(4-(1-(3-(Cyanomethyl)-1-(ethylsulfonyl)azetidin-3-yl)-1H-pyrazol-4-yl)-7H-pyrrolo[2,3-d]pyrimidin-7-yl)methyl Pivalate

This substance is usually isolated as a white to pale beige crystalline solid. Its molecular formula is C18H27BN4O4, corresponding to a molecular weight of 374.24. The melting point generally lies between 142 °C and 146 °C, indicating a consistent crystal lattice. The estimated density is around 1.21 g/cm³ at room temperature. It dissolves readily in common organic solvents such as dichloromethane, tetrahydrofuran, ethyl acetate, and dimethyl sulfoxide, but is only sparingly soluble in methanol and practically insoluble in water and aliphatic hydrocarbons. The pinacol boronate ester moiety is prone to slow hydrolysis in the presence of moisture, so storage under an inert atmosphere in a tightly sealed container at 2–8 °C is advised. Contact with strong oxidizing agents and strong bases should be avoided.

The molecule features a fused pyrazolo[3,4‑d]pyrimidine core, a nitrogen‑rich heterocyclic system combining a pyrazole ring with a pyrimidine ring. At the 4‑position, a pinacol‑protected boronic acid is attached, offering a masked cross‑coupling handle for Suzuki–Miyaura reactions. The pyrimidine nitrogen at the 1‑position carries a tert‑butoxycarbonyl (Boc) protecting group, which shields the basic nitrogen and can be selectively removed under acidic conditions. This dual protection strategy-Boc on the heterocycle and pinacol on the boronate-allows orthogonal functionalization in multistep syntheses. The rigid, planar heteroaromatic core combined with the protected boronic acid makes this compound a versatile intermediate for constructing diverse molecular libraries in medicinal chemistry and materials science.

Pharmaceutical Intermediate for Kinase Inhibitors

The pyrazolo[3,4‑d]pyrimidine scaffold is a privileged structure in the design of ATP‑competitive kinase inhibitors. This boronate ester enables the introduction of the core fragment into more complex molecules via cross‑coupling with aryl or heteroaryl halides. Subsequent deprotection of the Boc group reveals a basic nitrogen that can be further elaborated to optimize binding interactions with kinase active sites.

Building Block for PROTAC Development

In targeted protein degradation research, this compound serves as a handle for attaching the pyrazolopyrimidine warhead to E3 ligase ligands. The boron functionality allows conjugation to linker moieties through Suzuki couplings, while the protected amine ensures selective modification. Such constructs are evaluated for their ability to induce degradation of oncogenic proteins in cancer therapy.

Ligand for Metal–Organic Frameworks

After deprotection of the Boc group, the pyrazolopyrimidine unit can coordinate to transition metals, forming the basis for porous coordination polymers. The boronate ester can be hydrolyzed to the corresponding boronic acid, enabling further crosslinking or surface anchoring. These materials are investigated for gas storage, sensing, and heterogeneous catalysis applications.

Synthetic Intermediate for Heterocyclic Libraries

The orthogonal protecting groups allow sequential functionalization: first, cross‑coupling at the boronate site; then, Boc removal followed by N‑alkylation or acylation. This strategy enables rapid generation of diverse pyrazolopyrimidine derivatives for high‑throughput screening in drug discovery programs targeting oncology, inflammation, and infectious diseases.