Novel Folding Patterns in a Family of Oligoanthranilamides:  Non-Peptide Oligomers That Form Extended Helical Secondary Structures

Anthranilamide derivatives are used as the basis for a series of novel oligomers that fold into helical secondary structures in the solid state. When combined with pyridine-2,6-dicarboxylic acid and 4,6-dimethoxy-1,3-diaminobenzene subunits, oligoanthranilamides can be induced to take up a coiled conformation corresponding to two turns of a helix. X-ray crystallography shows that intramolecular hydrogen bonding and π−π stacking interactions are important in stabilizing the extended helical structures. Furthermore, both experimental and calculated 1 H NMR methods indicate that related conformations are taken up by the oligomers in chloroform solution.