反应详情

温度

23 °C

A solution of 6-2 (2.20 g, 9.90 mmol, 1 equiv), diethyl malonate (3.00 mL, 19.8 mmol, 2.00 equiv), and piperidine (0.490 mL, 4.95 mmol, 0.500 equiv) in ethanol (50 mL) was heated at reflux for 20 h. The reaction mixture was allowed to cool to 23° C., then concentrated to about half its volume. The white crystals which formed were filtered and washed with cold ethanol (20 mL) to give 2-oxo-1,2-dihydro-[1,7]naphthyridine-3-carboxylic acid ethyl ester (6-3). 1H NMR (400 MHz, CDCl3) δ 12.15 (br s, 1H), 8.94 (s, 1H), 8.52 (d, 1H, J=5.2 Hz), 8.46 (s, 1H), 7.52 (d, 1H, J=5.2 Hz), 4.48 (q, 2H, J=7.1 Hz), 1.46 (t, 3H, J=7.1 Hz); TLC (EtOAc), Rf=0.13.

1. temperatureat reflux for 20 h
2. concentrationconcentrated to about half its volume
3. customThe white crystals which formed
4. filtrationwere filtered
5. washwashed with cold ethanol (20 mL)