Chiral calix[4]azacrowns for enantiomeric recognition of amino acid derivatives

Enantioselective Fluorescent Sensors for N‐Boc‐Protected Amino Acid Anions Based on BINOL

“…mol/L) with L-Ala anion in CHCl 3 . The anion equivalents are 0, 2, 4,6,8,10,20,40,60,80,100,200, 300, 400 and 500, λ ex ＝278 nm. Inset: changes in the fluorescence intensity of S-1a at 371 nm upon addition of L-Ala anion.…”

“…The correlation coefficient (R) of the nonlinear curve fitting is 0.9972. mol/L) with D-Ala anion in CHCl 3 . The anion equivalents are 0, 2, 4,6,8,10,20,40,60,80,100,200,300,400 recognition ability between the L-and D-Ala anions, respectively. Satisfactory nonlinear curve fitting (the correlation coefficient is over 0.99) confirmed that S-1a and the L-or D-Ala formed a 1∶1 complex (see the insets of Figure 1 and Figure 2).…”

“…The mixture was poured into 30 mL of 10% Na-HCO 3 after removing the solvent under reduced pressure, and extracted with CHCl 3 for three times. The organic layers were combined and dried over anhydrous Na 2 SO 4 39.97, 45.51, 47.64, 49.89, 57.12, 57.37, 70.53, 71.80, 124.96, 125.24, 125.64, 125.86, 127.14, 127.17, 128.37, 129.94, 130.14, 130.51, 130.94, 131.29, 132.79, 132.91, 133.76, 133.96, 134.30, 152.53, 153.55, 173.31 25.37, 39.42, 41.72, 44.18, 45.50, 47.62, 49.91, 57.11, 57.31, 70.51, 71.87, 124.99, 125.36, 125.67, 125.89, 127.14, 127.23, 128.37, 129.97, 130.33, 130.92, 131.43, 131.35, 132.85, 132.99, 134.17, 134.39, 134.78, 152.83, 154.37, 174.82;IR (KBr) ν: 3414, 3102, 2951, 1680, 1539, 1263, 1231 cm -1 ; ESI-MS m/z (%): 975 (M＋Na ＋ , 100). Anal.…”

“…3 Many efforts involve the covalent linking of an optical signaling unit (a chromophore or a fluorophore) to a specific receptor for the chiral molecule. 4 Compared with other detection methods, such as capillary electrophoresis, 5 HPLC,6 absorption spectrometry, 7 and electrochemistry, 8 fluorescence techniques have often been used to study the interaction between enantiomers and receptors because of their sensitivity, selectivity, and versatility. 9 The binaphthyl unit was especially eyecatching for its stable chiral configuration and tunable dihedral angle between the two naphthalene rings.…”

Chiral calix[4]arenes bearing aminonaphthol moieties as membrane carriers for amino acid methyl esters and mandelic acid

“…Therefore, a study on the enantiomeric recognition of amino acids is of particular significance for understanding the transport process of these compounds through the cell membrane, the design of asymmetric catalysis systems, new pharmaceutical agents, 19 and separation materials. 20 In a continuation of our work on the synthesis of chiral receptors equipped with various functionalities including azacrown ethers, 21 Schiff bases, 22 and quaternary ammonium salts 23 as well as their catalytic activities and enantiomeric recognition properties toward chiral amines, 24 carboxylic acids, 25 and amino acid derivatives, 26 we herein report the synthesis of novel chiral receptors as organic carriers for the transport of mandelic acid and amino acid esters through a bulk liquid membrane.…”