1-(Tetrahydropyran-2-yl)-1H-pyrazole-5-boronic acid pinacol ester, CAS 903550-26-5, is primarily used as a boron-containing building block in medicinal chemistry and pharmaceutical intermediate synthesis. Its boronic ester group can participate in palladium-catalyzed Suzuki–Miyaura cross-coupling to form a carbon–carbon bond with a suitable aryl or heteroaryl halide. The tetrahydropyranyl group protects the pyrazole nitrogen during selected synthetic steps and may be removed later when the free pyrazole functionality is required.
In practical terms, research and process chemists use this compound to introduce a substituted pyrazole fragment into more complex molecules. It is usually purchased for route scouting, analogue synthesis, custom intermediate development, and small-scale process research rather than for direct formulation into a finished pharmaceutical product. The exact suitability depends on the customer’s coupling partner, reaction conditions, purity requirement, and downstream deprotection strategy.
The molecule combines a pyrazole ring with a tetrahydropyran-2-yl protecting group and a pinacol boronate ester. This structure allows a chemist to introduce a protected pyrazole-containing fragment into a target scaffold through a cross-coupling reaction. After coupling, the protecting group can be evaluated for removal under conditions compatible with the rest of the molecule.
The pyrazole ring is a common heteroaromatic motif in medicinal chemistry because it can contribute hydrogen-bonding, polarity, and molecular-recognition properties. However, the role of this particular intermediate is synthetic rather than pharmacological: the compound is generally a starting material or advanced building block, not an active pharmaceutical ingredient. Final use must therefore be determined from the complete synthetic route and product specifications.
The boronic ester is designed to serve as a transferable carbon partner in Suzuki–Miyaura coupling. In a typical route, the boronic ester is reacted with an aryl, heteroaryl, or vinyl halide under a suitable palladium catalyst and base system. The actual catalyst loading, solvent, temperature, reaction time, and purification method must be developed for the specific substrate pair rather than assumed from the product name.
The Suzuki–Miyaura reaction is widely documented for forming carbon–carbon bonds between organoboron compounds and organic halides. The Royal Society of Chemistry describes Suzuki coupling as a major method for constructing biaryl and related structures, while the U.S. National Library of Medicine’s PubChem database provides a reference point for chemical identity information associated with registered compounds. These sources support the general reaction role, but they do not replace route-specific laboratory validation.
Medicinal chemists may use CAS 903550-26-5 when preparing a series of pyrazole-containing analogues. By changing the halide coupling partner, researchers can vary the aryl or heteroaryl substituent while retaining the same protected pyrazole-boronate component. This approach can support structure–activity relationship studies, where multiple related compounds are prepared for biological evaluation.
The compound can be especially useful when a project requires a protected N-pyrazole structure during the bond-forming stage. Protecting-group selection is route-dependent, so researchers should confirm that the tetrahydropyranyl group is compatible with subsequent oxidation, reduction, hydrolysis, hydrogenation, or other planned operations. A small-scale compatibility experiment is advisable before committing to a larger campaign.
In pharmaceutical intermediate development, this material may be used as an input for preparing a more advanced heteroaromatic intermediate. Its value is the combination of a defined pyrazole fragment and a reactive boronate handle in one molecule. This can reduce the number of early-stage functionalization steps compared with constructing the pyrazole and carbon–carbon bond independently.
For process development, the important questions include reaction conversion, impurity profile, isolation behavior, residual palladium control, and the stability of the boronate during storage and handling. These factors cannot be inferred from CAS registration alone. A buyer should request a current certificate of analysis and, where relevant, analytical data such as HPLC, NMR, water content, and residual solvent results.
Custom synthesis teams may screen this building block in parallel with related pyrazole boronates or alternative protected intermediates. It can be used to compare coupling performance, deprotection behavior, and isolation yield across several route options. Because reaction performance varies with substrate electronics and steric effects, a supplier’s technical response should focus on documented batch information rather than generalized claims of universal compatibility.
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Buyers may encounter several material options for this type of intermediate. The first option is standard research-grade material for discovery chemistry, where the main need is identity confirmation and a defined assay range. The second is a higher-control batch intended for process research, where impurity limits, residual solvents, water content, and trace metals may receive greater attention.
Alternative route materials may include an unprotected pyrazole boronic ester, a different nitrogen-protecting group, or a halogenated pyrazole intermediate. These alternatives are not automatically interchangeable because they can differ in stability, solubility, coupling behavior, and deprotection conditions. Our role as a chemical supplier is to help compare the requested compound with the customer’s route requirements before quotation.
Public chemical databases and supplier records commonly identify this product by CAS 903550-26-5 and the name 1-(Tetrahydropyran-2-yl)-1H-pyrazole-5-boronic acid pinacol ester. A commonly reported molecular formula is C14H23BN2O3, with a calculated molecular weight of approximately 278.16 g/mol. These identity data should be checked against the specific batch documentation because naming conventions, database records, and commercial specifications may differ.
| Parameter | Reference information | Buyer action |
|---|---|---|
| CAS number | 903550-26-5 | Confirm that the CAS number matches the purchase request and documentation. |
| Approximate molecular formula | C14H23BN2O3 | Compare the formula with the supplier’s current COA and analytical records. |
| Approximate molecular weight | 278.16 g/mol | Use the batch-confirmed value for weighing and molar calculations. |
| Pyrazole nitrogen atoms | 2 atoms in the pyrazole ring | Consider nitrogen protection and deprotection requirements in the route. |
| Boronate ester function | 1 boron atom per molecule | Evaluate coupling performance with the selected electrophile. |
| Oxygen atoms | 3 atoms in the commonly listed formula | Confirm structure and identity by the supplier’s analytical package. |
Assay, appearance, water content, residual solvents, particle form, and storage instructions should not be assumed unless they are stated in the current product specification. For regulated or scale-up work, buyers should also clarify whether the material is supplied as a single defined batch, whether retest information is available, and which analytical methods are used for release. PubChem and other public databases are useful for identity cross-checking, but a batch-specific certificate of analysis remains the appropriate document for purchasing decisions.
First, confirm that the target route requires a protected N-substituted pyrazole boronate rather than an unprotected boronic acid or another boronate ester. Next, review whether the selected coupling partner contains functional groups that may interfere with palladium catalysis, base exposure, or boronate stability. Finally, determine whether the tetrahydropyranyl protecting group can be removed under conditions that will not damage the target scaffold.
For discovery use, identity confirmation and a practical assay specification may be sufficient. For process development, the buyer may need HPLC or GC data, NMR confirmation, water content, residual solvent information, elemental analysis, and trace-metal data where applicable. We recommend confirming the required specification before production because a material suitable for early route screening may not meet later-stage process expectations.
The required quantity may range from milligram-level material for initial screening to gram or kilogram quantities for process studies. Packaging should protect the material from unsuitable moisture, heat, light, or repeated exposure during handling, based on the supplier’s documented recommendations. Buyers should request the available pack sizes, minimum order quantity, lead time, shipping conditions, and export documentation before placing an order.
At Maison Chemical, we supply pharmaceutical intermediates and specialty chemical building blocks for research, development, and industrial sourcing programs. For CAS 903550-26-5, we can help customers confirm the requested chemical identity, review available quality documentation, and assess whether the requested specification fits discovery or process-development use. We use a practical B2B approach: clarify the route requirement first, then align the product, documentation, quantity, and delivery plan.
Our support may include quotation coordination, batch and packaging discussion, specification review, export documentation, and communication with technical or procurement teams. We do not treat a general product name as a substitute for batch verification. If your project has a defined assay range, impurity threshold, analytical method, or delivery schedule, sharing those requirements at the inquiry stage can improve sourcing accuracy.
1-(Tetrahydropyran-2-yl)-1H-pyrazole-5-boronic acid pinacol ester CAS 903550-26-5 is used primarily to introduce a protected pyrazole fragment into more complex molecules, especially through Suzuki–Miyaura cross-coupling. It is relevant to medicinal chemistry, pharmaceutical intermediate development, analogue synthesis, and custom route research. It is not normally selected as a finished drug substance; its value lies in its role as a functional synthetic intermediate.
Before purchasing, we recommend confirming the CAS number, molecular identity, required assay, analytical documentation, pack size, and intended reaction sequence. Contact Maison Chemical with your target quantity and specification requirements so we can review available supply options and provide a commercially appropriate quotation for your project.
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