Chemical Properties and Structure

2-Chloro-6-iodobenzoic acid (CAS 13421-13-1) is an ortho-disubstituted benzoic acid bearing a chlorine atom at the 2-position and an iodine atom at the 6-position relative to the carboxylic acid group. Its molecular formula is C₇H₄ClIO₂ with a molecular weight of approximately 282.46 g/mol.

The presence of two distinct halogen substituents on the aromatic ring provides orthogonal reactivity: the C–I bond is substantially more reactive than the C–Cl bond toward oxidative addition into palladium(0) and other transition-metal catalysts, enabling chemoselective functionalization. The carboxylic acid group further directs electrophilic and nucleophilic transformations and can serve as a handle for amide coupling or decarboxylation reactions.

The compound is typically obtained as a white to off-white crystalline solid with moderate stability under ambient conditions when stored away from light and moisture.

Synthetic Applications and Reactivity

The orthogonally reactive C–I and C–Cl bonds make 2-chloro-6-iodobenzoic acid an important building block in multistep synthesis. Key applications include:

• Selective Pd-catalyzed cross-coupling: Under standard Suzuki–Miyaura, Sonogashira, or Negishi coupling conditions, the aryl iodide reacts preferentially over the aryl chloride, allowing introduction of one coupling partner while retaining the C–Cl bond for subsequent functionalization.
• Sequential cross-coupling: The retained aryl chloride can be engaged in a second cross-coupling step using more active catalytic systems or harsher conditions, enabling the construction of unsymmetrical biaryl or heteroaryl frameworks.
• Directed ortho-metalation: The carboxylic acid can be converted to a directed metalation group (e.g., amide or oxazoline) to guide lithiation at specific ring positions.
• Decarboxylative functionalization: The carboxylate group can participate in transition-metal-catalyzed decarboxylative coupling strategies.
• Pharmaceutical and agrochemical intermediates: Halogenated benzoic acid derivatives are widely used precursors in the synthesis of active pharmaceutical ingredients and crop-protection compounds.

Researchers should note that chemoselectivity may vary depending on catalyst, ligand, base, and solvent; optimization of reaction conditions is recommended for each specific transformation.

Safe Handling, Storage, and Waste Disposal

Handling precautions: 2-Chloro-6-iodobenzoic acid should be treated as a potential irritant to skin, eyes, and the respiratory tract. Always handle in a well-ventilated fume hood. Wear appropriate personal protective equipment (PPE) including chemical-resistant gloves, safety goggles, and a lab coat. Avoid inhalation of dust.

Storage: Store the compound in a tightly sealed container in a cool, dry location away from direct light and incompatible materials (strong bases, strong oxidizers). Recommended storage temperature is typically 2–8 °C or as specified on the product label. Check the Certificate of Analysis (CoA) for lot-specific recommendations.

Waste disposal: Dispose of all waste containing this compound in accordance with local, regional, and national regulations governing halogenated organic waste. Do not dispose of via standard laboratory drain or municipal waste streams. Consult your institution's Environmental Health and Safety (EHS) office for approved disposal methods.

First aid: In case of skin or eye contact, flush immediately with copious amounts of water for at least 15 minutes and seek medical attention. If inhaled, move the affected person to fresh air and seek medical advice if symptoms persist.

Note: Always consult the current Safety Data Sheet (SDS) for this product (C190615) before use.

Quality, Purity, and Analytical Verification

For research applications, the purity of 2-chloro-6-iodobenzoic acid is critical to reproducible results. Aladdin Scientific provides a Certificate of Analysis (CoA) with each lot, detailing purity as determined by standard analytical methods such as high-performance liquid chromatography (HPLC) or gas chromatography (GC).

Identity confirmation: Identity of the compound can be confirmed by:

• ¹H NMR spectroscopy: Characteristic aromatic proton signals consistent with a 1,2,3-trisubstituted benzene ring pattern.
• IR spectroscopy: Broad O–H stretch (~2500–3300 cm⁻¹) and strong C=O stretch (~1680–1710 cm⁻¹) consistent with a carboxylic acid; C–I and C–Cl stretches in the fingerprint region.
• Mass spectrometry: Molecular ion consistent with M = 282.46 g/mol; characteristic isotope patterns for chlorine (³⁵Cl/³⁷Cl) and iodine (¹²⁷I).
• Melting point: Compare against literature values as an additional purity check (consult CoA for lot-specific data).

Researchers requiring higher purity grades for sensitive assays should contact Aladdin Scientific customer service to enquire about available specifications.

Ordering, Availability, and Technical Support

2-Chloro-6-iodobenzoic acid is available from Aladdin Scientific under SKU C190615. The product is offered in standard research quantities; please consult the Aladdin Scientific website or contact your regional sales representative for current pack sizes, pricing, and stock availability.

Ordering information:

• Product SKU: C190615
• Product Name: 2-Chloro-6-iodobenzoic acid
• CAS: 13421-13-1

Technical support: Aladdin Scientific's technical team is available to assist with product selection, application questions, and specification inquiries. For SDS, CoA, and NMR spectra, visit the product page on the Aladdin Scientific website or contact customer service directly.

Custom synthesis and bulk orders: For non-standard quantities or purity requirements, contact Aladdin Scientific to discuss custom synthesis options.