Other Cinchona-Based Selectors Toward Receptor-Like CSPs

Other Cinchona-Based Selectors Toward Receptor-Like CSPs 

Development of highly (enantio)selective synthetic receptors resembling those occurring in the nature is one of the primary goals of the target-specific application in life sciences, for example, as diagnostic tools or in separation technology (membrane enantioseparation) [105]. 

Although carbamate-type derivatives remain the most important group of cinchona-based selectors, Maier and Lindner have shown that bis-quinidine phtha-lazine ((DHQD)2PHAL) type ligands 61, well known for their applications in 

Further studies by Lindner and Maier have shown that substitution of one of the cinchona alkaloid moieties in dimeric cinchona phthalazine-type CSPs with a bulky naphthalene group still allows to maintain the high enantioselectivity of separation. For example, enantioseparation of DNZ-protected P-neopentylglydne on mixed CSP 63 occurs with excellent selectivity, a = 34.2 [106]. 

Cinchona-calix[4]arene hybrids 64 and 65 have also been evaluated as CSPs by Maier and Lindner. Interestingly, 64 showed a lower degree of selectivity toward a set of N-protected amino acids, compared to t-BuCQN CSP independently of the 9-configuration of cinchona alkaloid (QN or ept-QN), and no significant level of cooperativity between the cinchona and calix[4]arene units [109]. However, minor 

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