反应详情

温度

70 °C

A mixture of 6-methoxy-[1,5]naphthyridine-3-carboxylic acid (24.5 g, 120 mmol, 1.0 eq), triethylamine (50.2 mL, 360 mmol, 3.0 eq) and tert-butanol (292 mL, 3.54 mol, 32 eq) in dimethylformamide (338 mL) is added dropwise to diphenyl phosphoryl azide (49.5 g, 180 mmol. 1.5 eq) to form a yellow clear solution. The mixture is stirred at 70° C. for 40 minutes then warmed to 100° C. for 3 hours. The mixture is cooled to room temperature and concentrated to dryness. The residue is purified by column chromatography (silica gel, eluent: dichloromethane:petroleum ether:ethyl acetate, 25:25:2, v/v/v) to afford (6-methoxy-[1,5]naphthyridine-3-yl)-carbamic acid tert-butyl ester as a yellow solid (23.15 g, 69% yield).

1. customto form a yellow clear solution
2. temperaturethen warmed to 100° C. for 3 hours
3. temperatureThe mixture is cooled to room temperature
4. concentrationconcentrated to dryness
5. customThe residue is purified by column chromatography (silica gel, eluent: dichloromethane:petroleum ether:ethyl acetate, 25:25:2, v/v/v)