5-Bromo-2-fluorophenol
[CAS 112204-58-7]

Identification

• Classification: Organic raw materials >> Organic fluorine compound >> Fluorophenol series
• Name: 5-Bromo-2-fluorophenol
• Molecular Formula: C₆H₄BrFO
• Molecular Weight: 191.00
• CAS Registry Number: 112204-58-7
• EC Number: 674-942-1
• SMILES: C1=CC(=C(C=C1Br)O)F

Properties

• Density: 1.8±0.1 g/cm³ Calc.^*
• Boiling point: 205.8±20.0 °C 760 mmHg (Calc.)^*, 302.9 °C (Expl.)
• Flash point: 78.2±21.8 °C (Calc.)^*
• Index of refraction: 1.576 (Calc.)^*

^* Calculated using Advanced Chemistry Development (ACD/Labs) Software.

Safety Data

• Hazard Symbols: GHS07 Warning
• Risk Statements: H302-H312-H315-H319-H332-H335
• Safety Statements: P261-P264-P264+P265-P270-P271-P280-P301+P317-P302+P352-P304+P340-P305+P351+P338-P317-P319-P321-P330-P332+P317-P337+P317-P362+P364-P403+P233-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Skin irritation	Skin Irrit.	2	H315
Specific target organ toxicity - single exposure	STOT SE	3	H335
Eye irritation	Eye Irrit.	2	H319
Acute toxicity	Acute Tox.	4	H302
Acute toxicity	Acute Tox.	4	H312
Acute toxicity	Acute Tox.	4	H332
Eye irritation	Eye Irrit.	2A	H319

chemBlink Chemical Story

5-Bromo-2-fluorophenol, CAS 112204-58-7, is a halogenated phenol used primarily as a building block in organic, medicinal, and agrochemical synthesis. Its molecular formula is C₆H₄BrFO and its molecular weight is 191.00. The molecule is structurally simple: a phenol ring carries fluorine adjacent to the hydroxyl group and bromine at the 5-position. Yet those three substituents give chemists several chemically distinct ways to transform the molecule into more elaborate structures.

Phenol provides the basic framework. Replacing two additional hydrogen atoms on the aromatic ring with fluorine and bromine substantially changes both its physical properties and its synthetic possibilities. The hydroxyl group can participate in hydrogen bonding and can be converted into ethers, esters, and other derivatives. The bromine provides a valuable position for carbon-carbon or carbon-heteroatom bond formation, while fluorine can alter the electronic and steric environment of the aromatic ring and may remain embedded in the final target molecule.

Among these features, the aryl bromide is especially useful in modern synthesis. Carbon-bromine bonds on aromatic rings can participate in palladium-catalyzed reactions such as Suzuki-Miyaura, Buchwald-Hartwig, Sonogashira, and related cross-coupling processes. These reactions allow chemists to replace the bromine-bearing position with carbon, nitrogen, or other structural fragments without rebuilding the aromatic ring from the beginning.

The fluorine atom plays a different role. The carbon-fluorine bond is exceptionally strong, and aryl fluorides are frequently retained through many synthetic steps. In medicinal and agrochemical research, fluorine substitution is widely used to modify molecular properties without adding much steric bulk. Depending on the surrounding structure, fluorine can influence electronic distribution, lipophilicity, metabolic stability, acidity, conformation, and interactions with biological targets. These effects cannot be predicted from the presence of fluorine alone, but they explain why fluorinated aromatic building blocks occupy such an important place in chemical research.

The phenolic hydroxyl group provides another independent synthetic handle. It can be converted into an ether by reaction with an appropriate alkylating partner, allowing the aromatic oxygen to connect the fluorobromophenyl ring to another molecular fragment. Published synthetic chemistry provides a good example: 5-bromo-2-fluorophenol has been reacted with a substituted triazolylmethanol under Mitsunobu conditions to form a triazole-containing aryl ether.

In that transformation, the hydroxyl group is used first while the bromine remains on the aromatic ring. The resulting bromoaryl ether can subsequently undergo additional carbon-carbon bond-forming chemistry at the brominated position. This sequence demonstrates an important principle of multistep synthesis: useful building blocks often contain several reactive sites, but those sites do not have to be used simultaneously.

Chemists call this type of control chemoselectivity. One functional group is transformed while another is deliberately preserved for a later step. For CAS 112204-58-7, the phenolic oxygen may first become part of an ether linkage, after which the carbon-bromine bond can serve as a second connection point. Fluorine, meanwhile, may remain unchanged throughout the sequence and become part of the final molecule.

The compound has also appeared in agrochemical research. Published sources describe its use in preparing substituted arylcyclopropane derivatives investigated as insecticidal compounds. Cyclopropane structures are familiar motifs in agrochemical chemistry, and functionalized aromatic building blocks such as 5-bromo-2-fluorophenol allow researchers to vary the aromatic portion of candidate molecules systematically.

This is closely related to the structure-activity relationship strategy used in medicinal chemistry. Researchers often keep most of a candidate molecule unchanged while replacing one aromatic substituent or ring fragment. Comparing the resulting compounds can reveal whether bromine, fluorine, an ether linkage, or another structural modification improves or diminishes the desired property. Commercially available compounds such as 5-bromo-2-fluorophenol make this systematic exploration much more practical.

Several synthetic routes to the compound have also been reported. Published patent procedures include preparation from fluorobromobenzene through lithiation, boronation, and oxidative conversion to the phenol. Other approaches use the corresponding fluorobromophenylboronic acid as a precursor. These routes illustrate another characteristic of aromatic chemistry: the same substitution pattern can often be reached through different sequences depending on which starting materials and functional-group transformations are most convenient.

5-Bromo-2-fluorophenol is therefore not notable because it has one famous final use. Its importance lies in the options built into a small aromatic molecule. The hydroxyl group can become a molecular connection through oxygen; bromine provides a second site for cross-coupling; fluorine modifies the electronic environment and can remain in the final structure.

In this sense, CAS 112204-58-7 resembles a partially assembled molecular component with several connection points already marked. Synthetic chemists can choose one, preserve another, and carry a third unchanged through the entire route. That ability to control not only which bonds are formed but also the order in which they are formed is one of the foundations of modern medicinal and agrochemical synthesis.

References

1. PubChem. 5-Bromo-2-fluorophenol, CID 183421. CAS 112204-58-7.

2. TCI Chemicals. 5-Bromo-2-fluorophenol, Product No. B3064. CAS 112204-58-7.

3. WO 2004/041826 A1. Synthetic use of 5-bromo-2-fluorophenol in the preparation of substituted aryl ether intermediates.

4. WO 2003/099816 A1. Synthetic preparation and use of substituted fluorobromophenol derivatives.

5. Tetrahedron (2005), 61, 6590-6595. Synthetic chemistry involving 5-bromo-2-fluorophenol.