Mm. Conn et al., CONVERGENT FUNCTIONAL-GROUPS .13. HIGH-AFFINITY COMPLEXATION OF ADENOSINE DERIVATIVES WITHIN INDUCED BINDING POCKETS, Journal of the American Chemical Society, 115(9), 1993, pp. 3548-3557
Receptors based upon 3,6-diaminocarbazole have been synthesized that b
ind to adenosine derivatives with an interaction energy of approximate
ly 8 kcal/mol in CDCl3 and over 3 kcal/mol in CD3OD. The purine nucleu
s is bound within a cavity by simultaneous Watson-Crick and Hoogsteen
base-pairing, hydrogen bonding to N3, and stacking on both of its arom
atic faces. Hydrogen bond interactions can be estimated at approximate
ly 0.5-0.75 kcal/mol in methanol. The structure of the complex in solu
tion has been deduced through binding assays of incremental derivative
s, one- and two-dimensional NMR studies, and molecular modeling.