| Abstract
| - This paper describes the synthesis and characterization of the first series of hydrogen bonding-driven hydrazide foldamers and their recognition for alkyl saccharides in chloroform. Oligomers 1, 2−4, 5,6, and 7, which contain one, two, four, six, or twelve repeated dibenzoyl hydrazide residues, respectively,have been prepared. The rigid and planar conformations of 1 and 2 or 4 have been established with X-rayanalysis and 1H NMR spectroscopy, whereas the folding and helical conformations of 5−7 have beenevidenced by the 1D and 2D 1H NMR and IR spectroscopy and molecular mechanics calculations. Molecularmechanics calculations also revealed that 5, 6, and 7 possess a rigid cavity with size of ca. 10.6 to 11.1Å, and half of the carbonyl groups in the folding conformations are orientated inwardly inside the cavity. 1HNMR and CD experiments revealed that 5−7 efficiently complex alkylated mono- and disaccharides 32−35 in chloroform. The association constants (Kassoc) of the complexes have been determined with the 1HNMR and fluorescent titration methods. The energy-minimized conformation of 6·34 has been obtainedwith molecular mechanics calculation. The hydrazide-based folding structures described here representnovel examples of hydrogen bonding-driven foldamers that act as artificial receptors for selective molecularrecognition.
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