反应详情

温度

0 °C

5-Amino-6,7-dichloro-2,3-dimethoxyquinoxaline (from (c) above) (38.12 g, 0.14 mol) was dissolved in acetone (2 L) and cooled to 0° C. Whilst being agitated using a mechanical stirrer, the solution was treated first with 2M hydrochloric acid (396 mL, 0.79 mol) and then dropwise with 1M aqueous sodium nitrite (208 mL, 0.208 mol), maintaining the temperature of the mixture at 0° C. After the additions were complete, the mixture was stirred for 15 minutes, then treated with 5M aqueous potassium iodide (278 mL, 1.39 mol) maintaining the temperature below 5° C. The mixture was then allowed to warm to 10° C. over 30 minutes. The acetone was removed under reduced pressure and the residue partitioned between water and ethyl acetate (total of 4 L). The organic solution was washed with 10% aqueous sodium bisulphite, saturated aqueous sodium bicarbonate, dried (MgSO4), and concentrated under reduced pressure. Purification by flash chromatography (eluting with toluene) gave 6,7-dichloro-2,3-dimethoxy-5-iodoquinoxaline (16.9 g, 32%).

1. stirringthe mixture was stirred for 15 minutes
2. temperaturemaintaining the temperature below 5° C
3. temperatureto warm to 10° C. over 30 minutes
4. customThe acetone was removed under reduced pressure
5. customthe residue partitioned between water and ethyl acetate (total of 4 L)
6. washThe organic solution was washed with 10% aqueous sodium bisulphite, saturated aqueous sodium bicarbonate
7. dry with materialdried (MgSO4)
8. concentrationconcentrated under reduced pressure
9. customPurification
10. washby flash chromatography (eluting with toluene)