反応 #62936

反応方程式

ammonium hydroxide

6-bromo-7,8-dihydro

5,6-Dihydropyrido[2,3-h]quinazolin-2-amine

6H- quinolinone, hydrobromide

urea

→

4,5-Dihydrooxazolo[4,5-f]quinolin-2-amine

溶媒

water

反応条件

後処理

1. 1
   温度After cooling
2. 2
   抽出extracted with 2×250 ml of dichloromethane
3. 3
   抽出The organic extract
4. 4
   濃縮is concentrated
5. 5
   その他the residue is chromatographed (1% ammonium hydroxide, 99% ethyl acetate)
6. 6
   その他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)

実験手順

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).

出典