Design, Synthesis, and Evaluation of B-(Trifluoromethyl)phenyl Phosphine–Borane Derivatives as Novel Progesterone Receptor Antagonists

Abstract

We previously revealed that phosphine–boranes can function as molecular frameworks for biofunctional molecules. In the present study, we exploited the diversity of available phosphines to design and synthesize a series of B-(trifluoromethyl)phenyl phosphine–borane derivatives as novel progesterone receptor (PR) antagonists. We revealed that the synthesized phosphine–borane derivatives exhibited LogP values in a predictable manner and that the P–H group in the phosphine–borane was almost nonpolar. Among the synthesized phosphine–boranes, which exhibited PR antagonistic activity, B-(4-trifluoromethyl)phenyl tricyclopropylphosphine–borane was the most potent with an IC50 value of 0.54 μM. A docking simulation indicated that the tricyclopropylphosphine moiety plays an important role in ligand–receptor interactions. These results support the idea that phosphine–boranes are versatile structural options in drug discovery, and the developed compounds are promising lead compounds for further structural development of next-generation PR antagonists.