Development of Potent Mcl-1 Inhibitors: Structural Investigations on Macrocycles Originating from a DNA-Encoded Chemical Library Screen.

Evasion of apoptosis is critical for the development and growth of tumors. The pro-survival protein myeloid cell leukemia 1 (Mcl-1) is an antiapoptotic member of the Bcl-2 family, associated with tumor aggressiveness, poor survival, and drug resistance. Development of Mcl-1 inhibitors implies blocking of protein-protein interactions, generally requiring a lengthy optimization process of large, complex molecules. Herein, we describe the use of DNA-encoded chemical library synthesis and screening to directly generate complex, yet conformationally privileged macrocyclic hits that serve as Mcl-1 inhibitors. By applying a conceptual combination of conformational analysis and structure-based design in combination with a robust synthetic platform allowing rapid analoging, we optimized in vitro potency of a lead series into the low nanomolar regime. Additionally, we demonstrate fine-tuning of the physicochemical properties of the macrocyclic compounds, resulting in the identification of lead candidates 57/59 with a balanced profile, which are suitable for future development toward therapeutic use.

Protective group-free synthesis of 3,4-dihydroxytetrahydrofurans from carbohydrates: formal total synthesis of sphydrofuran.

Carbohydrates are taking a more prominent role in chemistry as an environmentally benign chemical feedstock. However, major efforts are still required to convert unprotected carbohydrates into high-value building blocks. We have investigated the protective group-free Wittig reaction and subsequential acid catalyzed intramolecular cyclization of unprotected carbohydrates to obtain 3,4-dihydroxytetrafurans. In this process, we have found that, when using Lewis acids and poly-alcohol substrates, additional attention should always be given to the catalytic nature of the acid as it might involve its ligands instead of the metal. Furthermore, we illustrate the viability of the concept by a straightforward formal total synthesis of the natural product sphydrofuran from d-xylose.