2-(Bromomethyl)-3,5-dimethylpyridine HBr: Key FAQs

2-(Bromomethyl)-3,5-dimethylpyridine hydrobromide is a bench-stable hydrobromide salt form of a reactive benzylic bromide building block widely used as an electrophilic alkylating agent in medicinal and synthetic organic chemistry.

Product Name

2-(Bromomethyl)-3,5-dimethylpyridine hydrobromide

SKU

B191337

Molecular Formula

C8H10BrN · HBr

Functional Class

Benzylic bromide electrophile / alkylating agent (hydrobromide salt)

Recommended Storage

Cool, dry, well-ventilated location; away from moisture and incompatible bases

Physical Form

Solid (salt form provides enhanced bench stability relative to free base)

What Is 2-(Bromomethyl)-3,5-dimethylpyridine Hydrobromide and How Is It Used?

2-(Bromomethyl)-3,5-dimethylpyridine hydrobromide (Aladdin SKU B191337) is the hydrobromide salt of 2-(bromomethyl)-3,5-dimethylpyridine. The pyridine nitrogen is protonated by hydrobromic acid, yielding a crystalline solid that is easier to weigh and handle than the moisture-sensitive free base.

The compound functions as a reactive electrophile through its benzylic carbon–bromine bond. It is primarily employed in N-alkylation of amines, thiols, and other nucleophiles, and in C-alkylation reactions under appropriate base conditions. The 3,5-dimethyl substitution pattern on the pyridine ring modifies electronic density and steric environment, making this building block valuable in medicinal chemistry programs targeting pyridine-containing drug candidates.

In practice, the free base is liberated in situ by treating an aqueous or organic solution of the salt with a suitable base (e.g., K₂CO₃, Et₃N) prior to or during the alkylation step.

Physical and Chemical Properties

The hydrobromide salt form confers several practical advantages: the compound is a solid at room temperature, exhibits improved stability compared with the free bromomethyl base, and has a defined melting point that can serve as a purity indicator. Key structural features include:

• Core heterocycle: pyridine ring substituted at positions 3 and 5 with methyl groups.
• Reactive handle: bromomethyl (–CH₂Br) group at position 2, adjacent to the ring nitrogen, conferring benzylic activation.
• Salt counterion: bromide from HBr protonation, removable by base treatment.

The benzylic C–Br bond is activated toward S_N2 substitution by both the adjacent aromatic ring and the electron-withdrawing pyridine nitrogen, making this reagent highly reactive toward soft and hard nucleophiles alike.

Note: Exact numerical values for molecular weight, melting point, and purity are available on the product datasheet for B191337 and should be consulted for QC purposes.

Handling, Safety, and Storage Guidelines

Personal Protective Equipment (PPE): Handle in a chemical fume hood. Wear nitrile gloves, safety goggles, and a laboratory coat. Benzylic bromides are potent alkylating agents and potential irritants to skin, eyes, and the respiratory tract.

Storage: Store in a tightly sealed container in a cool, dry, well-ventilated area. Protect from moisture, heat, and light. Keep away from strong bases and oxidizing agents. The hydrobromide salt is generally more stable than the free base but should still be stored under inert atmosphere or with a desiccant for long-term stability.

Incompatibilities: Strong bases (will liberate the reactive free base), strong oxidizers, and nucleophilic solvents that could cause premature reaction.

Disposal: Follow institutional and local regulatory guidelines for disposal of halogenated organic waste. Consult the Safety Data Sheet (SDS) for B191337 for complete hazard information before use.

Review flag: Specific GHS hazard classifications and H/P statements must be verified against the official SDS for B191337.

Typical Synthetic Applications and Reaction Protocols

2-(Bromomethyl)-3,5-dimethylpyridine hydrobromide is a versatile building block in several synthetic contexts:

1. N-Alkylation of amines: The salt is dissolved in a polar aprotic solvent (e.g., DMF, MeCN) with a base (e.g., K₂CO₃, DIPEA) and the amine nucleophile. The base both neutralizes HBr and drives the reaction. Room temperature to mild heating typically suffices given the high reactivity of the benzylic bromide.
2. S-Alkylation of thiols: Thiols react rapidly with benzylic bromides. Mild base conditions in DMF or EtOH are commonly employed. Reaction monitoring by TLC or LC-MS is recommended due to the potential for bis-alkylation.
3. Quaternary ammonium salt formation: Tertiary amines react with the electrophilic center to form quaternary pyridinium or ammonium salts, useful in materials science and as phase-transfer catalysts.
4. Medicinal chemistry fragment coupling: The 3,5-dimethylpyridine motif is a recognized pharmacophore fragment. This reagent is used to introduce the dimethylpyridylmethyl group onto drug scaffolds.

Note: Specific reaction yields, temperatures, and times depend on the nucleophile and conditions; consult primary literature for optimized protocols.

Ordering, Specifications, and Quality Information

SKU: B191337 — available exclusively through Aladdin Scientific.

Purity and Specifications: Certificate of Analysis (CoA) and purity data are provided with each lot. Customers requiring specific purity thresholds should contact Aladdin Scientific sales or technical support to confirm current lot specifications before ordering.

Available Quantities: Please consult the Aladdin Scientific website or contact customer service for current pack sizes and pricing. Bulk inquiries are welcome.

Documentation: SDS, CoA, and structural confirmation data (e.g., NMR, HPLC) are available upon request or via the product page for B191337.

Returns and Quality Issues: If the product does not meet stated specifications, contact Aladdin Scientific customer service within the warranty period. Review the returns policy on the Aladdin Scientific website for full details.

Frequently asked questions

What is the difference between 2-(Bromomethyl)-3,5-dimethylpyridine and its hydrobromide salt?

The free base form contains an unprotonated pyridine nitrogen and a benzylic bromide, making it an oil or low-melting solid that is sensitive to moisture and difficult to handle. The hydrobromide salt (B191337) is formed by protonation of the pyridine nitrogen with HBr, yielding a crystalline, bench-stable solid that is easier to weigh accurately. In reactions, the free base is typically regenerated in situ by addition of an appropriate base before or during the reaction step.

Which solvents and bases are recommended for using B191337 in N-alkylation reactions?

Polar aprotic solvents such as DMF, acetonitrile, or DMSO are commonly used because they solubilize both the salt and the amine nucleophile while not competing in the reaction. Inorganic bases such as potassium carbonate or cesium carbonate, or hindered organic bases such as DIPEA or triethylamine, are typically employed to neutralize the HBr and to deprotonate the salt in situ. The optimal combination depends on the specific nucleophile and desired reaction temperature; a literature search for analogous substrates is recommended.

How should B191337 be stored to maintain its stability?

Store B191337 in a tightly sealed container in a cool, dry location away from moisture, light, and heat sources. Although the hydrobromide salt is more stable than the free base, long-term storage under an inert atmosphere (nitrogen or argon) with a desiccant is advisable. Avoid exposure to strong bases, which will regenerate the reactive free base and may accelerate decomposition. Always consult the product SDS and CoA for lot-specific storage recommendations.

Is 2-(Bromomethyl)-3,5-dimethylpyridine hydrobromide suitable for scale-up synthesis?

The solid, bench-stable nature of the hydrobromide salt makes it more amenable to scale-up than the free base. However, benzylic bromides are potent alkylating agents and require appropriate engineering controls (e.g., closed systems, scrubbers for HBr vapors) at larger scales. Bulk quantities are available from Aladdin Scientific; contact the sales team for pricing and lead times. Always conduct a thorough risk assessment and consult the SDS before scaling up.

What analytical methods can confirm the identity and purity of B191337?

Identity is typically confirmed by ¹H NMR spectroscopy (characteristic signals for the pyridine ring protons, methyl groups, and the –CH₂Br methylene) and by mass spectrometry. Purity is assessed by HPLC with UV detection or by quantitative NMR. Elemental analysis and ion chromatography can be used to confirm the hydrobromide stoichiometry. Refer to the CoA for B191337 for lot-specific analytical data provided by Aladdin Scientific.

References

1. Clayden, J.; Greeves, N.; Warren, S. Organic Chemistry, 2nd ed.; Oxford University Press: Oxford, 2012. (General reference for SN2 reactivity of benzylic halides and alkylation reactions.)
2. Aladdin Scientific. Product Datasheet and Certificate of Analysis for 2-(Bromomethyl)-3,5-dimethylpyridine hydrobromide, SKU B191337. (Consult current lot CoA for purity, melting point, and spectral data.)

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