3,5-Dimethylbromobenzene

3,5-Dimethylbromobenzene (CAS: 556-96-7), also known as 1-Bromo-3,5-dimethylbenzene or 5-Bromo-m-xylene, is a versatile aryl bromide widely utilized as a building block in organic synthesis, pharmaceutical research, and material science applications . Its molecular formula is C₈H₉Br, with a molecular weight of 185.06 g/mol .

Physical Properties

The compound appears as a colorless to pale yellow transparent liquid at room temperature . It has a density of 1.362 g/mL at 25°C, a boiling point of 202-204°C, and a refractive index of n20/D 1.549 . The flash point is 87°C (188.6°F), indicating moderate flammability . Key calculated properties include a LogP value of approximately 3.07, indicating good lipophilicity, and a topological polar surface area of 0 Ų, reflecting the absence of hydrogen bond donors or acceptors .

Structural Features

The molecule consists of a benzene ring with two methyl groups at the 3 and 5 positions and a bromine atom at the 1 position. This symmetric 1,3-disubstitution pattern provides consistent reactivity and predictable steric effects during chemical transformations. The bromine atom serves as an excellent leaving group, making this compound highly valuable for cross-coupling reactions.

Key Applications

• Pharmaceutical Synthesis: This compound serves as an important intermediate in the synthesis of various pharmaceutical agents, enhancing the development of new medications . It has been used in the synthesis of substituted binaphthyl derivatives for asymmetric catalysis applications .

• Organic Synthesis: It is frequently employed in palladium-catalyzed cross-coupling reactions including Suzuki-Miyaura, Buchwald-Hartwig amination, and carbon-oxygen coupling reactions . For example, palladium-catalyzed carbon-oxygen coupling of 1-bromo-3,5-dimethylbenzene with o-cresol produces o-tolyl-3,5-xylyl ether .

• Material Science: The compound is applied in the production of specialty polymers and resins, contributing to advancements in materials with unique properties .

• Agrochemicals: It plays a role in the formulation of agrochemical products, helping to improve crop protection and yield .

Safety and Handling

The compound is classified as an irritant (Xi) with hazard statements H315 (causes skin irritation), H319 (causes serious eye irritation), and H335 (may cause respiratory irritation) . It should be stored in a cool, dry, well-ventilated area away from oxidizing agents. Personal protective equipment including gloves and safety goggles should be used during handling . The product has a WGK Germany classification of 3 .

Specifications

Commercial grades are available at ≥97-99% purity from major suppliers including Sigma-Aldrich, AK Scientific, and Chem-Impex . Typical packaging sizes range from 5g to 100g for research use, with larger quantities available for industrial applications .

In summary, 3,5-Dimethylbromobenzene is a valuable and reliable building block for synthetic chemists, enabling efficient access to diverse chemical libraries in drug discovery, crop protection, and advanced materials development. Its well-defined physical properties, commercial availability, and versatile reactivity make it an essential tool in both academic and industrial research settings.