'Ab Ovo' Chiral Phases and Chiral Reagents for Liquid Chromatographic Separation and Isolation of Enantiomers

The de-novo approach of mixing chirally pure reagents or Cu(II)-L-amino acid complexes in the slurry of silica gel for preparing TLC plates was reported from author's laboratory and was successful for separation and isolation of enantiomers. Using high molar absorptivity molecules, e. g., 1,5-difluoro-2,4-dinitrobenzene and cyanuric chloride, more than 38 new chiral derivatizing reagents were synthesized in our laboratory by straightforward nucleophilic substitution with simple chiral auxiliaries. Besides, (S)-naproxen, (S)-ketoprofen, and (S)-levofloxacin were used as chiral platforms. A conceptual approach using both achiral phases in chromatography for enantioseparation was also adopted. ¹ H NMR and DFT based software were used to explain structures of non-covalent and covalent diastereomeric pairs and determination of configuration and separation mechanism. The methods can be easily used to determine and control enantiomeric purity with advantages over a variety of commercial chiral phases.

Biennial review of planar chromatography: 2011–2013

The most important advances in planar chromatography published between November 1, 2011 and November 1, 2013 are reviewed in this paper. Included are an introduction to the current status of the field; student experiments, books, and reviews; theory and fundamental studies; apparatus and techniques for sample preparation and TLC separations (sample application and plate development with the mobile phase); detection and identification of separated zones (chemical and biological detection, TLC/mass spectrometry, and TLC coupled with other spectrometric methods); techniques and instruments for quantitative analysis; preparative layer chromatography; and thin layer radiochromatography. Numerous applications to a great number of compound types and sample matrices are presented in all sections of the review.