4-Tolylboronic acid CAS 5720-05-8 is an aryl boronic acid intermediate used primarily to introduce a para-methyl-substituted aryl group into more complex molecules. I see it most often specified for palladium-catalyzed Suzuki–Miyaura cross-coupling, where it reacts with aryl or heteroaryl halides to form biaryl structures. Its main commercial uses include pharmaceutical research and manufacturing, agrochemical intermediate development, specialty organic synthesis, and selected advanced-materials research. As a buyer, I recommend evaluating not only the chemical identity but also assay, impurity profile, packaging, documentation, and supply continuity.
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4-Tolylboronic acid is also known as 4-methylphenylboronic acid or p-tolylboronic acid. The “4-tolyl” description indicates that the methyl group is positioned para to the boronic acid functionality on the aromatic ring. The boronic acid group provides a useful reaction handle, while the methyl-substituted aromatic group becomes part of the target molecule after coupling.
The product is identified by CAS 5720-05-8 and has the molecular formula C7H9BO2. Its commonly reported molecular weight is approximately 135.96 g/mol. These identifiers help buyers compare supplier quotations, analytical documents, regulatory records, and internal material specifications before placing an order.
The most important use of 4-Tolylboronic acid is as a coupling partner in Suzuki–Miyaura chemistry. Under an appropriate catalyst and reaction system, the boronic acid group can participate in carbon–carbon bond formation with aryl, heteroaryl, or vinyl halides. This enables chemists to build substituted biaryl and heteroaryl compounds with a para-methylphenyl fragment.
The exact reaction performance depends on the substrate, palladium source, base, solvent, temperature, atmosphere, and work-up procedure. I therefore treat 4-Tolylboronic acid as a versatile synthesis building block rather than a guaranteed single-condition reagent. Process development teams generally confirm conversion, selectivity, residual palladium, and isolation performance at their own scale.
In pharmaceutical research, 4-Tolylboronic acid can be used to prepare small-molecule analogues, screening compounds, and advanced intermediates containing biaryl or aryl-heteroaryl motifs. Medicinal chemists may use it when they want to vary the aromatic substituent of a lead structure while retaining a methyl-substituted phenyl group. Its value is especially apparent in library synthesis, where a defined building block can support systematic structure–activity relationship work.
Its presence in a synthesis route does not by itself indicate a particular drug, therapeutic effect, or approved application. The final biological activity depends on the complete molecular structure and must be demonstrated through appropriate analytical and biological studies. I recommend describing the material as a pharmaceutical intermediate or research reagent unless the buyer has validated a specific manufacturing use.
4-Tolylboronic acid may also serve as an intermediate for agrochemical research and the preparation of specialty aromatic compounds. The para-methylphenyl group can contribute to the structure of compounds being investigated for crop-protection, formulation, or other industrial purposes. Actual suitability depends on the target route, required impurity limits, and the downstream regulatory status of the final product.
For commercial development, buyers should confirm whether the material is intended for route scouting, pilot production, or regulated manufacturing. A grade suitable for exploratory chemistry may not automatically meet the documentation and control requirements of a validated production process. This distinction is important when comparing low-cost laboratory packs with larger-volume B2B supply.
I normally divide purchasing scenarios into three categories: research use, process development, and routine manufacturing. Research users often prioritize availability, consistent identity, and a practical package size. Process teams usually need reproducible assay and impurity data, while manufacturing buyers place greater emphasis on batch-to-batch consistency, packaging integrity, lead time, and change-control communication.
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| Application stage | Typical buyer priority | Information to request |
|---|---|---|
| Laboratory research | Identity and suitability for screening | Specification, SDS, CoA, available pack sizes |
| Process development | Reproducibility and impurity control | Batch data, analytical method, sample evaluation |
| Commercial or scale-up supply | Continuity, documentation, and logistics | Supply plan, packaging, production lead time, change notification |
Material options may differ by package size, commercial grade, assay specification, and documentation package rather than by chemical identity. I advise buyers to avoid assuming that two products are equivalent simply because both are labeled CAS 5720-05-8. The supplier should clarify whether the quoted specification is a standard product specification, a customer-specific grade, or a development batch.
The first specification is identity: name, CAS number, molecular formula, and analytical confirmation should be consistent. The second is assay, which should be interpreted together with related substances, water, residual solvents, and any relevant inorganic residues. For a coupling reagent, impurity control can influence reaction selectivity and downstream purification, so a single headline purity number may not provide the complete picture.
I also recommend reviewing appearance, recommended storage conditions, packaging material, retest policy, and lot traceability. Boronic acids can be sensitive to handling and storage conditions, and the appropriate controls should follow the supplier’s SDS and product specification. Buyers should request a current certificate of analysis for the relevant lot instead of relying only on a general product webpage.
When I evaluate a supplier, I begin with technical fit. The supplier should be able to provide a clear specification, lot-specific CoA, SDS, packing information, and answers to questions about analytical methods. If the material will enter a regulated or tightly controlled process, I also ask about traceability, manufacturing-site information, document revision control, and the procedure for communicating specification or process changes.
Supply reliability is equally important. I suggest confirming available quantity, minimum order quantity, standard production lead time, sample availability, and the difference between stock supply and made-to-order production. These details should be confirmed in writing because lead time and MOQ can vary by pack size, destination, and required grade.
Price should be compared on a delivered and usable basis. A lower unit price may not be advantageous if the product requires additional testing, has an unsuitable package, or creates schedule risk. For larger projects, I recommend requesting a sample or technical review before committing to a full-volume order.
At Maison Chemical, I position 4-Tolylboronic acid CAS 5720-05-8 as a practical B2B sourcing option for customers requiring an identified organic boronic acid building block. I can support quotation discussions around target quantity, package requirements, destination, documentation, and intended application. Where the project requires additional clarification, I recommend sharing the buyer’s specification so that the proposed grade can be reviewed before shipment.
Our support approach focuses on clear communication rather than unsupported guarantees. We can discuss product availability, sample requirements, CoA and SDS documentation, packaging options, and production scheduling according to the current order conditions. For repeat demand, buyers may also request a supply discussion covering forecast quantities, delivery planning, and lot documentation expectations.
4-Tolylboronic acid CAS 5720-05-8 is used primarily to construct para-methyl-substituted biaryl and heteroaryl molecules through cross-coupling chemistry. It supports pharmaceutical and medicinal chemistry, agrochemical development, specialty intermediates, and other research or manufacturing routes that require this specific aryl fragment. Its practical value depends on both chemical performance and the consistency of the supplied material.
If I were preparing a purchase, my next steps would be to define the required quantity and grade, request the specification, SDS, and lot-specific CoA, and confirm MOQ, packaging, lead time, and shipping conditions. Contact Maison Chemical with your target quantity and technical requirements for a product and supply discussion tailored to your project.
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