3-Amino-6-bromo-2-methoxypyridine: Handling & Use Protocol

3-Amino-6-bromo-2-methoxypyridine is a multifunctional halogenated aminopyridine building block widely employed in heterocyclic synthesis, metal-catalyzed cross-coupling reactions, and medicinal chemistry lead-compound elaboration.

CAS Number

alt. registry; verify with certificate of analysis (CoA)

Molecular Formula

C6H7BrN2O

Molecular Weight

203.04 g/mol

Appearance

Typically a pale solid; verify with CoA

Key Functional Groups

Primary amine (–NH2), aryl bromide (C–Br), methoxy ether (–OCH3)

Recommended Storage

Cool, dry, dark conditions; seal under inert atmosphere after opening

Materials and Safety Precautions

Before beginning any work with 3-Amino-6-bromo-2-methoxypyridine (Aladdin SKU A187873), consult the current Safety Data Sheet (SDS). Halogenated aminopyridines may be irritating to skin, eyes, and the respiratory tract. Work in a well-ventilated fume hood at all times.

Personal protective equipment (PPE): chemical-resistant gloves (nitrile recommended), laboratory coat, and safety goggles. Avoid inhalation of dust or vapors.

Required materials:

• 3-Amino-6-bromo-2-methoxypyridine (A187873)
• Analytical balance (±0.1 mg)
• Suitable anhydrous solvents (e.g., DMF, DMSO, THF, DCM — see Section 2)
• Inert gas supply (N2 or Ar) for moisture-sensitive steps
• Standard glassware and magnetic stirring equipment
• Waste containers compliant with local regulations for halogenated organic waste

Dissolution and Stock Solution Preparation

3-Amino-6-bromo-2-methoxypyridine is generally soluble in polar aprotic solvents. The following guidance reflects general chemical principles for compounds bearing amine, aryl halide, and methoxy functionalities; confirm solubility empirically for your application.

1. Solvent selection: DMF and DMSO offer excellent solubility for stock solutions. For reactions requiring anhydrous conditions, use freshly dried THF or DCM over molecular sieves.
2. Stock concentration: Prepare stock solutions in the range of 0.1–1.0 M depending on downstream application. Higher concentrations may require gentle warming (≤40 °C) with caution.
3. Procedure:
   1. Tare a clean, dry vial under inert gas if moisture sensitivity is a concern.
   2. Weigh the required mass of A187873 accurately using an analytical balance.
   3. Add approximately 80% of the target solvent volume and stir or vortex until fully dissolved.
   4. Make up to the final volume with the remaining solvent and mix thoroughly.
   5. Filter through a 0.2 µm PTFE syringe filter if particulates are present.
4. Storage of stock solutions: Store at 2–8 °C under inert atmosphere, protected from light. Use within a validated timeframe; perform periodic purity checks by TLC or HPLC.

Synthetic Applications and Reaction Protocols

3-Amino-6-bromo-2-methoxypyridine is a versatile bifunctional intermediate. The aryl bromide site is amenable to transition-metal-catalyzed cross-coupling, while the primary amine enables condensation, acylation, sulfonylation, and cyclization reactions. The methoxy group can also serve as a handle for further functionalization.

A. Palladium-Catalyzed Suzuki–Miyaura Cross-Coupling (General Procedure)

1. Charge a Schlenk flask with A187873 (1.0 equiv), arylboronic acid (1.2–1.5 equiv), Pd catalyst (e.g., Pd(PPh3)4, 2–5 mol%), and base (e.g., K2CO3 or Cs2CO3, 2.0–3.0 equiv) under inert atmosphere.
2. Add degassed solvent (e.g., dioxane/H2O 4:1) and heat at 80–100 °C with stirring for 4–16 h; monitor by TLC or LC-MS.
3. Cool to room temperature, dilute with EtOAc, wash aqueous, dry over MgSO4, filter, and concentrate.
4. Purify by column chromatography or recrystallization.

B. Amide Bond Formation via the Amine Group

1. Dissolve A187873 (1.0 equiv) in anhydrous DCM or DMF under N2.
2. Add carboxylic acid (1.0–1.2 equiv), coupling reagent (e.g., HATU or EDC·HCl, 1.1–1.2 equiv), and base (e.g., DIPEA, 2.0–3.0 equiv).
3. Stir at room temperature for 2–18 h; monitor by TLC.
4. Work up and purify as appropriate for the target amide product.

Note: Reaction conditions should be optimized for each specific substrate. The above are general starting-point protocols.

Analytical Characterization and Quality Control

Prior to use, confirm the identity and purity of 3-Amino-6-bromo-2-methoxypyridine (A187873) using the following methods:

• TLC: Run on silica gel plates with an appropriate eluent (e.g., EtOAc/hexane mixtures). Visualize under UV (254 nm) and with ninhydrin stain (amine detection).
• HPLC: Reverse-phase C18 column with UV detection at 254 nm. Compare retention time against a reference standard or the CoA data provided by Aladdin Scientific.
• 1H NMR: Recorded in DMSO-d6 or CDCl3; expect signals consistent with the pyridine ring protons, NH2, and OCH3 group (verify chemical shifts against literature or CoA).
• Mass Spectrometry: ESI-MS or APCI-MS should yield [M+H]+ consistent with MW 203.04; note the characteristic bromine isotope pattern (1:1 for 79Br:81Br).

Accept the batch only if purity meets your experimental requirements (typically ≥97% for synthetic applications). Contact Aladdin Scientific for CoA documentation.

Waste Disposal and Regulatory Compliance

3-Amino-6-bromo-2-methoxypyridine contains an aryl bromide and should be classified and disposed of as halogenated organic waste in accordance with local, institutional, and national environmental regulations.

• Collect all waste solvents and reaction residues in clearly labeled, compatible waste containers designated for halogenated organic solvents.
• Do not pour waste down the drain or mix halogenated and non-halogenated waste streams unless your institutional waste management policy explicitly permits it.
• Consult your institution's Environmental Health and Safety (EHS) office for specific disposal guidance.
• Unused solid material should be stored securely or disposed of through an approved chemical waste contractor.

Always refer to the current SDS for emergency procedures, first-aid measures, and spill response information.

Frequently asked questions

What solvents are best for dissolving 3-Amino-6-bromo-2-methoxypyridine?

Polar aprotic solvents such as DMF and DMSO generally provide the best solubility. THF and DCM are suitable for reactions requiring anhydrous conditions. Solubility in protic solvents like methanol may be limited; always test empirically for your specific concentration and temperature requirements.

Can the aryl bromide in A187873 be selectively reacted without affecting the amine group?

Yes, under standard palladium-catalyzed cross-coupling conditions (e.g., Suzuki, Buchwald-Hartwig), the aryl bromide is typically reactive while the primary amine remains intact, provided mild bases and temperatures are used. However, protecting the amine (e.g., as a Boc carbamate) may be advisable for reactions using harsh conditions or strong bases to prevent side reactions.

How should 3-Amino-6-bromo-2-methoxypyridine be stored to maintain its purity?

Store the compound in a cool (2–8 °C recommended), dry, and dark environment. After opening, reseal the container under an inert atmosphere (N2 or Ar) to minimize exposure to moisture and air, which can degrade sensitive functional groups over time. Conduct periodic purity checks by HPLC or TLC for long-term storage.

Is 3-Amino-6-bromo-2-methoxypyridine suitable for use as a building block in medicinal chemistry?

Yes, this compound is a valuable bifunctional building block widely used in medicinal chemistry. Its aryl bromide enables C–C bond-forming cross-coupling reactions, while the primary amine facilitates the introduction of diverse pharmacophores via acylation, sulfonylation, or reductive amination. The methoxypyridine core is a privileged scaffold in drug discovery programs.

References

1. Aladdin Scientific. Product Page: 3-Amino-6-bromo-2-methoxypyridine, SKU A187873. Certificate of Analysis and Safety Data Sheet available on request.
2. Miyaura, N.; Suzuki, A. Palladium-Catalyzed Cross-Coupling Reactions of Organoboron Compounds. Chem. Rev. 1995, 95, 2457–2483. doi:10.1021/cr00039a007
3. Joule, J. A.; Mills, K. Heterocyclic Chemistry, 5th ed.; Wiley-Blackwell: Oxford, 2010.

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