反应详情

4-Hydroxy-5,6,7,8-tetrahydro-5-oxo-3-quinolinecarboxylic acid ethyl ester (11.5 g) was suspended in 600 ml of methyl alcohol, and 1.1 g of sodium boron hydride (NaBH4) was added to the suspension with its internal temperature kept at 20°-25° C. After completion of the reaction, the methyl alcohol was distilled off under reduced pressure and 200 ml of water was added to the residue. The resulting solution was adjusted to pH 2.4 with dilute hydrochloric acid and stirred for 30 minutes. Then, under cooling, the solution was adjusted to pH 6.5 with dilute aqueous sodium hydroxide and stirred for 30 minutes. The precipitate so formed was separated by filtration to obtain a yield of 10.4 g of the desired compound. This compound melted at 182°-183° C. (uncorrected values). Its infrared absorption spectrum (KBr tablet) had absorption peaks at 3440, 3160, 2960, 1730, 1655, 1540, 1305, and 1190 cm-1, and its n.m.r. spectrum (CF3COOH, 60Mc, TMS) had signals at δ values of 1.52 (3H, t, J=6.8 Hz), 1.9-2.4 (4H, m), 2.9-3.3 (2H, m), 4.64 (2H, q, J=6.8 Hz), 5.48 (1H, bs), and 8.95 (1H, d, J=6.0 Hz).

1. customkept at 20°-25° C
2. customAfter completion of the reaction
3. distillationthe methyl alcohol was distilled off under reduced pressure and 200 ml of water
4. additionwas added to the residue
5. temperatureThen, under cooling
6. stirringstirred for 30 minutes
7. customThe precipitate so formed
8. customwas separated by filtration