3395-91-3

554-12-1

3395-91-3

Methyl propiolate (52 mL, 0.583 mol) was mixed with recrystallized N-bromosuccinimide (120 g, 0.674 mol) in 1,700 mL of acetone under nitrogen protection. Pure silver nitrate (9.9 g, 0.0583 mol) was added to the solution in a single addition and the reaction mixture was stirred at room temperature for 6 hours. Upon completion of the reaction, the acetone was evaporated under reduced pressure (25 °C bath temperature) to give a gray slurry. The slurry was washed with hexane (2 x 200 mL), filtered to remove the gray solid, and the filtrate was concentrated under vacuum to give 95 g of a pale yellow oily crude product. The crude product was passed through a short distillation under reduced pressure (65 °C, ca. 25 mmHg) and the fractions were collected with a receiver cooled with dry ice/acetone to give 83.7 g (88% yield) of methyl 3-bromopropynoate as a pale yellow oil. Calculated values for elemental analysis of [C4H3BrO2]: C, 29.48; H, 1.86. Measured values: C, 29.09; H, 1.97.