Methanol → 2-Ethylcyclopentane-1,3-dione

HRID 1579744Notes

Reaction equation

HRID 1579744 reaction equation
C[O-].[Na+].CO.C(O[C:9](=[O:17])[CH2:10][CH2:11][C:12](=[O:16])[CH2:13][CH2:14][CH3:15])C>C1(C)C(C)=CC=CC=1>[CH2:14]([CH:13]1[C:9](=[O:17])[CH2:10][CH2:11][C:12]1=[O:16])[CH3:15]

Participants

5

Reactant 3

HCID 887MethanolHCID 10942334Sodium Methoxide2×HCID 12271529Ethyl 4-oxoheptanoate

Product 1

HCID 699782-Ethylcyclopentane-1,3-dioneYield 46%

Reagents, catalysts & solvents 1

HCID 7237O-XyleneSolvent2×

Procedure

A 1 l. three-necked flask, equipped with a dropping funnel, mechanical stirrer and a distillation head with thermometer and Liebig condenser was charged with 515 ml of xylene (b.p. 138°-140°), stirred and heated to boiling. 65.9 g of a 24% (wt/wt) sodium methoxide solution (prepared as in Example 1) in methyl alcohol (15.8 g = 0.293 moles) was added over 10 min., distilling off continuously the methyl alcohol. 300 ml of additional xylene were added and distillation was continued until the vapor temperature reached 135°. After the addition of 6.6 ml of dimethylsulfoxide, a solution of 40 g (0.232 moles) of 4-oxoheptanoic acid ethyl ester in 80 ml of xylene was added over 25 min. to the vigorously stirred sodium methoxide suspension while keeping the vapor temperature at ca. 135°C by continuous distillation of xylene. The orange-colored mixture was stirred and heated for an additional 5 min. and then allowed to cool to room temperature. Water was added, the mixture was acidified and the product filtered, washed, dried and recrystallized from water to afford 13.45 g (46%) of 2-ethyl-cyclopentan-1,3-dione, m.p. (uncorr.): 171°-172°C.

Workup

  1. customthree-necked flask, equipped with a dropping funnel, mechanical stirrer
  2. temperatureheated to boiling
  3. distillationdistilling off continuously the methyl alcohol
  4. addition300 ml of additional xylene were added
  5. distillationdistillation
  6. customreached 135°
  7. additionAfter the addition of 6.6 ml of dimethylsulfoxide
  8. customat ca. 135°C
  9. distillationby continuous distillation of xylene
  10. stirringThe orange-colored mixture was stirred
  11. temperatureheated for an additional 5 min.
  12. additionWater was added
  13. filtrationthe product filtered
  14. washwashed
  15. customdried
  16. customrecrystallized from water

Sources & evidence

ORD record
ord-00e9a7a80a3849f585a644732f770b14
Source dataset
uspto-grants-1976_01
Patent number
US03931322

Reaction notes

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