Examination of the Potential for Adaptive Chirality of the Nitrogen Chiral Center in Aza-Aspartame
| Autor: | Samir H. Bouayad-Gervais, William D. Lubell |
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| Jazyk: | angličtina |
| Rok vydání: | 2013 |
| Předmět: | |
| Zdroj: | Molecules, Vol 18, Iss 12, Pp 14739-14746 (2013) |
| Druh dokumentu: | article |
| ISSN: | 1420-3049 34468498 |
| DOI: | 10.3390/molecules181214739 |
| Popis: | The potential for dynamic chirality of an azapeptide nitrogen was examined by substitution of nitrogen for the α-carbon of the aspartate residue in the sweetener S,S-aspartame. Considering that S,S- and R,S-aspartame possess sweet and bitter tastes, respectively, a bitter-sweet taste of aza-aspartame 9 could be indicative of a low isomerization barrier for nitrogen chirality inter-conversion. Aza-aspartame 9 was synthesized by a combination of hydrazine and peptide chemistry. Crystallization of 9 indicated a R,S-configuration in the solid state; however, the aza-residue chiral center was considerably flattened relative to its natural amino acid counterpart. On tasting, the authors considered aza-aspartame 9 to be slightly bitter or tasteless. The lack of bitter sweet taste of aza-aspartame 9 may be due to flattening from sp2 hybridization in the urea as well as a high barrier for sp3 nitrogen inter-conversion, both of which may interfere with recognition by taste receptors. |
| Databáze: | Directory of Open Access Journals |
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