Stoichiometric and microenvironmental effects on hydrolysis of propantheline and oxyphenonium bromides in cyclodextrin solutions

Solution Structures of 1:1 Complexes of Oxyphenonium Bromide with β- and γ-Cyclodextrins

“…The basic hydrolysis of OB was suppressed by R-, β-, and γ-CD. 6 This will be due to shielding of the ester linkage from hydroxide ions by the CDs, as shown in Figures 5 and 7 for β-and γ-CD. If the ester linkage of OB was located near the secondary hydroxyl groups of β-and γ-CD, the hydrolysis would be accelerated by these CDs.…”

“…5 The basic hydrolysis of OB is suppressed by the CDs. 6 To analyze these applications of CDs at the molecular level, we need the solution structures of OB and its complexes with the CDs. Previously, the solution structures of OB and its complex with R-CD were determined by NMR and calculations of molecular mechanics, molecular dynamics, and molecular surface areas.…”

“…9,10 However, because most of the structures were determined on the basis of qualitative estimations of NOE cross-peak intensities, the precision in atomic coordinates is low. On the other hand, although detailed structures of CD complexes have been supplied by calculations of molecular mechanics and molecular dynamics, 6,11 they have not fully been compared to NMR data. 9,10 The solution structures of biopolymers have been determined by molecular mechanics or dynamics calculations using the structural information (interproton distances, dihedral angles, and others) obtained by NMR.…”

“…Electromotive force data indicated the 1:1 stoichiometry of OB with α-, β-, and γ-CD . The basic hydrolysis of OB is suppressed by the CDs . To analyze these applications of CDs at the molecular level, we need the solution structures of OB and its complexes with the CDs.…”

“…The solution structures of CD inclusion complexes have been estimated mainly by chemical shifts, vicinal spin−spin coupling constants, and NOE of NMR. , However, because most of the structures were determined on the basis of qualitative estimations of NOE cross-peak intensities, the precision in atomic coordinates is low. On the other hand, although detailed structures of CD complexes have been supplied by calculations of molecular mechanics and molecular dynamics, , they have not fully been compared to NMR data. , The solution structures of biopolymers have been determined by molecular mechanics or dynamics calculations using the structural information (interproton distances, dihedral angles, and others) obtained by NMR. , This strategy has not been applied to determine the solution structures of CD complexes. Very recently, we have determined rather fine solution structures of α-CD complexes on the basis of quantitative evaluation of NOE cross-peak intensities. , Because β- and γ-CDs have wider cavities than α-CD, their complexes can have many plausible structures.…”