Macrocyclic Compounds: Emerging Opportunities for Current Drug Discovery.

The macrocycles representing a unique chemical structure bridging conventional small molecules and large biomolecules, have attracted more and more attention in drug discovery over the past decade, and tremendous progress has been made toward the macrocyclization synthesis and structure diversification recently. Because of their favored size, flexibility and complexity, macrocycles can engage previously undruggable targets through numerous and spatially distributed binding interactions, and offer many privileged features including high potency, prominent selectivity, as well as favorable pharmacokinetics properties, and unique intellectual property(IP) space, and even safety profiles, etc. Currently around 70 macrocyclic molecules have been approved for clinical therapy, over 76 macrocycles are being evaluated in clinical trials from phase I to phase III. It is believed that the macrocycles will play more and more important role in the future, and provide very distinctive and promising opportunities for drug discovery along with the development of synthetic methodology, phenotypical screening, and computational studies.