New methods for determining the enantiomeric purity of erythro-sphingosine

Abstract

The enantiomeric purity of erythro -sphingosine samples can be determined simply, reliably, and accurately from 1 H or 19 F nuclear magnetic resonance spectra of the ␣ -methoxy-␣ -(trifluoromethyl)phenylacetate (MTPA) derivative. As little as 0.1% of the minor enantiomer could be observed in a 1-mg sample, and detection limits of 1% and 5% were estimated for samples of 100 g and 10 g. The two threo -sphingosine enantiomers and four dihydrosphingosine stereoisomers were also differentiated by this technique, which served as an effective method for assessing the purity of sphingosine and dihydrosphingosine samples. Enantiomeric and diastereomeric purities could also be determined by normal-phase high performance liquid chromatographic analysis of the MTPA derivatives. -Li, S., W. K. Wilson, and G. J. Schroepfer, Jr. New methods for determining the enantiomeric purity of erythro -sphingosine. J.

Absolute Configuration of the α,ω-Bifunctionalized Sphingolipid Leucettamol A from Leucetta microrhaphis by Deconvoluted Exciton Coupled CD

“…For example, the magnitudes of [α] D increase by 2- to 3-fold upon acetylation or benzoylation of sphingosine . Discrimination of threo from erythro isomers of sphingosine by 1 H NMR has been demonstrated with the corresponding Mosher’s acid derivatives, which are also useful for estimating optical purities of sphingosine samples containing as little as 1% of the minor enantiomer . Nevertheless, errors of assignment in configuration of even simple monomeric marine amino alcohols have been made, and sole reliance upon some methods may be risky.…”

“…20 Discrimination of threo from erythro isomers of sphingosine by 1 H NMR has been demonstrated with the corresponding Mosher's acid derivatives, which are also useful for estimating optical purities of sphingosine samples containing as little as 1% of the minor enantiomer. 21 Nevertheless, errors of assignment in configuration of even simple monomeric marine amino alcohols have been made, and sole reliance upon some methods may be risky. For example, the xestaminols 22 first reported by Gulavita and Scheuer as (2S,3R) compounds were later corrected to (2R,3S) after total synthesis and [R] D comparisons of their diacetyl derivatives.…”