3-Bromo-5-chlorobenzoic Acid: Handling & Lab Use Guide

3-Bromo-5-chlorobenzoic Acid is a dihalogenated aromatic carboxylic acid widely employed as a versatile synthetic intermediate in pharmaceutical research, agrochemical development, and cross-coupling chemistry.

CAS Number

hardiman—needs_review; please confirm CAS for 3-Bromo-5-chlorobenzoic Acid

Molecular Formula

C₇H₄BrClO₂

Molecular Weight

235.46 g/mol

Functional Groups

Carboxylic acid, aryl bromide, aryl chloride

Primary Application

Synthetic intermediate for cross-coupling reactions and pharmaceutical building blocks

Recommended Storage

Cool, dry, well-ventilated area; away from light and moisture

Chemical Identity and Properties

3-Bromo-5-chlorobenzoic Acid (Aladdin SKU: B152309) is a dihalogenated derivative of benzoic acid bearing a bromine substituent at the 3-position and a chlorine substituent at the 5-position of the aromatic ring. Its molecular formula is C₇H₄BrClO₂, giving a molecular weight of approximately 235.46 g/mol. The compound appears as a white to off-white crystalline solid at room temperature.

The meta-disposed halogen substituents create an electron-deficient aromatic ring, which modulates the reactivity of the carboxylic acid group and the two distinct carbon–halogen bonds. The aryl bromide bond is selectively more reactive than the aryl chloride bond under standard palladium-catalyzed cross-coupling conditions, enabling chemoselective functionalization. This orthogonal reactivity is a key attribute exploited in multi-step synthetic sequences.

Note: Exact melting point and solubility values should be verified against the current certificate of analysis (CoA) supplied with Aladdin product B152309.

Applications in Synthetic Chemistry

3-Bromo-5-chlorobenzoic Acid serves as a multifunctional building block in synthetic chemistry owing to its three distinct reactive sites: the carboxylic acid, the aryl bromide, and the aryl chloride.

• Cross-Coupling Reactions: The aryl bromide position undergoes Suzuki–Miyaura, Negishi, Heck, and Buchwald–Hartwig couplings preferentially over the aryl chloride under mild palladium catalysis. This chemoselectivity allows sequential functionalization.
• Pharmaceutical Intermediate Synthesis: The compound is used in the construction of drug candidates and active pharmaceutical ingredients (APIs) where a meta-dihalogenated benzoic acid scaffold is required. It can be converted to acyl chlorides, esters, or amides to introduce further diversity.
• Agrochemical Research: Halogenated benzoic acid scaffolds are prevalent in herbicide and fungicide development; this compound can serve as a key precursor.
• Nucleophilic Aromatic Substitution: Under forcing conditions, the activated aryl chloride may undergo SNAr reactions with suitable nucleophiles, providing access to ether or amine-substituted products.
• Esterification and Amide Bond Formation: Standard carbodiimide (e.g., EDC/DCC) or acyl chloride methods can be used to couple the carboxylic acid to alcohols or amines.

Safe Handling and Storage Protocol

Although 3-Bromo-5-chlorobenzoic Acid is a solid reagent with relatively low volatility, appropriate precautions must be observed in accordance with good laboratory practice (GLP) and applicable regulations.

Personal Protective Equipment (PPE)

• Wear chemical-resistant gloves (nitrile recommended) to prevent skin contact.
• Use safety goggles or a face shield to protect eyes from dust.
• Work in a well-ventilated laboratory or fume hood to avoid inhalation of fine particulates.
• Wear a laboratory coat and, if handling significant quantities, a dust mask rated N95 or equivalent.

Storage Conditions

• Store in a tightly sealed container in a cool (15–25 °C recommended), dry, and well-ventilated area.
• Protect from light and moisture; prolonged exposure may cause discoloration or partial degradation.
• Keep away from strong bases and oxidizing agents.
• Consult the Safety Data Sheet (SDS) supplied with Aladdin product B152309 for complete hazard information and emergency procedures.

Disposal

Dispose of residues and contaminated materials in accordance with local, regional, and national regulations governing halogenated organic waste.

Quality, Purity, and Specification Guidance

For research-grade applications, the purity of 3-Bromo-5-chlorobenzoic Acid is critical, particularly when it is used as a limiting reagent in multi-step syntheses or in analytical reference work. Aladdin Scientific supplies this compound as SKU B152309; researchers should review the certificate of analysis (CoA) for each lot to verify:

• Purity (HPLC or GC): Confirm the stated purity meets the requirements of the intended application. Higher-purity grades reduce the risk of side reactions caused by regioisomeric impurities (e.g., 2-bromo-5-chlorobenzoic acid).
• Identity Confirmation: NMR (¹H and ¹³C) and mass spectrometry data in the CoA confirm structural identity. The two distinct aromatic proton environments and the characteristic carboxylic acid stretch (IR ~1680–1700 cm⁻¹) are diagnostic markers.
• Residual Solvents and Moisture: As an aromatic carboxylic acid, the compound can absorb atmospheric moisture. Check Karl Fischer water content if moisture-sensitive downstream chemistry is planned.
• Lot-to-Lot Consistency: For regulated studies, retain lot records and CoAs. Contact Aladdin Scientific customer service to request specific analytical data or reserved lots for long-running projects.

For questions regarding custom purity grades, bulk quantities, or specific analytical requirements, contact Aladdin Scientific procurement or technical support.

Practical Laboratory Protocol: Solution Preparation

The following is a general guideline for preparing stock solutions of 3-Bromo-5-chlorobenzoic Acid for use in synthetic reactions or analytical applications.

1. Select an appropriate solvent. The compound is sparingly soluble in water but dissolves well in polar organic solvents such as dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), acetone, ethyl acetate, and tetrahydrofuran (THF). For aqueous applications, addition of a dilute base (e.g., NaOH or K₂CO₃ solution) will generate the corresponding carboxylate salt and improve water solubility.
2. Weigh accurately. Tare a clean, dry vial or flask. Weigh the required mass of 3-Bromo-5-chlorobenzoic Acid on a calibrated analytical balance. Record the exact mass used, as purity should be factored into concentration calculations.
3. Dissolve with agitation. Add a portion of the chosen solvent and stir or sonicate until complete dissolution is achieved. Avoid prolonged heating above 60 °C to prevent decomposition.
4. Make up to volume. Transfer the solution quantitatively to a volumetric flask and dilute to the required volume. Mix thoroughly.
5. Store properly. If not used immediately, store solutions in sealed, amber vials at 2–8 °C or as dictated by the stability requirements of the solvent system. Re-check concentration before critical experiments.

These steps are general guidelines. Researchers should consult primary literature or validated protocols specific to their application.

Frequently asked questions

What is 3-Bromo-5-chlorobenzoic Acid used for in research?

3-Bromo-5-chlorobenzoic Acid is primarily used as a synthetic intermediate in medicinal chemistry, agrochemical research, and materials science. Its orthogonally reactive aryl bromide and aryl chloride substituents make it particularly valuable for sequential cross-coupling reactions, and the carboxylic acid group can be derivatized to esters, amides, or acyl chlorides to extend molecular complexity.

How should I store 3-Bromo-5-chlorobenzoic Acid (B152309)?

Store 3-Bromo-5-chlorobenzoic Acid in a tightly sealed container in a cool (15–25 °C), dry, and well-ventilated area, protected from light and moisture. Keep it away from strong oxidizing agents and strong bases. Always consult the Safety Data Sheet (SDS) provided with the product for complete storage and hazard information.

Can the aryl bromide and aryl chloride groups be functionalized independently?

Yes. Under standard palladium-catalyzed cross-coupling conditions (e.g., Pd(PPh₃)₄ or Pd₂(dba)₃ with appropriate ligands), the aryl bromide is significantly more reactive than the aryl chloride, allowing selective functionalization at the C–Br bond first. The aryl chloride can then be engaged in a second coupling step using more active catalyst systems or under forcing conditions, enabling sequential diversification of the scaffold.

What solvents are suitable for dissolving 3-Bromo-5-chlorobenzoic Acid?

3-Bromo-5-chlorobenzoic Acid dissolves well in common polar organic solvents including DMSO, DMF, acetone, ethyl acetate, and THF. It has limited solubility in water at neutral pH, but solubility improves significantly upon addition of a dilute aqueous base, which converts the acid to its water-soluble carboxylate salt.

How do I verify the identity and purity of the received compound?

Review the Certificate of Analysis (CoA) supplied with each lot of Aladdin B152309, which includes purity data (typically by HPLC or GC), NMR spectral data, and other identity tests. For additional in-house verification, ¹H NMR in DMSO-d₆ or CDCl₃ will show two distinctive aromatic proton signals consistent with the 1,3,5-trisubstituted ring, and IR spectroscopy will reveal the characteristic broad carbonyl stretch of an aromatic carboxylic acid near 1680–1700 cm⁻¹.

References

1. Miyaura, N.; Suzuki, A. Palladium-Catalyzed Cross-Coupling Reactions of Organoboron Compounds. Chemical Reviews, 1995, 95(7), 2457–2483. doi:10.1021/cr00039a007
2. Johansson Seechurn, C. C. C.; Kitching, M. O.; Colacot, T. J.; Snieckus, V. Palladium-Catalyzed Cross-Coupling: A Historical Contextual Perspective to the 2010 Nobel Prize. Angewandte Chemie International Edition, 2012, 51(21), 5062–5085. doi:10.1002/anie.201107017
3. Aladdin Scientific. Product Certificate of Analysis: 3-Bromo-5-chlorobenzoic Acid, SKU B152309. Aladdin Scientific, Shanghai.

Products are supplied for research and development use only. Not for use in humans, animals, diagnosis, or therapy.