Highly efficient separation of amines by electrokinetic chromatography using resorcarene-octacarboxylic acids as pseudostationary phases

Discontinuous electrokinetic chromatography of parabens using different substituted resonances as pseudostationary phases

“…Resorcarenes 1 and octaacids 2 were prepared as previously described [17,20]. Tetraphosphorylated resorcarenes 4 were obtained in a three-step reaction following a modified procedure [27,28].…”

“…Recently the separation of 13 amines derivatized with o-phthaldialdehyde and 2-mercaptoethanole using resorcarene octacarboxylic acids 2 (see Fig. 1) was reported [20]. These resorcarenes provided good water solubility and high electrophoretic mobility under moderate pH conditions.…”

Synthesis and NMR elucidation of novel octa-amino acid resorcin[4]arenes derivatives

“…Even though it is possible to form resorcinarenes with formaldehyde, 2 the use of aliphatic aldehydes resulting in side chains or 'feet' is preferred for potential synthetic ion channels. 3 These macrocyclic compounds are known to possess hydrophilic (upper rim) and hydrophobic (lower rim) regions and a cavity, that can accommodate small organic molecules. 4 Resorcin [4]arenes are not planar and can adopt five possible conformational arrangements: the C 4v symmetrical 'crown' conformation, C 2v symmetrical 'boat' conformation, C 2h symmetrical 'chair' conformation, C s symmetrical 'diamond' conformation, and S 4 symmetrical 'saddle' conformation as illustrated in Fig.…”

“…6 These types of compounds also have found applications as synthetic ion channels. 3,7 . This study demonstrates an effort to functionalize resorcin [4] arene with amino acid residues at the upper rim.…”

“…The 1 H NMR spectra of these derivatives (4a-i) in CDCl 3 at room temperature showed a considerable broadening of the various signals. The relatively broad signals from these compounds are a result of the multiple conformations possible for the cavitand bowl.…”