NONLINEAR STRUCTURE ENANTIOSELECTIVE RETENTION RELATIONSHIPS IN A HOMOLOGOUS SERIES OF 1,4-DISUBSTITUTED PIPERAZINE DERIVATIVES

A high-performance Liquid chromatography method for the direct separat ion of enantiomers of a homologous series of 1,4-disubstituted piperaz ine derivatives, using a chiral cellulose tris(4-methylbenzoate) stati onary phase and a hexane-propan-2-ol eluent, is described. An atypical relationship was found between enantioselectivity and the carbon numb er of the alkyl substituent with a maximum corresponding to four-five carbon atoms in the substituent. The optimum enantioselectivity observ ed suggests the existence of a limited size interaction site on the st ationary phase and an input to retention due to the steric exclusion o f individual solutes. (C) 1997 Elsevier Science B.V.