反应详情

A mixture of the compound of part (i) (400 g), N-bromosuccinimide (730 g), azoisobutyronitrile (33.7 g), bromine (65.5 g) and water (6.4 L) was heated at 80–85° C. for 5 hours. Further N-bromosuccinimide (183 g) was added, heating continued for 2 hours then further azoisobutyronitrile (33.7 g) added. After heating for 2 hours at 85° C. further azoisobutyronitrile (33.7 g) was added and heating continued for 3 hours. The reaction was cooled, diluted with water (4 L) and extracted with dichloromethane (2×3 L). The combined organic extracts were washed with a solution of sodium metabisulphate (600 g) in water (2.5 L), followed by water (3 L). The solvent was removed by evaporation under reduced pressure, toluene (1.0 L) added and the solution concentrated under reduced pressure to give the product as an oil (534 g).

1. temperaturewas heated at 80–85° C. for 5 hours
2. temperatureheating
3. additionwas added
4. temperatureheating
5. waitcontinued for 3 hours
6. temperatureThe reaction was cooled
7. extractionextracted with dichloromethane (2×3 L)
8. washThe combined organic extracts were washed with a solution of sodium metabisulphate (600 g) in water (2.5 L)
9. customThe solvent was removed by evaporation under reduced pressure, toluene (1.0 L)
10. additionadded
11. concentrationthe solution concentrated under reduced pressure