What Is 4-Tolylboronic Acid CAS 5720-05-8? Properties, Uses, and Buying Considerations

4-Tolylboronic acid, also called 4-methylphenylboronic acid or p-tolylboronic acid, is an aromatic boronic acid used primarily as a coupling partner in organic synthesis. It is identified by CAS Registry Number 5720-05-8, has the molecular formula C₇H₉BO₂, and a molecular weight of approximately 135.96 g/mol. In practical terms, I would evaluate it as a functional building block for forming carbon–carbon bonds, especially in Suzuki–Miyaura coupling reactions.

Click here to get more.

For B2B purchasing, the chemical name alone is not enough. I recommend confirming identity, assay, water content, residual solvents, particle form, packaging, documentation, and supply continuity before approving a supplier. The most suitable grade depends on whether the material is required for medicinal chemistry, process development, agrochemical research, or larger-scale intermediate manufacturing.

What Is 4-Tolylboronic Acid?

4-Tolylboronic acid contains a methyl-substituted phenyl ring and a boronic acid functional group. The boronic acid group can participate in palladium-catalyzed cross-coupling with suitable aryl or vinyl halides, allowing chemists to introduce a 4-methylphenyl group into a target molecule. This reactivity is the main reason it is maintained in many organic synthesis catalogs and procurement programs.

I generally describe the material as a solid aromatic reagent that is commonly supplied as a white to off-white powder or crystalline solid, although actual appearance can vary with manufacturing history, particle size, and storage conditions. It has limited compatibility with water compared with many inorganic borates, while solvent behavior depends on concentration, temperature, and the selected organic solvent. Buyers should rely on the supplier’s current specification and certificate of analysis rather than appearance alone.

Core Functions and Chemical Value

Carbon–Carbon Bond Formation

The principal function of 4-tolylboronic acid is to provide a 4-methylphenyl group during cross-coupling. In a Suzuki–Miyaura reaction, the boronic acid commonly reacts with an aryl, heteroaryl, or vinyl halide in the presence of a suitable palladium catalyst and base. The exact catalyst, base, solvent, temperature, and reaction time must be selected for the substrate and process objective; they should not be assumed from the reagent name alone.

Flexible Synthetic Building Block

The para-methyl substituent can contribute useful hydrophobic and electronic characteristics to a target structure. For this reason, the compound may be considered during the preparation of pharmaceutical intermediates, fine chemicals, screening compounds, and advanced organic materials. Its value is usually measured by how reliably it supports the next synthetic step, rather than by its standalone physical properties.

Common Application Scenarios

In pharmaceutical and medicinal chemistry, 4-tolylboronic acid can be used to prepare substituted biaryl and heteroaryl compounds for discovery programs. Researchers may select it when a para-methylphenyl fragment is required and when the route benefits from a convergent coupling step. At this stage, small pack sizes and rapid analytical confirmation can be more important than long-term bulk pricing.

In process research and fine chemical manufacturing, the purchasing focus shifts toward lot consistency, impurity control, scalable packaging, and dependable replenishment. A manufacturing team may also need information about bulk density, dust handling, storage conditions, and transfer behavior. These operational details should be reviewed before moving from laboratory scale to pilot or production scale.

The material may also be relevant to agrochemical intermediates, specialty molecules, and research chemicals. However, suitability depends on the complete reaction route and regulatory requirements for the final product. I would not treat 4-tolylboronic acid as a universal substitute for other boronic acids or boronate esters without route-specific evaluation.

Types and Material Options to Consider

Buyers may encounter different commercial options based on assay, packaging, particle size, and intended use. A research grade may be offered in small containers for route screening, while a production-oriented supply program may require larger packaging, repeat lots, and stronger change-control communication. These labels are not standardized across all suppliers, so I recommend comparing the actual specification rather than relying only on the grade name.

If you want to learn more, please visit our website Maison Chemical.

4-Tolylboronic acid should also be distinguished from related materials such as 4-tolylboronic acid pinacol ester, other positional isomers, and substituted arylboronic acids. These compounds may perform differently in a reaction and should not be considered interchangeable without laboratory confirmation. If a process uses the pinacol ester, a buyer should request a separate quotation and specification for that exact product.

Key Specifications to Review

A practical specification review should begin with identity and assay. The molecular weight is approximately 135.96 g/mol, which is useful for calculating charge quantities; for example, 10 mmol corresponds to approximately 1.36 g before adjusting for assay. I recommend requesting an assay target, such as ≥98.0%, only when that level matches the needs of the application, because higher purity can affect cost and availability.

I also advise checking whether the certificate of analysis is lot-specific. A generic specification sheet can explain the product standard, but it does not replace data for the actual batch being shipped. For process work, the buyer may additionally request chromatographic data, elemental information, or a defined impurity profile based on the route requirements.

Buyer Selection Factors

Match Purity to the Process

Higher assay is not automatically the best commercial choice if the synthesis can tolerate a broader impurity profile. Conversely, a sensitive catalytic reaction may require tighter controls on metals, moisture, or reactive impurities. I recommend defining critical quality attributes with the chemist, process engineer, and quality team before requesting comparable quotations.

Evaluate Supply Reliability

Price should be reviewed together with minimum order quantity, lead time, batch availability, and replenishment planning. A low unit price may not be economical if the supplier cannot support repeat orders or if every shipment requires a new qualification. Ask whether the quoted quantity is available from stock, planned production, or a custom manufacturing schedule.

Check Documentation and Change Control

For B2B use, I suggest requesting a current specification, lot-specific certificate of analysis, safety data sheet, packaging details, and country-of-origin information where required. If the material will enter a regulated or quality-controlled workflow, clarify how the supplier communicates changes to raw materials, process, site, analytical method, or packaging. Documentation should be reviewed by the buyer’s quality and regulatory functions when applicable.

How Maison Chemical Can Support Procurement

At Maison Chemical, I approach 4-Tolylboronic acid sourcing as a specification-matching exercise rather than a simple catalog transaction. I can help organize an inquiry around CAS 5720-05-8, required assay, intended application, quantity, packaging, destination, and documentation needs. This information allows the supply proposal to be assessed against the buyer’s actual technical and commercial requirements.

For an initial inquiry, I recommend providing the estimated sample quantity, expected annual demand, target delivery date, required purity, and any special testing or packaging conditions. If the project is still in development, we can begin with a smaller evaluation quantity and discuss the information needed for later scale-up. Final availability, price, lead time, and specifications should always be confirmed in a formal quotation and current product documentation.

Key Takeaways for Buyers

• 4-Tolylboronic acid CAS 5720-05-8 is an aromatic boronic acid and a useful 4-methylphenyl building block.
• Its main synthetic role is participation in carbon–carbon coupling, particularly Suzuki–Miyaura chemistry.
• The molecular formula is C₇H₉BO₂, and the molecular weight is approximately 135.96 g/mol.
• Buyers should verify assay, identity, moisture, residual solvents, impurities, packaging, and lot-specific documentation.
• 4-Tolylboronic acid and its pinacol ester are related but distinct products and should be quoted and qualified separately.

Conclusion: Is 4-Tolylboronic Acid Right for Your Project?

4-Tolylboronic acid CAS 5720-05-8 is a practical synthetic intermediate when a route requires introduction of a para-methylphenyl group through cross-coupling. Its suitability depends on the reaction system, impurity tolerance, required scale, and quality documentation—not only on the product name or headline assay. I recommend confirming the exact material identity and reviewing a representative lot certificate before technical approval.

The next step is to define your target purity, quantity, packaging, delivery schedule, and documentation requirements. Send these details to Maison Chemical for a B2B quotation and supply assessment. We can then help you compare the appropriate material option against your synthesis, quality, and procurement objectives.

If you are looking for more details, kindly visit 4-Tolylboronic acid CAS 5720-05-8.