Chemical Structure and Physical Properties

5-Bromo-1,2,3,4-tetrahydronaphthalene (also known as 5-bromotetralin) consists of a benzene ring fused to a cyclohexane ring, with a bromine substituent at the 5-position of the aromatic ring. The molecular formula is C₁₀H₁₁Br and the molecular weight is approximately 211.10 g/mol. The compound retains the characteristic partial saturation of the tetralin (1,2,3,4-tetrahydronaphthalene) scaffold, combining the reactivity of an aryl bromide with the three-dimensional character of the alicyclic ring.

At room temperature, 5-bromo-1,2,3,4-tetrahydronaphthalene is typically a colorless to pale yellow liquid or low-melting solid. Key physical parameters such as precise boiling point, melting point, density, and refractive index should be confirmed against the supplier certificate of analysis or authoritative databases such as PubChem or Reaxys, as values may vary by source.

Synthesis and Synthetic Utility

5-Bromo-1,2,3,4-tetrahydronaphthalene can be accessed by regioselective electrophilic aromatic bromination of 1,2,3,4-tetrahydronaphthalene (tetralin). The fused alicyclic ring directs the incoming electrophile preferentially to the peri positions (C-5 and C-8) of the aromatic ring due to the electron-donating inductive effect of the adjacent methylene groups, making C-5 bromination achievable under controlled conditions.

As a synthetic building block, the aryl bromide functionality makes this compound highly amenable to a wide range of metal-catalyzed cross-coupling reactions, including Suzuki–Miyaura, Kumada, Negishi, Buchwald–Hartwig, and Heck couplings. These transformations allow researchers to install diverse carbon and heteroatom substituents at the 5-position, facilitating the construction of complex molecular architectures based on the tetralin scaffold. Such derivatives are relevant in medicinal chemistry, materials science, and the development of novel ligands or pharmacophores.

Research Applications

The tetralin scaffold is a privileged structure in medicinal chemistry, appearing in numerous bioactive natural products and drug candidates. The introduction of a bromine handle at the 5-position of tetralin greatly expands the chemical space accessible from this core. Researchers use 5-bromo-1,2,3,4-tetrahydronaphthalene as an intermediate in the synthesis of:

• Pharmaceutical intermediates: Tetralin-based compounds have been explored as dopamine receptor modulators, adrenergic receptor ligands, and other CNS-active agents. The 5-bromo derivative provides a handle for elaboration toward target structures.
• Functional materials: Brominated polycyclic hydrocarbons serve as precursors to organic semiconductors, liquid crystals, and fluorescent dyes via cross-coupling polymerization strategies.
• Ligand synthesis: The compound can be converted to boronic acids, organolithium species, or Grignard reagents for further functionalization in complex molecule assembly.

Specific literature examples should be verified independently; researchers are encouraged to conduct a primary literature search in SciFinder or Reaxys for the most current applications.

Handling, Storage, and Safety

As with all organobromine reagents, appropriate laboratory safety precautions should be observed when working with 5-bromo-1,2,3,4-tetrahydronaphthalene. Users should consult the Safety Data Sheet (SDS) provided by Aladdin Scientific before use. General guidelines include:

• Personal Protective Equipment (PPE): Wear chemical-resistant gloves, safety goggles, and a lab coat. Use in a well-ventilated fume hood.
• Storage: Store in a tightly sealed container in a cool, dry, well-ventilated location, away from incompatible materials such as strong oxidizers and strong bases. Specific recommended storage temperature should be confirmed on the product label or SDS.
• Disposal: Dispose of in accordance with local, regional, and national regulations governing halogenated organic waste.
• Incompatibilities: Avoid contact with strong oxidizing agents and strong bases, which may react with the aryl bromide or the alicyclic ring system.

Detailed hazard classification, GHS pictograms, and first-aid measures are provided in the official SDS. Always refer to the current SDS prior to use.