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Volumn 11, Issue 1, 2009, Pages 69-72

Efficient construction of oligocholate foldamers via "click" chemistry and their tolerance of structural heterogeneity

Author keywords

[No Author keywords available]

Indexed keywords

ALKYNE; AZIDE; CHOLIC ACID DERIVATIVE; METHANOL;

EID: 59649089776     PISSN: 15237060     EISSN: None     Source Type: Journal    
DOI: 10.1021/ol802364c     Document Type: Article
Times cited : (15)

References (52)
  • 1
    • 0542421525 scopus 로고    scopus 로고
    • For some representative reviews, see: a
    • For some representative reviews, see: (a) Gellman, S. H. Acc. Chem. Res. 1998, 31, 173-180.
    • (1998) Acc. Chem. Res , vol.31 , pp. 173-180
    • Gellman, S.H.1
  • 7
    • 57349134690 scopus 로고    scopus 로고
    • For a recent review, see
    • For a recent review, see: Horne, W. S.; Gellman, S. H. Acc. Chem. Res. 2008, 41, 1399-1408.
    • (2008) Acc. Chem. Res , vol.41 , pp. 1399-1408
    • Horne, W.S.1    Gellman, S.H.2
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    • 0035886802 scopus 로고    scopus 로고
    • (d) Gong, B. Chem.-Eur. J. 2001, 7, 4336-4342.
    • (2001) Chem.-Eur. J , vol.7 , pp. 4336-4342
    • Gong, B.1
  • 25
    • 64349099458 scopus 로고    scopus 로고
    • A longer oligocholate has more polar groups, which can concentrate the polar solvent more effectively into the hydrophilic interior of the folded helix. These polar solvent molecules in turn can solvate the introverted hydroxyl groups of the cholates more effectively in a nonpolar environment
    • A longer oligocholate has more polar groups, which can concentrate the polar solvent more effectively into the hydrophilic interior of the folded helix. These polar solvent molecules in turn can solvate the introverted hydroxyl groups of the cholates more effectively in a nonpolar environment.
  • 26
    • 64349104609 scopus 로고    scopus 로고
    • The longest oligocholate synthesized previously was a heptamer ref 5a
    • The longest oligocholate synthesized previously was a heptamer (ref 5a).
  • 27
    • 64349115177 scopus 로고    scopus 로고
    • The lack of reactivity in the terminal groups (azide or methyl ester) of 4 is peculiar. The compound is not expected to fold in the solvents used for the reactions. Our current hypothesis is that the curvature in the repeat unit makes an oligocholate curl back as the chain lengthens. Such a structure is disordered, different from the folded helix formed in special solvent mixtures. Derived from the monomer curvature, this curling back probably has little dependence on the solvents, should increase rapidly with an increase of the chain length, and may have buried the terminal groups of 4 to shield them from the chemical reagents. Unfortunately, the solubility of the oligocholates in the folding solvents (e.g, 2:1 hexane/EA with a few percent MeOH) is insufficient for us to test whether the reactivity is enhanced in the folding conditions. Further study is underway to investigate this effect
    • The lack of reactivity in the terminal groups (azide or methyl ester) of 4 is peculiar. The compound is not expected to fold in the solvents used for the reactions. Our current hypothesis is that the curvature in the repeat unit makes an oligocholate "curl back" as the chain lengthens. Such a structure is disordered, different from the folded helix formed in special solvent mixtures. Derived from the monomer curvature, this "curling back" probably has little dependence on the solvents, should increase rapidly with an increase of the chain length, and may have buried the terminal groups of 4 to shield them from the chemical reagents. Unfortunately, the solubility of the oligocholates in the folding solvents (e.g., 2:1 hexane/EA with a few percent MeOH) is insufficient for us to test whether the reactivity is enhanced in the folding conditions. Further study is underway to investigate this effect.
  • 28
    • 0000096835 scopus 로고    scopus 로고
    • For several reviews on click chemistry, see: a
    • For several reviews on "click" chemistry, see: (a) Kolb, H. C.; Finn, M. G.; Sharpless, K. B. Angew. Chem., Int. Ed. 2001, 40, 2004-2021.
    • (2001) Angew. Chem., Int. Ed , vol.40 , pp. 2004-2021
    • Kolb, H.C.1    Finn, M.G.2    Sharpless, K.B.3
  • 34
    • 37249012927 scopus 로고    scopus 로고
    • For recent examples of foldamers prepared by click chemistry, see: a
    • For recent examples of foldamers prepared by "click" chemistry, see: (a) Meudtner, R. M.; Ostermeier, M.; Goddard, R.; Limberg, C.; Hecht, S. Chem.-Eur. J. 2007, 13, 9834-9840.
    • (2007) Chem.-Eur. J , vol.13 , pp. 9834-9840
    • Meudtner, R.M.1    Ostermeier, M.2    Goddard, R.3    Limberg, C.4    Hecht, S.5
  • 39
    • 9344256088 scopus 로고    scopus 로고
    • For examples of using click chemistry on dendrimers or polymers, see: (a) Helms, B, Mynar, J. L, Hawker, C. J, Fréchet, J. M. J. J. Am. Chem. Soc. 2004, 126, 15020-15021
    • For examples of using "click" chemistry on dendrimers or polymers, see: (a) Helms, B.; Mynar, J. L.; Hawker, C. J.; Fréchet, J. M. J. J. Am. Chem. Soc. 2004, 126, 15020-15021.
  • 44
    • 18244371903 scopus 로고    scopus 로고
    • This condition previously afforded 1, 4-triazoles exclusively in our synthesis of water-soluble calixarenes; see: Ryu, E.-H, Zhao, Y. Org. Lett. 2005, 7, 1035-1037
    • This condition previously afforded 1, 4-triazoles exclusively in our synthesis of water-soluble calixarenes; see: Ryu, E.-H.; Zhao, Y. Org. Lett. 2005, 7, 1035-1037.
  • 46
    • 64349106671 scopus 로고    scopus 로고
    • Folding of an oligocholate requires the phase separation of the polar solvent (MeOH) into the hydrophilic cavity in the folded helix. The phase separation of methanol is easier with hexane in the solvent because hexane is immiscible with methanol but EA is
    • Folding of an oligocholate requires the phase separation of the polar solvent (MeOH) into the hydrophilic cavity in the folded helix. The phase separation of methanol is easier with hexane in the solvent because hexane is immiscible with methanol but EA is.
  • 49
    • 64349122424 scopus 로고    scopus 로고
    • The plateaus on the left and the right side of the titration curve generally correspond to the fully folded and the fully unfolded state for a two-state transition
    • The plateaus on the left and the right side of the titration curve generally correspond to the fully folded and the fully unfolded state for a two-state transition.
  • 51
    • 64349122198 scopus 로고    scopus 로고
    • Another possible reason is the flexibility introduced by the aspartatetriazole linker s
    • Another possible reason is the flexibility introduced by the aspartatetriazole linker (s).
  • 52
    • 84889454714 scopus 로고    scopus 로고
    • This is probably because solvophobic forces do not require precise alignment of functional groups to be effective; see: Zhao, Y, Moore, J. S. In Foldamers; Hecht, S, Huc, I, Eds, Wiley-VCH: Weinheim, 2007; pp 75-108
    • This is probably because solvophobic forces do not require precise alignment of functional groups to be effective; see: Zhao, Y.; Moore, J. S. In Foldamers; Hecht, S., Huc, I., Eds.; Wiley-VCH: Weinheim, 2007; pp 75-108.


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.