Chiral mono and diamide derivatives of calix[4]arene for enantiomeric recognition of chiral amines

Abstract

Novel chiral mono and diamide derivatives of calix[4]arene have been prepared from the aminolysis reaction of 5,11,17,23-tetra-tert-butyl-25,27-diethoxycarbonyl-methoxy-26,28-dihydroxycalix[4]arene 1 and 25,27-diethoxycarbonyl-methoxy-26,28-dihydroxycalix[4]arene 2 with chiral (S)-(-)-1-phenylethylamine (PEA) and (1S,2S)-(+)-2-amino-1-(4-nitrophenyl)-1,3-propanediol, respectively. Spectrophotometric titrations have been performed in CHCl(3) at 20-30 degrees C in order to obtain the binding constants (K) and the thermodynamic quantities (DeltaH and DeltaS) for the stoichiometric 1:1 inclusion complexation of various chiral amines with these new host compounds. Preliminary experiments were undertaken to confirm the complexation properties of receptors 9 and 13 with PEA by (1)H NMR in CDCl(3) at room temperature. The molecular recognition abilities and enantioselectivities for guests (R and S)-alpha-PEA and (R and S)-cyclohexylethylamine (CHEA) are discussed from a thermodynamic point of view.

Chiral Cups (Calixarenes) via Dötz Benzannulation

“…Shinkai and co-workers 27 first reported the synthesis of chiral calixarene derivatives 3a-c by the reaction of (S)-1-bromo-2-methylbutane (2) with psulfonate calixarenes 1 (Scheme 1). Following this report several research groups have incorporated various chiral moieties (e.g., amines, 22,28 alcohols, 21a,29 amino acids 30 and chiral pool materials like tartaric acids as the ester 31 ) at the upper or lower rim of calixarenes. These chiral calixarenes provided new platforms for chiral receptors for host-guest chemistry and potential applications in chiral recognition, asymmetric catalysis, synthesis, and the separation of enantiomers.…”

Synthesis and characterization of novel chiral calix[4]arene bearing (R)-(+)-1-phenylethylamine bonded silica particles

“…The introduction of chiral substituents on the lower rim, through the phenolic oxygens or at the para positions of the calix [4]arene skeleton, or via the synthesis of 'inherently' chiral derivatives could, in turn, lead to the chirality of the artificial receptors. Chiral receptors that are based on the calixarene platform may have potential applications in the preparation, separation, and analysis of enantiomers [21,22]. In this regard, investigations of the synthesis of chiral calix [4]arene derivatives have attracted considerable attention.…”

Investigating Chiral Recognizability of Diastereomeric Crystallization of Mandelic Acid and L-Phenylalanine

“…In the process of chiral discrimination, the functional groups in the molecular receptor preferentially interact with one of the enantiomers in the chiral molecule based on a noncovalent interaction, such as hydrogen bonding, electrostatic interaction, or hydrophobic interaction. 1 In many cases, while one enantiomer exhibits desirable physiological, pharmacological, pharmacodynamic, and pharmacokinetic properties, the other enantiomer can display toxicity towards living organisms and a different activity in chemical or biotechnological processes. Therefore, replacing the racemic form with a single-enantiomeric form in the drug market has * Author to whom correspondence should be addressed.…”