Reaction #54964

Reaction equation

Methyl 2-[2-ethyl-3-methyl-4-oxo-4H-1-benzopyran-6-yl]propionate

Jones reagent

barium sulphate

→

title compound

Methyl 2-[2,3-dihydro-2-ethyl-3-methyl-4-oxo-4H-1-benzopyran-6-yl]propionate

Solvents

ethanol

acetone

Conditions

Workup

1. 1
   Otherfor a total of 48 hours
2. 2
   OtherThe catalyst was removed by filtration (`Hyflo` supercel) and the ethanol
3. 3
   Otherremoved in vacuo
4. 4
   Otheraffording an oil
5. 5
   OtherThe excess oxidant was destroyed with methanol
6. 6
   workup.DISSOLUTIONthe reaction mixture was dissolved in water (200 ml)
7. 7
   Extractionextracted with ether
8. 8
   WashThe combined ethereal extracts were washed with water, dilute aqueous sodium bicarbonate solution and water
9. 9
   Dryingdried (MgSO4)
10. 10
    Concentrationconcentrated in vacuo

Procedure

Methyl 2-[2-ethyl-3-methyl-4-oxo-4H-1-benzopyran-6-yl]propionate (6.61 g) was taken up in dry ethanol (150 ml) and hydrogenated at 85 p.s.i. with 5% palladium on carbon (0.2 g) and 5% palladium on barium sulphate (0.49) for a total of 48 hours. The catalyst was removed by filtration (`Hyflo` supercel) and the ethanol removed in vacuo affording an oil. The oil was taken up in acetone (50 ml) and treated with a slight excess of Jones reagent. The excess oxidant was destroyed with methanol and the reaction mixture was dissolved in water (200 ml) and extracted with ether. The combined ethereal extracts were washed with water, dilute aqueous sodium bicarbonate solution and water, dried (MgSO4) and concentrated in vacuo to give the title compound as an oil--6 g.

Source