Design, Synthesis, and Structural Analysis of d,l-Mixed Polypyrrolinones. 2. Macrocyclic Hexapyrrolinones

The design, synthesis, and structural analysis of two macrocyclic d,l-alternating hexapyrrolinones have been achieved. These cyclic peptide mimics adopt a flat, hexagonal conformation, stabilized by intramolecular hydrogen bonding between adjacent pyrrolinone rings. Extensive NMR studies and X-ray analysis reveal, respectively, that the macrocyclic hexapyrrolinones aggregate in solution and in the solid state form staggered stacked nanotube-like assemblies.