3-Bromo-2-methyl-5-nitropyridine: Properties & Synthesis Uses

3-bromo-2-methyl-5-nitropyridine is a halogenated, methyl-substituted nitropyridine heterocycle widely used as a versatile building block in pharmaceutical synthesis, agrochemical research, and the preparation of complex nitrogen-containing scaffolds.

CAS Number

23056-37-3

Molecular Formula

C₆H₅BrN₂O₂

Molecular Weight

217.02 g/mol

SKU

B175303

Functional Groups

Bromo, methyl, nitro substituents on a pyridine ring

Primary Application

Synthetic building block for medicinal and heterocyclic chemistry

Chemical Structure and Properties

3-Bromo-2-methyl-5-nitropyridine is a trisubstituted pyridine derivative bearing a bromine atom at the 3-position, a methyl group at the 2-position, and a nitro group at the 5-position of the pyridine ring. Its molecular formula is C₆H₅BrN₂O₂ with a molecular weight of approximately 217.02 g/mol.

The combination of an electron-withdrawing nitro group and an electron-donating methyl group on the electron-deficient pyridine ring creates a differentiated electronic environment around the ring. This arrangement renders the carbon bearing the bromine atom particularly amenable to palladium-catalyzed cross-coupling reactions, while the nitro group can serve as a handle for further functionalization via reduction to an amine or other transformations.

The compound typically appears as a solid at room temperature. It should be stored in a cool, dry, well-ventilated location, away from incompatible materials such as strong oxidizers and strong bases, in accordance with standard laboratory safety protocols for halogenated nitroaromatic compounds.

Synthesis and Key Reactions

3-Bromo-2-methyl-5-nitropyridine is primarily valued in synthetic chemistry for the reactivity introduced by its halogen substituent. The C–Br bond at the 3-position participates readily in a variety of metal-catalyzed coupling reactions, making this compound a practical precursor for constructing more complex molecular architectures.

Palladium-Catalyzed Cross-Coupling: The aryl bromide functionality supports Suzuki–Miyaura, Negishi, Stille, and Heck coupling reactions with appropriate reaction partners. These transformations allow introduction of aryl, alkenyl, or alkyl groups at the 3-position, expanding the accessible chemical space from this scaffold.

Nucleophilic Aromatic Substitution: The electron-deficient character of the nitropyridine ring, particularly at positions activated by the nitro group, can facilitate nucleophilic aromatic substitution (SNAr) under appropriate conditions, enabling introduction of heteroatom nucleophiles.

Nitro Group Reduction: The nitro group at the 5-position can be selectively reduced to a primary amine using standard reductants (e.g., iron/acetic acid, catalytic hydrogenation), yielding an aminobromopyridine intermediate for further elaboration such as diazotization or amide bond formation.

Directed Metalation: The methyl group at the 2-position and the ring nitrogen can act cooperatively to direct ortho-metalation, offering additional regioselective functionalization opportunities under appropriate conditions.

Applications in Medicinal and Agrochemical Research

The pyridine ring is one of the most prevalent heterocyclic motifs in approved pharmaceuticals and agrochemicals. 3-Bromo-2-methyl-5-nitropyridine, by virtue of its multiple reactive handles, serves as a key intermediate in the preparation of bioactive molecules and candidate compounds.

Pharmaceutical Synthesis: Substituted nitropyridines and aminopyridines are common pharmacophores in kinase inhibitors, antiviral agents, antibacterials, and CNS-active compounds. The bromo substituent allows rapid diversification via parallel or combinatorial synthesis, while the nitro group can be converted to an amine for elaboration into urea, amide, or sulfonamide motifs frequently found in drug candidates.

Agrochemical Intermediates: Halogenated methylnitropyridines are employed as intermediates in the synthesis of herbicides, fungicides, and insecticides, where the pyridine nitrogen contributes to the biological activity and physicochemical properties of the final active ingredient.

Materials and Ligand Chemistry: Pyridine-containing building blocks are also used in the design of metal-organic frameworks (MOFs), coordination polymers, and ligands for catalysis. The electron-withdrawing nitro group modulates the Lewis basicity of the ring nitrogen, tuning metal-binding properties.

Handling, Safety, and Storage

As with all halogenated nitroaromatic compounds, appropriate safety precautions must be observed when working with 3-bromo-2-methyl-5-nitropyridine. Researchers should consult the Safety Data Sheet (SDS) provided by Aladdin Scientific before use.

Personal Protective Equipment (PPE): Use chemical-resistant gloves, safety glasses or goggles, and a laboratory coat when handling this compound. Work in a well-ventilated fume hood to minimize inhalation exposure to dust or vapors.

Storage Conditions: Store in a tightly sealed container in a cool, dry place, away from direct sunlight, heat sources, strong oxidizing agents, and strong bases. Standard ambient laboratory storage conditions are generally suitable; refer to the product label and SDS for specific temperature recommendations.

Waste Disposal: Dispose of the compound and any contaminated materials in accordance with local, regional, and national regulations governing halogenated and nitro-containing organic waste.

Stability: The compound is expected to be stable under normal storage conditions. Avoid prolonged exposure to moisture, which may affect purity over time.

Ordering Information and Specifications

Aladdin Scientific supplies 3-bromo-2-methyl-5-nitropyridine under SKU B175303. Researchers and procurement professionals can obtain detailed specification sheets, certificate of analysis (CoA), and safety data sheets directly from the Aladdin Scientific product page.

Standard quality attributes for research-grade reagents include purity verification by techniques such as HPLC, GC, or NMR. Please refer to the current product listing for available pack sizes, purity grades, and pricing. For bulk inquiries or custom requirements, contact Aladdin Scientific's technical sales team.

When ordering, confirm that the CAS number (23056-37-3) and the molecular formula (C₆H₅BrN₂O₂) match your application requirements. Always cross-reference the CoA upon receipt to verify purity and identity before use in critical synthetic steps.

Frequently asked questions

What is 3-bromo-2-methyl-5-nitropyridine used for in research?

3-Bromo-2-methyl-5-nitropyridine is primarily used as a synthetic building block in medicinal chemistry, heterocyclic chemistry, and agrochemical research. Its aryl bromide functionality enables palladium-catalyzed cross-coupling reactions, and its nitro group can be reduced to an amine for further derivatization, allowing access to a broad range of substituted pyridine targets.

How should 3-bromo-2-methyl-5-nitropyridine be stored?

The compound should be stored in a tightly sealed container in a cool, dry, well-ventilated area, away from strong oxidizers, strong bases, direct sunlight, and heat sources. Researchers should consult the Aladdin Scientific SDS for specific storage temperature recommendations and incompatibility information.

What cross-coupling reactions can be performed with 3-bromo-2-methyl-5-nitropyridine?

The aryl bromide at the 3-position of 3-bromo-2-methyl-5-nitropyridine supports several palladium-catalyzed cross-coupling reactions, including Suzuki–Miyaura (with boronic acids), Negishi (with organozinc reagents), Stille (with organotin reagents), and Heck (with alkenes) couplings. These reactions provide efficient access to 3-substituted methylnitropyridine derivatives.

What is the CAS number for 3-bromo-2-methyl-5-nitropyridine?

The CAS number for 3-bromo-2-methyl-5-nitropyridine is 23056-37-3. This identifier can be used to confirm the compound's identity when cross-referencing the certificate of analysis or ordering from Aladdin Scientific (SKU B175303).

Can the nitro group in 3-bromo-2-methyl-5-nitropyridine be selectively reduced?

Yes, the nitro group at the 5-position can be selectively reduced to a primary amine using reductants such as iron in acetic acid or via catalytic hydrogenation, yielding an aminobromopyridine intermediate. Care should be taken to optimize conditions to preserve the C–Br bond if it is needed for subsequent transformations.

References

1. Joule, J. A.; Mills, K. Heterocyclic Chemistry, 5th ed.; Wiley-Blackwell: Oxford, 2010. (General reference for pyridine chemistry and reactivity.)
2. Miyaura, N.; Suzuki, A. Palladium-Catalyzed Cross-Coupling Reactions of Organoboron Compounds. Chem. Rev. 1995, 95, 2457–2483. doi:10.1021/cr00039a007
3. Clayden, J.; Greeves, N.; Warren, S. Organic Chemistry, 2nd ed.; Oxford University Press: Oxford, 2012. (Reference for nitro group reductions and nucleophilic aromatic substitution.)

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