反应详情

Trifluoroacetic acid (101 mL, 1.32 mol, 20.85 eq) is added to a stirred solution of (6-methoxy-[1,5]naphthyridine-3-yl)-carbamic acid tert-butyl ester (18.2 g, 66.11 mmol, 1.0 eq) in dichloromethane (500 mL). After 19 hours stirring at room temperature, the solution is evaporated to dryness, 6N sodium hydroxide aqueous solution is added to adjust pH to 9˜10 and a lot of solid precipitated. The mixture is extracted with dichloromethane (200 mL) and the residue is extracted with ethyl acetate (3×250 mL). Evaporation of the dichloromethane phase gives 2.44 g of product with 83% purity, which is then purified by column chromatography (silica gel, eluent: dichloromethane:petroleum ether:ethyl acetate, 25:25:2, v/v/v) to afford 6-methoxy-[1,5]naphthyridin-3-ylamino as a light yellow solid (1.95 g with 98% purity). Evaporation of the ethyl acetate phase yields additional 9.88 g of light yellow product with 99% purity. Total: 11.83 g (98% yield).

1. customthe solution is evaporated to dryness, 6N sodium hydroxide aqueous solution
2. additionis added
3. customa lot of solid precipitated
4. extractionThe mixture is extracted with dichloromethane (200 mL)
5. extractionthe residue is extracted with ethyl acetate (3×250 mL)
6. customEvaporation of the dichloromethane phase