Reaction #1256723

Reaction equation

methyl 2-oxo-5-propylcyclohexanecarboxylate

resorcinol

phosphoryl chloride

potassium carbonate

ethyl iodide

→

3-ethoxy-8-propyl-7,8,9,10-tetrahydrobenzo[c]chromen-6-one

Solvents

water

toluene

Conditions

Workup

1. 1
   Temperaturethe mixture is heated
2. 2
   Temperatureunder reflux for 3 h
3. 3
   OtherAfter hydrolysis
4. 4
   Filtrationthe deposited precipitate is filtered off with suction
5. 5
   Washwashed with toluene
6. 6
   Otherdried
7. 7
   workup.DISSOLUTIONThe product is dissolved in 200 ml of acetone
8. 8
   Temperaturethe mixture is heated
9. 9
   Temperatureunder reflux for 5 h
10. 10
    OtherThe majority of the solvent is removed under reduced pressure
11. 11
    OtherThe aqueous phase is separated off
12. 12
    Extractionextracted with MTB ether
13. 13
    WashThe combined organic phases are washed with water
14. 14
    Dryingdried over sodium sulfate
15. 15
    OtherThe solvent is removed under reduced pressure
16. 16
    Otherthe crude product is recrystallised from ethanol

Procedure

16.6 g (78.5 mmol) of methyl 2-oxo-5-propylcyclohexanecarboxylate, 7.65 g (69.5 mmol) of resorcinol and 5.6 ml (6.1 mmol) of phosphoryl chloride are dissolved in 55 ml of toluene, and the mixture is heated under reflux for 3 h. After hydrolysis using water, the deposited precipitate is filtered off with suction, washed with toluene and dried. The product is dissolved in 200 ml of acetone, 20 g (145 mmol) of potassium carbonate and 9.00 g (57.7 mmol) of ethyl iodide are added, and the mixture is heated under reflux for 5 h. The majority of the solvent is removed under reduced pressure, and the residue is taken up in MTB ether/water. The aqueous phase is separated off and extracted with MTB ether. The combined organic phases are washed with water and dried over sodium sulfate. The solvent is removed under reduced pressure, and the crude product is recrystallised from ethanol, giving 3-ethoxy-8-propyl-7,8,9,10-tetrahydrobenzo[c]chromen-6-one as colourless crystals. The melting point is 108° C. The other physical properties are: Δ∈=−7.5 (extrapolated from 5% solution in ZLI-2857), Δn=0.1302 (5% in ZLI-4792).

Source