[1,5]-Naphthyridin-2-ylamine

4318-76-7

56-81-5

17965-80-9

Using 2,5-diaminopyridine (5.2 g, 33.9 mmol) and glycerol (15.6 g, 169.5 mmol) as raw materials, sodium 3-nitrobenzenesulfonate (15.2 g, 67.8 mmol) and sulfuric acid (20 mL) were added in water (30 mL), and the mixture was heated to 135 °C and reacted with stirring for 16 hours. Upon completion of the reaction, the mixture was cooled to room temperature and subsequently slowly poured into an ice-water mixture (150 g). The pH of the mixture was adjusted to neutral with an appropriate base. Subsequently, the reaction mixture was extracted with ethyl acetate (3 x 100 mL), the organic layers were combined and dried over anhydrous sodium sulfate. The solvent was removed by concentration under reduced pressure to give the crude product. The crude product was purified by silica gel column chromatography using dichloromethane/methanol (20:1, v/v) as eluent to afford 1,5-naphthyridin-2-amine as a yellow solid (2.0 g, 41% yield). The product was analyzed by ESI MS showing m/z 146 [M + H]+. 1H NMR (400 MHz, DMSO-d6) data were as follows: δ 8.50 (dd, J = 1.6 Hz, 4.4 Hz, 1H), 7.94 (d, J = 8.8 Hz, 1H), 7.82-7.80 (m, 1H), 7.47 (dd, J = 4.0 Hz 8.4 Hz, 1H), 7.00 (d, J = 9.2 Hz, 1H), 6.72 (s, 2H).