Formaldehyde → 2-Cyclopentyl-1-(2,3-dichloro-4-methoxyphenyl)prop-2-en-1-one

HRID 596993Notes

Reaction equation

HRID 596993 reaction equation
[Cl:1][C:2]1[C:7]([Cl:8])=[C:6]([O:9][CH3:10])[CH:5]=[CH:4][C:3]=1[C:11](=[O:18])[CH2:12][CH:13]1[CH2:17][CH2:16][CH2:15][CH2:14]1.[CH2:19]=O.S(=O)(=O)(O)O>O1CCOCC1>[Cl:1][C:2]1[C:7]([Cl:8])=[C:6]([O:9][CH3:10])[CH:5]=[CH:4][C:3]=1[C:11](=[O:18])[C:12]([CH:13]1[CH2:14][CH2:15][CH2:16][CH2:17]1)=[CH2:19]

Participants

5

Reactant 3

HCID 712FormaldehydeHCID 1118Sulfuric AcidHCID 123955472-Cyclopentyl-1-(2,3-dichloro-4-methoxyphenyl)ethanone

Product 1

HCID 123955522-Cyclopentyl-1-(2,3-dichloro-4-methoxyphenyl)prop-2-en-1-oneYield 61.8%

Reagents, catalysts & solvents 1

HCID 312751,4-DioxaneSolvent

Procedure

2',3'-Dichloro-4'-methoxy-2-cyclopentylacetophenone (51.6 g., 0.18 mole) is dissolved in dioxane (460 ml.) and paraformaldehyde (21.6 g., 0.72 mole) and concentrated sulfuric acid (9.65 g.) are added. The mixture is heated at 80°-85° C. for 20 hours. The dioxane is evaporated at reduced pressure. Water is added to the residual gum which then is extracted into ether. The ether extract is washed with water and dried over magnesium sulfate. The ether is evaporated and upon triturating the residue with hexane (5 ml.) there is obtained a solid that is crystallized from ligroin to obtain 2',3'-dichloro-4'-methoxy-2-cyclopentylacrylophenone (33.3 g.), m.p. 59°-63° C. Crystallization from butyl chloride affords a sample (m.p. 66°-67.5° C.) for analysis.

Workup

  1. temperatureThe mixture is heated at 80°-85° C. for 20 hours
  2. customThe dioxane is evaporated at reduced pressure
  3. additionWater is added to the residual gum which
  4. extractionthen is extracted into ether
  5. extractionThe ether extract
  6. washis washed with water
  7. dry with materialdried over magnesium sulfate
  8. customThe ether is evaporated
  9. customupon triturating the residue with hexane (5 ml.) there
  10. customis obtained a solid
  11. customthat is crystallized from ligroin

Sources & evidence

ORD record
ord-cacf1411c85e46c9918ba4be1d295c53
Source dataset
uspto-grants-1977_03
Patent number
US04012524

Reaction notes

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