2,6-Difluorobenzyl Chloride: Properties, Uses & Safety FAQ

2,6-Difluorobenzyl chloride is a fluorinated benzyl halide reagent widely used in organic synthesis as an alkylating agent and as a key building block for the preparation of pharmaceuticals, agrochemicals, and other specialty fluorine-containing compounds.

IUPAC Name

2-(chloromethyl)-1,3-difluorobenzene

Molecular Formula

C7H5ClF2

Molecular Weight

163.56 g/mol

CAS Number

72496-68-5

Appearance

Colorless to pale yellow liquid

Key Functional Groups

Benzyl chloride (electrophilic CH2Cl), two ortho-fluorine substituents

Primary Application

Alkylating agent and fluorinated building block in medicinal and synthetic chemistry

What Is 2,6-Difluorobenzyl Chloride?

2,6-Difluorobenzyl chloride (CAS 72496-68-5, SKU D122814) is an organofluorine compound belonging to the benzyl halide family. Its structure consists of a benzene ring bearing fluorine atoms at the 2- and 6-positions (both ortho positions relative to the methylene group) and a chloromethyl (–CH₂Cl) group at the 1-position.

The two flanking fluorine atoms exert a strong inductive withdrawal effect on the ring, modifying the electronic character of the benzylic carbon and influencing the compound's reactivity profile compared with unsubstituted benzyl chloride. This combination of electrophilicity at the benzylic position and the metabolic stability conferred by fluorine substitution makes 2,6-difluorobenzyl chloride a valued reagent in both academic and industrial research settings.

Synthesis and Reactivity

As a benzyl chloride derivative, 2,6-difluorobenzyl chloride undergoes a range of well-established reactions exploited in synthetic chemistry:

• N-Alkylation: Reaction with amines (primary, secondary, or heteroaromatic nitrogen nucleophiles) under mild base conditions introduces the 2,6-difluorobenzyl group onto nitrogen, a motif found in numerous bioactive molecules.
• O-Alkylation: Alcohols, phenols, and carboxylate anions react with the benzylic chloride to yield ethers and esters bearing the difluorobenzyl group.
• C-Alkylation: Stabilized carbanions (malonates, β-ketoesters, active methylene compounds) can be alkylated via S_N2 displacement.
• Coupling reactions: Conversion to the corresponding Grignard reagent or organolithium species allows further elaboration through addition or cross-coupling chemistry.

The ortho fluorines sterically flank the CH₂Cl group, which may influence reaction rates in sterically sensitive systems. Researchers should consider this when designing reaction conditions.

Applications in Medicinal and Agrochemical Research

Fluorine-containing benzyl groups are prominent pharmacophoric elements in modern drug discovery. The 2,6-difluorobenzyl motif specifically offers several advantages:

• Metabolic stability: Fluorine substitution at the ortho positions resists oxidative metabolism at those ring positions, potentially prolonging compound half-life in biological systems.
• Lipophilicity tuning: Fluorine atoms modulate log P values, which can improve membrane permeability or aqueous solubility depending on the broader molecular context.
• Binding interactions: Fluorine can participate in orthogonal non-covalent interactions (C–F···H–N, C–F···π) with protein residues, contributing to binding affinity and selectivity.

In agrochemical research, difluorobenzyl-containing structures appear in fungicide and herbicide scaffolds. 2,6-Difluorobenzyl chloride serves as an efficient electrophilic synthon for introducing this fragment at late or early stages of target synthesis.

Handling, Storage, and Safety

2,6-Difluorobenzyl chloride is a reactive benzyl halide and must be handled with appropriate precautions:

• Irritant and lachrymatory properties: Like most benzyl chlorides, this compound is expected to be a skin, eye, and respiratory tract irritant and may have lachrymatory properties. All manipulations should be conducted in a well-ventilated fume hood.
• Personal protective equipment (PPE): Chemical-resistant gloves (nitrile or neoprene), safety goggles, and a laboratory coat are required at a minimum. A face shield is recommended when handling larger quantities.
• Storage: Store in a tightly sealed container in a cool, dry, well-ventilated area away from heat sources, moisture, and incompatible materials (strong bases, strong oxidizers, active metals). Refrigerated storage (2–8 °C) is typically recommended to minimize hydrolysis and decomposition.
• Waste disposal: Dispose of residues and contaminated materials in accordance with local, regional, and national hazardous-waste regulations. Do not pour down drains.
• SDS: Always consult the Safety Data Sheet (SDS) for D122814 available on the Aladdin Scientific website before first use.

Ordering and Quality Information

Aladdin Scientific supplies 2,6-Difluorobenzyl chloride under SKU D122814. When placing an order or evaluating the reagent, consider the following:

• Purity: Check the current certificate of analysis (CoA) on the product page for the confirmed purity specification and analytical data (e.g., GC purity, NMR).
• Pack sizes: Multiple pack sizes may be available to suit discovery-scale and scale-up needs. Contact Aladdin Scientific customer service for bulk or custom packaging inquiries.
• Lead time and shipping: The product is shipped in accordance with applicable transport regulations for reactive organics. Confirm availability and lead time at the time of ordering.
• Returns and quality issues: If the reagent does not meet the stated specification, contact Aladdin Scientific customer service within the applicable return window with your order number and CoA for resolution.

Frequently asked questions

What is 2,6-difluorobenzyl chloride used for in organic synthesis?

2,6-Difluorobenzyl chloride is primarily used as an electrophilic alkylating agent to introduce the 2,6-difluorobenzyl group onto nitrogen, oxygen, or carbon nucleophiles via SN2 reactions. It serves as a key building block in the synthesis of pharmaceutically active compounds, agrochemicals, and fluorinated specialty materials where the 2,6-difluorobenzyl motif is required.

How should 2,6-difluorobenzyl chloride be stored to maintain stability?

The compound should be stored in a tightly sealed container at 2–8 °C in a cool, dry, and well-ventilated area, away from moisture, strong bases, strong oxidizers, and active metals. Proper sealing prevents hydrolysis of the benzylic chloride by atmospheric moisture. Always refer to the current SDS and CoA for Aladdin Scientific SKU D122814 for confirmed storage recommendations.

What safety precautions are required when handling 2,6-difluorobenzyl chloride?

All operations should be performed in a well-ventilated fume hood due to the compound's expected irritant and potentially lachrymatory properties. Researchers must wear appropriate PPE including chemical-resistant gloves, safety goggles, and a laboratory coat. Refer to the full Safety Data Sheet for SKU D122814 on the Aladdin Scientific website before handling.

Why are the two ortho-fluorine atoms significant in 2,6-difluorobenzyl chloride?

The ortho-fluorine atoms serve multiple roles: they exert an inductive electron-withdrawing effect on the aromatic ring, they provide metabolic stability at those ring positions by resisting cytochrome P450-mediated oxidation, and they introduce steric bulk adjacent to the benzylic carbon. In drug discovery, these properties can enhance compound half-life and modulate binding interactions with biological targets.

What nucleophiles react efficiently with 2,6-difluorobenzyl chloride?

Primary and secondary amines, phenolates, alkoxide anions, thiolates, and stabilized carbanions (e.g., from malonates or β-ketoesters) all react with 2,6-difluorobenzyl chloride through SN2 displacement under standard conditions. The steric environment imposed by the two ortho-fluorines may reduce reaction rates with bulky nucleophiles, so reaction conditions such as solvent, base, and temperature should be optimized accordingly.

Is 2,6-difluorobenzyl chloride the same as 2,6-difluorobenzyl alcohol or 2,6-difluorotoluene?

No, these are distinct compounds. 2,6-Difluorobenzyl chloride (–CH2Cl) is the chloride, which is electrophilic and used for alkylation. 2,6-Difluorobenzyl alcohol (–CH2OH) is the corresponding alcohol, a nucleophile or precursor. 2,6-Difluorotoluene (–CH3) lacks any reactive benzylic substituent. Ensure you order the correct compound (SKU D122814 for the chloride) for your intended transformation.

References

1. O'Hagan, D. Understanding organofluorine chemistry. An introduction to the C–F bond. Chemical Society Reviews, 2008, 37, 308–319. doi:10.1039/b711844a
2. Müller, K.; Faeh, C.; Diederich, F. Fluorine in pharmaceuticals: Looking beyond intuition. Science, 2007, 317, 1881–1886. doi:10.1126/science.1131943
3. Aladdin Scientific. Product page and Safety Data Sheet for 2,6-Difluorobenzyl chloride, SKU D122814.

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