octaédrica (materials treated with ammonium fluoride), aluminum in different alumnossilicatos while the 19F has served as technical edentificativa of species of fluoride present in lso fluorinated materials . We have used the techniques of chromatography and Desorción Thermal Pulse Programmed (TPD) for the determination of the acidic properties of alumnosilicatos. The aluminosilicates have a high surface acidity, comparable to the materials zeolíticos, while the galosilicatos MCM-41 has a very low acidity, which hinders the application of genetic themselves to the reactions catalyzed by acid centers. The Al-M41S has been described as active in the reaction conversion isopropibenceno, conversion ciclohexeno, alkylation of aniline and the reaction of alkylation of toluene with dimethyl carbonate is the study of the revival of the catalysts used in most trials. Finally, we have conducted reactions hidroconversión of n-alkanes (n-hexane, n-heptane and n-octano) with materials Pt supported on Al-MCM-41 and Al-MCM-48 and CC coupling reactions as of Sonogashira-Hagihara and homoacoplamiento oxidative of alquinos terminals complexes Pd and Ni supported.

Author: HIDALGO HERRADOR JOSE MIGUEL.
Year: 2004.
University: CÓRDOBA.
Place of defense: FACULTAD DE CIENCIAS.
Place of preparation: FACULTAD DE CIENCIAS.

Summary: Work performed at the Department of Organic Chemistry at the University of Cordoba is studying the characterization químico-superficial and catalytic activity of catalytic reforming Pt-Re/Al203. It examines the behavior of fiferentes catalysts, as a catalyst for reform processes in both laboratory and industrial interest between those who emphasize the conversion of cyclohexane, metilciclohexano, metilciclopentano and lasa conversions n-parafinas C6-C8. The work is as follows: History and nomenclature assigned to the different catalysts Pt/Re/Al203, characterization of the catalysts using different analytical techniques, characterization of the surface acidity of the catalysts of Reformed and finally the study of the influence of coke the catalytic activity and product selectivity of the catalysts Pt-Re/Al203 to model reactions. As a result of the work carried out, we can draw the following conclusions: The catalysts Pt-Re/Al203 have been standardized through a heat pretreatment at 673 K. Elemental analysis shows an increase in the amount of coke and surface area decreased with the increase in the number of days for catalytic reaction from the same reactor. Using Analysis ATG-ATD and mass spectrometry experiments temperature programmed, as well as the spectra have allowed DRIFT optimize the procedure standardization delos catalysts and know the nature of the different species adsorbed, physically or chemically and / or placed on the catalysts are disabled. With the techniques of chromatography and Desorción Thermal Pulse Programmed for determining the acidic properties of catalysts Pt-Re/Al203, we can conclude that you increase in the content of coke, the catalysts involves a decrease of the total acidity. The tests show that all DTP catalysts show the relative concentration of acids prodominantemente nature centers middle and strong. The diffuse reflection infrared spectroscopy shows like most centers are of Lewis acids. Using catalysed conversion of 2-metil-3-butín-2-ol, has revealed the existence of acidic and basic. Reactions conversion model showed that the molar conversion decreases with the degree of deactivation and the coke deposits to lower response times, preferably on the acid function and then to use times greater role on the metal.

Author: PÉREZ FERNÁNDEZ MARTA.
Year: 2005.
University: LA RIOJA.
Place of defense: UNIVERSIDAD DE LA RIOJA.
Place of preparation: UNIVERSIDAD DE LA RIOJA.

Summary: The present report describes the synthesis of different structures from ciclobutano by cicloadición [2 +2]. It starts from 2-acilaminoacrilatos methyl different olefins dadoras using Lewis acids such as a (2,6-di-terc-butil-4-bromofenóxido) metilaluminio (MABr) and metilaluminoxano (MAO). The olefins dadoras have been used vinyl ethers and vinyl tioéteres both chiral as racémicos with different substitution patterns and cyclical. The mechanism of the reaction in the absence of catalyst between 2-acilaminoacrilatos methyl 1,1-dietoxieteno has been studied from a theoretical and experimental. Some of the derivatives ciclobutano obtained have been used for the synthesis of amino acid derivatives, in particular, the two isomers of phenyl cisteínas with structure ciclobutano, 2-metilenciclobutano-a-aminoácido and two stereoisomers of 2.4 - metanovalinas. In addition, there have been synthesized 2-amino-1 ,3-dioles and derivatives 5-hidroxiprolina. Finally, through a combination of experimental methods, magnetic resonance imaging and X-ray diffraction, and theoretical methods, the density functional theory (DFT) and molecular dynamics with restrictions (DM-tar) has been studied shaping some of these derivatives ciclobutano in solid state and in solution.

Author: MUÑOZ CALLE JESÚS MANUEL.
Year: 2005.
University: SEVILLA.
Place of defense: FACULTAD DE BIOLOGÍA.
Place of preparation: UNIVERSIDAD DE SEVILLA.

Summary: Understanding the mechanism of chemical reactions is one of the most powerful tools available to the Chemical. Their usefulness is applicable to the interpretation and prediction of all types of properties, including the reactivity of molecules, as well as for designing new compounds or materials with any particular property. Historically, however, this task has proven to be an extraordinary challenge. Today, Quantum chemistry therefore provides not only the ability to determine the structure of the balance of molecules that correspond to the minimum of energy, but most importantly, it allows some simulated chemical processing step at a time, recreating the break and training links, reproducing the association and the separation of atoms in the process and determine the energy barrier to achieving a state of transition. The possibility of using the theoretical methods to investigate and explain the ways of reaction sparked our interest at the outset of this investigation. Therefore, the objective of this Doctoral Thesis we intended use of the calculations computations to complement the laboratory experiments carried out in our research group, combining theory and experimentation in the quest for a better understanding of the different processes study for possible optimization. Specifically calculations have been performed by "ab inito" on the structure and reactivity of N, N-dialquilhidrazonas of aldehydes with the following compounds: compounds carbonílicos, nitroalquenos to, beta-insaturados compounds orgnaometálicos and cetenas with the aim of drawing up proposals mecanísticas on the processes that are involved. This study has also been entered in conducting considerations estereoquímicas aimed at justiciar the estereoselectividad observed in the process of experimental interest. The results are quite satisfactory, having obtained a high degree of concordance of the results theoretically model with the experimental results. The calculation ab inito "have been made with the methods B3LUP and MP2 and the basis 6-31G *, implemented in the package GAUSSIAn in their versions 94, 98 and 2003.

Author: NIETO FAZA OLALLA.
Year: 2005.
University: VIGO.
Place of defense: FACULTAD DE QUÍMICA.
Place of preparation: FACULTAD DE QUÍMICA.

Author: GULÍAS COSTA MOISÉS.
Year: 2005.
University: SANTIAGO DE COMPOSTELA.
Place of defense: FACULTAD DE QUÍMICA.
Place of preparation: FACULTAD DE QUÍMICA.

Summary: In this dissertation is a study of the oxidation catolizadas by transition metal systems alquinildicarbonílicos leading to the formation of oxabiciclos on a highly selective basis. It also makes a detailed study of cicloadiciones catalysed Pd or systems alquilidenciclopropánicos with alquinos, alquenos, alenos and dienos leading to processes [3 +2] and [3 +4] with high yields and diastereoselectividades.

Author: MONTAOS VARELA MARCOS ANTONIO.
Year: 2005.
University: SANTIAGO DE COMPOSTELA.
Place of defense: FACULTAD DE QUÍMICA.
Place of preparation: FACULTAD DE QUÍMICA.

Summary: Based on amino acids as chiral compounds of natural origin have been followed two lines of inquiry: 1 Part: We have developed a new methodology for the synthesis of aziridinas and azetidinas so enantioméricamente pure. It has also been studied their reactivity to various nucleotide front, the results can be applied to the synthesis of compounds with potential activity armacológica. 2 Part: There were synthesized various ligands ciclopentadienílicos, which are precursors metalocenos, from fulvenos taking alpha center estereogénico with an amino group. We have made preliminary studies of their behavior with respect to nucleotide and comparing with the carbonyl group, both in terms of its reactivity as estereoselectividad in the reactions.

Author: ROSOL MALGORZATA.
Year: 2006.
University: BARCELONA.
Place of defense: FACULTAT DE QUÍMICA.
Place of preparation: FACULTAD DE QUÍMICA - UNIVERSITAT DE BARCELONA.

Summary: 1 - The methodology designed for the synthesis of complexes dicobalto carbonyl replaced by Phosphine of aldehydes propargílicos in enantioméricamente pure could not be implemented experimentally. 2 - The catalytic behavior overall octacarbonilo dicobalto at the opening of cyclic ethers such as tetrahydrofuran by acid chlorides, which leads to the formation of ésteres-4-clorbutílicos, it has been revealed. 3-It has developed a synthetic route for accessing beta-ferrocenil beta-amino alcohols with different types of substitution in the ferroceno. 4, has been developed, a general methodology that enables easily obtain 4-ferrocenil, 1,3-oxazolinas monkey and disubstituidas (1.1 "and 1.2-). 5-It has established a new type of ciclopaladación interanular of ferroceno. The reaction seems to be general 4-ferrocenil-1 ,3-oxazolinas with varying degrees of substitution in the ferroceno, as long as the replacement to C2 of the oxazolina lacks hidrógenos in alpha. The reaction of 4-ferrocenil-1 ,3-oxazolinas with palladium acetate in benzene leads to the formation of complex symmetry C2 with two fragments ferroceno ciclopaladados at position 1 ', and connected by a central palladium acetate and four bridges. When ciclopaladación is conducted with tetracloropaladato disodium, you get a complex similar but with two bridges chloride. 6-studies have been conducted reactivity of the new paladaciclos interanulares. 7 - The 4-ferrocenil-1 ,3-oxazolinas ciclopaladadas interanualmente behave as active promoters of the olefinación Heck, allowing the reaction to take place at lower temperatures than with pre-cataliadores type CN-paladaciclo derivatives ferroceno formerly known. For the first time, it has been possible to isolate and characterize the uniquely adduct ligando-olefina, and has obtained additional support for a catalytic cycle Pd (0) / Pd (II). 8 - The new ferrocenos ciclopaladados interanualmente have proved to be good catalysts for the transposition of aza-Claisen enantioselectiva. 9, - have been identified and extraordinary new catalysts for the transposition of aza-Claisen of tricloroacetimidatos (E) - and (Z) -alílicos.

Author: ROMERO ZAMBRANO RAFAEL.
Year: 2006.
University: CÓRDOBA.
Place of defense: FACULTAD DE CIENCIAS.
Place of preparation: FACULTAD DE CIENCIAS.

Summary: The main aim of the thesis, has been researching new zirconium oxide catalysts that are active and more selective and / or economic, as described so far, in the process of reducing compounds carbonílicos alpha beta-insaturados. In the first part dela thesis, in order to enhance the properties acidic and basic catalytic ZRO2, joined additives such solid. This was introduced by the side of boron oxide to increase the acidity of the systems, and on the other hand, metals alaclinotérreos to increase its basicity. Thus, all systems were evaluated compared to the reaction of Meerwein-Ponndfor-Verley, obtaining results catalytic enrome interest. It got a good activity, and a great product selectivity was most interesting from the point of view industrial and economic (unsaturated alcohol), close to 100%. In addition, with the introduction of these additives, was achieved match or improve performance, as opposed to pure zirconium oxides. In a second part, was used ZrO2 as a support, catalysts metálicos-soportados, Pd and Pd / Fe and found to be catalytic behavior, as opposed to the hydrogenation compounds carbonílicos alpha beta-insaturados, with a high selectivity towards the saturated aldehyde. It identified the reaction conditions suitable for maximum selectivity unsaturated alcohol, through the use of various additives added to the reaction medium, thinner, etc., reaching a maximum -12% unsaturated toward alcohol. Therefore, the investigation yields of solid catalysts perfectly characterized (composition and surface characterization textural, structural, and the acid-base metal properties), which could also be applied in future to reduce other compounds carbonílicos alpha, beta-insaturados, to obtain products of great interest in the Fine Chemistry.

Author: LUQUE MUÑO JESUS.
Year: 2006.
University: CÓRDOBA.
Place of defense: FACULTAD DE CIENCIAS.
Place of preparation: FACULTAD DE CIENCIAS.

Summary: The main aim of the thesis has been the investigation of new catalysts supported vanadium that are active and more selective and / or economic, as described so far, in partial oxidation processes hydrocarbons. Among the catalysts possessing vanadium in its formulation highlights systems supported and vanadium including those used as a support titanium dioxide (TiO2). In order to improve the mechanical properties and thermal properties as well as the surface area of TiO2 we intended to use a Sepiolite natural-silicato magnesium-hydrated which is a cheap material and good surface properties as a source material for the preparation of media mixed TiO2- Sepiolite. Until now, there is no bibliographic data on the use of systems supported on these vanadium mixed media. The behavior of catalytic systems vanadium has been evaluated in the selective oxidation, gas phase, metilbenceno and derivatives (p-cloro-metilbenceno and p-metoxi-metilbenceno). The value of the products targeted (Benzaldehído and / or acid benzóicos) both from the standpoint of Fine Chemical Industrial as well as the high environmental impact reflecting the industrial processes used today in its collection, arouses interest in finding a suitable catalyst. In this regard, the results obtained with catalytic systems surveyed in this Doctoral Thesis are comparable and even better to those described in the literature. Therefore, the investigation yields of solid catalysts perfectly characterized (composition and surface caracterizador textural, structural and acid-base and redox), which could also be applied in future in the oxidation of other aromatic and non-aromatic hydrocarbons. On the other hand, research also on systems vanadium carried out in two stays (22 weeks) at the University of Cardiff (UK), which allows the presentation of the thesis in the European mode, has resulted in the development of new the method of preparation of precursors catalysts vanadium and phosphorus that allows control structure and morphology using co-disolvente organic.

Author: GIRONÈS MOLERA JORDI.
Year: 2006.
University: GIRONA.
Place of defense: UNIVERSITAT DE GIRONA.
Place of preparation: UNIVERSITAT DE GIRONA.

Summary: In the first part of this paper presents the research conducted on the reaction of hidroesterificación of olefins. It discusses the factors that affect the reactivity and quimioselectividad the reactions of hidroesterificación and deuterioesterificación in catalytic systems based on palladium complexes with phosphine ligands assistants type. We present a detailed study of the catalytic mechanism through which these reactions take place. The determination of the reaction mechanism has been applied to obtain a version enantioselectiva of the same. In a second part of the work has been analyzed various systems for surface modification of natural fibers and its effect on compatibilitat fiber-matrix composites matrix poliolefinica. We have characterized the surface properties of chemically modified pine fibers. These modified fibers have been used in the preparation of composite materials, the mechanical properties, thermal and termomecánicas of which have been characterized and analyzed.

Author: MORAN RAMALLAL ANTONIO.
Year: 2006.
University: OVIEDO.
Place of defense: FACULTAD DE QUIMICA.
Place of preparation: FACULTAD DE QUIMICA.

Summary: This report describes the theoretical study of the mechanism of a series of reactions, highly selective, with a common way of addition nucleófila systems unsaturated, and the study of a new mechanism of the reaction of condensation aldólica catalysed by proline. The calculations have been performed described with the method of functioning of the electron density (using functional Becke3LYP) and the method Möller-Plesset. In Chapter 1 describes the theoretical study of the mechanism of the desaromatización anion derivatives fosfinamidas and amides. This process implies a step metalación followed by a ciclación intramolecular on the ortho position of the aromatic ring. The effect of solvent on the reactivity and nature of the passage of addition are some of the topics covered in this chapter. Chapter 2 focuses on the computational study of the addition aza-Michael of amines to acrylamide, in the presence of a nitrogenous base as trimethylamine. The mechanism consists of two steps, adding nucleófila the amine to the position? The acrylamide and the transfer of hydrogen from nitrogen nucleófilo-carbon position? Regarding the carbonyl group of Michael acceptor. It examines in detail the effect exerted by a group trifluorometilo in position? The acrylamide and origin of the diastéreoselectividad in step transfer of hydrogen. In Chapter 3 presents the results concerning the theoretical study of the mechanism of the reaction of condensation aldólica intramolecular of tricetona of Hajos-Parrish, catalysed by proline. This chapter proposes an alternative mechanism to that described in the literature. This mechanism is based on the catalysis of the reaction of condensation aldólica by proline without the formation of any covalent intermediate between the reagent and catalyst. It examines the potential energy surface of this mechanism and compared to the potential energy surface of the mechanism enamínico.