Synthesis
Step a: Bromine (38 g, 0.24 mol) was slowly added dropwise to a solution of 2-amino-5-nitropyridine (30 g, 0.22 mol) in acetic acid (200 mL) at 10 °C. After the dropwise addition was completed, the reaction mixture was warmed to 20 °C and stirring was continued for 30 min. Upon completion of the reaction, the solid product was collected by filtration and dissolved in ethyl acetate (200 mL). The pH of the mixture was adjusted to 8-9 with saturated aqueous sodium bicarbonate. the organic layer was separated and the aqueous layer was extracted with ethyl acetate (100 mL x 3). The organic layers were combined, washed sequentially with water and brine, dried over anhydrous sodium sulfate, and concentrated under reduced pressure to give 2-amino-3-bromo-5-nitropyridine (14.8 g, 32% yield). The product was characterized by 1H-NMR (CDCl3,400MHz): δ 8.94 (d, J=2.4Hz, 1H), 8.50 (d, J=2.4Hz, 1H), 5.67 (brs, 2H).
References
[1] Patent: US2009/253736, 2009, A1. Location in patent: Page/Page column 25
[2] Bioorganic and Medicinal Chemistry, 2017, vol. 25, # 14, p. 3853 - 3860
[3] Zhurnal Russkago Fiziko-Khimicheskago Obshchestva, 1920, vol. 50, p. 494
[4] Chem. Zentralbl., 1923, vol. 94, # III, p. 1021
[5] Zhurnal Obshchei Khimii, 1940, vol. 10, p. 1827,1836
