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Abstract
Helical oligonaphthalenes were constructed by bottom-up synthesis (repeating dimerization reactions), their absolute configurations were determined by an exciton chirality method and their functions, such as energy transfer, are also reported.
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77
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Tsubaki K, Tanima D, Kuroda Y, Fuji K, Kawabata T. Bidirectional and Colorimetric Recognition of Sodium and Potassium Ions. Org Lett 2006; 8:5797-800. [PMID: 17134275 DOI: 10.1021/ol062351+] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Host 1 based on the phenolphthalein skeleton and two crown ether moieties demonstrated opposite behaviors toward sodium and potassium cations caused by bidirectional complexation. [reaction: see text]
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78
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Morimoto T, Henmi M, Naito R, Tsubaki K, Aoki N, Bird JP, Ochiai Y. Resonantly enhanced nonlinear conductance in long quantum point contacts near pinch-off. PHYSICAL REVIEW LETTERS 2006; 97:096801. [PMID: 17026388 DOI: 10.1103/physrevlett.97.096801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2005] [Indexed: 05/12/2023]
Abstract
We report on a remarkable resonance in the differential conductance of long quantum point contacts (QPCs) that is observed as a precursor to regular quantized transport. This effect is increasingly pronounced in longer QPCs, in which the differential conductance may resonantly exceed 2e2/h. From a study of the experimental characteristics of this feature, we suggest that it may be associated with the formation of a well-resolved energy gap that opens dynamically as a result of enhanced many-body interactions in long QPCs.
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79
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Takaishi K, Tsubaki K, Tanaka H, Miura M, Kawabata T. Synthesis and Optical Properties of the Helical Oligonaphthalenes. YAKUGAKU ZASSHI 2006; 126:779-87. [PMID: 16946591 DOI: 10.1248/yakushi.126.779] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We have developed an efficient synthesis method for optically active oligonaphthalenes (from 2 mer to 16 mer), which are connected at their 1,4-positions, under oxidative homo coupling with a stoichiometric amount of CuCl(2) and amines. The absolute configuration of the newly formed axis bond was determined based on the CD spectra of oligonaphthalenes with 1) two pyrene rings on the central naphthalenes or 2) two tetraphenylporphyrins (TPP) on the top and bottom naphthalenes. The fluorescence quantum yields increased as the number of naphthalene units increased in methoxy derivatives 10-12, and the intramolecular energy transfer quantum yields of bispyrene derivatives 7-9 were around 20% regardless of the number of naphthalene units. Furthermore, the hexadecanaphthalene derivative 4b with two TPPs exhibited a clear exciton coupling over an interchromophore distance to ca. 66 A.
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80
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Tsubaki K, Tanaka H, Takaishi K, Miura M, Morikawa H, Furuta T, Tanaka K, Fuji K, Sasamori T, Tokitoh N, Kawabata T. Bottom-Up Synthesis of Optically Active Oligonaphthalenes: Three Different Pathways for Controlling Axial Chirality1. J Org Chem 2006; 71:6579-87. [PMID: 16901146 DOI: 10.1021/jo060974v] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The oxidative homocoupling of optically active binaphthalenes 1a-d with a stoichiometric amount of CuCl2 and amines afforded quaternaphthalenes 2a-d in up to 93% de. The high diastereoselectivities were achieved through three different pathways (epimerization of the axis together with diastereoselective crystallization, thermodynamic, and kinetic control pathways). The type of side chains on the naphthalene influenced which pathway dominates. Three pathways were applicable to octinaphthalenes (8a-d) and hexadecanaphthalene 10a with 46-99% de. The absolute configuration of the newly formed axial bond was determined by (1) X-ray crystallographic analysis, (2) transformation to known compounds 15 and 16, (3) CD spectra of oligonaphthalenes with two pyrene rings as exciton parts, and (4) the shift values in 13C NMR spectra of 13C-enriched derivatives 29-31 toward chiral shift reagent Eu(+tfc)3.
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81
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Tsubaki K, Nakajima Y, Hanajiri T, Yamaguchi H. Proposal of Carbon Nanotube Inductors. ACTA ACUST UNITED AC 2006. [DOI: 10.1088/1742-6596/38/1/013] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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82
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Tsubaki K, Takaishi K, Tanaka H, Miura M, Kawabata T. Long-Range Exciton-Coupled Circular Dichroism: Application for Determination of the Absolute Configuration of Oligonaphthalenes. Org Lett 2006; 8:2587-90. [PMID: 16737320 DOI: 10.1021/ol060843g] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Hexadecanaphthalenes (S,S,S,S,S,S,S,S,S,S,S,S,S,S,S)-4b and (S,S,S,S,S,S,S,R,S,S,S,S,S,S,S)-4b that possess two tetraphenylporphyrins (TPP) on the upper and lower naphthalene rings were synthesized. Long-range exciton-coupled CD in the Soret region of TPP (about 66 A) was observed. [structure: see text]
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83
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Pieraccini S, Ferrarini A, Fuji K, Gottarelli G, Lena S, Tsubaki K, Spada GP. Homochiral Helices of Oligonaphthalenes Inducing Opposite-Handed Cholesteric Phases. Chemistry 2006; 12:1121-6. [PMID: 16247829 DOI: 10.1002/chem.200500683] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The helical structure of the chiral nematic phases (cholesterics) obtained by doping nematic solvents with chiral non-racemic compounds is a macroscopic proof of the solute chirality. Oligonaphthalene (tetra-, hexa-, octa-) derivatives linked at the 1,4-positions have been used as chiral dopants: When the chirality axes are configurationally homogeneous (that is, all-S), the molecular structures correspond to right-handed helices. Yet, we have found series of derivatives with the surprising property that the handedness of the induced cholesteric phase alternates from positive to negative and to positive again, on passing from tetra- to hexa- and to octanaphthalene. A comparison with oligonapthalene derivatives, which do not exhibit this twisting ability, points to the importance of the substitution pattern. Both the possibility of inducing oppositely-handed cholesteric phases by homochiral helices of different length, and the role played of substituents, are confirmed by calculations performed with the surface chirality model.
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84
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Tsubaki K, Tanima D, Nuruzzaman M, Kusumoto T, Fuji K, Kawabata T. Visual enantiomeric recognition of amino acid derivatives in protic solvents. J Org Chem 2005; 70:4609-16. [PMID: 15932296 DOI: 10.1021/jo050387u] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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.
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85
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Tsubaki K, Kusumoto T, Hayashi N, Tanima D, Fuji K, Kawabata T. Convenient preparation of optically active N,N-bis(4-substituted-4-aminobutyl)amines. ACTA ACUST UNITED AC 2005. [DOI: 10.1016/j.tetasy.2004.12.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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86
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Kawabata T, Majumdar S, Tsubaki K, Monguchi D. Memory of chirality in intramolecular conjugate addition of enolates: a novel access to nitrogen heterocycles with contiguous quaternary and tertiary stereocenters. Org Biomol Chem 2005; 3:1609-11. [PMID: 15858636 DOI: 10.1039/b416535g] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Nitrogen heterocycles with contiguous quaternary and tertiary stereocenters have been prepared in high enantiomeric purity by intramolecular conjugate addition of enolates generated from alpha-amino acid derivatives via memory of chirality.
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87
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Kinoshita N, Marx KH, Tanaka K, Tsubaki K, Kawabata T, Yoshikai N, Nakamura E, Fuji K. Enantioselective Allylic Substitution of Cinnamyl Esters Catalyzed by Iridium−Chiral Aryl Phosphite Complex: Conspicuous Change in the Mechanistic Spectrum by a Countercation and Solvent. J Org Chem 2004; 69:7960-4. [PMID: 15527276 DOI: 10.1021/jo048834d] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Iridium-catalyzed asymmetric allylic alkylation of monoaryl substrates 4-6 with chiral phosphites 1-3 has been investigated. Although branched isomers were formed with high regioselectivities, the enantioselectivities of these products were remarkably influenced by solvents, countercations, and additives (ZnCl(2) and LiCl).
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88
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Tsubaki K, Miura M, Morikawa H, Tanaka H, Kawabata T, Furuta T, Tanaka K, Fuji K. Synthesis of Optically Active Oligonaphthalenes via Second-Order Asymmetric Transformation. J Am Chem Soc 2003; 125:16200-1. [PMID: 14692756 DOI: 10.1021/ja038910e] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Synthesis of numerous optically active rod-shaped oligo(2,3-dioxyfunctionalized)naphthalenes connected at their 1,4-positions was achieved using oxidative coupling under CuCl2/alpha-methylbenzylamine conditions by second-order asymmetric transformation. We believe this method is practical and should contribute to the field of material science.
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89
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Tsubaki K, Morikawa H, Tanaka H, Fuji K. Convenient synthesis and efficient resolution of 3,3′-bis(benzyloxy)-1,1′-binaphthalene-2,2′-diol. ACTA ACUST UNITED AC 2003. [DOI: 10.1016/s0957-4166(03)00219-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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90
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Tsubaki K, Tanaka H, Morikawa H, Fuji K. Synthesis and recognition of amino acids by binaphthyl-crown receptors. Tetrahedron 2003. [DOI: 10.1016/s0040-4020(03)00478-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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91
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Katsu T, Ido K, Sagara S, Tsubaki K, Fuji K. Homooxacalix[3]arene Derivatives as Ionophores for Serotonin-Selective Membrane Electrodes. ELECTROANAL 2003. [DOI: 10.1002/elan.200390036] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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92
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Tsubaki K, Otsubo T, Morimoto T, Maruoka H, Furukawa M, Momose Y, Shang M, Fuji K. Modification of the upper rim of homooxacalix[3]arenes and complexation between a nitrohomooxacalix[3]arene derivative and n-hexylamine. J Org Chem 2002; 67:8151-6. [PMID: 12423145 DOI: 10.1021/jo026152p] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Several functional groups were introduced on the upper rim of (lower rim free) homooxacalix[3]arene for the first time. The swinging nitrohomooxacalix[3]arene host 1 was fixed in the cone conformation by complexation with n-hexylamine.
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93
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Tsubaki K, Mukoyoshi K, Morikawa H, Kinoshita T, Fuji K. Enantiomeric recognition of amino acids using a chiral spiropyran derivative. Chirality 2002; 14:713-5. [PMID: 12237830 DOI: 10.1002/chir.10111] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
An optically active spiropyran 1 with a binaphthol moiety as a chiral source was synthesized. The colored merocyanine form of (R)-1 obtained by the UV irradiation remained in the presence of D-amino acids longer than with L-amino acids.
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94
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Tsubaki K, Kusumoto T, Hayashi N, Nuruzzaman M, Fuji K. Sequence-Selective Visual Recognition of Nonprotected Dipeptides. Org Lett 2002. [DOI: 10.1021/ol026866m] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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95
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Tsubaki K, Morimoto T, Otsubo T, Fuji K. Recognition of alkaline metals and amines by a chromogenic homooxacalix[3]arene receptor. Org Lett 2002; 4:2301-4. [PMID: 12098232 DOI: 10.1021/ol026019j] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
[structure: see text] The artificial host molecule 1, consisting of homooxacalix[3]arene and pyridinium N-phenolate dye (Reichardt dye E(T)1) has been prepared. Host 1 contains a proton-ionizable phenol group that acts as a chemical switch to generate color change against alkaline metals and various kind of amines.
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96
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Tsubaki K, Kusumoto T, Hayashi N, Nuruzzaman M, Fuji K. Sequence-selective visual recognition of nonprotected dipeptides. Org Lett 2002; 4:2313-6. [PMID: 12098235 DOI: 10.1021/ol026191n] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
[structure: see text] A receptor 1 with phenolphthalein and two crown ethers in the molecule develops brilliant purple color in the presence of dipeptides with a specific amino acid-sequence containing a C-terminal lysine. This type of color development could be extended to the detection of oligopeptides of a specific sequence at the N-terminal such as scyliorhinin I and APP(770)(394-410).
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97
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Tsubaki K, Tanaka H, Furuta T, Tanaka K, Kinoshita T, Fuji K. Use of meso-ternaphthalene derivatives: linear recognition of the α,ω-diamines by homoditopic receptors. Tetrahedron 2002. [DOI: 10.1016/s0040-4020(02)00547-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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98
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Ochiai H, Tamaru Y, Tsubaki K, Yoshida Z. Unsaturated ester synthesis via copper(I)-catalyzed allylation of zinc esters. J Org Chem 2002. [DOI: 10.1021/jo00228a059] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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99
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Aihara M, Miyazawa M, Osuna H, Tsubaki K, Ikebe T, Aihara Y, Ikezawa Z. Food-dependent exercise-induced anaphylaxis: influence of concurrent aspirin administration on skin testing and provocation. Br J Dermatol 2002; 146:466-72. [PMID: 11952547 DOI: 10.1046/j.1365-2133.2002.04601.x] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Provocation tests in patients with food-dependent exercise-induced anaphylaxis (FDEIA) are often negative, even after a sufficient quantity of the implicated food and exercise have been taken. OBJECTIVES To investigate the effect of aspirin in provocation tests and in skin prick testing (SPT) of patients with FDEIA. Gluten as a major allergen in wheat-dependent FDEIA was also investigated. METHODS Provocation tests and SPT with suspected foods were performed in 12 patients with FDEIA. Provocation tests were performed with combinations of foods, exercise and aspirin. Detection of gluten-specific IgE was also performed by the CAP System FEIA radioallergosorbent test, SPT and a histamine release test. RESULTS The SPT reaction was enhanced by pretreatment with oral aspirin in five of eight (62.5) patients. Aspirin facilitated provocation in five of seven (71%) patients tested. Ingestion of wheat and aspirin without exercise provoked symptoms in two patients. Aspirin provoked symptoms even with a small amount of wheat and exercise in one patient. Only the combination of aspirin, wheat and exercise provoked anaphylaxis in one patient. Specific IgE, SPT and/or the histamine release test with gluten were positive in nine of 11 patients with wheat-dependent FDEIA. CONCLUSIONS Aspirin enhances symptoms of FDEIA, and prior ingestion of aspirin under controlled conditions can be used to confirm FDEIA. In practice, such patients should avoid aspirin ingestion. Gluten appears to be the major allergen in these patients with wheat-dependent FDEIA.
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100
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Tsubaki K, Nuruzzaman M, Kusumoto T, Hayashi N, Bin-Gui W, Fuji K. Visual enantiomeric recognition using chiral phenolphthalein derivatives. Org Lett 2001; 3:4071-3. [PMID: 11735587 DOI: 10.1021/ol016825a] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
[structure: see text] Optically active artificial host molecules 2-5 based on a phenolphthalein skeleton have been prepared for visual enantiomeric recognition of alanine derivatives 8 and 9. The receptor 3 discriminates (R)-8 and (R)-9 from (S)-8 and (S)-9, respectively, to develop a purple color.
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