Dinitrobenzoyl enantioseparation

In another approach, reactive monodisperse porous poly(chloromethylstyrene-co-styrene-co-divinylbenzene) beads have been employed for the preparation of chiral HPLC packings. Thus, reactive chloromethyl groups were derivatized to yield amino functionalized beads onto which both rt-basic and rt-acidic type chiral. selectors, (/ )- -(l-naphthyl)ethylamine and (/ )-A -(3.5-dinitrobenzoyl)phenylglycine, respectively, were attached. The resulting chiral particles were chromatographically tested for the enantioseparation of model SAs. Despite the presence of strongly competitive it-TT-binding sites of the styrenic support these chirally modified beads afforded baseline separations for 2,2,2-trifluoro-l-(9-anthryl) ethanol and Af-(3.5-dinitro-benzoyl) leucine enantiomers, respectively [369. ... 

Also, it is expected that the micellar size is controlled easier than with a conventional low-molecular-mass surfactant (EMMS). The first report on enantiomer separation by MEKC using a chiral HMMS appeared in 1994, where poly(sodium A-undecylenyl-L-valinate) [poly(L-SUV)] was used as a chiral micelle and binaphthol and laudanosine were enantioseparated. The optical resolution of 3,5-dinitrobenzoylated amino acid isopropyl esters by MEKC with poly(sodium (10-undecenoyl)-L-valinate) as well as with SDVal, SDAla, and SDThr was also reported. 

For enantioseparation of selected /3-blockers, propranolol, metoprolol, and alpren-olol, amino acids such as L-arginine [16,17], L-lysine [16], L-aspartic acid [18], or derivatives of amino acids, /V-(3,5-dinitrobenzoyl)-/ -(-)-a -phenyl glycine, and A-(3,5-dinitrobenzoyl)-L-leucine were the most frequently used chiral selectors impregnated in TLC layer [19]. Tartaric acid was employed not only as a chiral selector impregnated in the layer, but also as the CMA [20]. The structures of these chiral selectors are presented in Figure 11.2. 

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