84539-34-4

504-24-5

84539-34-4

General procedure for the synthesis of 4-amino-3,5-dibromopyridine from 4-aminopyridine: To a suspension of 4-aminopyridine (188.2 mg, 2.0 mmol, 1.0 eq.) in dichloromethane (10 mL) was added slowly over a period of 1 hour a dichloromethane (30 mL) solution of N-bromosuccinimide (818.7 mg, 4.6 mmol, 2.3 eq.). ) solution. The reaction mixture was stirred at room temperature for 24 hours. Upon completion of the reaction, the solvent was removed by distillation under reduced pressure to give a mixture of succinimide and 4-amino-3,5-dibromopyridine. The mixture was purified by silica gel column chromatography (eluent: hexane/ethyl acetate = 1/1) to afford the target product 4-amino-3,5-dibromopyridine (464.8 mg, 1.84 mmol, 92% yield) as a colorless solid. Thin layer chromatography (TLC) Rf value was 0.62 (unfolding agent: hexane/ethyl acetate = 1/1). The melting point is 163-167 °C. Infrared spectrum (KBr, cm^-1): 3535, 3429, 3266, 3100, 2667, 2536, 2329, 1872, 1825, 1785, 1626, 1566, 1522, 1485, 1408, 1323, 1262, 1154, 1138, 1081, 1051, 892, 855. 747, 726, 658, 589, 573, 517, 468, 431.NMR hydrogen spectrum (300 MHz, CDCl3) δ 8.31 (2H, s, H2/6), 5.06 (2H, s, NH). NMR carbon spectra (75 MHz, CDCl3) δ 149.9, 147.8, 106.2. electron bombardment mass spectra (EI-MS) m/z calculated value C5H4Br2N2 [M]+ 249.87, measured value 249.90.