3-Bromo-6-chloropyridazine: Properties, Uses & Handling FAQ

3-Bromo-6-chloropyridazine is a dihalogenated six-membered nitrogen-containing heterocycle widely used as a versatile building block in medicinal chemistry and materials science synthesis.

CAS Number

7752-89-8

Molecular Formula

C₄H₂BrClN₂

Molecular Weight

193.43 g/mol

SKU

B187829

Appearance

White to off-white crystalline solid

Recommended Storage

Cool, dry place; away from light and moisture

What Is 3-Bromo-6-chloropyridazine?

3-Bromo-6-chloropyridazine (CAS 7752-89-8) is a dihalogenated pyridazine derivative featuring a bromine substituent at the 3-position and a chlorine substituent at the 6-position of the pyridazine ring. The pyridazine core is a six-membered aromatic heterocycle containing two adjacent nitrogen atoms. The presence of two electronegative halogens renders the ring electron-deficient, increasing its susceptibility to nucleophilic aromatic substitution and making it an excellent electrophilic partner in transition-metal-catalyzed cross-coupling reactions such as Suzuki–Miyaura, Negishi, and Buchwald–Hartwig couplings.

Because bromine and chlorine exhibit different reactivities under palladium catalysis — bromine being selectively activated at lower temperatures — 3-Bromo-6-chloropyridazine allows sequential, chemoselective functionalization at each halogen position, giving synthetic chemists precise control over the elaboration of the heterocyclic scaffold.

Key Chemical Properties and Specifications

The molecular formula of 3-Bromo-6-chloropyridazine is C₄H₂BrClN₂ with a molecular weight of approximately 193.43 g/mol. The compound typically presents as a white to off-white crystalline solid at room temperature. Key physicochemical parameters include:

• Melting point: Refer to the Certificate of Analysis (CoA) for the specific lot value; literature values should be verified against primary sources.
• Solubility: Soluble in common polar aprotic solvents such as DMF, DMSO, and acetonitrile; sparingly soluble in water.
• Purity: Aladdin Scientific supplies this compound at research-grade purity; the exact purity specification is stated on the product page and CoA for SKU B187829.
• Stability: Stable under normal laboratory storage conditions when kept dry and away from strong bases, strong nucleophiles, and light.

Researchers should always consult the CoA accompanying their specific lot for authoritative purity, melting point, and spectral data.

Synthetic Applications and Reactivity

3-Bromo-6-chloropyridazine is valued primarily for its dual electrophilic handles, enabling sequential cross-coupling chemistry:

1. Selective C–Br functionalization: Under standard Suzuki–Miyaura conditions with Pd(PPh₃)₄ or Pd(dppf)Cl₂ at mild temperatures, the C–Br bond undergoes preferential oxidative addition, allowing aryl or heteroaryl boronic acids to be coupled selectively at C-3 while the C–Cl bond is retained for subsequent use.
2. Nucleophilic aromatic substitution (SNAr): The electron-deficient ring facilitates SNAr at C-6 (C–Cl) with nitrogen, oxygen, or sulfur nucleophiles under appropriate conditions, providing access to amino-, alkoxy-, or thio-substituted pyridazines.
3. Buchwald–Hartwig amination: Both C–Br and C–Cl bonds can serve as substrates for palladium-catalyzed C–N coupling, with the C–Br bond again showing higher reactivity.

This orthogonal reactivity profile makes 3-Bromo-6-chloropyridazine a key intermediate in the synthesis of kinase inhibitors, antiviral agents, and other bioactive heterocyclic scaffolds encountered in drug discovery programs.

Safe Handling, Storage, and Disposal

Handling: 3-Bromo-6-chloropyridazine should be handled in a well-ventilated fume hood. Appropriate personal protective equipment (PPE) — including nitrile gloves, safety glasses, and a laboratory coat — must be worn at all times. Avoid inhalation of dust or vapors and contact with skin and eyes.

Storage: Store in a tightly sealed container in a cool, dry, well-ventilated location away from light, moisture, oxidizing agents, and strong bases. Recommended storage temperature is typically 2–8 °C or as specified on the product label. Always verify storage conditions on the CoA and Safety Data Sheet (SDS) supplied with SKU B187829.

Disposal: Dispose of in accordance with all applicable local, regional, and national regulations governing halogenated organic waste. Do not discharge into drains or the environment. Consult your institution's Environmental Health and Safety (EHS) office for guidance.

First Aid: In case of skin or eye contact, flush immediately with copious water for at least 15 minutes and seek medical advice. For inhalation, move to fresh air and consult a physician if symptoms persist. Refer to the SDS for complete hazard and first-aid information.

Ordering and Quality Assurance at Aladdin Scientific

3-Bromo-6-chloropyridazine is available from Aladdin Scientific under SKU B187829. Orders can be placed directly through the Aladdin Scientific website, by contacting your regional sales representative, or via established procurement channels. The following quality-assurance information is relevant to purchasers:

• Purity verification: Each lot is tested and accompanied by a Certificate of Analysis (CoA) specifying purity, appearance, and analytical data (e.g., HPLC, NMR, or GC as applicable).
• Documentation: SDS, CoA, and, where available, spectral data can be downloaded from the product page or requested from customer service.
• Custom quantities: If the standard pack size does not meet your project requirements, contact Aladdin Scientific's sales team to inquire about custom quantities or bulk pricing.
• Returns and quality issues: If a product does not meet the stated specifications, contact Aladdin Scientific customer service with your order number and CoA for resolution under the applicable returns and refund policy.

Frequently asked questions

What makes 3-Bromo-6-chloropyridazine useful for sequential functionalization?

The compound carries two chemically distinct halogen leaving groups: a C–Br bond that undergoes preferential oxidative addition under palladium catalysis at mild temperatures, and a C–Cl bond that remains intact under those conditions but can be activated separately for SNAr or subsequent cross-coupling. This orthogonal reactivity allows chemists to install two different substituents in a controlled, stepwise manner on the pyridazine ring.

How should I store 3-Bromo-6-chloropyridazine (SKU B187829) to maintain its integrity?

Store the compound in a tightly sealed container in a cool, dry, and well-ventilated area, protected from light and moisture. The recommended storage temperature is typically 2–8 °C, but always verify the conditions stated on the product label, CoA, and SDS for your specific lot. Exposure to moisture, strong bases, or nucleophiles should be avoided to prevent degradation.

Which solvents are suitable for dissolving 3-Bromo-6-chloropyridazine in laboratory reactions?

3-Bromo-6-chloropyridazine is generally soluble in polar aprotic solvents such as DMF, DMSO, acetonitrile, and THF, which are commonly used in cross-coupling and SNAr reactions. It shows limited solubility in water. Solvent selection should be guided by the specific reaction conditions and compatibility with reagents and catalysts being employed.

Can 3-Bromo-6-chloropyridazine be used in Buchwald–Hartwig amination reactions?

Yes. Both the C–Br and C–Cl bonds in 3-Bromo-6-chloropyridazine are amenable to palladium-catalyzed Buchwald–Hartwig C–N coupling reactions. The C–Br bond typically exhibits higher reactivity and can be selectively aminated first; the remaining C–Cl bond can subsequently be engaged under more forcing conditions or with appropriate catalyst systems.

How do I obtain a Certificate of Analysis or Safety Data Sheet for SKU B187829?

The Certificate of Analysis (CoA) and Safety Data Sheet (SDS) for 3-Bromo-6-chloropyridazine (SKU B187829) can be downloaded directly from the product page on the Aladdin Scientific website using your lot number. If you cannot locate the documents online, please contact Aladdin Scientific customer service with your order details and they will provide the relevant documentation promptly.

References

1. Aladdin Scientific product page for 3-Bromo-6-chloropyridazine, SKU B187829.
2. Joule, J. A.; Mills, K. Heterocyclic Chemistry, 5th ed.; Wiley-Blackwell: Oxford, 2010. General reference for pyridazine chemistry and reactivity.
3. Miyaura, N.; Suzuki, A. Palladium-Catalyzed Cross-Coupling Reactions of Organoboron Compounds. Chem. Rev. 1995, 95, 2457–2483. doi:10.1021/cr00039a007
4. Hartwig, J. F. Palladium-catalyzed amination of aryl halides: Mechanism and rational catalyst design. Synlett 1997, 329–340.

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