Novel cage-type cyclophanes, which are constructed with two rigid macrocyclic skeletons, tetraaza[126.96.36.199]paracyclophanes, and four bridging segments composed of either β-L-aspartyl-L-aspartyl or β-D-aspartyl-D- aspartyl residues were prepared [(-)-1 and (+)-1, respectively]. Structural and asymmetric properties of these cage-type cyclophanes were characterized by 1H NMR and circular dichroism (CD) spectroscopy. The guest-binding behavior of the cage-type hosts toward fluorescent guests, such as 8- anilinonapththalene-1-sulfonate and 6-p-toluidinonaphthalene-2-sulfonate, was examined in comparison with those demonstrated by the corresponding non-cage hosts in aqueous media. The microenvironmental polarity around the fluorescent guests and their fluorescence polarization values in the presence of the cage-type hosts revealed that these guest molecules were incorporated into apolar host cavities, and their rotational motion was largely restricted. Furthermore, chiral host-guest interactions between the hosts and a hydrophobic guest, pamoic acid (PA), were examined by CD spectroscopy. PA was subjected to stereochemical changes to assume P- and M-helix configurations in the presence of (-)-1 and (+)-1, respectively.
All Science Journal Classification (ASJC) codes
- Drug Discovery
- Organic Chemistry