| Abstract
| - The liquid-phase synthesis and the conformational analysis of a small library of fully protectedtetramers containing l-pyroglutamic acid (l-pGlu), (4S,5R)-4-methyl-5-carboxybenzyloxazolidin-2-one (l-Oxd), or (4R,5S)-4-methyl-5-carboxybenzyloxazolidin-2-one (d-Oxd) as residue i + 1 arereported to test the tendency of these oligomers to assume a β-hairpin conformation. The mostpromising molecule is Boc-l-Val-d-Oxd-Gly-l-Ala-OBn, which assumes a preferential β-turnconformation in CDCl3, as shown by IR and 1H NMR analysis. These findings have been confirmedby DFT calculations, which provide an interpretation for the available experimental data and agreewith the reported observations.
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