1. Product Overview
3,4-Dichlorobenzyl Bromide (CAS 64018-22-0) is a versatile halogenated aromatic compound featuring both chloro and bromo substituents on the benzyl moiety. With the molecular formula C₇H₅BrCl₂ and a molecular weight of 240.92 g/mol, this reactive intermediate is widely employed in nucleophilic substitution reactions, cross-coupling processes, and the construction of complex pharmaceutical and agrochemical architectures. The benzylic bromine serves as an excellent leaving group for S_N1/S_N2 reactions, while the aromatic chlorines provide additional handles for selective metal-catalyzed transformations.
2. Key Features and Benefits
• Reactive Benzylic Bromine: The primary alkyl bromide undergoes facile nucleophilic substitution with amines, thiols, alkoxides, and carbanions, enabling rapid scaffold diversification.
• Orthogonal Halogen Reactivity: The aromatic C–Cl bonds can be selectively activated in cross-coupling reactions (Suzuki, Buchwald-Hartwig, Ullmann) while preserving the benzylic position, or vice versa depending on reaction conditions.
• Crystalline Stability: White to off-white solid at room temperature (mp ~50–70 °C), convenient for weighing and handling compared to liquid benzyl bromides.
• High Purity: Supplied at ≥95% or ≥98% (GC/HPLC), ensuring minimal interference from dehalogenated byproducts or positional isomers in multi-step synthesis.
• Versatile Building Block: Serves as a key intermediate for introducing the 3,4-dichlorobenzyl moiety into target molecules via alkylation, acylation, or cross-coupling strategies.
3. Major Applications
• Pharmaceutical Intermediate: Key building block for synthesizing APIs targeting diverse therapeutic areas including oncology, CNS disorders, and infectious diseases. The 3,4-dichlorobenzyl scaffold is present in several drug candidates.
• Agrochemical R&D: Used in the development of pesticides, herbicides, and fungicides where the dichlorobenzyl moiety contributes to bioactivity and metabolic stability.
• Cross-Coupling Reactions: Employed in Pd-catalyzed Suzuki-Miyaura, Stille, and Buchwald-Hartwig couplings to construct biaryl or aryl-amine linkages for complex molecule assembly.
• Nucleophilic Substitution Library Synthesis: The benzylic Br serves as an electrophile for reaction with diverse nucleophiles (amines, thiols, phenols, enolates) in Diversity-Oriented Synthesis (DOS) to generate compound libraries for high-throughput screening.
• Materials Science: Incorporated into liquid crystals, organic electronic materials, and functional polymers where halogenated aromatic systems are required.
• Academic Research: Studied in methodology development for selective halogen activation, benzylic functionalization, and orthogonal cross-coupling strategies.
4. Technical Specifications
Item Description
Product Name 3,4-Dichlorobenzyl Bromide
Synonyms 3,4-Dichlorobenzyl bromide; 1-(Bromomethyl)-3,4-dichlorobenzene; 3,4-DCBnBr
CAS Number 64018-22-0
Molecular Formula C₇H₅BrCl₂
Molecular Weight 240.92 g/mol
MDL Number MFCD00236085
PubChem CID 2738005
Assay (Purity) ≥95% / ≥98% (GC / HPLC)
Appearance White to off-white crystalline solid or powder
Melting Point ~50–70 °C (Literature, typical for dichlorobenzyl halides)
Boiling Point ~275–285 °C (Predicted)
Density ~1.68 g/cm³ (Predicted)
Flash Point ~115 °C (Predicted)
Refractive Index ~1.590 (Predicted)
pKa (Predicted) ~44 ± 5 (Benzylic C-H acidity; very weak)
Calculated LogP ~3.5–4.0
Polar Surface Area (PSA) 0 Ų (no H-bond donors/acceptors in the neutral form)
Hydrogen Bond Donors 0
Hydrogen Bond Acceptors 0 (halogens not H-bond acceptors in this context)
Rotatable Bonds 1
Solubility Soluble: DCM, Chloroform, THF, Acetone, Ethyl acetate, Toluene, DMF, DMSO.
Slightly Soluble:Methanol, Ethanol.
Practically Insoluble:Water (hydrolyzes slowly).
Spectral Data (Predicted) ¹H NMR (CDCl₃, 400 MHz): δ 4.45 (s, 2H, CH₂Br), 7.15 (dd, J≈8.5, 2.5 Hz, 1H, ArH), 7.35 (d, J≈2.5 Hz, 1H, ArH), 7.50 (d, J≈8.5 Hz, 1H, ArH).
¹³C NMR (CDCl₃):δ 33.5 (CH₂Br), 128–135 (aromatic Cs), 137.0 (C-Cl), 140.5 (C-Cl).
SMILES BrCC1=CC(=C(C=C1)Cl)Cl
InChI Key ewmrhzfkjkwsk-uHFFFAOYSA-N
Storage (Powder) 2–8 °C, sealed, protected from light & moisture; stable ≥12–18 months
Sensitivity Light-sensitive; moisture-sensitive (benzylic Br can hydrolyze); store under inert atmosphere
HS Code 2903.69.90 / 2903.99.90
5. Storage and Handling
• Storage: Store in a tightly sealed container at 2–8 °C, protected from light and moisture. For long-term storage (>12 months), keep under an inert atmosphere (N₂ or Ar) in a desiccator. The benzylic C–Br bond is susceptible to hydrolysis and photodegradation; stable for ≥12–18 months under proper conditions.
• Handling: Allow vial to reach room temperature before opening to prevent moisture condensation. Dissolve in anhydrous DCM, THF, acetone, or DMF as required. Minimize light exposure and moisture contact during handling.
• Reactivity Considerations: The benzylic bromide is highly reactive toward nucleophiles. Avoid contact with amines, thiols, alcohols, or water for prolonged periods to prevent premature substitution. Use anhydrous conditions for storage and reactions.
• Solution Preparation: Prepare fresh for each reaction. The compound is highly soluble in most organic solvents. Avoid protic solvents (MeOH, EtOH, H₂O) for long-term storage of solutions.
• Stability Monitoring: The appearance of a yellow to brown discoloration indicates decomposition (HBr elimination or oxidation); discard and obtain fresh material if significant discoloration is observed.
6. Safety Summary (Full SDS Highlights)
• GHS Classification: GHS05 (Corrosive) + GHS06 (Toxic) + GHS07 (Warning)
• Signal Word: Danger
• Hazard Statements:
• H301: Toxic if swallowed.
• H311: Toxic in contact with skin.
• H314: Causes severe skin burns and eye damage.
• H331: Toxic if inhaled.
• H335: May cause respiratory irritation.
• H372: Causes damage to organs (liver/kidney) through prolonged or repeated exposure (organohalogen compound).
• H410: Very toxic to aquatic life with long lasting effects.
• Precautionary Statements:
• P201: Obtain special instructions before use.
• P202: Do not handle until all safety precautions have been read and understood.
• P260: Do not breathe dust/mist/vapors. Use only in a well-ventilated area or fume hood.
• P261: Avoid breathing dust/mist/vapors.
• P264: Wash hands, forearms, and face thoroughly after handling.
• P270: Do not eat, drink, or smoke in areas where this material is used.
• P271: Use only outdoors or in a well-ventilated area.
• P280: Wear protective gloves (nitrile), safety glasses with side shields, face shield, and lab coat. Consider double-gloving.
• P284: Wear respiratory protection (if adequate ventilation not available).
• P301+P310: IF SWALLOWED: Immediately call a POISON CENTER or physician.
• P302+P352: IF ON SKIN: Wash with plenty of soap and water.
• P304+P340: IF INHALED: Remove person to fresh air and keep comfortable for breathing.
• P305+P351+P338: IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses if present and easy to do. Continue rinsing.
• P310: Immediately call a POISON CENTER or physician.
• P330: Rinse mouth if swallowed.
• P308+P313: IF exposed: Get medical advice/attention.
• P405: Store locked up.
• P501: Dispose of contents/container in accordance with local, regional, and national regulations.
• First Aid Measures:
• Inhalation: Remove to fresh air immediately. If breathing difficult, administer oxygen and seek medical attention IMMEDIATELY.
• Skin Contact: Immediately flush with plenty of water for at least 15 minutes. Remove contaminated clothing. Seek medical attention IMMEDIATELY.
• Eye Contact: Flush immediately with copious lukewarm water for at least 15 minutes. Remove contact lenses if possible. Seek medical attention IMMEDIATELY.
• Ingestion: Rinse mouth. Do NOT induce vomiting. Give water to drink if conscious. Call a POISON CENTER immediately.
• Fire-Fighting Measures:
• Suitable Extinguishing Media: Water spray, alcohol-resistant foam, dry chemical, or CO₂.
• Special Hazards: Combustion may produce highly toxic fumes including HBr (hydrogen bromide), HCl (hydrogen chloride), Br₂ (bromine gas), Cl₂ (chlorine gas), CO, and NOₓ. Hydrogen halides and halogen gases are extremely toxic and corrosive.
• Protective Equipment: Wear self-contained breathing apparatus (SCBA) and full protective clothing.
• Spill Response:
• Absorb with inert material (sand, vermiculite). Do NOT use combustible materials for cleanup. Prevent runoff from entering waterways or drains. Ventilate area after cleanup.
• Handling & Storage:
• Handle in fume hood ONLY. Keep container closed when not in use. Store at 2–8 °C, protected from light and moisture, under N₂/Ar. Keep away from strong oxidizers, strong bases, and heat sources.
• Hazardous Decomposition Products: Hydrogen bromide (HBr), hydrogen chloride (HCl), bromine (Br₂), chlorine (Cl₂), nitrogen oxides (NOₓ), carbon monoxide (CO), carbon dioxide (CO₂).
• Intended Use: For laboratory research and development ONLY. Not for human or veterinary therapeutic, diagnostic, or food use. Handle as a toxic, corrosive, and environmentally hazardous organohalogen compound.
