5-(5-Bromo-1H-2-pyridinyl)-2,2-dimethyl-[1,3]dioxane-4,6-dione (4.53 g, 15.09 mmol) was used as a starting material and dissolved in dioxane (20 mL). Concentrated hydrochloric acid (10 mL) was added to this solution and the mixture was subsequently stirred at 100 °C for 1 hour. Upon completion of the reaction, the mixture was cooled and concentrated under reduced pressure. The concentrated residue was dissolved in a solvent mixture of methanol (20 mL) and toluene (20 mL). To this solution was added trimethylsilylated diazomethane (2M ethyl ether solution, 25 mL) and stirred for 30 minutes at room temperature. Reaction termination was achieved by addition of acetic acid. Subsequently, the reaction mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography (eluent: hexane/ethyl acetate = 100:0 to 30:70, 40 min) to afford the target product methyl 2-(5-bromopyridin-2-yl)acetate as a colorless oil (2.50 g, 72% yield). The product was characterized by 1H-NMR (chloroform-d): δ 3.73 (3H, s), 3.82 (2H, s), 7.21 (1H, d, J=8.24 Hz), 7.79 (1H, dd, J=8.25,2.31 Hz), 8.62 (1H, d, J=2.31 Hz).
