Preparative resolution of the enantiomers of tert-leucine derivatives by simulated moving bed chromatography.
The enantiomers of two different derivatives of tert-leucine were separated by continuous chromatography on chiral stationary phases applying the simulated moving bed technique. About 1 kg of racemic N-carbobenzoxy-tert-leucine was resolved on the cellulose-based phase Chiralcel OD using a mixture of heptane/ethanol and 0.1% of trifluoroacetic acid modifier as the mobile phase, while 520 g of the N-Boc-tert-leucine-benzylester was resolved on the amylose-based phase Chiralpak AD with a mixture of heptane/2-propanol as the mobile phase. In both instances the corresponding enantiomers were obtained in high yield and high optical purity.
Francotte
Eric
E
Central Technologies, Novartis Pharma AG, Basel, Switzerland. eric.francotte@pharma.novartis.com
Leutert
Thomas
T
La Vecchia
Luiggi
L
Ossola
Flavio
F
Richert
Paul
P
Schmidt
Alfred
A