797060-52-7

67515-76-8

797060-52-7

General procedure for the synthesis of methyl 5-amino-6-bromopyridine-2-carboxylate from methyl 5-aminopyridine-2-carboxylate: 2.0 mL of hydrogen peroxide solution (32% concentration) was slowly added to a mixed solution containing methyl 5-aminopyridine-2-carboxylate (2.0 g, 13.15 mmol) and 30 mL of 48% concentration hydrobromic acid. The reaction mixture was stirred at room temperature for 2 hours. Subsequently, an additional 0.32 mL of hydrogen peroxide solution was added and stirring was continued for 1 hour. Upon completion of the reaction, the mixture was cooled by an ice bath and the pH of the mixture was adjusted slowly by adding concentrated ammonia to 8. The mixture was extracted three times with ethyl acetate (60 mL each time) and the organic phases were combined. The organic phase was dried with anhydrous sodium sulfate, filtered and concentrated on a rotary evaporator. The crude product was purified by silica gel column chromatography (mobile phase: cyclohexane/ethyl acetate). 1.32 g of the target compound was finally obtained in 42.3% yield. The product was analyzed by HPLC-MS: log P = 0.96; mass (m/z): 231.0. 1H NMR (D6-DMSO) data: δ 3.79 (s, 3H), 6.40 (broad peak, 2H), 7.1 (d, 1H), 7.8 (d, 1H).