Influence of organic modifier and temperature on the enantiomeric separation of γ-lactams by HPLC

Enantioselective recognition of 2,3-benzodiazepin-4-one derivatives with anticonvulsant activity on several polysaccharide chiral stationary phases

The retention behaviour of racemic 1-(4-aminophenyl)-1,2,3,5-tetrahydro-7,8-methylendioxy-4H-2,3-benzodiazepin-4-one derivatives with anticonvulsant activity on several chiral stationary phases was investigated. The selective performances of six polysaccharide phases, namely, Chiralcel OA, OD, OF, OG, OJ and Chiralpak AD were studied and normal phase HPLC methods were optimized to separate the enantiomeric forms of this class of compounds. The chiral recognition mechanism between the analytes and the chiral selectors was discussed. A molecular modeling study was carried out with the aim to explore the enantioselective molecular recognition process with the Chiralcel OG stationary phase.

Reviewing mobile phases used on Chiralcel OD through an application of data mining tools to CHIRBASE database

During the past decade, thousands of compounds have been resolved on Chiralcel OD (a cellulose-based chiral stationary phase) under diverse eluting conditions. Many researches have documented the effects of mobile phase on enantioselectivity for a given family of samples but today no comprehensive study aimed at identifying the associations between the structural features present on solute and appropriate mobile phase conditions has yet been proposed. In this review of mobile phases used on Chiralcel OD, we try to go far beyond a simple enumeration of eluting conditions and an effort is made to explore the utility of data mining tools for assessing the knowledge contained in CHIRBASE database. We have extracted from CHIRBASE the chemical features of 2363 chiral compounds separated on Chiralcel OD and their corresponding mobile phases. This data set was submitted to data mining programs for molecular pattern recognition and mobile phase predictions for new cases. Some substructural characteristics of solutes were related to the efficient use of some specific mobile phases. For example, the application of CH3CN/salt buffer at pH 6-7 was found convenient for reversed-phase separation of compounds bearing a tertiary amine functional group. Furthermore, a cluster analysis allowed the arrangement of the mobile phases according to similarity found in molecular patterns of solutes. A decision tree, which may lead to a more rational choice of the mobile phase under reversed-phase conditions, is also proposed.