2,4-Difluorophenylboronic acid
[CAS# 144025-03-6]

Identification

• Classification: Organic raw materials >> Organic fluorine compound >> Fluorophenylboric acid series
• Name: 2,4-Difluorophenylboronic acid
• Molecular Formula: C₆H₅BF₂O₂
• Molecular Weight: 157.91
• CAS Registry Number: 144025-03-6
• EC Number: 604-390-9
• SMILES: B(C1=C(C=C(C=C1)F)F)(O)O

Properties

• Density: 1.4±0.1 g/cm³, Calc.^*
• Melting point: 247-250 °C
• Index of Refraction: 1.486, Calc.^*
• Boiling Point: 251.0±50.0 °C (760 mmHg), Calc.^*
• Flash Point: 105.6±30.1 °C, Calc.^*

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

Safety Data

• Hazard Symbols: GHS07 Warning
• Risk Statements: H315-H319-H335
• Safety Statements: P261-P264-P264+P265-P271-P280-P302+P352-P304+P340-P305+P351+P338-P319-P321-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
Eye irritation	Eye Irrit.	2A	H319

Discovery and Applications

2,4-Difluorophenylboronic acid is an important boronic acid derivative, primarily recognized for its utility in organic synthesis and medicinal chemistry. The compound features a boron atom bonded to a phenyl group that contains two fluorine substituents at the 2 and 4 positions on the aromatic ring. The discovery of 2,4-difluorophenylboronic acid arose from ongoing research into boron-containing compounds, which are known for their versatile reactivity and applications in various chemical transformations.

The synthesis of 2,4-difluorophenylboronic acid typically involves the reaction of 2,4-difluorophenyl lithium with boron trifluoride etherate or other boron sources. This synthetic approach allows for the introduction of the boronic acid functional group, which is crucial for its subsequent applications. The ability to tune the electronic properties of the phenyl ring by introducing fluorine substituents enhances the reactivity of the boronic acid, making it a valuable reagent in synthetic chemistry.

One of the primary applications of 2,4-difluorophenylboronic acid lies in its use as a building block in the synthesis of pharmaceuticals and agrochemicals. Boronic acids are key intermediates in Suzuki-Miyaura cross-coupling reactions, a widely used method for forming carbon-carbon bonds. This reaction allows for the coupling of aryl or vinyl halides with boronic acids to produce biaryl compounds, which are prevalent in various biologically active molecules. The introduction of fluorine atoms in 2,4-difluorophenylboronic acid often improves the biological activity and selectivity of the resulting compounds, making it an attractive choice for drug discovery.

Moreover, 2,4-difluorophenylboronic acid is utilized in the development of fluorescent sensors and probes. The unique properties of boronic acids, such as their ability to form reversible complexes with diols, lend themselves to applications in sensing technologies. Researchers have explored its potential in detecting biologically relevant molecules, including sugars and nucleic acids, which can enhance the specificity and sensitivity of various assays.

The compound has also been investigated for its role in materials science, particularly in the development of polymeric materials. Boronic acids can undergo dynamic covalent bonding, allowing for the creation of adaptive and self-healing materials. The incorporation of 2,4-difluorophenylboronic acid into polymer matrices can impart unique mechanical properties and responsiveness to environmental stimuli, broadening its application scope.

Furthermore, the use of 2,4-difluorophenylboronic acid extends to the field of catalysis. Its boron atom can act as a Lewis acid, facilitating various reactions, including nucleophilic additions and electrophilic substitutions. This characteristic makes it a valuable component in catalytic systems, enhancing reaction efficiency and selectivity.

In summary, 2,4-difluorophenylboronic acid is a significant compound in organic synthesis, particularly in the pharmaceutical and materials science sectors. Its discovery and continued study highlight its versatility and potential in developing new compounds and technologies that can address various scientific challenges.

References

2017. Synthesis and photodiode characterization of novel twisted carbazole derivatives with 1,3,5-benzene core. Silicon, 9(2).
DOI: 10.1007/s12633-016-9514-9

2014. Hydrogen-bonded dimeric synthon of fluoro-substituted phenylboronic acids versus supramolecular organization in crystals. Crystal Growth & Design, 14(10).
DOI: 10.1107/s160053680804064