反应详情

温度

180 °C

6-Amino-3,8-dibromoquinoline (0.15 g) was suspended in phosphoric acid (75%, 11 ml) and heated in a sealed glass, tube at 180° C. for 72 hours. The mixture was allowed to cool to ambient temperature, diluted with ice (50 ml) and taken to pH 2 with aqueous sodium hydroxide (4M). The brown suspension that formed was extracted with ethyl acetate (twice), dried over magnesium sulphate then evaporated under reduced pressure to give 3,8-dibromo-6-hydroxyquinoline (M+−H 300, 2×Br) as a dark red solid that was used in the next stage without further purification, 1H NMR (d6 DMSO) δ: 7.14(1H, d); 7.60(1H, d); 8.52(1H, d); 8.71(1H, d). In a similar procedure to Step 3, 6-amino-3-bromoquinoline was converted to 3-bromo-6-hydroxyquinoline, brown solid, 1H NMR (d6 DMSO) δ: 7.19(1H, d); 7.40(1H, dd); 7.92(1H, d); 8.66(1H, s); 8.79(1H, s).

1. temperatureto cool to ambient temperature
2. customThe brown suspension that formed
3. extractionwas extracted with ethyl acetate (twice),
4. dry with materialdried over magnesium sulphate
5. customthen evaporated under reduced pressure