77123-59-2

10601-99-7

Step 2: Methyl 3-((trimethylsilyl)ethynyl)benzoate (105) (2.42 g) was dissolved in methanol (30 mL), and 2N aqueous sodium hydroxide solution (10.4 mL) was slowly added under cooling in an ice bath, and the reaction was stirred at room temperature for 7 hours. After completion of the reaction, the pH of the reaction mixture was adjusted to 3~4 with 2N hydrochloric acid, followed by concentration under reduced pressure. Water (100 mL) was added to the residue and extracted with ethyl acetate (100 mL). The organic layer was washed with saturated brine (100 mL), dried over anhydrous sodium sulfate and filtered. The filtrate was concentrated under reduced pressure to give 3-ethynylbenzoic acid (106) as a white solid (1.50 g, 99% yield).