Pyrazole-3-boronic Acid Hydrate | CAS 1310383-92-6 | ≥98%

Pyrazole-3-boronic Acid Hydrate (1H-pyrazol-3-ylboronic acid hydrate) is an unprotected N-heteroarylboronic acid for installing the pyrazol-3-yl unit into coupled aryl and heteroaryl frameworks.

May contain small amounts of the cyclic anhydride pyrazol-3-ylboroxine. Under aqueous or basic coupling conditions the two forms re-equilibrate and the impact on yield is minor.

Applications and Reactions

• Suzuki–Miyaura cross-coupling: used to prepare 3-arylpyrazole and heteroaryl-pyrazole products; because the unprotected N-heteroarylboronic acid is prone to protodeboronation, condition screening is required.
• Protodeboronation-sensitive substrate: pyrazolylboronic acids are prone to C–B loss under mismatched conditions; protected boron forms or milder coupling conditions may improve reliability.
• Unprotected pyrazole handle: the NH-bearing ring is retained in the coupled product, giving direct access to pyrazoles available for later N-functionalisation or salt formation.
• N-heteroaryl scaffold installation: introduces a compact diazole unit with adjacent donor/acceptor nitrogens for structure–property and fragment-extension studies.
• Medicinal-chemistry intermediates: provides pyrazolyl fragments for heteroaryl libraries, kinase-research scaffolds, and other pharmaceutical-intermediate series.
• Agrochemical intermediate synthesis: supports preparation of arylated pyrazole intermediates for crop-science and heterocycle research programmes.

Further Reading

For boronic acids, boronic esters, organotrifluoroborates, protodeboronation, boroxine content, and Suzuki–Miyaura reagent selection, see NorrChemica's Lab Journal guide: Choosing Your Boron Source for Suzuki–Miyaura Coupling.