Novel cinchona carbamate selectors with complementary enantioseparation characteristics for N-acylated amino acids was written by Krawinkler, Karl Heinz;Maier, Norbert M.;Ungaro, Rocco;Sansone, Francesco;Casnati, Alessandro;Lindner, Wolfgang. And the article was included in Chirality in 2003.Electric Literature of C21H21NO4 The following contents are mentioned in the article:
The synthesis and chromatog. evaluation of the enantiomer separation capabilities of covalently immobilized calix[4]arene-cinchona carbamate hybrid type receptors derived from quinine (QN) and its corresponding C9-epimer (eQN) in different solvents are reported. The receptors display complementary enantiomer separation profiles in terms of elution order, chiral substrate specificity, and mobile phase characteristics, indicating the existence of two distinct chiral recognition mechanisms. The QN-derived receptor binds the (S)-enantiomers of N-acylated amino acids more strongly, shows preferential recognition of open-chained amino acids, and superior enantioselectivity in polar media such as methanol/acetic acid. In contrast, the eQN congener preferentially recognizes the corresponding (R)-enantiomers, displays good enantioselectivity (伪 up to 1.74) for cyclic amino acids, and enhanced stereodiscriminating properties in apolar mobile phases, e.g., chloroform/acetic acid. A comparison of the enantiomer separation profiles with those of the corresponding QN and eQN tert-Bu carbamate congeners indicates no significant level of cooperativity between the calix[4]arene module and the cinchona units in terms of overall chiral recognition, most probably as a consequence of residual conformational flexibility of the calixarene module and the carbamate linkage. This study involved multiple reactions and reactants, such as (S)-1-(((9H-Fluoren-9-yl)methoxy)carbonyl)piperidine-2-carboxylic acid (cas: 86069-86-5Electric Literature of C21H21NO4).
(S)-1-(((9H-Fluoren-9-yl)methoxy)carbonyl)piperidine-2-carboxylic acid (cas: 86069-86-5) belongs to piperidine derivatives.Piperidine is a key saturated heterocyclic scaffold found in several of the top-selling small molecule pharmaceuticals and natural alkaloids, with a diverse range of biological activities. Some chemotherapeutic agents have piperidine moiety within their structure, foremost among them, vinblastine and raloxifene.Electric Literature of C21H21NO4
Referemce:
Piperidine – Wikipedia,
Piperidine | C5H11N – PubChem