Preparation
Under nitrogen atmosphere, toluene (2.0 mL), powdered AlBr3 (267 mg, 1.00 mmol), and Ph3SiCl (1.00 mmol) were loaded into a 50 mL autoclave equipped with a glass inner tube and a magnetic stir bar. The apparatus was purged with CO2 by repeated pressurization and expansion. The final pressure was adjusted to 3.0 MPa. After stirring the mixture at room temperature for 3 hours, the reactor was depressurized. The mixture was quenched by adding 2 M HCl. The mixture was extracted with diethyl ether. The organic layer was extracted with 0.5 M Na2CO3. The extract was acidified with concentrated hydrochloric acid to release free acid. The solution was extracted with diethyl ether. The extract was dried with MgSO4. The extract was evaporated to leave a residue. The residue was purified by TLC with hexane-diethyl ether (1:1) to give 2,4-dimethylbenzoic acid.
Chemical Properties
white crystalline powder
Uses
2,4-Dimethylbenzoic acid was used in capillary electrophoretic separation of α-, β-, γ- and δ-cyclodextrins.
Definition
ChEBI: A dimethylbenzoic acid in which the two methyl groups are located at positions 2 and 4.
General Description
2,4-Dimethylbenzoic acid has antibacterial activity. It is a metabolite of pseudocumene (1,2,4-trimethylbenzene).
Purification Methods
Crystallise the acid from EtOH or H2O, and sublime it in a vacuum. [Beilstein 9 H 531, 9 III 2436, 9 IV 1801.]
