Enantioseparation of Organophosphonat Derivatives on Amylose Tris(3,5-Dimethylphenylcarbamate) Chiral Stationary Phase by HPLC

摘要

The enantiomers of fourteen O,O-dialkyl-2-benzyl-oxycarbonyl-aminoaryl-methyl-phosphonates are directly separated on tris(3,5-dimethyl-phenylcarbamate) amylose chiral stationary phases, known as Chiralcel AD. All of the selected compounds are baseline separated. The influence of the position and properties of substituents in benzene rings, the length and steric hindrance of alkoxyl groups of the phosphonate ester on the chiral separation are discussed. When the substituents are in the para-position of the benzene ringe, the separation factor is in the following order α_(p-NO_2) α_(p-Cl) > α_(p-CH_3) > α_(p-H) > α_(p-OCH_3). When the same substituent is in a different position of the benzene ring, the order of the separation factor is α_(p-Cl) > α_(m-Cl) and α_(p-NO_2) α_(m-NO_2). The values of the separation factor α of the enantiomers where R_1 substituent is a hydrogen (R_1 = H) are always smaller than those of the enantiomers with p-Cl substituent, whether R_2 was Me, Et, Pr or i-Pr. Compounds with different substituent R_2 and R_1 where the substituent is H or p-Cl, and α values always show an order of α_(Pr) > α_(Et) > α_(Me) > α_(i-Pr). The chiral discrimination in the amylose tris(3,5-dimethyl-phenylcarbamate) was based on π-π interaction and H-bond interaction.