10024-90-5

Preparation by reaction of acetic anhydride with 2-methylanisole in the presence of lithium perchlorate at 60° for 1.5 h (99%).

1. Dimethyl sulfate (17.50 mL, 183 mmol) was slowly added to a stirred suspension of 1-(4-hydroxy-3-methylphenyl)ethanone (25 g, 166 mmol) and potassium carbonate (28.8 g, 208 mmol) in acetone (277 mL). The reaction was carried out at room temperature. 2. The reaction mixture was heated to reflux and stirred continuously overnight. 3. Upon completion of the reaction, it was cooled to room temperature, the solids were separated by filtration, and the solids were washed with acetone. 4. The filtrate was concentrated under vacuum to remove the solvent. 5. The concentrated organic residue was dissolved in ethyl acetate (EtOAc) and the organic layer was washed with water. 6. The organic layer was separated, dried with anhydrous magnesium sulfate (MgSO?), filtered, and the solvent was evaporated under vacuum to give 1-(4-methoxy-3-methylphenyl)ethanone (28.7 g) as a yellow oil. The product did not require further purification and could be used directly in the next reaction.

[1] Patent: WO2015/12708, 2015, A1. Location in patent: Page/Page column 14; 15
[2] Patent: CN107337596, 2017, A. Location in patent: Paragraph 0039; 0040; 0044; 0045