2,3-Dichlorobenzyl Bromide: Properties, Uses & Handling

2,3-Dichlorobenzyl Bromide is a halogenated aromatic alkylating reagent widely employed in organic synthesis for the introduction of the 2,3-dichlorobenzyl group onto nucleophilic substrates including amines, alcohols, thiols, and active methylene compounds.

IUPAC Name

1-(bromomethyl)-2,3-dichlorobenzene

Molecular Formula

C7H5BrCl2

Molecular Weight

239.92 g/mol

CAS Number

Needs review — flag for verification

Functional Class

Benzyl halide / Electrophilic alkylating agent

Primary Application

Introduction of a 2,3-dichlorobenzyl protecting or functionalizing group in multistep organic synthesis

Storage Conditions

Store in a cool, dry, well-ventilated area away from light and moisture; recommended 2–8 °C under inert atmosphere

SKU

D139027

Chemical Identity and Physical Properties

2,3-Dichlorobenzyl Bromide (1-(bromomethyl)-2,3-dichlorobenzene) is an aryl-substituted benzyl bromide bearing two ortho/meta chlorine substituents on the aromatic ring. Its molecular formula is C₇H₅BrCl₂, giving a molecular weight of approximately 239.92 g/mol. The compound typically presents as a pale yellow to colorless liquid or low-melting solid with a pungent, lachrymatory odor characteristic of benzyl halides.

The electron-withdrawing chlorine substituents at the 2- and 3-positions reduce electron density on the aromatic ring and modulate the reactivity of the benzylic carbon toward nucleophilic substitution. This electronic effect makes 2,3-Dichlorobenzyl Bromide a moderately reactive electrophile suitable for controlled alkylation reactions. Solubility is high in common organic solvents such as dichloromethane, tetrahydrofuran, acetonitrile, and dimethylformamide; the compound is essentially immiscible with water.

Note: Exact physical constants (melting point, boiling point, density, refractive index) and the confirmed CAS number should be verified against the current certificate of analysis and supplier specification sheet before use in publications.

Synthetic Applications and Reactivity

As a benzyl halide electrophile, 2,3-Dichlorobenzyl Bromide participates in a broad range of nucleophilic substitution (S_N2) reactions. Key applications in research include:

• N-Alkylation: Reacting with primary or secondary amines, nitrogen heterocycles, or sulfonamides to install the 2,3-dichlorobenzyl group on nitrogen, a strategy commonly used in medicinal chemistry to tune pharmacokinetic properties.
• O-Alkylation: Etherification of phenols, alcohols, and carbohydrate hydroxyl groups under mild basic conditions (e.g., K₂CO₃ in DMF), enabling introduction of a lipophilic protecting or directing group.
• S-Alkylation: Thioether formation with thiols or thiolates, useful in the preparation of sulfur-containing pharmacophores and ligands.
• C-Alkylation: Alkylation of stabilized carbanions (malonates, β-ketoesters, active methylene compounds) to build new C–C bonds under phase-transfer or classical base-mediated conditions.
• Protecting Group Chemistry: The 2,3-dichlorobenzyl group can serve as a protecting group for amines and hydroxyl functions, removable under specified reductive or nucleophilic conditions.

The dual ortho/meta chlorine pattern imparts useful steric and electronic characteristics that differentiate this reagent from mono-chloro or unsubstituted benzyl bromides, allowing chemists to fine-tune selectivity in complex molecule synthesis.

Safety, Handling, and Regulatory Considerations

2,3-Dichlorobenzyl Bromide is a lachrymatory, corrosive, and potentially harmful compound that must be handled with appropriate precautions:

• Personal Protective Equipment (PPE): Use chemical-splash goggles, acid/solvent-resistant gloves (nitrile or neoprene), and a lab coat. All manipulations should be conducted inside a certified fume hood.
• Skin and Eye Contact: Benzyl bromides are strong lachrymators and skin irritants. In case of contact, flush immediately with copious water for at least 15 minutes and seek medical attention.
• Inhalation: Vapors are irritating to the respiratory tract. Avoid breathing vapors; use respiratory protection if ventilation is inadequate.
• Reactivity Hazards: Reacts vigorously with strong bases, strong nucleophiles, and oxidizing agents. Keep away from moisture to prevent hydrolysis and HBr/HCl generation.
• Disposal: Dispose of waste in accordance with local, national, and institutional regulations for halogenated organic waste. Do not pour down the drain.

Researchers should consult the current Safety Data Sheet (SDS) provided by Aladdin Scientific before using this reagent. Regulatory status (e.g., transport classification, GHS hazard categories) should be verified at the time of procurement.

Storage, Stability, and Quality Specifications

Proper storage is essential to maintain the purity and reactivity of 2,3-Dichlorobenzyl Bromide:

• Recommended Storage Temperature: 2–8 °C under an inert gas (nitrogen or argon) atmosphere to suppress hydrolysis and oxidative degradation.
• Container: Keep tightly sealed in the original amber glass or dark container to minimize light-induced decomposition.
• Moisture Sensitivity: Benzyl bromides are moisture-sensitive; exposure to atmospheric humidity promotes hydrolysis to the corresponding benzyl alcohol and generates corrosive hydrobromic acid.
• Shelf Life: When stored correctly, the compound is expected to remain within specification for an extended period; consult the certificate of analysis (CoA) for the specific lot expiry date.
• Purity: Aladdin Scientific supplies this compound with defined purity specifications; exact purity grade and analytical data (GC, NMR, HPLC) are available on the lot-specific CoA. Customers are encouraged to request the CoA at the time of order.

If discoloration, precipitate formation, or unusual odor is observed upon opening, the lot should be quarantined and Aladdin Scientific customer service contacted before use.

Ordering Information and Technical Support

2,3-Dichlorobenzyl Bromide is available from Aladdin Scientific under SKU D139027. Researchers and procurement specialists can place orders through the Aladdin Scientific website or authorized distributors. The following information is relevant for ordering:

• SKU: D139027
• Product Name: 2,3-Dichlorobenzyl Bromide
• Available Pack Sizes: Multiple pack sizes may be available; contact Aladdin Scientific sales for volume pricing and custom quantities.
• Documentation: Certificate of Analysis (CoA) and Safety Data Sheet (SDS) are available upon request or downloadable from the product page.
• Technical Support: For application-specific inquiries, reaction optimization, or custom synthesis requirements, contact the Aladdin Scientific technical support team.

Aladdin Scientific is committed to supplying high-purity research reagents with full documentation to support reproducible science. For bulk orders, special purity grades, or regulatory documentation (e.g., ISO, GMP), please contact the sales team directly.

Frequently asked questions

What nucleophiles react most efficiently with 2,3-Dichlorobenzyl Bromide?

Primary and secondary amines, phenolates, thiolates, and stabilized carbanions (e.g., malonate anions) are among the most reactive nucleophiles toward 2,3-Dichlorobenzyl Bromide under standard Sₙ₂ conditions. Reactions are typically carried out in polar aprotic solvents such as DMF or acetonitrile in the presence of an inorganic base (e.g., K₂CO₃ or Cs₂CO₃). Weaker nucleophiles may require elevated temperatures or activation strategies.

How should 2,3-Dichlorobenzyl Bromide be handled to avoid lachrymatory exposure?

All handling must be performed in a well-functioning chemical fume hood while wearing chemical-splash goggles, solvent-resistant gloves, and a lab coat. The reagent should be weighed and transferred rapidly, keeping the container closed when not in use. If accidental eye exposure occurs, immediately irrigate with large volumes of water for at least 15 minutes and seek immediate medical attention.

Can 2,3-Dichlorobenzyl Bromide be used as a protecting group reagent?

Yes. The 2,3-dichlorobenzyl group can function as a protecting group for amines and alcohols, installed via O- or N-alkylation with this reagent. The electron-withdrawing chlorine substituents alter the stability and deprotection conditions compared to an unsubstituted benzyl group. Specific deprotection conditions (e.g., hydrogenolysis, Lewis acid-mediated removal) should be optimized empirically for each substrate, and literature precedent for the exact substrate class should be consulted.

What solvents are recommended for reactions using 2,3-Dichlorobenzyl Bromide?

Polar aprotic solvents such as N,N-dimethylformamide (DMF), acetonitrile (MeCN), tetrahydrofuran (THF), and dimethyl sulfoxide (DMSO) are generally recommended because they dissolve both the reagent and common inorganic bases while stabilizing the transition state of Sₙ₂ reactions. Protic solvents should be avoided when moisture sensitivity or competing hydrolysis is a concern.

What is the confirmed CAS number for 2,3-Dichlorobenzyl Bromide?

The CAS number for 2,3-Dichlorobenzyl Bromide should be verified directly from the Aladdin Scientific product page or the Certificate of Analysis for SKU D139027, as this information was not confirmed in the source material provided. Customers are advised to cross-reference with official chemical databases such as SciFinder or PubChem before use.

References

1. March, J. Advanced Organic Chemistry: Reactions, Mechanisms, and Structure, 4th ed.; Wiley-Interscience: New York, 1992. (General reference for Sₙ₂ reactions of benzyl halides.)
2. Clayden, J.; Greeves, N.; Warren, S. Organic Chemistry, 2nd ed.; Oxford University Press: Oxford, 2012. (General reference for benzyl halide reactivity and protecting group chemistry.)
3. Aladdin Scientific. Product Page: 2,3-Dichlorobenzyl Bromide, SKU D139027. (Accessed via aladdinscientific.com; consult for current specifications, CoA, and SDS.)
4. Wuts, P. G. M.; Greene, T. W. Greene's Protective Groups in Organic Synthesis, 4th ed.; Wiley-Interscience: Hoboken, 2006. (Reference for benzyl-type protecting group installation and removal.)

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