It is proposed the study of the conformational analysis of some methyl esters of amino acids non-acetylated L-serine,L- threonine, and L-tryptophan) and N-acetylated (glycine,L-alanine, L-serine,L-threonine and L-tryptophan) by NMR spectroscopy, vibrational spectroscopy and theoretical calculations of electronic structure. The theoretical calculations will be carried out at the B3LYP level and with the Density Functional Theory ("DFT") using different basis sets, available on GAUSSIAN-09 package , to determine the energy and geometry of the most stable conformers in the vapor phase. The infrared spectra on the carbonyl group stretching region and in several solvents, will be used to determine the number and populations of rotamers present in solution. Also, It will be carried out NMR detailed study of 1H and 13C to verify if the JHH couplings, geminal and vicinal, between the hydrogen atoms of the CH and CH2 groups show variation with the change of the population of conformers. The analysis of all these data will enable assessment of the factors responsible for the conformational stability of the amino acids derivatives.
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