What Is 4-Ethylphenylboronic Acid CAS 63139-21-9? Uses, Properties, and Specifications

4-Ethylphenylboronic acid CAS 63139-21-9 is an aromatic boronic acid used primarily as an organic synthesis intermediate. Its molecular formula is C₈H₁₁BO₂, and its molecular weight is approximately 149.98 g/mol. The compound contains a phenyl ring with an ethyl substituent and a boronic acid group, making it suitable for palladium-catalyzed cross-coupling research, especially Suzuki–Miyaura reactions. At Maison Chemical, we support buyers with identity review, specification alignment, documentation, packaging, and supply planning for laboratory, process-development, and manufacturing applications.

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Key Takeaways

• 4-Ethylphenylboronic acid is an aromatic boronic acid building block identified by CAS 63139-21-9.
• Its primary role is to introduce a 4-ethylphenyl group into a target molecule through organic coupling chemistry.
• Important purchasing factors include assay, water content, residual solvents, appearance, packaging, and batch documentation.
• It is generally selected for research and process chemistry rather than treated as a finished pharmaceutical or active ingredient.
• Maison Chemical can help match the material grade and documentation package to the buyer’s intended use.

What Is 4-Ethylphenylboronic Acid?

4-Ethylphenylboronic acid is a substituted aryl boronic acid. In its molecular structure, the boronic acid group is attached to an aromatic ring, while an ethyl group occupies the para, or 4-position, relative to that boronic acid functionality. This substitution pattern gives chemists a defined aryl fragment for incorporation into more complex molecules.

The boronic acid group is chemically useful because it can participate in carbon–carbon bond-forming reactions under suitable conditions. In Suzuki–Miyaura coupling, an aryl boronic acid is commonly reacted with an aryl or vinyl halide in the presence of a compatible palladium catalyst, base, solvent, and reaction environment. Actual conversion, selectivity, and work-up performance depend on the complete reaction system rather than on the boronic acid alone.

Identity and Chemical Profile

Core Functions and Uses

The main function of 4-Ethylphenylboronic acid is to act as a coupling partner in synthetic chemistry. It can provide a 4-ethylphenyl structural unit when the reaction conditions are appropriate and the other coupling partner is compatible. This makes it relevant to medicinal chemistry, discovery chemistry, agrochemical research, and the preparation of specialty organic molecules.

Suzuki–Miyaura Coupling Research

In a typical Suzuki–Miyaura application, the compound is evaluated with an aryl halide, heteroaryl halide, or related electrophile. The reaction may require a palladium catalyst, an inorganic or organic base, and a solvent selected according to substrate solubility and thermal stability. Because the optimum conditions vary by substrate, buyers should treat the material as a synthesis input rather than as a guarantee of a specific reaction yield.

Medicinal and Discovery Chemistry

Research teams may use 4-Ethylphenylboronic acid to prepare analogues containing a hydrophobic ethyl-substituted aromatic region. The resulting products can then be evaluated in structure–activity relationship studies or other screening programs. The compound itself should not be described as a drug, active pharmaceutical ingredient, or therapeutic agent unless a separate regulatory basis supports that classification.

Specialty Materials and Intermediate Synthesis

Aryl boronic acids can also be used in the preparation of functional organic intermediates and research materials. In these applications, control of identity and impurity profile may be more important than a generic product description. The required specification should therefore be linked to the customer’s reaction route, downstream purification method, and final product requirements.

Available Material and Specification Options

Commercial buyers may request different supply formats depending on project stage. Early discovery work may require a small quantity for screening, while process development may require repeatable batches with tighter documentation and a defined supply schedule. At Maison Chemical, we discuss the intended use before confirming the most suitable grade, quantity, and analytical package.

Assay values should always be verified against the actual batch certificate rather than inferred from a product page. For example, a buyer may request 25 g for laboratory work or 100 g for a larger development campaign, but the appropriate pack size depends on consumption rate and handling requirements. We can review requested quantities ranging from small research packs to larger project volumes without presenting an unverified standard as a guaranteed stock format.

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Important Handling and Storage Considerations

4-Ethylphenylboronic acid should be handled according to the current safety data sheet and the procedures of the receiving laboratory or facility. Personnel should review the supplied hazard information, use suitable personal protective equipment, and avoid exposure to dust or unnecessary contact. The product should also be evaluated for compatibility with the customer’s storage container and environmental controls.

Boronic acids can be sensitive to moisture, heat, and prolonged unfavorable storage conditions, although the practical stability profile must be confirmed for the specific batch and packaging configuration. Buyers should request recommended storage conditions, retest information, and any available stability guidance before placing a long-term inventory order. If the material will be shipped internationally, packaging and transport requirements should be reviewed before dispatch.

How Buyers Should Select a Supplier

The lowest quoted price is not always the most useful purchasing criterion for a specialty intermediate. A better evaluation considers whether the supplier can provide consistent identity data, clear assay reporting, responsive technical communication, and a realistic fulfillment plan. These factors can reduce avoidable delays when the material enters a validated or time-sensitive synthesis program.

Supplier Evaluation Checklist

1. Confirm that the supplier identifies the product by both name and CAS 63139-21-9.
2. Request a current certificate of analysis or representative analytical information for review.
3. Define the required assay, impurity limits, water specification, and packaging before quotation.
4. Ask whether the quoted material is available from existing inventory or requires production planning.
5. Clarify minimum order quantity, lead-time assumptions, shipping terms, and documentation scope.
6. Check whether the supplier can support repeat orders with consistent specifications.

For process development, I recommend discussing the downstream reaction before finalizing the purchase specification. A chemist may need a different impurity profile or moisture limit depending on catalyst loading, base selection, solvent system, and purification strategy. This application-based discussion is often more valuable than selecting a specification solely from a generic catalogue description.

How Maison Chemical Supports Procurement

Maison Chemical supplies organic boronic acids and related chemical intermediates for B2B customers seeking a practical connection between technical requirements and commercial execution. We can help review the product identity, intended application, quantity, assay target, packaging preference, and documentation needs. Our role is to provide a clear basis for quotation and avoid unsupported assumptions about grade or availability.

For buyers comparing several sources, we can organize the inquiry around the information that affects project risk: batch consistency, analytical documentation, packaging, shipping destination, and repeat-supply expectations. We also distinguish between a research quantity and a larger development requirement so that the commercial proposal reflects the actual project stage. Specific availability, pricing, and lead time should be confirmed for each inquiry because they depend on quantity, destination, and current production planning.

Conclusion: Is 4-Ethylphenylboronic Acid CAS 63139-21-9 Right for Your Project?

4-Ethylphenylboronic acid CAS 63139-21-9 is a defined aryl boronic acid building block used mainly for carbon–carbon bond formation and the synthesis of more complex organic intermediates. Its key identity data include the formula C₈H₁₁BO₂ and an approximate molecular weight of 149.98 g/mol. It may be a suitable choice when your route requires incorporation of a 4-ethylphenyl group through a compatible coupling reaction.

The next step is to provide the intended application, required quantity, target assay, destination, and documentation expectations. Maison Chemical can then help confirm the appropriate specification, packaging approach, and supply plan for your project. Contact our B2B team with your purchasing requirements so we can prepare a focused quotation based on the actual batch and delivery conditions.

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