GENERAL STEPS: 3-Bromopropionic acid (1.00 g, 6.6 mmol) was dissolved in EtOH/DMF (30 mL/15 mL) mixed solvent, and NaCN (0.96 g, 19.6 mmol) was added. The reaction mixture was heated to reflux for 15 hours. The reaction progress was monitored by TLC and after confirming the complete consumption of the raw material, the solvent was removed by distillation under reduced pressure. The resulting crude product was poured into ice water (70 mL) and the pH was adjusted to 1 with 3M HCl solution, followed by extraction with EtOAc (3 x 50 mL). The organic layers were combined, dried with anhydrous Na2SO4, filtered and concentrated to dryness under reduced pressure. Purification by fast column chromatography (eluent: CH3CN/H2O, 1/1) afforded the target product 3-cyanopropionic acid (0.35 g, 3.55 mmol, 54% yield) as a colorless solid. rf = 0.60 (CH3CN/H2O: 1/1).1H NMR (300 MHz, CDCl3): δ (ppm) = 2.64 (2H, t. J = 6.5 Hz, CH2-CN), 2.73 (2H, t, J = 6.5 Hz, CH2-CO), 9.63 (1H, br s, COOH).13C NMR (75 MHz, CDCl3): δ (ppm) = 12.8, 29.8, 118.8, 175.6.
