Full text
| |
| Author(s): |
Claudimar Junker Duarte
Total Authors: 1
|
| Document type: | Doctoral Thesis |
| Press: | Campinas, SP. |
| Institution: | Universidade Estadual de Campinas (UNICAMP). Instituto de Química |
| Defense date: | 2015-05-03 |
| Examining board members: |
Roberto Rittner Neto;
Teodorico de Castro Ramalho;
Jarbas Magalhães Resende;
Rogério Custodio;
Sebastião Ferreira Fonseca
|
| Advisor: | Roberto Rittner Neto |
| Abstract | |
In this work, the conformational equilibrium of some methyl esters of amino acids non-acetylated (L-Serine, L-Threonine and L-Tryptophan) e N-acetylated (Glycine, L-Alanine, L-Serine, L-Threonine and L-Tryptophan) was evaluated by theoretical calculations and Infrared and 1H NMR spectroscopies. The applied methodology was based on the 1H NMR data (through the behavior of the 3JHH spin spin coupling constant) and analytical deconvolution of infrared spectra on the C=O stretching region. The obtained results were used to determine the populational variation of each amino acid derivative in several solvents. In addition, theoretical calculations in isolated phase and taking into account the solvent effect were carried out in order to obtain the values of 3JHH and C=O stretching vibration. The calculated results are in good agreement with the experimental data and provide insights into the conformational behavior induced by each solvent. Additionally, Natural Bond Orbital analysis and the Quantum Theory Atoms In Molecules were employed to investigate the importance of classic and non-classic effects over the conformational isomerism of aforementioned systems. In disagreement of several publications in the literature, it was found that steric effect and hyperconjugation are interactions important to conformational preferences of all amino acid derivatives evaluated whereas H-bonding plays a secondary role (AU) | |
| FAPESP's process: | 11/11098-6 - Conformational analysis of some methyl esters of amino acids and their N-acetyl-derivatives. |
| Grantee: | Claudimar Junker Duarte |
| Support Opportunities: | Scholarships in Brazil - Doctorate |