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Cucurbit[7]uril: A High‐Affinity Host for Encapsulation of Amino Saccharides and Supramolecular Stabilization of Their α‐Anomers in Water
Author(s) -
Jang Yoonjung,
Natarajan Ramalingam,
Ko Young Ho,
Kim Kimoon
Publication year - 2014
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201308879
Subject(s) - isothermal titration calorimetry , chemistry , anomer , supramolecular chemistry , stereochemistry , hydrochloride , nuclear magnetic resonance spectroscopy , protonation , organic chemistry , molecule , biochemistry , ion
Cucurbit[7]uril (CB[7]), an uncharged and water‐soluble macrocyclic host, binds protonated amino saccharides ( D ‐glucosamine, D ‐galactosamine, D ‐mannosamine and 6‐amino‐6‐deoxy‐ D ‐glucose) with excellent affinity ( K a =10 3 to 10 4 M −1 ). The host–guest complexation was confirmed by NMR spectroscopy, isothermal titration calorimetry (ITC), and MALDI‐TOF mass spectral analyses. NMR analyses revealed that the amino saccharides, except D ‐mannosamine, are bound as α‐anomers within the CB[7] cavity. ITC analyses reveal that CB[7] has excellent affinity for binding amino saccharides in water. The maximum affinity was observed for D ‐galactosamine hydrochloride ( K a =1.6×10 4 M −1 ). Such a strong affinity for any saccharide in water using a synthetic receptor is unprecedented, as is the supramolecular stabilization of an α‐anomer by the host.