Benzene → Ethyl alpha-(2,5-dimethoxybenzyl)acetoacetate

HRID 1032815Notizen

Reaktionsgleichung

Reaktionsgleichung von HRID 1032815
[CH3:1][O:2][C:3]1[CH:10]=[CH:9][C:8]([O:11][CH3:12])=[CH:7][C:4]=1[CH:5]=O.[C:13]([O:19][CH2:20][CH3:21])(=[O:18])[CH2:14][C:15]([CH3:17])=[O:16].C1C=CC=CC=1.N1CCCCC1>C(O)(=O)C>[CH3:1][O:2][C:3]1[CH:10]=[CH:9][C:8]([O:11][CH3:12])=[CH:7][C:4]=1[CH2:5][CH:14]([C:15]([CH3:17])=[O:16])[C:13]([O:19][CH2:20][CH3:21])=[O:18]

Komponenten

6

Edukt 4

HCID 241BenzeneHCID 8082PiperidineHCID 8868Ethyl AcetoacetateHCID 667262,5-Dimethoxybenzaldehyde

Produkt 1

HCID 12597482Ethyl alpha-(2,5-dimethoxybenzyl)acetoacetate

Reagenzien, Katalysatoren, Lösungsmittel 1

HCID 176Acetic AcidLösungsmittel

Versuchsvorschrift

A mixture of 2,5-dimethoxybenzaldehyde (100 g), ethyl acetoacetate (84.5 g) and anhydrous benzene (200 ml), piperidine (6 ml) and acetic acid (12 ml) was heated at reflux for 3 hours in an apparatus fitted with a Dean-Stark trap to collect the azeotropically distilled water. The reaction mixture was cooled, benzene (300 ml) added, and the solution was washed successively with water (100 ml), cold 0.1N hydrochloric acid (200 ml), 5% aqueous sodium bicarbonate (200 ml) and dilute acetic acid (100 ml) and dried over anhydrous magnesium sulfate. The solvent was then removed under reduced pressure and the residual oil distilled, b.p. 169°-170° C./0.3 mm Hg. The product, ethyl α-(2,5-dimethoxybenzylidene)acetoacetate, solidified on standing (104 g, m.p. 68°-69° C.) and was recrystallized from ethanol-pentane (m.p. 72°-73° C.). A portion (38 g) of the product was reduced catalytically in the presence of palladium on charcoal catalyst (Pd/C) in ethyl acetate (150 ml). The product, after removal of solvent, was purified by distillation under reduced pressure to give ethyl α-(2,5-dimethoxybenzyl)acetoacetate, b.p. 146°-148° C./0.3 mm Hg.

Aufarbeitung

  1. temperaturewas heated
  2. temperatureat reflux for 3 hours in an apparatus
  3. customfitted with a Dean-Stark trap
  4. distillationto collect the azeotropically distilled water
  5. temperatureThe reaction mixture was cooled
  6. additionbenzene (300 ml) added
  7. washthe solution was washed successively with water (100 ml), cold 0.1N hydrochloric acid (200 ml), 5% aqueous sodium bicarbonate (200 ml) and dilute acetic acid (100 ml)
  8. dry with materialdried over anhydrous magnesium sulfate
  9. customThe solvent was then removed under reduced pressure
  10. distillationthe residual oil distilled
  11. customwas recrystallized from ethanol-pentane (m.p. 72°-73° C.)
  12. customThe product, after removal of solvent
  13. distillationwas purified by distillation under reduced pressure

Quellen und Nachweise

ORD-Eintrag
ord-2910f5dfe1ef48dca13e63832e452c20
Quelldatensatz
uspto-grants-1990_09
Patentnummer
US04959474

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