MAGNETIC RESONANCE SPECTROSCOPY

Author: SANTOS GONZALEZ JOSE IGNACIO.
Year: 2004.
University: PAÍS VASCO [www.ehu.es].
Place of defense: FACULTAD DE CIENCIAS QUIMICAS.
Place of preparation: FACULTAD DE CIENCIAS QUIMICAS.

Summary: This paper is an extensive study of the cider, and especially apple cider on the Basque Country. You can destacr therein the following aspects:-have proposed two new methods for determining acid clorogénico and epicatequina, which applied for the first time the technique of internal standard in proton nuclear magnetic resonance. - There has been a thorough characterization of apple cider, using both conventional methods of analysis as nuclear magnetic resonance spectra. The huge experimental work carried out has generated a large amount of data and parameters that have allowed then to effectively implement various statistical methods. This has enabled properly classify and differentiate varieties of apples used. - Based on a single batch of apples have been selected obtained two musts, with a traditional press and another with pneumatics. Subsequently, it has been followed by the fermentation of wine each in two warehouses, one of wood and the other of steel. This study has permitted to see the pneumatic press and storage of steel, in general, give less trouble obtaining wine and allow better control of fermentation. - Has been identified for the first time in the Basque Country of cider called chopped acroleico, which so far was unidentified. - There have been 5 different mosmos from different varieties of apple mixed in different proportions and has been followed by the fermentation of them all. This study has permitted to see the influence of the composition of the initial development wine fermentation, and thus ultimately in the cider obtained. It has been found that the malolactic fermentation can occur before the alcoholic and that this produces greater stability of the microbial cider obtained.

Author: Palomino SchÒ¤tzlein Martina.
Year: 2005.
University: AUTÓNOMA DE BARCELONA [www.uab.es].
Place of defense: Facultat de ciencias, Dept.de química.
Place of preparation: Universidad Autónoma de Barcelona.

Summary: Introduction To study natural processes, able to influence them or imitate them, important challenge of science today, it is essential to take into account the interactions enantioespecíficas. Accordingly, it has developed a keen interest in the synthesis enantioselectiva, methods of resolution of enantiomers, the analysis of enantiomeric purity and the determination of the absolute configuration. In this area, there is also this dissertation. Specifically, it raised the following objectives: Objectives To perform the synthesis of various molecular compounds type gripper and macrocíclicos with chiral cavities. Study your capacitad of enantiodiferenciación as agents solvatación chirality and the geometry of the compounds obtained. Studying the enantioselectividad of the Diels - Alder reaction of acid fumárico and various dienos using the agent solvatación 1-(9-antril) -2.2, 2-trifluoroetanol as chiral auxiliary. Synthesizing various compounds deuterados through exchange of hidrógenos labile water deuterada and explore enantiodiferenciación obtained in a liquid crystal nuclear magnetic resonance (NMR). Results Regarding the first objective, have synthesized two new receivers chiral molecular clamp type, and has performed his study structural and conformacional by NMR and molecular mechanics. In the case of compound 1 has been tested their ability enantiodiferenciadora with various solutes chiral, performing very satisfacotorios. We have studied some of the complex diastereoméricos trained by deducting the capacitat of enantiodiscriminación comes from geometric factors rather than differences in stability. Changes in the spectrum of proton NMR of 1 suggest that conformational changes in the complexion leads in the solvatación agent, it seems that this compound has some ability to adapt to the guest molecule. As for the second objective proposed, it has synthesized the dienófilo chiral 3, and has studied enantioselectividad gained in the Diels - Alder reaction with different dienos. There has been studying structural dienófilo and the adducts obtained, and it has been deduced that the chiral induction in the presence of EtAlCl2 as a catalyst is due to the formation of a complex between the catalyst and a preferential formation of dienófilo, which favors the attack on one side of the double bond. It has studied the effect of various factors such as temperature, solvent, the catalyst, etc.. On excess enantiomérico obtained, and the conditions have been optimized reaction to the overall process involves the minimum number of steps. Finally, as the third objective of the thesis, has developed a new method to measure excess enantiomérico various alcohols using deuterium NMR in chiral liquid crystals. Alcohols have deuterado through simple exchange in water deuterada, and spectra have been performed on stage anisótropa chiral low temperature. It has been shown that the exchange also may be made at the same NMR tube, but still need to optimize the conditions of this process.