title: Visual enantiomeric recognition of amino acid derivatives in protic solvents.
abstract: Various types of chiral host molecules 2-7 based on a phenolphthalein skeleton and two crown ethers were prepared for use in visual enantiomeric recognition, and we examined their enantioselective coloration in complexation with chiral amino acid derivatives 9-22 in methanol solution. Methyl-substituted host (S,S,S,S)-3 showed particularly prominent enantiomer selectivity for the alanine amide derivatives 11 and 12. A combination of methyl-substituted host (S,S,S,S)-3 with guest (R)-11 or (R)-12 developed a purple color, whereas no color development was observed with (S)-11 or (S)-12. On the other hand, phenyl-substituted host (S,S,S,S)-6 showed deeper coloration with a wide range of (S)-beta-amino alcohols compared to that seen with host (S,S,S,S)-6 and the corresponding (R)-beta-amino alcohols at 0 degrees C. Furthermore, absorbance inversion temperatures (AIT) were observed within the range of 0-50 degrees C in many cases.
authors.affiliation: Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan. tsubaki@fos.kuicr.kyoto-u.ca.jp
authors.forename: Kazunori
authors.initials: K
authors.lastname: Tsubaki
authors.forename: Daisuke
authors.initials: D
authors.lastname: Tanima
authors.forename: Mohammad
authors.initials: M
authors.lastname: Nuruzzaman
authors.forename: Tomokazu
authors.initials: T
authors.lastname: Kusumoto
authors.forename: Kaoru
authors.initials: K
authors.lastname: Fuji
authors.forename: Takeo
authors.initials: T
authors.lastname: Kawabata
mesh_terms: D000596:Amino Acids / Q000032:analysis / Q000737:chemistry*; D043844:Crown Ethers / Q000737:chemistry; D015394:Molecular Structure; D020113:Phenolphthalein / Q000737:chemistry; D012997:Solvents; D013237:Stereoisomerism; D013696:Temperature
chemical_list: D000596:Amino Acids; D043844:Crown Ethers; D012997:Solvents; D020113:Phenolphthalein