Chemical Identity and Physicochemical Properties

3-Chloro-4-fluoropyridine is a dihalogenated pyridine derivative bearing a chlorine atom at the 3-position and a fluorine atom at the 4-position of the pyridine ring. Its molecular formula is C₅H₃ClFN with a molecular weight of approximately 131.54 g/mol.

The compound belongs to the class of fluorinated heteroaromatic building blocks. The electron-withdrawing nature of both the ring nitrogen and the two halogen substituents renders the aromatic ring highly electron-deficient, making it particularly reactive toward nucleophilic aromatic substitution (SNAr). The fluorine at the 4-position is especially activated for SNAr due to its position para to the ring nitrogen, which stabilizes the Meisenheimer complex intermediate.

The compound typically presents as a colorless to pale yellow liquid or low-melting solid. It is miscible with common organic solvents such as dichloromethane, tetrahydrofuran, and acetonitrile, but has limited miscibility with water.

Synthetic Applications and Reaction Scope

3-Chloro-4-fluoropyridine serves as a key bifunctional electrophilic building block in synthetic chemistry. Its two distinct C–X bonds (C–F and C–Cl) exhibit differential reactivity that chemists can exploit in sequential functionalization strategies.

Nucleophilic Aromatic Substitution (SNAr): The C4–F bond is preferentially displaced by hard nucleophiles such as amines, alkoxides, and thiols under mild conditions, owing to fluorine's superior leaving-group ability in SNAr relative to chlorine in electron-deficient arenes. This selectivity enables chemoselective introduction of heteroatom-containing substituents.

Transition-Metal-Catalyzed Cross-Coupling: The C3–Cl bond is well-suited for palladium- or nickel-catalyzed cross-coupling reactions, including Suzuki–Miyaura, Negishi, and Buchwald–Hartwig amination. This orthogonal reactivity allows sequential diversification of the pyridine scaffold in a programmable manner.

Pharmaceutical and Agrochemical Intermediates: The compound is frequently employed in the synthesis of biologically active molecules, including kinase inhibitors, antibacterial agents, and crop-protection compounds, where a fluorinated pyridine motif is a pharmacophore of interest due to its influence on lipophilicity, metabolic stability, and binding interactions.

Safe Handling, Storage, and Waste Disposal

Personal Protective Equipment (PPE): Always wear appropriate PPE when handling 3-Chloro-4-fluoropyridine, including chemical-resistant gloves (nitrile or neoprene), a laboratory coat, and safety goggles. Where vapor concentrations may be elevated, use a fume hood or respiratory protection.

Hazard Profile: As a halogenated aromatic compound, 3-Chloro-4-fluoropyridine may cause skin, eye, and respiratory irritation. Refer to the current Safety Data Sheet (SDS) for GHS classification, first-aid measures, and regulatory data prior to use. Specific toxicological data should be confirmed from the supplier SDS.

Storage: Store in a tightly closed container in a cool (typically 2–25 °C), dry, well-ventilated location away from incompatible materials such as strong bases, strong oxidizers, and moisture-sensitive reagents. Protect from light for long-term storage.

Waste Disposal: Dispose of waste material in accordance with local, regional, and national regulations governing halogenated organic compounds. Do not pour down the drain. Segregate halogenated waste streams as required by your institution's environmental health and safety (EHS) guidelines.

Quality, Purity, and Procurement Guidance

Purity Considerations: For sensitive synthetic applications, particularly SNAr reactions and transition-metal-catalyzed couplings, reagent purity is critical. Trace impurities, including other halopyridine isomers or hydrolysis products, can reduce yields and complicate purification. Request a Certificate of Analysis (CoA) confirming purity (typically ≥98% by GC or HPLC) and lot-specific data before committing to large-scale use.

Specification Verification: Confirm the compound's identity using standard analytical techniques: NMR spectroscopy (¹H and ¹³C, ¹⁹F) for structural confirmation, GC-MS or LC-MS for purity and molecular weight verification, and melting point or refractive index as physical identity checks.

Packaging and Scale: Aladdin Scientific offers 3-Chloro-4-fluoropyridine (SKU: C1369404) in research-scale quantities suitable for laboratory use. Contact our technical team or your account manager for bulk pricing, custom packaging, or additional quality documentation requirements.

Ordering: Place orders directly through the Aladdin Scientific website or contact your regional representative. Reference SKU C1369404 to ensure accurate order fulfillment.