✦ LIBER ✦
4-Oxo-α-amino acids: a caution when determining absolute configurations by 1H NMR using MPA derivatization and Ba2+ complexation
✍ Scribed by Marion A Earle; Philip G Hultin
- Publisher
- Elsevier Science
- Year
- 2000
- Tongue
- French
- Weight
- 67 KB
- Volume
- 41
- Category
- Article
- ISSN
- 0040-4039
No coin nor oath required. For personal study only.
✦ Synopsis
A method for determining the absolute configurations of chiral amines based on changes in the 1 H NMR spectra of their (R)-MPA amides on addition of Ba 2+ was applied to both enantiomers of a series of g-oxo-a-amino acid methyl esters. The chemical shift changes Dl Ba observed for these compounds were inconsistent with the recently proposed model relating them to the absolute configuration of the amino group. These results suggest that care must be taken when using this technique.