What Is 1-(Tetrahydropyran-2-yl)-1H-pyrazole-5-boronic Acid Pinacol Ester CAS 903550-26-5?

1-(Tetrahydropyran-2-yl)-1H-pyrazole-5-boronic acid pinacol ester is a protected pyrazole boronic ester used primarily as a synthetic building block in medicinal chemistry, pharmaceutical intermediate research, and advanced organic synthesis. Its CAS number is 903550-26-5, and its calculated molecular formula is C₁₄H₂₃BN₂O₃, with a molecular weight of approximately 278.16 g/mol. The molecule combines a pyrazole ring, a tetrahydropyranyl protecting group, and a pinacol boronic ester, allowing chemists to introduce a substituted pyrazole unit through cross-coupling chemistry.

Please visit our website for more information on this topic.

In practical terms, I would classify this material as a research and production intermediate rather than as a finished pharmaceutical ingredient. Its suitability depends on the intended reaction, required purity, analytical documentation, packaging, and supply quantity. Maison Chemical supports B2B buyers by coordinating product specifications and quotation requirements for this type of specialty chemical.

Structure and Chemical Identity

The compound contains three important structural elements. The first is a pyrazole ring, which is a five-membered aromatic heterocycle containing two nitrogen atoms. The second is a tetrahydropyran-2-yl group attached to the pyrazole nitrogen, while the third is a boronic acid pinacol ester at the 5-position of the pyrazole ring.

The boronic ester portion is particularly important in synthetic planning because organoboron compounds are commonly used as partners in carbon–carbon bond-forming reactions. The tetrahydropyranyl group can serve as a nitrogen-protecting group, helping control the reactivity of the pyrazole during selected synthetic steps. Whether deprotection is appropriate depends on the reaction sequence, substrate sensitivity, and process conditions selected by the chemist.

Core Functions in Synthetic Chemistry

Pyrazole Building-Block Function

This compound provides a preorganized pyrazole framework for the preparation of more complex molecules. Pyrazoles are present in many medicinal chemistry programs because their nitrogen-containing aromatic structure can contribute to molecular recognition and can be modified at several positions. The protected form may be useful when a synthetic route requires selective manipulation of the boronic ester before exposing the pyrazole nitrogen.

Cross-Coupling Precursor

The pinacol boronic ester is designed to act as an organoboron coupling partner in suitable palladium-catalyzed or related cross-coupling processes. In a typical route, the boron-containing position can be connected to an appropriately functionalized aryl, heteroaryl, or vinyl reaction partner. Reaction performance is not automatic, however, and depends on the catalyst system, base, solvent, temperature, substrate structure, and handling of the boronic ester.

Protected Intermediate

The tetrahydropyranyl group can reduce the direct participation of the pyrazole nitrogen in certain reactions. This protection strategy may improve chemoselectivity in a multistep synthesis, although the optimal protecting group is route-dependent. I recommend evaluating both protection and deprotection requirements before selecting this compound for process development.

Typical Application Scenarios

Researchers may use CAS 903550-26-5 during the discovery and development of heterocyclic compounds. Common project settings include small-molecule library synthesis, route scouting, medicinal chemistry optimization, and preparation of advanced intermediates for further functionalization. The material may also be considered when a project needs a pyrazole fragment that can be coupled before final nitrogen deprotection.

For laboratory screening, a chemist may plan a reaction using a sub-millimole to several-millimole scale, depending on substrate availability and experimental objectives. For example, a 0.10 mmol trial can help assess conversion and selectivity before larger experimentation. This is a planning example rather than a guaranteed operating condition; the correct scale must be established through the buyer’s own reaction development work.

Link to Maison Chemical

Material Options and Specification Considerations

Buyers generally need to distinguish between material identity, assay, physical form, packaging, and documentation. A supplier quotation should clearly state the product name, CAS number, batch information where available, net quantity, and the applicable specification. Appearance and storage recommendations should also be confirmed because boronic esters can require controlled handling to preserve quality during storage.

Purity should be discussed in relation to the intended use. Discovery screening may accept a different specification from a regulated process intermediate, while a scale-up project may require impurity profiling, residual solvent information, and batch-to-batch consistency. I recommend treating any stated purity value as a product-specific specification that must be confirmed by a current certificate of analysis rather than assuming that all lots have identical performance.

Key Information to Request

• CAS number and chemical name confirmation
• Molecular formula and molecular weight
• Assay or purity method and result
• Water content or other relevant quality indicators, when required
• Residual solvent information, when relevant to the project
• Analytical data such as HPLC, NMR, or mass spectrometry, subject to availability
• Packaging, storage conditions, shelf-life statement, and lot traceability

How Buyers Should Select a Supplier

Supplier selection should begin with technical identity and documentation, not only with price. I suggest checking whether the supplier can confirm the exact CAS number, provide a product-specific specification, and explain the available package sizes. For an initial evaluation, a buyer may request a 1 g or 5 g quantity if available, then discuss larger quantities after confirming reaction performance and material suitability.

Lead time and minimum order quantity should be confirmed in writing because specialty intermediates may be supplied from available inventory, scheduled production, or an external manufacturing arrangement. A short quoted lead time does not necessarily mean that the same lot can be replenished later. For continuing projects, buyers should ask about repeat-batch planning, packaging format, shipment conditions, and the process for handling technical questions.

Technical and Commercial Evaluation Checklist

1. Confirm the product identity against CAS 903550-26-5.
2. Compare the offered specification with the project’s required assay and impurity limits.
3. Review the available analytical and batch documentation.
4. Confirm quantity, packaging, MOQ, lead time, and delivery terms.
5. Assess whether the supplier can support repeat orders or route-development requirements.

Maison Chemical Supplier Support

At Maison Chemical, I focus on helping chemical and pharmaceutical-intermediate buyers translate a technical requirement into a practical sourcing request. For 1-(Tetrahydropyran-2-yl)-1H-pyrazole-5-boronic acid pinacol ester, the inquiry should include the desired quantity, target purity, intended use, destination country, and documentation requirements. This information helps us assess the appropriate supply route and prepare a more relevant quotation.

Our support can include product identity confirmation, specification discussion, packaging coordination, and communication about available quantities and lead time. If the material is intended for route development or scale-up, I also recommend sharing whether the project requires a single evaluation lot or a repeat supply plan. Any technical or quality requirement should be agreed before purchase so that the supplied material can be evaluated against the buyer’s actual process needs.

Key Takeaways

• CAS 903550-26-5 is a protected pyrazole boronic ester used as a synthetic intermediate.
• Its structure contains a pyrazole ring, a tetrahydropyranyl protecting group, and a pinacol boronic ester.
• The calculated molecular formula is C₁₄H₂₃BN₂O₃, with an approximate molecular weight of 278.16 g/mol.
• Its principal value is as a coupling-ready building block for medicinal chemistry and advanced organic synthesis.
• Buyers should verify purity, analytical documentation, packaging, MOQ, lead time, and repeat-supply capability before ordering.

Conclusion: Is This the Right Intermediate for Your Project?

1-(Tetrahydropyran-2-yl)-1H-pyrazole-5-boronic acid pinacol ester CAS 903550-26-5 is a useful choice when a synthesis requires a protected pyrazole fragment with an organoboron handle for further functionalization. Its structure supports cross-coupling-based route design, while the tetrahydropyranyl group may provide useful control over pyrazole nitrogen reactivity. The final decision should be based on the complete reaction sequence, not on the product name alone.

As a next step, prepare your required quantity, target specification, delivery location, and documentation list. Send these details to Maison Chemical for product and supply evaluation. We can then discuss the appropriate package size, available quality information, lead time, and commercial terms for your project.

If you want to learn more, please visit our website 1-(Tetrahydropyran-2-yl)-1H-pyrazole-5-boronic acid pinacol ester CAS 903550-26-5.