反应详情

A suspension of 6-methoxy-4-oxo-1,4-dihydro-[1,5]naphthyridine-3-carboxylic acid ethyl ester (74.57 g, 300 mmol) in dry DMF (260 mL) under argon was stirred efficiently* in a water bath (to maintain approximately room temperature—may need slight ice-cooling on a large scale). Phosphorus tribromide (30.0 mL, 316 mmol) was added dropwise over 15 min and stirring was continued for an additional 30 min. Water (1 L) was added, followed by saturated sodium carbonate solution to pH 7. The solid was collected by suction filtration, washed with water and dried under vacuum over phosphorus pentoxide to give the title compound (83.56 g, 90%).

1. temperatureto maintain approximately room temperature—
2. temperaturecooling on a large scale)
3. stirringstirring
4. filtrationThe solid was collected by suction filtration
5. washwashed with water
6. dry with materialdried under vacuum over phosphorus pentoxide