6-Bromo-2-naphthoic acid
[CAS# 5773-80-8]

Identification

• Classification: Organic raw materials >> Aryl compounds >> Naphthalenes
• Name: 6-Bromo-2-naphthoic acid
• Molecular Formula: C₁₁H₇BrO₂
• Molecular Weight: 251.08
• CAS Registry Number: 5773-80-8
• EC Number: 611-572-1
• SMILES: C1=CC2=C(C=CC(=C2)Br)C=C1C(=O)O

Properties

• Density: 1.6±0.1 g/cm³ Calc.^*
• Melting point: 292 - 296 °C (Expl.)
• Boiling point: 387.3±17.0 °C 760 mmHg (Calc.)^*
• Flash point: 188.0±20.9 °C (Calc.)^*
• Index of refraction: 1.698 (Calc.)^*

^* Calculated using Advanced Chemistry Development (ACD/Labs) Software.

Safety Data

• Hazard Symbols: GHS07 Warning
• Risk Statements: H315-H319-H335
• Safety Statements: P261-P264-P264+P265-P271-P280-P302+P352-P304+P340-P305+P351+P338-P319-P321-P332+P317-P337+P317-P362+P364-P403+P233-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Skin irritation	Skin Irrit.	2	H315
Eye irritation	Eye Irrit.	2	H319
Specific target organ toxicity - single exposure	STOT SE	3	H335
Eye irritation	Eye Irrit.	2A	H319
Chronic hazardous to the aquatic environment	Aquatic Chronic	1	H410

Discovery and Applications

6-Bromo-2-naphthoic acid is an aromatic carboxylic acid derivative characterized by a naphthalene ring system substituted with a bromine atom at the 6-position and a carboxyl group at the 2-position. The naphthalene core consists of two fused benzene rings, and the substitution pattern places the bromine and carboxyl functional groups at specific positions that influence the compound’s chemical properties and reactivity.

The synthesis of 6-bromo-2-naphthoic acid typically involves bromination of 2-naphthoic acid under controlled conditions to selectively introduce the bromine atom at the 6-position. This regioselective bromination can be achieved using brominating agents such as bromine or N-bromosuccinimide (NBS) in the presence of catalysts or under specific temperature controls. Alternative synthetic approaches include multi-step procedures starting from naphthalene derivatives involving functional group interconversions and halogenation steps.

Chemically, 6-bromo-2-naphthoic acid exhibits typical behavior of aromatic carboxylic acids and aryl bromides. The carboxyl group imparts acidic properties, allowing for salt formation and participation in esterification and amidation reactions. The bromine substituent serves as a reactive site for further functionalization via palladium-catalyzed cross-coupling reactions, such as Suzuki, Heck, or Stille couplings, enabling the synthesis of more complex molecules. The presence of both groups in defined positions allows for diverse chemical modifications.

Applications of 6-bromo-2-naphthoic acid include its use as an intermediate in the synthesis of dyes, pharmaceuticals, agrochemicals, and organic electronic materials. The bromine substituent facilitates the introduction of various functional groups, expanding the compound’s utility in organic synthesis. It can be employed in the preparation of naphthoic acid derivatives with tailored electronic and steric properties relevant for catalysis and material science.

Analytical characterization involves nuclear magnetic resonance (¹H and ¹³C NMR) spectroscopy to verify the aromatic proton and carbon environments and confirm substitution patterns. Infrared (IR) spectroscopy detects characteristic carboxyl group absorptions near 1700 cm^–1 and broad O–H stretches due to the acid group. Mass spectrometry confirms molecular weight and fragmentation consistent with the bromo-naphthoic acid structure.

Physically, 6-bromo-2-naphthoic acid is generally a solid crystalline material with moderate solubility in organic solvents such as ethanol, acetone, and dimethylformamide, while exhibiting low solubility in water. Its melting point varies depending on purity and crystal form.

In summary, 6-bromo-2-naphthoic acid is a halogenated aromatic carboxylic acid with significant synthetic utility due to the reactivity of its bromine and carboxyl functional groups. Its well-established chemical properties and methods of synthesis make it an important intermediate in various chemical industries and research applications.

References

2024. Design and synthesis of novel factor XIa Inhibitors with bicyclic isoquinoline and naphthalene fragments. Medicinal Chemistry Research, 33(6).
DOI: 10.1007/s00044-024-03245-9

2011. New synthesis of 6[3-(1-adamantyl)-4-methoxyphenyl]-2-naphthoic acid and evaluation of the influence of adamantyl group on the DNA binding of a naphthoic retinoid. Bioorganic Chemistry, 39(4).
DOI: 10.1016/j.bioorg.2011.07.003

2008. Structures and vibrational frequencies of 2-naphthoic acid and 6-bromo-2-naphthoic acid based on density functional theory calculations. Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy, 70(1).
DOI: 10.1016/j.saa.2007.06.039