Synthesis of phosphoryl-tethered β-cyclodextrins and their molecular and chiral recognition thermodynamics

Yu Liu, Li Li, Xiao Yun Li, Heng Yi Zhang, Takehiko Wada, Yoshihisa Inoue

Research output: Contribution to journalArticlepeer-review

32 Citations (Scopus)

Abstract

Two novel phosphoryl-bridged bis- and tris(β-cyclodextrin)s of different tether lengths, i.e., bis[m-(N-(6-cyclodextryl)-2-aminoethylaminosulfonyl)phenyl]-m- (chlorosulfonyl)phenylphosphine oxide (5) and tris[m-(N-(6-cyclodextryl)-8-amino-3,6-diazaoctylaminosulfonyl)phenyl] phosphine oxide (6), have been synthesized by reactions of 6-oligo(ethylenediamino)-6-deoxy-β-cyclodextrins with tris[m-(chlorosulfonyl)phenyl]phosphine oxide. The complex stability constants (Ks), standard molar enthalpy (δH°), and entropy changes (δS°) were determined at 25 °C for the inclusion complexation of phosphoryl-modified bis- and tris-cyclodextrins (5 and 6, respectively), mono [6-O-(ethoxyhy-droxyphosphoryl)]-β-cyclodextrin (2), mono [6-O-(diethylamino-ethoxyphosphoryl)]-β-cyclodextrin (3), and mono [6-O-(diphenoxyphosphoryl)]-β-cyclodextrin (4) with representative alicyclic and N-Cbz-D/L-alanine guests in 0.1 M phosphate buffer solution at pH 7.2 by means of titration microcalorimetry. The thermodynamic parameters obtained indicate that the charge-dipole interaction between the phosphoryl moiety and the negatively charged guests, as well as the conformational difference of modified β-cyclodextrins in aqueous solution, significantly contribute to the inclusion complexation and the enhanced chiral discrimination. The interactions and binding modes between the hosts and chiral guests were further studied by two-dimensional NMR spectroscopy to elucidate the influence of the structural features of hosts on their increased chiral recognition ability and to establish the correlation between the conformation of the resulting complexes and the thermodynamic parameters obtained.

Original languageEnglish
Pages (from-to)3646-3657
Number of pages12
JournalJournal of Organic Chemistry
Volume68
Issue number9
DOIs
Publication statusPublished - 2003 May 2
Externally publishedYes

ASJC Scopus subject areas

  • Organic Chemistry

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