反应详情

A solution of 6-chloro-4-hydroxy-1-(4-methoxy-benzyl)-2-oxo-1,2-dihydro-[1,8]-naphthyridine-3-carboxylic acid ethyl ester (75) (6.0 g, 15.43 mmol) and triethylamine (5.36 mL, 38.57 mmol) was heated in neat POCl3 at 90° C. for 3 h. The solution was cooled and the excess POCl3 was distilled under vacuum. The residue was suspended in saturated NaHCO3 solution, sonicated briefly and filtered. The solids were dissolved in dichloromethane, washed subsequently by saturated NaHCO3 solution, water and brine. The organic phase was dried over MgSO4 and evaporated to yield 6.2 g (85%) of 4,6-dichloro-1-(4-methoxy-benzyl)-2-oxo-1,2-dihydro-[1,8]-naphthyridine-3-carboxylic acid ethyl ester (77) as yellow waxy solids. 1H-NMR (DMSO-d6): δ 1.30 (t, J=7.2 Hz, 3H), 3.69 (s, 3H), 4.38 (q, J=7.2 Hz, 2H), 5.50 (s, 2H), 6.82 (m, 2H), 7.24 (m, 2H), 8.48 (d, J=2.4 Hz, 1H), 8.87 (d, J=2.4 Hz, 1H); EIMS: 407 (M).

1. temperatureThe solution was cooled
2. distillationthe excess POCl3 was distilled under vacuum
3. customsonicated briefly
4. filtrationfiltered
5. dissolutionThe solids were dissolved in dichloromethane
6. washwashed subsequently by saturated NaHCO3 solution, water and brine
7. dry with materialThe organic phase was dried over MgSO4
8. customevaporated