2-Bromo-3-Thiophenecarboxylic Acid: Properties & Applications
2-Bromo-3-Thiophenecarboxylic Acid: Properties & Applications
2-Bromo-3-thiophenecarboxylic acid is a versatile halogenated heterocyclic building block widely employed in medicinal chemistry, materials science, and organic synthesis as a key intermediate for cross-coupling reactions and further functionalization.
- Chemical Name
- 2-Bromo-3-thiophenecarboxylic acid
- CAS Number
- 7311-61-7
- Molecular Formula
- C5H3BrO2S
- Molecular Weight
- 207.04 g/mol
- Key Functional Groups
- Aryl bromide, carboxylic acid, thiophene ring
- Primary Application
- Synthetic intermediate for cross-coupling and heterocyclic chemistry
- Aladdin SKU
- B168947
Chemical Identity and Physical Properties
2-Bromo-3-thiophenecarboxylic acid (CAS 7311-61-7) is a brominated thiophene derivative bearing a carboxylic acid group at the 3-position and a bromine substituent at the 2-position of the thiophene ring. Its molecular formula is C5H3BrO2S, with a molecular weight of approximately 207.04 g/mol.
The compound typically appears as a white to off-white crystalline solid at room temperature. The presence of both the electron-withdrawing carboxylic acid group and the bromine atom on the thiophene ring imparts distinct electronic properties, making the aromatic system amenable to directed metalation and selective functionalization. The carboxylic acid functionality also allows for straightforward conversion to esters, amides, and acid chlorides, broadening the range of downstream synthetic transformations.
Recommended storage conditions are in a cool, dry, and well-ventilated environment, away from moisture and incompatible materials such as strong oxidizers and bases. Handling should follow standard laboratory safety practices, including the use of appropriate personal protective equipment (PPE).
Synthesis Utility and Reactivity
The defining synthetic value of 2-Bromo-3-thiophenecarboxylic acid lies in the dual reactivity of its two principal functional handles: the C–Br bond and the carboxylic acid group. The aryl bromide at the 2-position is an excellent electrophilic partner in transition-metal-catalyzed cross-coupling reactions, including Suzuki–Miyaura, Kumada, Negishi, Stille, and Sonogashira couplings. These reactions enable the introduction of diverse aryl, alkenyl, alkyl, and alkynyl groups at the 2-position of the thiophene scaffold, facilitating rapid diversification of molecular structure.
The carboxylic acid group can be independently manipulated through esterification, amide bond formation (including via activated intermediates such as acid chlorides or NHS esters), decarboxylation, or reduction to the corresponding alcohol or aldehyde. This orthogonal reactivity of the two functional groups makes the compound a powerful bifunctional building block in multi-step synthesis.
Additionally, the compound can serve as a precursor for directed ortho-metalation (DoM) strategies, where the carboxylic acid (or its derivatives, such as the corresponding Weinreb amide or directed metalation group-bearing amides) directs organolithium or organomagnesium bases to specific ring positions, enabling the preparation of highly substituted thiophene derivatives with controlled regiochemistry.
Applications in Medicinal Chemistry and Materials Science
Thiophene-containing scaffolds are prominent in pharmaceutical research due to their favorable pharmacokinetic profiles, metabolic stability, and ability to mimic carbocyclic aromatic rings in bioactive molecules. 2-Bromo-3-thiophenecarboxylic acid serves as a key starting material or intermediate in the synthesis of thiophene-based drug candidates, agrochemicals, and bioactive natural product analogs.
In drug discovery, the compound's bromo substituent enables rapid library synthesis via parallel cross-coupling, while the carboxylic acid group provides a handle for introducing pharmacophoric amide or ester linkages. Researchers have employed related bromothiophene carboxylic acids in the preparation of kinase inhibitors, antimicrobial agents, and compounds targeting G-protein-coupled receptors (GPCRs), though specific published examples using this exact compound should be verified in the primary literature.
In materials science, thiophene-based conjugated systems are foundational components of organic semiconductors, conducting polymers (such as polythiophenes), and organic photovoltaic (OPV) materials. 2-Bromo-3-thiophenecarboxylic acid and its derivatives can be incorporated into monomer design for electropolymerization or Suzuki/Stille polycondensation routes to produce functional π-conjugated polymers with tailored optoelectronic properties.
Handling, Safety, and Storage Recommendations
As with all brominated organic acids, appropriate precautions should be observed when handling 2-Bromo-3-thiophenecarboxylic acid in the laboratory. Users should consult the current Safety Data Sheet (SDS) supplied by Aladdin Scientific before use. General safety measures include working in a well-ventilated fume hood, wearing nitrile or chemical-resistant gloves, safety goggles, and a laboratory coat to minimize dermal and ocular exposure.
The compound should be stored in a tightly sealed container at room temperature or as specified on the product label, protected from light, moisture, and heat. Incompatibilities with strong oxidizing agents, strong bases, and reactive metals should be noted. In the event of spillage, the material should be collected mechanically and disposed of in accordance with local regulations for halogenated organic waste.
First-aid measures in case of skin or eye contact include immediate flushing with copious amounts of water for at least 15 minutes, followed by seeking medical attention if irritation persists. Inhalation of dust should be avoided; if exposure occurs, move to fresh air and seek medical advice as needed.
Frequently asked questions
What is 2-Bromo-3-thiophenecarboxylic acid used for?
2-Bromo-3-thiophenecarboxylic acid is primarily used as a bifunctional synthetic building block in organic and medicinal chemistry. Its aryl bromide group participates in palladium- or nickel-catalyzed cross-coupling reactions (e.g., Suzuki, Negishi, Stille), while the carboxylic acid group enables further derivatization to esters, amides, or reduced functional groups. It is also employed in the preparation of conjugated materials for organic electronics.
How should 2-Bromo-3-thiophenecarboxylic acid be stored?
The compound should be stored in a tightly sealed container at room temperature, away from moisture, light, heat, strong oxidizers, and strong bases. Always refer to the current Aladdin Scientific Safety Data Sheet (SDS) for the most up-to-date storage and handling guidance specific to this product.
What cross-coupling reactions are compatible with 2-Bromo-3-thiophenecarboxylic acid?
The aryl C–Br bond in 2-Bromo-3-thiophenecarboxylic acid is compatible with a broad range of transition-metal-catalyzed cross-coupling reactions, including Suzuki–Miyaura (with aryl/alkenyl boronic acids), Stille (with organostannanes), Negishi (with organozinc reagents), Kumada (with Grignard reagents), and Sonogashira (with terminal alkynes) couplings. Reaction conditions should be optimized to avoid competitive decarboxylation under harsh basic or high-temperature conditions.
Is 2-Bromo-3-thiophenecarboxylic acid suitable for polymer synthesis?
Yes, 2-Bromo-3-thiophenecarboxylic acid and its derivatives can serve as monomers or co-monomers in the synthesis of π-conjugated polymers via polycondensation routes such as Suzuki or Stille polymerization. The carboxylic acid group may be converted to other functional groups prior to polymerization to tune solubility, processability, or electronic properties of the resulting polymer.
What is the Aladdin Scientific SKU for 2-Bromo-3-thiophenecarboxylic acid?
2-Bromo-3-thiophenecarboxylic acid is available from Aladdin Scientific under SKU B168947. Please visit the Aladdin Scientific website or contact customer service for current availability, purity specifications, and pricing.
References
- Joule, J. A.; Mills, K. Heterocyclic Chemistry, 5th ed.; Wiley-Blackwell: Oxford, 2010. (General reference for thiophene chemistry and reactivity.)
- Miyaura, N.; Suzuki, A. Palladium-Catalyzed Cross-Coupling Reactions of Organoboron Compounds. Chem. Rev. 1995, 95, 2457–2483. doi:10.1021/cr00039a007
- Roncali, J. Conjugated poly(thiophenes): synthesis, functionalization, and applications. Chem. Rev. 1992, 92, 711–738. doi:10.1021/cr00012a009
- Aladdin Scientific Product Page: 2-Bromo-3-thiophenecarboxylic acid, SKU B168947. Aladdin Scientific, Shanghai.
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