The general procedure for the synthesis of 2-hydroxy-1,7-naphthyridine from ethyl (E)-3-(3-aminopyridin-4-yl)acrylate was as follows:
1. Sodium metal (3.6 g, 156 mmol) was slowly added to anhydrous ethanol (300 mL) in batches under stirring, and after the sodium was completely dissolved, ethyl (E)-3-(3-aminopyridin-4-yl)acrylate (20 g, 104 mmol) was added.
2. The reaction mixture was stirred at 90 °C for 1 hour.
3. After completion of the reaction, the mixture was cooled to room temperature and subsequently concentrated under reduced pressure to remove the solvent.
4. The crude product was purified by silica gel column chromatography (eluent: dichloromethane/methanol=10/1) to afford the target compound 1,7-naphthyridin-2(1H)-one (10 g, yield: 66%) as a yellow solid. 5. The product was subjected to ESI-MRI analysis.
5. The product was detected by ESI-MS and showed a molecular ion peak (M + H)+ m/z of 147.1. 6. 1H NMR (1H NMR, 1H NMR, 1H NMR, 1H NMR) was performed.
6. 1H NMR (400 MHz, CDCl3) data were as follows: δ 8.76 (s, 1H), 8.46 (d, J=5.2 Hz, 1H), 7.78 (d, J=9.6 Hz, 1H), 7.44 (d, J=5.2 Hz, 1H), 6.90 (d, J=9.6 Hz, 1H).
