反应详情

A solution of 6-bromo-7,8-dihydro-5(6H- quinolinone, hydrobromide, 10.0 g (32.5 mmol), (Example 2), in 150 ml of hot water is refluxed with 6.0 g (100 mmol) of urea for 24 hours. After cooling, the solution is made basic with concentrated ammonium hydroxide and extracted with 2×250 ml of dichloromethane. The organic extract is concentrated and the residue is chromatographed (1% ammonium hydroxide, 99% ethyl acetate) to separate the two products, 4,5-dihydrooxazolo[4,5-f]quinolin-2-amine (Example 28) and 4,5-dihydrooxazolo[5,4-f]quinolin-2-amine (Example 27).

1. temperatureAfter cooling
2. extractionextracted with 2×250 ml of dichloromethane
3. extractionThe organic extract
4. concentrationis concentrated
5. customthe residue is chromatographed (1% ammonium hydroxide, 99% ethyl acetate)
6. customto separate the two products, 4,5-dihydrooxazolo[4,5-f]quinolin-2-amine (Example 28) and 4,5-dihydrooxazolo[5,4-f]quinolin-2-amine (Example 27)