Reaktion #215482

Reaktionsgleichung

ethyl p-(2-oxocyclohexyloxy)-benzoate

sodium carbonate

→

ethyl 6,7,8,9-tetrahydro-2-dibenzofurancarboxylate

Lösungsmittel

sulfuric acid

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.ADDITIONDuring this addition
2. 2
   Sonstigethe temperature is kept at between 10° and 20° with an ice-water bath
3. 3
   workup.ADDITIONWhen the addition
4. 4
   ExtraktionThe aqueous phase is extracted once with about 1,000 ml of ether
5. 5
   Waschena further three times with 300 ml of ether each time and the combined organic phases are washed four times with 300 ml of 2 N sodium hydroxide solution each time
6. 6
   Trocknendried over sodium sulfate
7. 7
   Sonstigeevaporated under a waterpump vacuum
8. 8
   FiltrationThe oily residue is purified by filtration over a layer of silica gel, chloroform being
9. 9
   Wascheneluting agent
10. 10
    SonstigeAfter evaporating off the chloroform

Vorschrift

262.3 g (1 mol) of ethyl p-(2-oxocyclohexyloxy)-benzoate are cooled to 10° and 250 ml of concentrated sulfuric acid are added dropwise in the course of about 2 hours. During this addition, the temperature is kept at between 10° and 20° with an ice-water bath. When the addition has ended, the mixture is stirred at room temperature for a further 3 hours and then poured onto a 2:1 mixture of saturated aqueous sodium carbonate solution and ice. The aqueous phase is extracted once with about 1,000 ml of ether and then a further three times with 300 ml of ether each time and the combined organic phases are washed four times with 300 ml of 2 N sodium hydroxide solution each time, dried over sodium sulfate and evaporated under a waterpump vacuum. The oily residue is purified by filtration over a layer of silica gel, chloroform being used as the solvent and eluting agent. After evaporating off the chloroform, ethyl 6,7,8,9-tetrahydro-2-dibenzofurancarboxylate is obtained as a yellowish oil.

Quelle