Potassium Carbonate → Methyl 5-chloro-2-ethynylbenzoate

Participants

Reaction Steps

A suspension of potassium carbonate (5.0 g, 36 mmol) in methanol (20 ml) was stirred under nitrogen whilst adding a solution of methyl 5-chloro-2-[2-(trimethylsilyl)ethynyl]benzoate (4.8 g, 18.0 mmol) in methanol (50 ml). The resulting mixture was stirred at 20° C. for 2 hours. The reaction mixture was filtered, and the solid washed with methanol. The filtrate was concentrated in-vacuo and then re-dissolved in methanol (50 ml) and carefully treated with acetyl chloride (4.0 ml). The reaction mixture was stirred overnight and concentrated in-vacuo. TBME (50 ml) was added to the residue and the resulting suspension filtered. The filtrate was washed with a saturated solution of NaHCO3 (40 ml). The layers were separated and the aqueous phase was extracted with TBME (3×40 ml). The combined organics were dried over MgSO4, filtered and concentrated in-vacuo. The crude residue was purified by flash column chromatography (50 g Isolute cartridge, 0-10% TBME:Heptanes) to give the title compound (1.2 g, 33%) as a white solid. LC-MS 93%, m/z=194.9, 196.9; 1H NMR (500 MHz, Chloroform-d) δ ppm 7.94 (s, 1H), 7.56 (d, J=8.4 Hz, 1H), 7.46 (d, J=8.4 Hz, 1H), 3.95 (s, 3H), 3.44 (s, 1H).

Provenance & Evidence