3,5-Dimethyl-4-methoxybenzoic acid

152775-45-6

21553-46-8

General procedure for the synthesis of 3,5-dimethyl-4-methoxybenzoic acid from 4-methoxy-3,5-dimethylbenzenecarbonitrile: 4-methoxy-3,5-dimethylbenzenecarbonitrile (1664 mg) was suspended in ethanol (32 mL), to which 8M NaOH solution (163 mL) was added. The mixture was placed in a pressure reactor and the reaction was stirred at 120 °C overnight. Upon completion of the reaction, ethanol was removed by rotary evaporation. Water was added to the residue and the aqueous solution was washed with ether to remove non-polar impurities. Subsequently, the aqueous layer was acidified with concentrated hydrochloric acid to pH < 2, at which point the target product precipitated as a solid. The acidified aqueous layer was extracted with ethyl acetate and the organic phases were combined and washed sequentially with water and saturated brine. The organic layer was dried over anhydrous magnesium sulfate, filtered and concentrated to afford 3,5-dimethyl-4-methoxybenzoic acid as a white solid in 99% yield.LRMS (m/z): 181 ([M+H]+).HPLC retention time: 5.52 min (Method B).