Reaktion #4360

Reaktionsgleichung

diethyl malonate

magnesium

2,4-dichloro-5-fluoro-3-nitro-benzoyl chloride

hydrogen

sulphuric acid

→

diethyl (2,4-dichloro-5-fluoro-3-nitro-benzoyl)-malonate

Ausbeute 91.0%

Lösungsmittel

toluene

ethanol

ethanol

toluene

water

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.ADDITIONis added dropwise at 50°-60° C
2. 2
   Temperaturis cooled to -5° to -10° C.
3. 3
   workup.STIRRINGThereafter, the mixture is stirred at 0° C. for 1 hour
4. 4
   workup.WAITbrought to room temperature overnight
5. 5
   Temperaturwarmed at 40°-50° C. for a further 2 hours
6. 6
   workup.ADDITIONis added to the reaction mixture
7. 7
   Temperaturwhile cooling with ice
8. 8
   Sonstigethe organic phase is separated off
9. 9
   ExtraktionThe aqueous phase is extracted with toluene
10. 10
    Extraktionthe combined organic extract
11. 11
    Waschenis washed with saturated sodium chloride solution
12. 12
    Trocknendried with sodium sulphate

Vorschrift

2.1 g of carbon tetrachloride are added to 10.1 g of magnesium filings in 21 ml of ethanol and, when the evolution of hydrogen has started, a mixture of 66.6 g of diethyl malonate, 40 ml of ethanol and 150 ml of toluene is added dropwise at 50°-60° C. The mixture is subsequently stirred at this temperature for 1 hour and is cooled to -5° to -10° C. and a solution of 109.2 g of 2,4-dichloro-5-fluoro-3-nitro-benzoyl chloride in 50 ml of toluene is slowly added dropwise. Thereafter, the mixture is stirred at 0° C. for 1 hour, brought to room temperature overnight and warmed at 40°-50° C. for a further 2 hours. A mixture of 160 ml of water and 10.4 ml of concentrated sulphuric acid is added to the reaction mixture, while cooling with ice, and the organic phase is separated off. The aqueous phase is extracted with toluene, the combined organic extract is washed with saturated sodium chloride solution and dried with sodium sulphate and the solvent is stripped off. 144.5 g of diethyl (2,4-dichloro-5-fluoro-3-nitro-benzoyl)-malonate are obtained as a crude product. This is heated under reflux for 3 hours, after addition of 200 ml of water and 0.6 g of 4-toluenesulphonic acid, and the mixture is extracted with methylene chloride and dried with sodium sulphate and the solvent distilled off in vacuo. 118 g of substituted benzoylacetic acid ester are obtained as a crude product. The product is of sufficient purity for the subsequent reactions.

Quelle