Pentanal → (2E)-2-Pentylidenecyclopentanone

HRID 1655656Notes

Reaction equation

HRID 1655656 reaction equation
[C:1]1(=[O:6])[CH2:5][CH2:4][CH2:3][CH2:2]1.[OH-].[Na+].[CH:9](=O)[CH2:10][CH2:11][CH2:12][CH3:13]>C(O)(=O)C>[CH:9](=[C:2]1/[C:1](=[O:6])[CH2:5][CH2:4][CH2:3]/1)\[CH2:10][CH2:11][CH2:12][CH3:13]

Participants

5

Reactant 3

HCID 8063PentanalHCID 8452CyclopentanoneHCID 14798Sodium Hydroxide

Product 1

HCID 1621050(2E)-2-PentylidenecyclopentanoneYield 74.9%

Reagents, catalysts & solvents 1

HCID 176Acetic AcidSolvent

Procedure

A stirred solution of 42.0 grams (g) (0.5 mole) of cyclopentanone in 80 milliliters (ml) of 1 percent (%) NaOH was treated with 21.5 g (0.25 mole) of n-pentanal at about 30 degrees Celsius (°C.). After stirring for about 2 hours, the solution was neutralized with 36% acetic acid, then extracted with three 30 ml portions of benzene. Then 1.0 ml of phosphoric acid was added to the combined extracts. After the resulting mixture was refluxed through a condenser equipped with a Dean-Stark trap for about 2 hours, the solvent was removed on a rotary evaporator to give an oil residue, which was subjected to distillation to give 28.5 g of 2-(E)-pentylidene cyclopentanone as a yellowish liquid. The boiling point of this intermediate compound was determined to be 98°-102° C. at a pressure of 6 millimeters (mm) mercury (Hg).

Workup

  1. extractionextracted with three 30 ml portions of benzene
  2. additionThen 1.0 ml of phosphoric acid was added to the combined extracts
  3. temperatureAfter the resulting mixture was refluxed through a condenser
  4. customequipped with a Dean-Stark trap for about 2 hours
  5. customthe solvent was removed on a rotary evaporator
  6. customto give an oil residue, which
  7. distillationwas subjected to distillation

Sources & evidence

ORD record
ord-ea7dda1191fd4a77ba8aca1206956b31
Source dataset
uspto-grants-1993_10
Patent number
US05250735

Reaction notes

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