5-Bromo-2-Hydroxyphenylacetic Acid: Handling & Use Protocol

5-Bromo-2-hydroxyphenylacetic acid is a halogenated aromatic organic acid used as a synthetic building block and analytical reagent in chemical and biochemical research.

CAS Number

1878-91-7

Molecular Formula

C₈H₇BrO₃

Molecular Weight

231.04 g/mol

Appearance

White to off-white crystalline solid

Recommended Storage

Store at room temperature in a cool, dry place, protected from light and moisture

SKU

B184213

Materials and Safety Precautions

Before beginning any experimental work with 5-Bromo-2-hydroxyphenylacetic acid (Aladdin SKU: B184213), ensure that the current Safety Data Sheet (SDS) has been reviewed. The compound contains a bromine substituent and a free phenolic hydroxyl group, which necessitates standard precautionary handling for halogenated aromatic acids.

Required personal protective equipment (PPE):

• Chemical-resistant gloves (nitrile recommended)
• Safety goggles or face shield
• Laboratory coat
• Work in a well-ventilated area or fume hood when handling powders or concentrated solutions

Materials required:

• 5-Bromo-2-hydroxyphenylacetic acid (B184213)
• Analytical balance (0.1 mg readability)
• Appropriate solvent (see Dissolution section)
• Volumetric flasks, amber glass vials for storage
• pH meter or indicator paper (if preparing buffered solutions)

Dissolution and Stock Solution Preparation

5-Bromo-2-hydroxyphenylacetic acid is a solid organic acid with limited aqueous solubility at neutral pH. The following guidance is based on the general physicochemical properties of halogenated hydroxyphenylacetic acid derivatives.

Recommended solvents:

• DMSO: High solubility; suitable for preparing concentrated stock solutions (e.g., 10–100 mM). DMSO stocks are compatible with most biochemical assays when diluted to ≤0.1% v/v final concentration.
• Ethanol or Methanol: Good solubility; useful for analytical and organic chemistry applications.
• Aqueous alkaline buffer (pH 8–10): The phenolic hydroxyl and carboxylic acid groups ionize under alkaline conditions, improving aqueous solubility. Adjust pH with NaOH (0.1 M) as needed.

Procedure for stock solution preparation:

1. Equilibrate the reagent vial to room temperature before opening to avoid moisture condensation.
2. Accurately weigh the required amount of 5-Bromo-2-hydroxyphenylacetic acid using a calibrated analytical balance.
3. Transfer to a clean volumetric flask or amber vial.
4. Add the chosen solvent in approximately 80% of the target volume and mix by gentle swirling or vortexing until fully dissolved.
5. Make up to the final volume with solvent.
6. Label the container with compound name, SKU (B184213), concentration, solvent, date of preparation, and preparer's initials.
7. Store stock solutions in amber glass vials at –20 °C for long-term stability, or at 4 °C for short-term use (≤2 weeks). Avoid repeated freeze-thaw cycles.

Application in Synthetic and Analytical Workflows

5-Bromo-2-hydroxyphenylacetic acid serves primarily as a halogenated aromatic building block in organic synthesis and as a reference standard or substrate in analytical chemistry workflows. Its key functional features include the electron-withdrawing bromine atom at the 5-position, the ortho-hydroxyl (phenolic) group, and the acetic acid side chain, collectively enabling diverse chemical transformations.

Synthetic applications:

• Cross-coupling reactions: The aryl–bromine bond can be exploited in palladium-catalyzed cross-coupling reactions (e.g., Suzuki–Miyaura, Sonogashira) to introduce aryl, alkenyl, or alkynyl substituents. Protect the carboxylic acid and/or phenol as needed prior to coupling.
• Esterification and amidation: The carboxylic acid moiety can be activated (e.g., with DCC/NHS or via acid chloride formation) for coupling to alcohols or amines to yield esters or amides.
• Phenolic derivatization: The free OH group can be alkylated, acylated, or used in etherification reactions.

Analytical applications:

• May serve as a reference compound or internal standard in HPLC, LC-MS, or GC-MS analyses of phenolic acid metabolite panels.
• Useful as a model substrate for studying enzymatic reactions involving phenolic acid decarboxylases or oxidases, given the structural similarity to naturally occurring hydroxyphenylacetic acid derivatives.

Note: Specific reaction conditions, catalysts, and yields should be optimized empirically for each application. Consult primary literature for detailed synthetic procedures.

Quality Control and Characterization

Before use in sensitive applications, confirm compound identity and purity using one or more of the following analytical techniques:

• Thin-layer chromatography (TLC): Visualize under UV (254 nm) or with appropriate staining reagents. A single spot indicates acceptable purity for many synthetic purposes.
• HPLC (reverse-phase, C18 column): Use a UV detector at 254 nm or 280 nm. Compare retention time against a certified reference standard where available.
• ¹H and ¹³C NMR: Dissolve in deuterated DMSO (DMSO-d₆) for NMR characterization. Key signals include the aromatic protons, the phenolic OH, and the methylene (–CH₂–) protons of the acetic acid group.
• Mass spectrometry (ESI-MS or APCI-MS): Expect a characteristic isotope pattern (approximately 1:1 ratio of M and M+2 ions) confirming the presence of one bromine atom. The [M–H]⁻ ion in negative-ion ESI mode is expected at approximately m/z 228.9/230.9.
• Melting point: Determine and compare with literature values to assess purity (review flag: confirm literature melting point from primary source).

Record all characterization data in a laboratory notebook and retain with the batch record for traceability.

Waste Disposal and Regulatory Compliance

Dispose of 5-Bromo-2-hydroxyphenylacetic acid and its solutions in accordance with local, national, and institutional regulations governing halogenated organic waste.

• Collect all waste (solid and liquid) in clearly labelled, chemically compatible waste containers designated for halogenated organic waste.
• Do not pour solutions containing this compound down the drain without verifying local discharge regulations.
• Arrange for disposal through your institution's environmental health and safety (EHS) office or an approved hazardous waste contractor.
• Consult the SDS (available from Aladdin Scientific product page for B184213) for specific disposal codes and regulatory classifications applicable in your jurisdiction.

Maintain records of waste generation, collection, and disposal as required by your institution's chemical hygiene plan.

Frequently asked questions

What solvents are recommended for dissolving 5-Bromo-2-hydroxyphenylacetic acid?

DMSO is the preferred solvent for preparing concentrated stock solutions due to its high solvating power for polar organic compounds. Ethanol and methanol are also suitable. Aqueous solubility improves significantly under alkaline conditions (pH 8–10), where both the phenolic OH and carboxylic acid are ionized.

How should 5-Bromo-2-hydroxyphenylacetic acid (B184213) be stored?

The compound should be stored as a solid in a cool, dry place at room temperature, protected from light and moisture. Stock solutions prepared in DMSO or organic solvents should be stored at –20 °C in amber glass vials for long-term stability and at 4 °C for short-term use (up to two weeks). Avoid repeated freeze-thaw cycles to maintain solution integrity.

Can 5-Bromo-2-hydroxyphenylacetic acid be used in palladium-catalyzed cross-coupling reactions?

Yes. The aryl C–Br bond is amenable to palladium-catalyzed cross-coupling reactions such as Suzuki–Miyaura and Sonogashira couplings. Functional group protection of the carboxylic acid and/or phenolic hydroxyl may be required prior to coupling, depending on the reaction conditions and coupling partner chosen. Reaction conditions should be optimized empirically.

How can I confirm the identity and purity of the received batch?

Identity and purity can be confirmed using TLC, reverse-phase HPLC with UV detection (254 nm or 280 nm), ¹H/¹³C NMR in DMSO-d₆, and mass spectrometry. ESI-MS in negative-ion mode should show a [M–H]⁻ ion cluster at approximately m/z 228.9/230.9, reflecting the characteristic bromine isotope pattern. Melting point determination provides an additional purity check.

Is this compound hazardous and what PPE is required?

As a halogenated aromatic organic acid, standard laboratory precautions apply. Wear nitrile gloves, safety goggles, and a laboratory coat. Handle powders and solutions in a well-ventilated area or fume hood to avoid inhalation of dust. Consult the current SDS available on the Aladdin Scientific product page for B184213 for complete hazard information and first aid measures.

References

1. Aladdin Scientific Product Page: 5-Bromo-2-hydroxyphenylacetic acid, SKU B184213. Aladdin Scientific.
2. March, J. Advanced Organic Chemistry: Reactions, Mechanisms, and Structure. 4th ed. Wiley-Interscience, 1992.
3. Miyaura, N.; Suzuki, A. Palladium-Catalyzed Cross-Coupling Reactions of Organoboron Compounds. Chemical Reviews, 1995, 95(7), 2457–2483. doi:10.1021/cr00039a007

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