反应详情

mb) 4.2 g of magnesium shavings are suspended in 8.3 ml of anhydrous ethanol and treated with 0.83 ml of carbon tetrachloride. A solution of 27.63 g of diethyl malonate in 17 ml of ethanol and 62 ml of toluene is added dropwise in such a manner that the temperature remains at 50°-60°. Subsequently, the mixture is heated at 60° for a further 1 hr. The reaction mixture is cooled to -30° and a solution of 51.9 g 2-chloro-4-iodo-benzoyl chloride in 70 ml of anhydrous toluene is added dropwise within 30 min. The reaction mixture is stirred while slowly warming to room temperature within 1.30 hrs., then cooled to 0° and treated dropwise with a solution of 4 ml of conc. sulphuric acid in 60 ml of water. After 20 min. the phases are separated and the aqueous solution is back-extracted twice with 100 ml of toluene each time. The combined organic phases are washed with 100 ml of saturated, aqueous sodium chloride solution, dried over magnesium sulphate and concentrated. 70.3 g (96%) of diethyl 2-(2-chloro-4-iodo-benzoyl)-malonate are obtained as a yellowish oil. Mass spectrum: peaks inter alia at 424 (M+, 0.4%), 389 (48%), 343 (63%), 265 (100%).

1. customremains at 50°-60°
2. temperatureSubsequently, the mixture is heated at 60° for a further 1 hr
3. temperatureThe reaction mixture is cooled to -30°
4. temperature, then cooled to 0°
5. customAfter 20 min. the phases are separated
6. extractionthe aqueous solution is back-extracted twice with 100 ml of toluene each time
7. washThe combined organic phases are washed with 100 ml of saturated, aqueous sodium chloride solution
8. dry with materialdried over magnesium sulphate
9. concentrationconcentrated