反应详情

温度

-20 °C

18.9 g of N-bromosuccinimide was gradually added to a stirred solution of 17.4 g of 3-chloro-2,4-difluoroaniline in 150 cm3 of dry dimethylformamide, cooled to a temperature in the region of −20° C., while this temperature was maintained. After stirring for 1 hour, the temperature was brought to the region of 20° C. and then the mixture was concentrated under reduced pressure (5 kPa), at a temperature in the region of 60° C. The residue obtained was supplemented with 400 cm3 of hexane and 200 cm3 of water. The mixture was stirred and the aqueous phase decanted off. The latter was extracted three times with successively 200, 200, and 100 cm3 of hexane. The extracts were combined, washed twice with 200 cm3 of water and twice with 200 cm3 of a saturated aqueous sodium chloride solution. After drying over magnesium sulphate, the organic solution was concentrated under reduced pressure (5 kPa) at a temperature in the region of 40° C. 19.2 g of 2-bromo-5-chloro-4,6-difluoroaniline was obtained in the form of a white solid, which melted at 62° C.

1. temperaturewas maintained
2. customwas brought to the region of 20° C.
3. concentrationthe mixture was concentrated under reduced pressure (5 kPa), at a temperature in the region of 60° C
4. customThe residue obtained
5. stirringThe mixture was stirred
6. customthe aqueous phase decanted off
7. extractionThe latter was extracted three times with successively 200, 200, and 100 cm3 of hexane
8. washwashed twice with 200 cm3 of water and twice with 200 cm3 of a saturated aqueous sodium chloride solution
9. dry with materialAfter drying over magnesium sulphate
10. concentrationthe organic solution was concentrated under reduced pressure (5 kPa) at a temperature in the region of 40° C