The determination of enantiomeric excess of valine by ODESSA solid-state NMR experiment.

The enantiomeric excess (ee) can be determined by many methods; one among them is nuclear magnetic resonance in solid-state (SS NMR). In this study we used the SS NMR ODESSA experiment for determination of the ee of valine.

Synthesis of phosphonic analogues of carnitine and gamma-amino-beta-hydroxybutyric acid.

The involvement of carnitine and gamma-amino-beta-hydroxybutyric acid in the biology of mammalian cells, the physiology of the human body, and some important aspects of medicinal treatment has induced many research groups to develop their pharmacologically potent analogues. Among them are the very important phosphonic analogues: phosphocarnitine and gamma-amino-beta-hydroxypropylphosphonic acid. This mini-review describes the various methodologies used for the synthesis of these compounds.

A new method for distinguishing between enantiomers and racemates and assignment of enantiomeric purity by means of solid-state NMR. Examples from oxazaphosphorinanes.

It is shown that enantiomers and racemates that have identical isotropic NMR chemical shift as well as anisotropic chemical-shift tensor parameters can be easily distinguished by means of the ODESSA (One Dimensional Exchange Spectroscopy by Sideband Alternation) technique. The method is based on the fact that the molecular symmetries and packing of enantiomers and racemates are usually significantly different. The power of the proposed approach is demonstrated by employing as model compounds P-chiral oxazaphosphorine derivatives, which are widely used in clinical oncology. Correlation of the amplitude of the ODESSA decay (AOD) with enantiomeric excess is also presented.