Step 2: Synthesis of 3-(6-bromopyridin-3-yl)acrylic acid
To a tetrahydrofuran (THF) solution of methyl 3-(6-bromopyridin-3-yl)acrylate (120 mg, 0.495 mmol) was added an aqueous 0.5 N lithium hydroxide (LiOH) solution (2 equiv). The reaction mixture was stirred at room temperature for 3 hours. After completion of the reaction, the resulting residue was dissolved in water (H2O) and washed three times with ether (Et2O). Subsequently, it was neutralized with 1 N hydrochloric acid (HCl) to pH 5~7. The resulting solid was collected by filtration, washed with water and dried under vacuum to afford 3-(6-bromopyridin-3-yl)acrylic acid (100 mg, 88% yield).
1H NMR (300 MHz, DMSO-d6): δ 8.67 (d, 1H, J = 2.1 Hz), 8.11 (dd, 1H, J = 8.4, 2.1 Hz), 7.69 (d, 1H, J = 8.4 Hz), 7.59 (d, 1H, J = 15.9 Hz), 6.71 (d, 1H, J = 15.9 Hz).
