PREPARATIVE CHROMATOGRAPHIC RESOLUTION OF RACEMATES ON CHIRAL STATIONARY PHASES ON LABORATORY AND PRODUCTION SCALES BY CLOSED-LOOP RECYCLING CHROMATOGRAPHY

The time-saving, economical and practical advantages that are obtained when closed-loop recycling chromatography under overload conditions a nd peak shaving is applied for the preparative chromatographic separat ions of enantiomers on chiral stationary phases are described. The res ults of this study indicate that this kind of operation presents an al ternative means for the preparation of pure enantiomeric compounds on a large-scale starting from racemic mixtures to the stereoselective sy nthetic and enzymatic routes currently available. The straightforward scaling up of the procedure from an analytical scale to gram amounts p er day in the laboratory or even multi-kilogram separations by automat ed industrial production chromatography was demonstrated using mixture s of synthetically prepared racemates mainly of pharmaceutical interes t.