4-Bromo-3-fluorophenol: Properties, Uses & Handling FAQ

4-Bromo-3-fluorophenol is a halogenated aromatic phenol widely used as a versatile building block in pharmaceutical synthesis, medicinal chemistry, and agrochemical research.

CAS Number

27407-11-0

Molecular Formula

C₆H₄BrFO

Molecular Weight

191.00 g/mol

Appearance

White to off-white crystalline solid

Aladdin SKU

B120805

Primary Use

Pharmaceutical and agrochemical intermediate; cross-coupling substrate

What Is 4-Bromo-3-fluorophenol and What Is Its Chemical Structure?

4-Bromo-3-fluorophenol (CAS 27407-11-0, MW 191.00 g/mol, molecular formula C₆H₄BrFO) is a dihalogenated phenol in which a bromine atom is substituted at the para position (C-4) and a fluorine atom at the meta position (C-3) of the phenol ring. The hydroxyl group at C-1 confers phenolic reactivity, while the two halogen substituents modulate electron density and provide handles for selective functionalization.

The combination of bromine and fluorine on a single aromatic ring makes this compound particularly valuable: the C–Br bond participates readily in transition-metal-catalyzed cross-coupling reactions (e.g., Suzuki, Negishi, Buchwald–Hartwig), while the C–F bond contributes metabolic stability and lipophilicity adjustments in drug design contexts. The phenolic –OH can be protected, alkylated, or used directly in etherification reactions.

What Are the Main Applications of 4-Bromo-3-fluorophenol in Research?

4-Bromo-3-fluorophenol serves as a key intermediate across several research domains:

• Pharmaceutical synthesis: It is commonly used to introduce a fluorinated phenol motif into drug candidates. Fluorine at the meta position can improve binding affinity, membrane permeability, and metabolic resistance of bioactive molecules.
• Medicinal chemistry libraries: The compound is incorporated into diversity-oriented synthesis and fragment-based drug discovery programs as a privileged scaffold for kinase inhibitors, receptor modulators, and other therapeutic targets.
• Agrochemical research: Halogenated phenols are established precursors in the preparation of herbicides, fungicides, and insecticides with enhanced environmental persistence profiles.
• Materials science: Used as a monomer or coupling partner in the preparation of functional polymers and liquid-crystal materials where fluorine substitution influences material properties.

Its dual halogen functionality enables orthogonal synthetic strategies, allowing chemists to selectively transform the C–Br bond while retaining the C–F bond for later-stage modifications.

How Should 4-Bromo-3-fluorophenol Be Stored and Handled Safely?

Storage: Store 4-Bromo-3-fluorophenol in a tightly sealed container in a cool, dry, well-ventilated location away from direct sunlight, heat sources, and incompatible materials such as strong oxidizers and strong bases. Recommended storage temperature is typically 2–8 °C or at room temperature under inert atmosphere depending on supplier specifications; consult the product SDS for definitive conditions.

Personal Protective Equipment (PPE): Use appropriate PPE when handling this compound, including chemical-resistant gloves (e.g., nitrile), safety goggles, and a laboratory coat. Work in a fume hood to minimize inhalation of dust or vapors. Phenolic compounds can cause skin and eye irritation, and some halogenated phenols exhibit toxicity upon prolonged exposure.

Waste disposal: Dispose of waste material in accordance with local, national, and institutional regulations for halogenated organic chemical waste. Do not pour down the drain.

Always consult the current Safety Data Sheet (SDS) for this product before use. The SDS is available on the Aladdin Scientific product page for SKU B120805.

What Purity and Specification Options Are Available for SKU B120805?

Aladdin Scientific offers 4-Bromo-3-fluorophenol under SKU B120805. Researchers should visit the product page on the Aladdin Scientific website to view current purity grades, package sizes, and pricing. Typical research-grade halogenated phenols are offered at ≥97% or ≥98% purity as determined by GC or HPLC analysis, but the definitive specification should be confirmed from the current product certificate of analysis (CoA).

For applications requiring higher purity — such as reference standard use, quantitative NMR, or highly sensitive biological assays — contact Aladdin Scientific's technical support team to inquire about higher-grade options or custom specification orders.

How Does the Fluorine Substituent Affect Reactivity Compared to Non-fluorinated Analogs?

The fluorine atom at the C-3 position exerts a strong inductive electron-withdrawing effect through the sigma framework, which measurably lowers the pKa of the phenolic –OH relative to non-halogenated phenol (phenol pKa ≈ 10). This increased acidity can facilitate deprotonation under milder basic conditions and enhance reactivity in O-alkylation and O-arylation reactions.

Fluorine's high electronegativity also reduces the electron density of the aromatic ring, which can slow electrophilic aromatic substitution reactions but facilitates nucleophilic aromatic substitution (SNAr) under appropriate conditions, particularly when additional electron-withdrawing groups are present.

In cross-coupling chemistry, the presence of fluorine does not significantly interfere with the oxidative addition of Pd(0) into the C–Br bond, making 4-Bromo-3-fluorophenol a well-behaved substrate in Suzuki–Miyaura and related reactions. The C–F bond itself is largely inert under standard Pd-catalyzed conditions, providing chemoselectivity.

These electronic effects are well-established principles of physical organic chemistry; specific rate constants and pKa values for this exact compound should be verified against primary literature or experimental measurement.

Frequently asked questions

What is the CAS number for 4-Bromo-3-fluorophenol?

The CAS registry number for 4-Bromo-3-fluorophenol is 27407-11-0. This number can be used to unambiguously identify the compound when searching supplier catalogs, chemical databases such as SciFinder or Reaxys, and regulatory documents.

Is 4-Bromo-3-fluorophenol suitable for Suzuki–Miyaura cross-coupling reactions?

Yes, 4-Bromo-3-fluorophenol is a suitable substrate for Suzuki–Miyaura cross-coupling via the aryl C–Br bond. The C–F bond is largely inert under standard palladium-catalyzed conditions, providing useful chemoselectivity. Researchers should protect the phenolic –OH (e.g., as a methyl or benzyl ether) if necessary to avoid interference with the catalyst or base used in the reaction.

How should I confirm the purity of 4-Bromo-3-fluorophenol upon receipt?

Upon receipt, consult the Certificate of Analysis (CoA) included with the shipment or available for download on the Aladdin Scientific product page for SKU B120805. The CoA will specify the purity as determined by GC or HPLC, as well as other identity tests such as melting point or NMR. If independent verification is required, GC analysis with an internal standard or ¹H/¹⁹F NMR spectroscopy are appropriate techniques.

Can 4-Bromo-3-fluorophenol be used in nucleophilic aromatic substitution (SNAr) reactions?

4-Bromo-3-fluorophenol can participate in SNAr reactions under appropriate conditions. The fluorine atom is a better leaving group than bromine in SNAr due to its ability to stabilize the Meisenheimer complex through strong inductive effects. However, efficient SNAr typically requires additional electron-withdrawing substituents on the ring to sufficiently activate the aromatic system. Reaction feasibility should be assessed on a case-by-case basis.

What are common incompatibilities or hazards associated with 4-Bromo-3-fluorophenol?

As a halogenated phenol, 4-Bromo-3-fluorophenol should be kept away from strong oxidizing agents, strong bases, and reactive metals. It may cause skin, eye, and respiratory irritation upon contact or inhalation. Handle with appropriate PPE in a well-ventilated fume hood. Always refer to the current Safety Data Sheet (SDS) for SKU B120805 on the Aladdin Scientific website for comprehensive hazard information and first-aid measures.

References

1. Clayden, J.; Greeves, N.; Warren, S. Organic Chemistry, 2nd ed.; Oxford University Press: Oxford, 2012. (General reference for aromatic substitution and phenol reactivity.)
2. Bunnett, J. F.; Zahler, R. E. Aromatic Nucleophilic Substitution Reactions. Chem. Rev. 1951, 49, 273–412. (Foundational reference for SNAr reactivity and leaving-group ability of fluorine.) doi:10.1021/cr60154a002
3. Miyaura, N.; Suzuki, A. Palladium-Catalyzed Cross-Coupling Reactions of Organoboron Compounds. Chem. Rev. 1995, 95, 2457–2483. (General reference for Suzuki–Miyaura cross-coupling applicable to aryl bromides.) doi:10.1021/cr00039a007
4. Hagmann, W. K. The Many Roles for Fluorine in Medicinal Chemistry. J. Med. Chem. 2008, 51, 4359–4369. (Reference for the effect of fluorine substitution on drug properties.) doi:10.1021/jm800219f

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