Chiral Separations Using Marfey’s Reagent
The separation of enantiomers has always been regarded as one of the most challenging problems for chemists/scientists since the times of Louis Pasteur, van’t Hoff and Le Bell when the idea of stereochemistry and stereoselectivity started coming in. There have been two basic approaches for the chromatographic resolution of enantiomers: a direct and an indirect method. The separation of diastereomeric pair via the indirect technique is sometimes simpler to perform and often has better resolution than with a direct method, because chromatographic conditions are much easily optimized. Marfey’s Reagent (MR) has such attributes. The MR can safely be considered as a chiral variant of the Sanger’s reagent. The general approach to synthesize the reagent and derivatization is that reported by P. Marfey. Amino acids such as tyrosine and histidine or containing two amino groups such as ornithine and lysine can form both mono- and di-substituted Marfey’s derivatives; thus, doubling the number of peaks in a chromatogram for these amino acids.