Amino imprinted chiral phases

Despite this, there are examples of molecularly imprinted chiral stationary phases that are capable of resolving more than the raceme corresponding to the template. In these cases, minor structural differences are possible without compromising the separation. For example, a polymer imprinted with L-phenylalanine anilide efficiently separated the protected amino acids with different side chains or amide substituents [36]. Anilides of all aromatic amino acids were resolved as well as p-naphthylamides and -nitroanilides of leucine and alanine [40]. 

Figure 6 Chiral HPLC separation of amino acid derivatives on imprinted stationary phases packed with Z-L-Glu-OH (a), Boc-L-phe-Gly-OEt (b), Z-L-Ala-L-Ala-Ome (c) Z-L-Ala-Gly-L-Phe-OMe (d). Mobile phase chloroform - acetic acid. Column 250 x 4.6 mm. Flow rate, 1 mL/min. Detection, UV 260 nm. Reproduced from Ref. 22, with permission.

Optical isomer separations that are carried out on a chiral layer produced from C-18 modified silica gel impregnated with a Cu(II) salt and an optically active enantiomerically pure hydroxyproline derivative, on a silica layer impregnated with a chiral selector such as brucine,on molecularly imprinted polymers of alpha-agonists,or on cellulose with mobile phases having added chiral selectors such as cyclodextrins have been reported mostly for amino acids and their derivatives. Mixtures of sorbents have been used to prepare layers with special selectivity properties. 

The high selectivity of M IPs is demonstrated when an optically active compound is imprinted the resulting MIP will normally resolve the racemate. Numerous reports on MIP chiral stationary phases have appeared [184—188]. Chiral templates studied include amino acids [26, 29, 120, 139, 189-192], peptides [139, 192, 193], carbohydrates [58, 194, 195] and dmgs [127, 196]. 

Andersson, L.I. O Shannessy, D.J. Mosbach, K. Molecular recognition in synthetic polymers preparation of chiral stationary phases by molecular imprinting of amino acid amides. J. Chromatogr. 1990, 513, 167-179. 

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