3,5-Dimethylchlorobenzene

3,5-Dimethylchlorobenzene (CAS: 556-97-8), also known as 1-Chloro-3,5-dimethylbenzene or 5-Chloro-m-xylene, is an important aryl halide widely utilized as a building block in organic synthesis, pharmaceutical research, and material science applications . Its molecular formula is C₈H₉Cl, with a molecular weight of 140.61 g/mol .

Physical Properties

The compound appears as a colorless to pale yellow transparent liquid at room temperature . Key physical properties include a boiling point of approximately 187°C, a density of 1.04 g/cm³, and a flash point of 63.1°C . The calculated XLogP3 value is 3.3, indicating good lipophilicity, and the topological polar surface area is 0 Ų, reflecting the absence of hydrogen bond donors or acceptors . The compound is insoluble in water but soluble in most organic solvents such as ethanol, ether, and chloroform .

Structural Features

The molecule consists of a benzene ring with two methyl groups at the 3 and 5 positions and a chlorine atom at the 1 position. This symmetric 1,3-disubstitution pattern provides consistent reactivity and predictable steric effects during chemical transformations . The systematic IUPAC name is 1-chloro-3,5-dimethylbenzene, and common synonyms include 5-chloro-m-xylene and 5-chloro-1,3-xylene .

Key Applications

3,5-Dimethylchlorobenzene serves as a valuable intermediate in multiple industries:

• Pharmaceutical Synthesis: It is widely used as a pharmaceutical intermediate in the synthesis of drug candidates and biologically active molecules .

• Organic Synthesis: The compound is frequently employed in palladium-catalyzed cross-coupling reactions including Suzuki-Miyaura, Buchwald-Hartwig amination, and other coupling reactions . The chlorine atom attached to the aromatic ring serves as a leaving group, enabling efficient carbon-carbon and carbon-heteroatom bond formation.

• Functional Materials: It is utilized in the synthesis of specialty polymers and advanced materials, contributing to developments in organic electronics and polymer chemistry .

• Agrochemicals: The compound also plays a role in the formulation of herbicides and other crop protection products .

• Safety and Handling

3,5-Dimethylchlorobenzene is classified as an irritant with GHS hazard statements H315 (causes skin irritation), H319 (causes serious eye irritation), and H335 (may cause respiratory irritation) . The signal word is "Warning" . 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 .

Specifications

Commercial grades are available at ≥97-98% purity from suppliers including Aromsyn, AK Scientific, and MolCore . Typical packaging sizes range from 1g to 25g for research use, with larger quantities (1kg, 25kg, 200kg) available for industrial applications .

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