Part A: Synthesis of ethyl 4-bromobutyrate
To a solution of 4-bromobutyric acid (3 g, 18 mmol) in ethanol (30 mL) was added 5 mL of a dioxane solution of 4N HCl. The reaction mixture was stirred at room temperature for 16 hours. Upon completion of the reaction, the volatile components were removed under vacuum. The concentrated residue was dissolved in 150 mL of dichloromethane. The organic phase was washed sequentially with saturated aqueous NaHCO3 (1 x 150 mL) and brine (1 x 150 mL), dried over anhydrous MgSO4, filtered, and the filtrate was concentrated under reduced pressure. The concentrated residue was dried under vacuum to give 3 g (85.5% yield) of ethyl 4-bromobutyrate as a yellow oil.1H NMR (300 MHz, CDCl3): δ1.22 (t, 3H, J = 7.15 Hz), 2.13 (m, 2H, J = 6.80 Hz), 2.45 (t, 2H, J = 7.15 Hz), 3.43 (t , 2H, J = 6.44Hz), 4.10 (q, 2H, J = 7.25Hz).
