Boron-Based Heterocycles in Medicinal Chemistry
Boron has become an increasingly valued element in the medicinal chemist's toolkit. Its Lewis acidity, arising from an electron-deficient boron centre, allows it to form reversible covalent interactions with nucleophilic residues in a target's active site. When incorporated into carbon or heterocyclic frameworks, boron can act as a bioisostere, altering polarity, hydrogen bonding and solubility in ways few other elements can offer. Five boron-containing drugs have now been approved by the FDA, spanning four therapeutic areas. In oncology, bortezomib and ixazomib use a C-terminal boronic acid to inhibit the proteasome in multiple myeloma. The benzoxaboroles have proven particularly versatile. Tavaborole inhibits fungal leucyl-tRNA synthetase for onychomycosis, while in crisaborole the boron atom has been shown to bind the zinc and magnesium ions in the active site of PDE4 for atopic dermatitis. Vaborbactam, a cyclic boronate β-lactamase inhibitor, extends the reach of meropenem against resistant bacterial infections. Late-stage benzoxaborole candidates such as epetraborole and acoziborole suggest the clinical pipeline remains active. Beyond these approved examples, the toolkit is widening. A 2026 review in ChemMedChem highlights BN-for-CC replacement in azaborines and BN-indoles, with several azaborine-based HDAC inhibitors reported to reach nanomolar potency. Carboranes, whose spherical volume is often compared to a rotating phenyl ring, are being explored as three-dimensional phenyl replacements, and in some series have been reported to outperform their parent compounds. Explore our range of building blocks using the advanced search tools at https://lnkd.in/eVbfw6Ua To read more, take a look at the following papers: 1\) Boron-Based Bioisosteres in Medicinal Chemistry: Advances in Heterocycles and Therapeutic https://lnkd.in/eZXr8-qn 2\) Recent Advancements in the Diversification and Applications of Boron-Containing Compounds in Medicinal Chemistry https://lnkd.in/ejBwW4nu 3\) Escaping from Flatland: 3D Carborane-Based Bioisosteres of Erlotinib as Potential Anticancer Agents https://lnkd.in/eRcdrM8A