1-Bromo-2-methyl-3,4-dinitrobenzene: Properties & Uses

1-Bromo-2-methyl-3,4-dinitrobenzene is a polyfunctionalised aromatic building block bearing a bromo, a methyl, and two ortho-nitro substituents that make it a versatile electrophilic intermediate for advanced organic synthesis.

CAS Number

3433-93-0

Molecular Formula

C₇H₅BrN₂O₄

Molecular Weight

261.03 g/mol

Functional Groups

Aryl bromide, two nitro groups, methyl substituent

SKU

B728600

Appearance

Pale yellow to yellow solid (typical for polynitro aromatics)

Storage Condition

Cool, dry place; away from heat and ignition sources

Chemical Structure and Physicochemical Properties

1-Bromo-2-methyl-3,4-dinitrobenzene (CAS 3433-93-0) is a substituted benzene ring carrying a bromine atom at position 1, a methyl group at position 2, and nitro groups at positions 3 and 4. The molecular formula is C₇H₅BrN₂O₄, giving a molecular weight of approximately 261.03 g/mol.

The compound typically presents as a pale yellow to yellow crystalline solid at room temperature, consistent with the chromophoric character of aromatic nitro groups. The electron-withdrawing nitro groups at positions 3 and 4 strongly deactivate the ring toward electrophilic aromatic substitution while simultaneously activating it toward nucleophilic aromatic substitution (SNAr) at the carbon bearing the bromine, since the nitro groups are positioned to stabilise the Meisenheimer complex intermediate.

The ortho methyl group introduces steric effects that influence reactivity and regioselectivity in further functionalisation reactions. These combined electronic and steric features make the compound a differentiated synthon compared with simpler bromonitrobenzenes.

Synthetic Applications and Reactivity

1-Bromo-2-methyl-3,4-dinitrobenzene serves as a multifunctional building block in medicinal chemistry, agrochemical research, and materials science. Its principal synthetic utilities include:

• Cross-coupling reactions: The aryl C–Br bond participates in palladium-catalysed cross-coupling reactions such as Suzuki–Miyaura, Buchwald–Hartwig amination, and Sonogashira couplings, enabling introduction of aryl, amino, or alkynyl groups with retention of the nitro functionality.
• Nucleophilic aromatic substitution (SNAr): Activation by the flanking nitro groups facilitates displacement of the bromine by amines, alkoxides, and thiolates under mild conditions, providing access to diaryl ethers, anilines, and thioethers bearing the dinitrotoluene scaffold.
• Nitro group reduction: Selective or exhaustive reduction of the nitro groups using catalytic hydrogenation or chemical reductants (e.g., iron/acetic acid, SnCl₂) yields ortho-diaminotoluene derivatives useful in heterocyclic synthesis, particularly for benzimidazoles and quinoxalines.
• Directed metalation: The methyl group can be oxidised or halogenated at the benzylic position to introduce further diversity.

The combination of leaving-group (Br) and reducible groups (NO₂ × 2) in a single molecule allows sequential, orthogonal transformations, making this compound particularly attractive for library synthesis and lead optimisation campaigns.

Safe Handling, Storage, and Disposal

As with most polynitro aromatic compounds, appropriate precautions must be observed when handling 1-Bromo-2-methyl-3,4-dinitrobenzene:

Personal Protective Equipment (PPE): Wear nitrile gloves, laboratory coat, and safety glasses as a minimum. Use a fume hood for weighing and handling operations to avoid inhalation of fine dust or vapours.

Storage: Store in a tightly sealed container in a cool (below 25 °C), dry, and well-ventilated location away from open flames, oxidisers, and reducing agents. Polynitro aromatics can be sensitive to heat and shock under certain conditions; avoid grinding or exposing to elevated temperatures.

Stability: The compound is expected to be stable under recommended storage conditions, but prolonged exposure to moisture or strong bases may promote hydrolytic or reductive degradation of the nitro groups.

Disposal: Dispose of waste material in accordance with local, regional, and national regulations governing halogenated and nitro-aromatic chemical waste. Do not pour down the drain.

Note: Always consult the current Safety Data Sheet (SDS) provided by Aladdin Scientific before use. The information above is general guidance only.

Reagent Specifications and Quality

Aladdin Scientific supplies 1-Bromo-2-methyl-3,4-dinitrobenzene under SKU B728600. Researchers and procurement teams should request the current Certificate of Analysis (CoA) to confirm lot-specific purity, appearance, and analytical data prior to use in critical synthetic steps.

Typical quality attributes for research-grade aromatic halides include:

• Purity assessed by GC or HPLC
• Identity confirmed by ¹H NMR or IR spectroscopy
• Appearance and colour within specification
• Melting point as an additional identity check

For high-throughput screening or pharmaceutical intermediate applications where trace metal content is critical, request an ICP-MS metals report and inquire about higher-purity grades if available.

Frequently asked questions

What is 1-Bromo-2-methyl-3,4-dinitrobenzene used for in organic synthesis?

It is primarily used as an aromatic building block. The aryl bromide enables palladium-catalysed cross-coupling reactions (e.g., Suzuki, Buchwald–Hartwig), while the two nitro groups activate the ring toward nucleophilic aromatic substitution and can be selectively reduced to amines for heterocyclic synthesis such as benzimidazoles and quinoxalines.

How should 1-Bromo-2-methyl-3,4-dinitrobenzene be stored to maintain stability?

Store the compound in a tightly sealed container in a cool (below 25 °C), dry, and well-ventilated area away from heat sources, flames, oxidisers, and reducing agents. Avoid grinding or mechanical shock, as polynitro aromatic compounds may be sensitive under stress conditions. Always consult the current SDS for full storage guidance.

Can the bromine and nitro groups in this compound be functionalised independently?

Yes. The aryl C–Br bond can be selectively engaged in transition-metal-catalysed cross-coupling reactions under mild conditions without reducing the nitro groups, which are stable to typical palladium catalysis conditions. Conversely, catalytic hydrogenation or chemical reduction of the nitro groups can be performed while the aryl bromide remains intact under carefully controlled conditions, enabling orthogonal sequential transformations.

What purity and analytical data does Aladdin Scientific provide for SKU B728600?

Aladdin Scientific provides a Certificate of Analysis (CoA) for each lot of B728600, which typically includes purity data (GC or HPLC), identity confirmation (NMR or IR), and appearance. Contact Aladdin Scientific's technical support or your account manager to obtain the CoA for your specific lot number.

References

1. March, J. Advanced Organic Chemistry: Reactions, Mechanisms, and Structure, 4th ed.; Wiley-Interscience: New York, 1992. (General reference for SNAr and cross-coupling reactivity of halonitrobenzenes.)
2. Clayden, J.; Greeves, N.; Warren, S. Organic Chemistry, 2nd ed.; Oxford University Press: Oxford, 2012. (Textbook reference for nucleophilic aromatic substitution and Meisenheimer complexes.)
3. Negishi, E. (Ed.) Handbook of Organopalladium Chemistry for Organic Synthesis; Wiley-Interscience: New York, 2002. (Reference for palladium-catalysed cross-coupling of aryl bromides.)

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