Stereoselective recognition of dipeptide derivatives in molecularly imprinted polymers which incorporate an l-valine derivative as a novel functional monomer

A polymerizable l-valine derivative was synthesized for use as a novel functional monomer in molecular imprinting applications. This monomer is expected to form multiple hydrogen bonds with peptide derivatives, thus allowing a specific molecular memory in molecularly imprinted polymers. Several dipeptide derivatives were imprinted and the resulting polymers were used as stationary phases for liquid chromatography. It was shown that the molecularly imprinted polymers incorporating the l-valine derivative exhibited high diastereoselectivity to templates. A remarkable imprinting effect was observed when a Phe-Ala derivative was imprinted. High stereoselectivity of the imprinted polymer (separation factor α=2.84) suggested successful imprinting especially for a bulky template peptide. The ratios of template to functional monomer and solvent in the prepolymerization mixture were optimized. Moreover, it was demonstrated that the molecularly imprinted polymers possessed amino acid sequence selectivity as well as diastereoselectivity.