反应详情

Sodium hydride (3.1 g, 60% dispersion) is added at 0° C. to a stirred solution of ethyl 8-((acetyloxy)methyl)-4-hydroxy-6-methyl-3-quinolinecarboxylate (Preparation 25, 29.6 g) in N-methylpyrrolidinone (250 ml). The solution is allowed to warm to room temperature over 10 min and isobutyl chloroformate (25.5 g) is then added. After 30 min, acetic acid (3.6 g) is added. The solvent is evaporated under reduced pressure, and the residual oil is partitioned between ethyl acetate and water. The ethyl acetate layer is concentrated to give an oil. The crude product is dissolved in ethyl acetate (50 ml) and is chromatographed on silica gel with 10% ethyl acetate/hexane as the initial eluant to give 19.5 g of the title compound. A sample is recrystallized from ethyl acetate/hexane for analysis. Physical characteristics: M.p. 101-103° C.; 1H NMR (CDCl3) δ1.05, 1.44, 2.12, 2.18, 2.59, 4.15, 4.45, 5.82, 7.74, 7.88, 9.40. Anal. Found: C, 62.42; H, 6.34; N, 3.45.

1. customThe solvent is evaporated under reduced pressure
2. customthe residual oil is partitioned between ethyl acetate and water
3. concentrationThe ethyl acetate layer is concentrated
4. customto give an oil
5. customis chromatographed on silica gel with 10% ethyl acetate/hexane as the initial eluant