5-Ethynylisophthalic acid

313648-72-5

432025-97-3

Dimethyl 5-(trimethylsilyl ethynyl) isophthalate (3) (0.7 g, 3.2 mmol) was synthesized in one step by reacting with NaOH (1.412 g, 35.3 mmol) in THF (20 ml) for 4 h at room temperature. After completion of the reaction, the resulting precipitate was separated by centrifugation and dissolved in water. NaOH (0.1 M, 50 ml) was added and stirred for 2 h at room temperature. Subsequently, the reaction mixture was cooled to 0 °C in an ice bath and acidified to pH 1-2 with 10% HCl. The resulting precipitate was separated by centrifugation, washed twice with water and dried to give 5-alkynyl phthalic acid as a powdered product. Yield: 0.47 g, 77% yield.