反应详情

To a solution of 21.5 g (0.143 mol) of 20 in 40 mL of dry dichloromethane, 0.3 g of iron turnings was added, and then a solution of 10.7 mL (34.2 g, 0.215 mol) of bromine in 100 mL of dichloromethane was added dropwise by vigorous stirring for 20 min. This mixture was refluxed for 30 min, and then 300 mL of water was added. The organic layer was separated, and the aqueous layer was extracted with 2×100 mL of dichloromethane. The combined organic extract was washed by saturated aqueous Na2SO3, dried over K2CO3, and then evaporated to dryness. Rectification of the residue in vacuum gave 15.7 g (48%) of the title product (bp 105-115° C./1 mm).

1. temperatureThis mixture was refluxed for 30 min
2. customThe organic layer was separated
3. extractionthe aqueous layer was extracted with 2×100 mL of dichloromethane
4. extractionThe combined organic extract
5. washwas washed by saturated aqueous Na2SO3
6. dry with materialdried over K2CO3
7. customevaporated to dryness