Direct determination of enantiomeric enrichment of chiral, underivatized aminophosphonic acids — useful for enantioselective bioconversion results evaluation

摘要

The possibility of applying 31P NMR spectroscopy for the determination of the enantiomeric excess of the racemic mixture of non-derivatized aminophosphonic acids with small side chains has been investigated. It is proven, that the effectiveness of the application of a chiral solvating agent strongly depends on the concentration of applied shift reagent and on the pH of the particular experiment. Effectual resolution protocols are elaborated for following phosphonic acids: 1-aminoethanephosphonic acid, 1-amino-2-methylpropanephosphonic acid, 1-aminophenylmethanephosphonic acid, 1-aminophenylmethane-phosphonic acid and 1-amino-2-phenylethanephosphonic acid. Graphical