2-Cyclopentene-1,4-dione → 2-(alpha-Methoxypropylidene)cyclopent-4-ene-1,3-dione

HRID 397462

Reaction equation

HRID 397462 reaction equation
[C:1]1(=[O:7])[CH:5]=[CH:4][C:3](=[O:6])[CH2:2]1.[C:8]([O-])([O-])([O:12][CH2:13]C)[CH2:9][CH2:10]C>C(OC(=O)C)(=O)C.[Cl-].[Cl-].[Zn+2]>[CH3:13][O:12][C:8](=[C:2]1[C:3](=[O:6])[CH:4]=[CH:5][C:1]1=[O:7])[CH2:9][CH3:10]

Participants

5

Reactant 2

HCID 702582-Cyclopentene-1,4-dioneHCID 865847631-Ethoxybutane-1,1-diolate

Product 1

HCID 234976152-(alpha-Methoxypropylidene)cyclopent-4-ene-1,3-dione

Reagents, catalysts & solvents 2

HCID 3007855ZincchlorideCatalystHCID 7918Acetic AnhydrideSolvent

Procedure

To a suspension of cyclopent-4-ene-1,3-dione (1.22 g, 12.6 mmol) in acetic anhydride (4 ml) were added ethyl orthobutyrate (3.74 g, 25.3 mmol) and anhydrous ZnCl2. The reaction was heated at 80° for 24 h, solid removed by filtration, the filtrate concentrated in vacuo and the residues purified by chromatography (SiO2; 70:30 hexane/EtOAc) to give 2-(α-methoxypropyl idene)cyclopent4-ene-1,3-dione as a brown oil. δH (CDCl3) 6.88 (2H, s), 4.07 (3H, s), 3.00 (2H, t), 1.63 (2H, m), 1.08 (3H, t). m/z (ESI, 70V) 181 (MH+).

Workup

  1. temperatureThe reaction was heated at 80° for 24 h
  2. customsolid removed by filtration
  3. concentrationthe filtrate concentrated in vacuo
  4. customthe residues purified by chromatography (SiO2; 70:30 hexane/EtOAc)

Sources & evidence

ORD record
ord-ea46766711ae4b419720c1a197c4e199
Source dataset
uspto-grants-2003_08
Patent number
US06610700B2

Linked notes

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