Tetravalent Boron-based Therapeutics
The pharmacological uses of boron-containing compounds have been known for several decades, and many compounds have been investigated in preclinical and clinical trials. Of these, four are clinically approved: bortezomib (Velcade®) for the treatment of multiple myeloma, tavaborole (Kerydin®) for the treatment of onychomycosis of the toenails, and boron-10-enriched boronophenylalanine and sodium borocaptate for the boron neutron capture therapy of high-grade gliomas and head and neck cancers. The number of boron-containing therapeutics continues to increase as more efficient and greener synthetic procedures are discovered, and new compounds are available for preclinical and clinical evaluations. This chapter reviews the main classes of tetravalent boron-containing therapeutics under investigation, with emphasis on boron dipyrromethene (known as BODIPY) derivatives, and on naturally occurring or inspired compounds. Such boron-containing therapeutics can display an array of biological activities, including anticancer, antiviral, antibacterial, and antifungal properties.