( l)- or ( d)-Valine tert-butylamide grafted on permethylated β-cyclodextrin derivatives as new mixed binary chiral selectors

This work deals with the synthesis of two mixed binary chiral selectors prepared by grafting ( l)- or ( d)-valine tert-butylamide on permethylated cyclodextrin macrocycle. The enantioselective properties of the new chiral selectors diluted in OV11 polysiloxane (35% phenyl- and 65% methylsiloxane) were investigated by means of injections of 117 racemic mixtures. The mixed chiral selectors with ( l)-valine and, to a lesser extent with ( d)-valine, were found to have an improved enantioselectivity toward amino acid derivatives by comparison to permethylated cyclodextrin. The enantioseparation capability of these new chiral selectors has proven to be slightly less efficient than Chirasil- l-Val (Alltech) for amino acid derivatives, but it has been extended to include terpenes, lactones, esters, aliphatic compounds and aryl alcohols.