Pyridin-3-ylboronic Acid | CAS 1692-25-7 | ≥95%

Suzuki–Miyaura cross-coupling and the 3-pyridyl advantage: Pyridin-3-ylboronic acid is one of the most widely used heteroaryl boronic acids in palladium-catalysed Suzuki–Miyaura cross-coupling, enabling efficient installation of the 3-pyridyl fragment onto aryl, heteroaryl, and vinyl halides. The pyridine ring is the most frequently encountered nitrogen heterocycle in FDA-approved drugs — present in over 90 approved pharmaceuticals. The 3-position offers a critical stability advantage over the 2-pyridyl isomer: in 2-pyridylboronic acid, the adjacent ring nitrogen promotes rapid protodeboronation via intramolecular coordination to boron, while at C-3 the nitrogen is two bonds removed, significantly reducing this degradation. Pyridin-3-ylboronic acid therefore couples efficiently under standard conditions — Pd(PPh₃)₄ or Pd(dppf)Cl₂ with K₂CO₃ — without requiring MIDA boronates or trifluoroborate salts. Phosphine-free palladium protocols are also documented.

Kinase inhibitor and anticancer drug synthesis: Pyridin-3-ylboronic acid is a documented key intermediate in the synthesis of Bcr-Abl tyrosine kinase inhibitors for chronic myeloid leukaemia (J. Med. Chem. 2005, 48, 224). It is also associated with the synthesis of CYP17A1 inhibitor analogues for metastatic prostate cancer treatment, where the 3-pyridyl pharmacophore is a core structural element. The compound has been used in microwave-assisted Suzuki coupling to prepare pyridinyl estradiol CYP 1B1 inhibitors with sub-nanomolar potency, relevant to breast cancer chemoprevention where CYP 1B1 catalyses carcinogenic estrogen metabolite formation.

• Broader medicinal chemistry: The 3-pyridyl group is a privileged pharmacophore across virtually all therapeutic areas, present in approved drugs spanning oncology (kinase inhibitors), infectious disease (antiretrovirals, antitubercular agents), inflammation (NSAIDs, PDE4 inhibitors), and gastroenterology (proton pump inhibitors). The pyridine nitrogen enhances water solubility and membrane permeability relative to phenyl, and participates in hydrogen bonding with protein targets — making the 3-pyridyl group a preferred phenyl bioisostere that frequently improves oral bioavailability and metabolic stability without major loss of target affinity.

Coordination chemistry, OLEDs, and metal–organic frameworks: The pyridine nitrogen in Suzuki coupling products serves as a directional donor ligand for Pd, Ir, Pt, Ru, and lanthanide complexes — exploited in catalysis, phosphorescent OLED emitters, and magnetic materials. In MOF chemistry, 3-pyridyl linkers coordinate to metal nodes (Zn²⁺, Cu²⁺, Co²⁺), constructing porous frameworks for gas storage, separation, and sensing. The compound is also employed in fluorescent sensor construction where the pyridine nitrogen recognises metal cations (Zn²⁺, Cu²⁺, Fe³⁺) or protons, providing measurable fluorescence changes upon analyte binding.

Agrochemical and functional materials: The pyridine ring appears in several herbicide and fungicide active ingredients. This boronic acid provides a cross-coupling route for introducing the 3-pyridyl group into agrochemical scaffolds for analogue library generation. In organic electronics, 3-arylpyridine products serve as electron-transport and hole-blocking materials in OLED architectures, where the electron-deficient pyridine ring lowers the LUMO energy and improves electron injection properties.