In an argon-filled glove box, a cesium salt of 2-(3,4,5-methoxyphenyl)acetic acid (35.8 mg) was introduced and transferred to a reaction flask. Dry dimethyl sulfoxide (0.5 mL) was added to the flask, and the mixture was shaken to dissolve the product in the dimethyl sulfoxide. The reaction tube was removed from the glove box and connected to a carbon dioxide system to displace the argon gas in the reaction flask, filling the reaction system with carbon dioxide. The resulting reaction mixture was stirred at room temperature for 2 minutes, then heated to 150 °C. After the reaction was complete, the reaction mixture was cooled at room temperature, and the reaction was quenched with 2M dilute hydrochloric acid (5 mL) to convert the corresponding cesium salt into the target product acid. The reaction mixture was stirred for 2 minutes. The reaction mixture was extracted with ethyl acetate (3-5 mL, 3 times). The combined organic layers (ethyl acetate) were dried with magnesium sulfate. The combined organic layers were filtered to remove the magnesium sulfate solid. The combined organic layers were concentrated under reduced pressure. The resulting solid (after evaporating the solvent) was then vacuum-pumped for 30 minutes to remove any remaining solvent, yielding the target product, 3,4,5-trimethoxyphenylacetic acid.
3,4,5-Trimethoxyphenylacetic Acid is a reagent in the preparation of 3-phenylcoumarins as antidepressant agents.
