Design, Properties and Recent Application of Macrocycles in Medicinal Chemistry.

Macrocyclic compounds have recently received increasing attention in drug discovery as these compounds offer the potential to modulate difficult targets and to access novel chemotypes. Approaches towards libraries of macrocyclic compounds based on modular organic synthesis and applications of these technology platforms to find and improve biologically active compounds are introduced in this minireview. Alternatively, lead compounds may be obtained by truncation and modification of macrocyclic natural products. Selected medicinal chemistry programs are discussed, illustrating a macrocyclization approach toward ligands with improved properties. The design of such ligands is often informed by X-ray crystal structures of protein-ligand complexes. Efforts to understand cellular permeability and oral bioavailability of cyclic peptides and non-peptidic macrocycles are summarized.