6-Bromoquinoline-3-Carboxylic Acid: Properties & Lab FAQ

6-bromoquinoline-3-carboxylic acid is a halogenated bicyclic heteroaromatic building block bearing both a bromine substituent at the 6-position and a carboxylic acid group at the 3-position of the quinoline ring, making it a versatile intermediate for medicinal chemistry, cross-coupling reactions, and the synthesis of pharmacologically active quinoline derivatives.

CAS Number

573675-25-9

Molecular Formula

C₁₀H₆BrNO₂

Molecular Weight

252.06 g/mol

Key Functional Groups

Carboxylic acid (–COOH) and aryl bromide (C–Br)

Appearance

Typically a pale yellow to off-white solid powder

Primary Application

Synthetic intermediate for cross-coupling (Suzuki, Buchwald–Hartwig) and amide coupling reactions

Chemical Identity and Structure

6-Bromoquinoline-3-carboxylic acid (SKU B480821) is a bifunctional quinoline derivative. The quinoline core is a benzene ring fused to a pyridine ring, providing a planar, electron-deficient aromatic system. The carboxylic acid at the 3-position enables amide bond formation, esterification, and decarboxylative coupling, while the bromine at the 6-position serves as a handle for palladium-catalyzed cross-coupling reactions such as Suzuki–Miyaura, Negishi, and Buchwald–Hartwig amination. This combination of two orthogonally reactive sites in a single molecule makes it particularly attractive for the sequential, modular construction of complex heterocyclic scaffolds.

Solubility, Storage, and Handling

6-Bromoquinoline-3-carboxylic acid is sparingly soluble in water due to the hydrophobic quinoline ring system; solubility is improved under basic aqueous conditions (e.g., dilute NaOH or K₂CO₃ solution) where the carboxylate anion is formed. It is moderately soluble in polar aprotic solvents such as DMSO and DMF, and partially soluble in ethanol and methanol. For reaction use, DMSO or DMF stock solutions are recommended. The compound should be stored in a tightly sealed container, away from moisture and light, at room temperature or under refrigeration (2–8 °C) to maintain long-term stability. Standard laboratory PPE—gloves, safety glasses, and a lab coat—should be worn when handling the material, and operations should be carried out in a well-ventilated area or fume hood.

Synthetic Applications in Medicinal and Organic Chemistry

The quinoline scaffold is a privileged structure in medicinal chemistry, present in numerous bioactive natural products and approved drugs. 6-Bromoquinoline-3-carboxylic acid serves as a key intermediate in several synthetic strategies:

• Suzuki–Miyaura coupling: The aryl bromide reacts with aryl or heteroaryl boronic acids in the presence of a palladium catalyst and base to install diverse aryl groups at the 6-position.
• Buchwald–Hartwig amination: The C–Br bond undergoes palladium-catalyzed coupling with primary or secondary amines, enabling the introduction of amino functionality.
• Amide coupling: The carboxylic acid is activated (e.g., with HATU, EDC, or SOCl₂) to form amide bonds with amines, enabling the rapid construction of quinoline-3-carboxamide libraries used in drug discovery.
• Esterification: Reaction with alcohols under acidic or coupling conditions yields methyl or ethyl esters, which are useful masked carboxylate equivalents or prodrug precursors.

These capabilities make B480821 a valuable building block for the synthesis of kinase inhibitors, antimicrobial agents, and fluorescent probes.

Purity, Quality, and Analytical Characterization

Aladdin Scientific supplies 6-bromoquinoline-3-carboxylic acid (B480821) as a research-grade reagent. Typical purity is verified by HPLC and/or GC analysis; lot-specific certificates of analysis (CoA) are available on request and include purity data, appearance, and analytical results. Researchers are encouraged to verify identity and purity upon receipt using standard analytical techniques:

• ¹H and ¹³C NMR: Confirm regiochemistry of bromine and carboxylic acid substitution. The aromatic protons of the quinoline ring appear as characteristic multiplets in the 8–9 ppm region, with the 4-H proton typically appearing as a singlet near 9.2–9.4 ppm.
• HPLC: Reverse-phase C18 column with UV detection (254 nm) provides purity assessment.
• LC-MS: Confirms molecular ion at m/z 252/254 (isotope pattern characteristic of one bromine atom).
• Melting point: Useful as an additional identity check; literature values should be confirmed against the CoA.

Ordering, Packaging, and Lead Time

6-Bromoquinoline-3-carboxylic acid is available from Aladdin Scientific under SKU B480821. Standard packaging options typically include small quantities (e.g., 1 g, 5 g) suitable for exploratory synthesis and larger quantities for scale-up campaigns. For current stock availability, pricing, and lead times, please check the product page on the Aladdin Scientific website or contact our customer service team. Custom quantities, bulk pricing, and expedited shipping can be arranged upon request. All orders are accompanied by a safety data sheet (SDS) and, where applicable, a certificate of analysis.

Frequently asked questions

What is the molecular weight and molecular formula of 6-bromoquinoline-3-carboxylic acid?

6-Bromoquinoline-3-carboxylic acid has the molecular formula C₁₀H₆BrNO₂ and a molecular weight of approximately 252.06 g/mol. The compound contains one nitrogen atom within the quinoline ring, one carboxylic acid group, and one aryl bromine substituent.

Which solvents are best for dissolving 6-bromoquinoline-3-carboxylic acid?

DMSO and DMF are the most effective solvents for dissolving 6-bromoquinoline-3-carboxylic acid and are recommended for preparing stock solutions. Partial solubility is observed in ethanol and methanol. Solubility in water is low under neutral conditions but increases significantly in dilute aqueous base (e.g., NaOH or K₂CO₃ solution) due to deprotonation of the carboxylic acid.

What cross-coupling reactions can be performed using the aryl bromide of B480821?

The aryl C–Br bond in 6-bromoquinoline-3-carboxylic acid is well-suited for palladium-catalyzed cross-coupling reactions, including Suzuki–Miyaura coupling with boronic acids or esters, Negishi coupling with organozinc reagents, Buchwald–Hartwig amination with primary or secondary amines, and Sonogashira coupling with terminal alkynes. These reactions enable the efficient diversification of the quinoline scaffold at the 6-position.

How should 6-bromoquinoline-3-carboxylic acid be stored to ensure stability?

The compound should be stored in a tightly sealed container, protected from moisture and direct light, at room temperature or under refrigeration (2–8 °C). Under these conditions the solid is expected to be stable for an extended period. Always reseal the container promptly after use and keep it away from strong oxidizing agents and strong bases.

Can the carboxylic acid group of 6-bromoquinoline-3-carboxylic acid be converted to an amide without affecting the aryl bromide?

Yes. Amide coupling reagents such as HATU, EDC/HOBt, or T3P can activate the carboxylic acid selectively toward reaction with amines under mild conditions (room temperature, DMF or DCM solvent, organic base such as DIPEA) without affecting the aryl C–Br bond. This orthogonal reactivity allows sequential functionalization: amide coupling first, followed by palladium-catalyzed cross-coupling at the bromine site.

Is 6-bromoquinoline-3-carboxylic acid (B480821) available in bulk quantities?

Aladdin Scientific can accommodate bulk and custom quantity requests for B480821 beyond standard packaging sizes. Please contact our customer service or sales team directly to discuss quantities, lead times, and pricing for larger-scale orders.

References

1. March, J. Advanced Organic Chemistry: Reactions, Mechanisms, and Structure, 4th ed.; Wiley: New York, 1992. (General reference for carboxylic acid activation and cross-coupling reactions.)
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. (Quinoline chemistry and reactivity reference.)
4. Hartwig, J. F. Palladium-Catalyzed Amination of Aryl Halides and Related Reactions. Acc. Chem. Res. 1998, 31, 852–860. doi:10.1021/ar970281j

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