Studies on the Synthesis and Transformations of a few Bicyclic and Dispiro Compounds

In this thesis, we report our endeavours in the synthesis of a few polycyclic compounds. We were interested in the synthesis of a few bicyclic compounds designed to undergo interesting photochemical transformations including tripletmediated di-π-methane rearrangement and/or competing singlet-mediated electrocyclic reactions. Our target molecules have "inbuilt" structural features which will potentially alter the photochemistry of the substrate under consideration.The present investigation was undertaken to test our hypothesis on selective intramolecular quenching of singlet or triplet excited states of molecules.We adopted Dies-Alder reaction for the synthesis of several of the bicyclic compounds we were interested in. Some of the precursor dienes synthesised by us are capable of undergoing intramolecular cycloaddition reactions as well. So, it was important to delineate the conditions and structural features that will enable a particular molecule to undergo intermolecular and intramolecular Dies-Alder reaction when treated with a suitable dienophile.Though, the main focus of this thesis is on the synthesis of bicyclic and tricyclic systems capable of undergoing di-π-methane rearrangement, in the last chapter of this thesis, we describe our findings on the synthesis of a few dispirocompounds. These systems were encountered as unexpected products in the attempted synthesis of novel dibenzoylalkene-type systems. Consequently, a brief survey on the synthesis and transformations of dibenzoylalkenes is also included as an integral part of this thesis.

Lewis acidity of rare earth exchanged zeolites

The Lewis acidity of yttrium and dysprosium exchanged zeolite Y and ZSM-5 has been determined by titration method using Hammett indicators. The acidity of the Y form increases with increase in concentration of the rare earth cation in the Y zeolite. It is independent of the amount of the rare earth ion for ZSM-5. The data have been correlated with the activity of these zeolites for the esterification of butanol using acetic acid.

Richard Rorty i una aproximació pragmatista al liberalisme polític de John Rawls

Aquest article es proposa explorar la possibilitat d'apropar a la concepció del liberalisme polític metafilosòfic de John Rawls des del punt de vista pragmatista de Richard Rorty. La proposta està motivada per les similituds que es poden observar entre elles respecte de la finalitat i la sortida d'una concepció política. El resultat final de l'article és ambigua: d'una banda, no sembla tan descabellat afirmar que la teoria de Rawls es pot llegir sense més dificultats des d'una perspectiva pragmàtica, d'altra banda, hi ha alguns aspectes importants en els quals un liberalisme polític de Rawls segueix sent incompatible amb una concepció política de Rorty

La influencia del marketing político en el electorado estadounidense. Un análisis a las elecciones presidenciales del 2004 : George Walker Bush Vs John Forbes Kerry

Este estudio de caso, pretende analizar el uso de las herramientas de marketing político, desde las elecciones primarias hasta la elección presidencial en el 2004 en Estados Unidos, en la que George W. Bush del Partido Republicano busca la reelección frente a su rival John F. Kerry del Partido Demócrata.

Aproximaci?? a les estrat??gies de lluita contra el plagi acad??mic desenvolupades per les universitats brit??niques d'East Anglia (Norwich) i John Moore's University (Liverpool)

Resumen tomado del autor