Effect of achiral support on the resolution of tetramisole by supercritical fluid extraction

Abstract

The enantiomers of tetramisole were produced by partial diastereomeric salt formation with O, O′-dibenzoyl-(2 R,3 R)-tartaric acid monohydrate and subsequent supercritical fluid extraction (SFE) of the unreacted enantiomers in the presence of an achiral support. The effect of the activated carbon and Perfil 100™ on the efficiency of chiral separation were studied. The kinetics of the process was found to be an important factor affecting enantioselectivity. When the parameters were properly set, much better resolution efficiency ( F) and higher enantiomeric purity were achieved than in the equilibrium. The presence of Perfil 100™ and activated carbon caused an increase as high as 53 and 84% in F, respectively, compared to that achieved without using any supporting material. Thus during the development of a resolution procedure, beside the proper resolution agent, optimised molar ratio and other parameters, the selection of achiral addict(s) may be also an important point.