反应详情

温度

23 °C

A solution of 5-2 (1.53 g, 6.88 mmol, 1 equiv), diethyl malonate (2.09 mL, 13.8 mmol, 2.00 equiv), and piperidine (0.340 mL, 3.44 mmol, 0.500 equiv) in ethanol (20 mL) was heated at reflux for 16 h. The reaction mixture was allowed to cool to 23° C. The white crystals which formed were filtered and washed with ethanol (20 mL) to give 2-oxo-1,2-dihydro-[1,8]naphthyridine-3-carboxylic acid ethyl ester (5-3). 1H NMR (400 MHz, CDCl3) δ 11.9 (br s, 1H), 8.85 (dd, 1H, J=4.8, 1.7 Hz), 8.46 (s, 1H), 8.03 (dd, 1H, J=7.9, 1.6 Hz), 7.27 (dd, 1H, J=7.9, 4.8 Hz), 4.45 (q, 2H, J=7.1 Hz), 1.43 (t, 3H, J=7.1 Hz).

1. temperatureat reflux for 16 h
2. customThe white crystals which formed
3. filtrationwere filtered
4. washwashed with ethanol (20 mL)