Optimisation of the preparation and purification of three monocarboxylic acid derivatives of vitamin B12 and their characterisation by 13C NMR

High-performance liquid chromatographic analysis of the (cyanoaquo) stereoisomers of several putative vitamin B12 precursors

The cyanoaquo and aquocyano stereoisomers of several putative vitamin B12 precursors are reversibly formed and can be separated using analytical high-performance liquid chromatographic methods. The behavior of these stereoisomers varies somewhat depending on the type of column used and the chromatographic conditions employed. Both reversed-phase and ion-exchange columns can be used to observe the reversible formation and separation of the stereoisomers of (H2O,CN)cobyric acid, cobinamide and the cobinic acid pentaamide-1, -2 and -3 structural isomers. The greatest differences in retention times are seen when the pH of the eluting buffer is less than 4.0 and the buffer contains no KCN.