反应详情

温度

0 °C

150 ml of CH2Cl2, 25 g of (I) and 21 g of N-bromosuccinimide are loaded under nitrogen in a 500 ml pyrex round-bottom flask, and irradiated from the outside with a 300 watt halogen lamp, refluxing for 2 hours. 150 ml of water are added. 80 ml of CH2Cl2 are distilled off, 150 ml of toluene and 5 g of PEG 6000 are added while distilling off CH2Cl2 at inner temperature of 85-90° C. The mixture is left for 3 hours at said temperature, water is removed at 60° C., the mixture is washed with 2×50 ml of water and 30-40 ml of toluene are distilled off at 40 mm/Hg. The mixture is cooled at 0° C. for 2-3 hours, filtered, washed with 20 ml of toluene at 0° C. and air-dried at 60° C., to obtain 20.4 g of (VI) m.p. 110-111° C., with good purity. From mother liquors a further 1.8 g are recovered (overall yield 82%).

1. temperaturerefluxing for 2 hours
2. distillation80 ml of CH2Cl2 are distilled off
3. addition150 ml of toluene and 5 g of PEG 6000 are added
4. distillationwhile distilling off CH2Cl2 at inner temperature of 85-90° C
5. customis removed at 60° C.
6. washthe mixture is washed with 2×50 ml of water and 30-40 ml of toluene
7. distillationare distilled off at 40 mm/Hg
8. filtrationfiltered
9. washwashed with 20 ml of toluene at 0° C.
10. customair-dried at 60° C.